Teachers and Students

Investigating Plants in Space

A Teacher’s Guide with Activities for Life Sciences

Educational Product

Teachers Grades 5-12 National Aeronautics and

Space Administration
Teachers and Students

Investigating Plants in Space

A Teacher’s Guide with Activities for Life Sciences

National Aeronautics and Space Administration

Office of Human Resources and Education

Education Division

and

Office of Life and Microgravity Sciences and Applications

Life Sciences Division

Washington, DC

With the Wisconsin Fast Plants Program

University of Wisconsin—Madison

This publication is in the Public Domain and is not protected by copyright.

Permission is not required for duplication.

EG-1997-02-113-HQ
Acknowledgments This publication was developed for the National

Aeronautics and Space Administration and the National

Space Agency of Ukraine with the input and support of

many individuals.

Writer:

Paul H. Williams

Department of Plant Pathology

University of Wisconsin

Madison, WI

Editors:

Paul H. Williams

Christie M. Roden

Coe M. Williams

Daniel W. Lauffer

Wisconsin Fast Plants

University of Wisconsin

Madison, WI

Layout and Design:

Christie M. Roden

Activity Development:

Paul H. Williams

Michelle A. Graham

Daniel W. Lauffer

Carey K. Wendell

The Wisconsin Fast Plants Program would like to

gratefully acknowledge Bonnie J. McClain and Tom K.

Scott for their contribution of the text for "The

Importance of Plants in Space," and Greg L. Vogt for his

contribution of the text for "Microgravity."

Special thanks to Bonnie J. McClain, Pamela L. Mountjoy

and Rosalind A. Grymes for their guidance and advice.

Wisconsin Fast Plants

University of Wisconsin-Madison

College of Agricultural and Life Sciences

Department of Plant Pathology

1630 Linden Drive

Madison, WI 53706

tel: 800-462-7417 or 608-263-2634

email: fastplants@calshp.cals.wisc.edu

WWW: http://fastplants.cals.wisc.edu
Table of Contents Introduction

Overview of CUE-TSIPS.................................................1

Road Map: How Do I Use This Guide? ..........................3

The Importance of Plants in Space ................................6

Microgravity..................................................................8

The Life Cycle of AstroPlants .......................................10

Understanding the Environment .................................13

CUE-TSIPS Science and Technology ............................18

CUE-TSIPS Activities

CUE-TSIPS Mission Calendar......................................29

Getting Started ...........................................................32

Constructing the PGC, page 32

Planting AstroPlants in the PGC, page 35

Growth, Development and Flowering ...........................37

AstroPlants Growth Group Data Sheet, page 41

Pollination ..................................................................43

Floral Clock Student Data Sheet, page 51

Double Fertilization and Post-Fertilization Events .......53

Ovule and Embryo Student Data Sheet, page 65

Supplementary Activities:

Germination ................................................................. 66

Orientation and Guidance ............................................. 78

Additional CUE-TSIPS Materials

Mission Information ....................................................92

Sources of Supplies ....................................................94

Black Line Masters .....................................................99

Selected References .................................................. 101

NASA Educational Materials

NASA Educational Resources .................................... 104

Evaluation Reply Card .............................................. 107
1

Overview of CUE-TSIPS

The Collaborative Ukrainian Experiment

In May of 1995, the presidents of the United States and Ukraine issued a joint statement on

cooperation in space, directing the National Aeronautics and Space Administration (NASA) and the

National Space Agency of Ukraine (NSAU) to cooperate on a joint Space Shuttle mission. The United

States and Ukraine announced that a Ukrainian payload specialist would fly aboard this mission,

STS-87, scheduled for October of 1997. The project was named the "Collaborative Ukrainian

Experiment," or "CUE."

The CUE Science Questions

From plant science microgravity experiments on previous

missions of the Russian, Ukrainian and American space

programs, scientists have observed various abnormal growth and

developmental phenomena in plants. The CUE projects are designed to

address specific questions raised in prior experiments.

American scientists and their teams of colleagues and students, with Ukrainian

scientists and their research teams, will be running 12 separate experiments as

part of the science payload on STS-87. Several plant biology experiments will be

run in an environmentally controlled Plant Growth Facility.

One experiment involves the controlled pollination and in-flight fixation of

pollinated flowers of a special dwarf stock of rapid-cycling Brassica rapa

(Wisconsin Fast Plants) known as "AstroPlants." A Ukrainian payload specialist

will be performing these experimental procedures. The principal scientists and their question in this

CUE experiment are:

Project acronym: B-STIC

Investigation of: microgravity effects on pollination and fertilization

Scientists: Dr. Mary Musgrave, Louisiana State University, United States

Dr. Antonina Popova, National Academy of Science of Ukraine

Question: What developmental events during plant reproduction fail to function

normally in the microgravity environment?

This question is part of the more general question: how will plants grow and function in microgravity

considering that they have evolved and existed in an environment of the Earth's gravity?

The CUE Education Project: TSIPS

As a part of the total CUE mission, an Education Project has been established with the Wisconsin Fast

Plants Program at the University of Wisconsin in Madison and the National Academy of Science of

Ukraine, through the Ukrainian Junior Academy of Science in Kiev. The Education Project involves

teachers and students in both countries and is called "TSIPS" – Teachers and Students Investigating

Plants in Space.

During the same time as the joint Space Shuttle flight, students throughout the United States and

Ukraine will be undertaking experiments to determine what is normal for biological events or stages in

the life cycle of AstroPlants under the Earth's gravity. Seedlings of other plants may also be used to
2

examine the effects of gravity and light on orientation and guidance in plants. The information that

students gather will provide them with the basis for understanding a number of biological phenomena

and principles, including phenotypic expression, variation, growth, orientation, reproduction and

embryogeny. Students can compare their observations with those made in the microgravity

environment by the CUE researchers.

The Central CUE-TSIPS Experiment

The CUE-TSIPS activities have been designed to address mainly those questions raised in the B-STIC

investigation of Drs. Mary Musgrave and Antonina Popova, relating to the effects of microgravity on

plant growth and reproduction.

The CUE-TSIPS activities center on the Science Exploration Flowchart (page 20). Students will grow

AstroPlants through a life cycle, and in the process will become well acquainted with germination,

orientation, growth, flowering, pollination, fertilization, embryogenesis and seed development.

Students will gain insight into the life cycle of AstroPlants by making many careful observations,

measuring and recording what they observe, and organizing and displaying data in a way that they

can make analyses. The data will provide both you and your students with a better understanding of

what is "normal" development in AstroPlants and will serve as the basis for comparison with data

taken by the CUE investigators to help determine what developmental events during plant

reproduction are affected by microgravity.

The Science-Technology Partnership

Perhaps more than any other endeavor, experiments in space illustrate the essential interdependency

of science and technology. Vast technological resources are marshalled in the execution of spacebased science. Because of this interdependency of science and technology, the CUE-TSIPS project has

emphasized both by including the design and construction of the experimental equipment as part of

the science activities (page 19). Throughout the activities teachers are provided with instruction on

how to engage students in this construction.

The CUE-TSIPS Questions

Are there any basic life processes that will be affected by microgravity in a way that will result in

altered function? What are the significant growth processes that can be identified and observed under

the conditions of microgravity?

1. Impact of the environment on a model organism.

Much of what the CUE flight and ground experiments will be about is coming to understand the

many environmental variables that impact on the growth and development of the model organism,

the AstroPlants. This stock was developed to grow rapidly under specified environmental

conditions, in an apparatus with limited volume and restricted energy inputs.

2. Microgravity.

If microgravity affects one or more life processes in AstroPlants such that deviation from the

normal phenotype can be observed, then questions may be posed and research undertaken,

leading to an understanding of how the processes are being affected.

3. What is "normal"?

How would you define "normal"? In order to determine what the effects of microgravity are on

AstroPlants, it is important to have an accurate understanding of how they grow under standard

environmental conditions on Earth.
3

Road Map: How Do I Use This Guide?

The lessons in this guide can be used to engage your students in the fascination of space biology

through plant investigations long after the CUE Space Shuttle mission has entered the history books.

It is NASA's goal that the information in these pages will motivate both you and your students to

become active and involved participants in the Space Life Sciences enterprise, now and in the future.

1. The CUE-TSIPS teacher guide. The CUE-TSIPS teacher guide.

• The CUE teacher guide is written for the teacher. Where

"you" is used in the text, it refers to the teacher.

• The target audience for the CUE-TSIPS experiments is

one of high school biology teachers and middle school life

sciences teachers and their students.

• The CUE-TSIPS activities are intended to be run in "real

time" with the NASA Space Shuttle flight, STS-87,

scheduled for lift-off in October, 1997.

2. The plants being used for the CUE-TSIPS activities. The plants being used for the CUE-TSIPS activities.

• A special genetic stock of Wisconsin Fast Plants called

"AstroPlants" is used in the CUE-TSIPS activities.

- AstroPlants are the research organisms being used by scientists

for the Shuttle experiment that is the central CUE-TSIPS

experiment for students and have been used in previous flights.

- AstroPlants have a rapid life cycle and have been

genetically selected to be very short, fitting within the

limited space of the Shuttle Plant Growth Chambers (PGCs).

• Basic Fast Plants seed, as opposed to AstroPlants seed, will also

work for the CUE-TSIPS experiments, however:

- the plants will grow over the top of the student PGC, and

- data on plants from the basic seed will be compiled

separately from the AstroPlants data.

• Activities focused on germination (page 66) and orientation

(page 78), are supplementary to the mission and may be

done with other kinds of seeds (turnip, lettuce, alfalfa).

These activities are marked with the bean symbol.

3. Performing the CUE-TSIPS activities. Performing the CUE-TSIPS activities.

• The central CUE-TSIPS activities focus on specific

segments of the AstroPlants life cycle:

- growth, development and flowering,

- pollination, and

- double fertilization and embryo development.

• If you have not used Fast Plants previously:

- a trial run before the "real time" activities is advised, and

- to be successful you must understand the biology of the

plants and the importance of creating an environment

conducive to growth. Essential reading includes "The Life

Cycle of AstroPlants," "Understanding the Environment,"

and the background sections from "Growth, Development

and Flowering," "Pollination" and "Double Fertilization and

Post-Fertilization Events" (see Table of Contents).
4

• For the "real time" activities you and your students will:

- provide the proper growing environment (lighting, nutrient, temperature, etc.),

- construct the Plant Growth Chamber (PGC) from low-cost, readily available materials to

simulate growing conditions on the Space Shuttle,

- plant the AstroPlants in the PGC,

- grow the AstroPlants through the entire life cycle, and

- complete the AstroPlants Growth Data Sheets and Floral Clock Data Sheets.

• The "CUE-TSIPS Mission Calendar"

(page 29) provides a clear day-to-day

guide and schedule for the activities.

• Teachers may wish to customize the

data keeping, depending on the age

and ability level of their students.

4. The supplementary activities. The supplementary activities.

• For students to fully benefit from the

CUE-TSIPS experiments, the

supplementary activities (7 to 11) in the

"Germination" and "Orientation and

Guidance" sections should be carried

out prior to the experiments on reproduction.

• These activities are particularly rich in quantitative biology and mathematics.

5. Post-mission follow-up. Post-mission follow-up.

• Class summary statistics from the AstroPlants Growth and Floral Clock Class Data Sheets can

be sent to the Wisconsin Fast Plants Program for compilation with data submissions from other

classrooms in the United States and Ukraine (see page for the mailing address).

- Data will be entered for compilation only if specified environmental growing conditions have

been met and recorded on the Class Data Sheets.

- Parameters that must be reported with the data are:

▲ irradiance (number of fluorescent bulbs, wattage, distance of plants from bulbs),

▲ temperature of the growing environment (average daily temperature),

▲ nutrient solution used,

▲ root medium (e.g., specific soil or soilless mixture),

▲ seed type (AstroPlants or basic Fast Plants), and

▲ plants grown in a student PGC or in another capillary wicking system.

- Data for compilation must be received by January 31, 1998.

- Results will be posted on the Wisconsin Fast Plants World Wide Web site at the time of the

National Science Teachers Association National Convention in April, 1998.

• Teachers complete evaluations by either:

- completing and mailing in the printed "Teacher Reply Card" at the end of this guide, or

- using the NASA EDCATS on-line forms (the "Teacher Reply Form,"

http://ednet.gsfc.nasa.gov/edcats/teacher_guide and the "Plant Experiment

Follow-Up Form," http://ednet.gsfc.nasa.gov/edcats/fastplants_report.html).

Activity Matrix: Standards and Skills Activity Matrix: Standards and Skills

Use the matrices on page 5 to align the CUE-TSIPS activities to the National Science

Standards and Benchmarks. In each matrix, the teacher guide sections are listed

along the left edge. If the activities in a given section fulfill a listed standard or

include the development of a listed skill, the activity is marked with the symbol " "

in the appropriate column. The section entitled "CUE-TSIPS Science and

Technology" provides the foundations for experimentation and is aligned with many

aspects of the content standards.

For teachers:

The most important guidance

items in this book are:

• "Understanding the

Environment" (page 13), and

• the "CUE-TSIPS Mission Calendar" (page 29).

i

✓
5

Science as Inquiry

Physical Science

- position and motion of objects

- properties of objects and materials

Unifying Concepts and Processes

-

Science and Technology

 change, constancy and measurement

- evidence, models and explanation

- abilities of technological design

Science in Personal and

Social Perspectives

- science and technology in

 local challenges

Science Standards

- understanding science and technology

Growth and

Development

Pollination

Fertilization

Germination

Growth and

Development

Pollination

Fertilization

Observing

Measuring

Communicating

Collecting Data

Inferring

Predicting

Making Models

Making Graphs

Hypothesizing

Interpreting Data

Controlling Variables

Defining Operationally

Investigating

Problem Solving

Communication

Reasoning

Connections

Number Relationships

Computation and Estimation

Patterns and Functions

Statistics

Probability

Geometry

Measurement

Functions

Trigonometry

Growth and

Development

Pollination

Fertilization

Germination

Mathematics Standards

Science Process Skills

Orientation ✓ ✓✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓

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Germination

Orientation

Orientation
6

The Importance of Plants in Space

Contributed by Bonnie J. McClain (Purdue University Grantee, Education Programs Coordinator, NASA

Space Life Sciences) and Tom K. Scott (Senior Scientist, NASA Space Life Sciences).

The relationship between plants and humans has always been a close and

interdependent one. Research about basic plant processes helps in

understanding and augmenting this interdependence. Ground-based

investigations yield information vital to this understanding; however, the

knowledge gained from plant research in space is exciting and extends potential

for new discoveries beneficial to humans.

There is abundant evidence that microgravity affects virtually every aspect of

plant growth. Space flight provides the only known environment in which

fundamental biological processes and mechanisms can be studied in the

absence of the sometimes overriding effects of gravity. Removal of the effects of

gravity for long periods of time allows new perspectives in the study of plants.

Answers to important questions about the basics of plant growth and

development lie in understanding the role gravity has on plant processes and

responses to the environment. For example, gravitropism is the bending

response of plants to the force of gravity with the roots growing downward and

the shoots growing upward. Charles Darwin began experiments on plant gravitropism during the

nineteenth century, yet the mechanisms of this process are still not clear. The more knowledge

generated about how plants function, the more likely we can adapt that information into practical,

useful new applications and products enhancing life on Earth and in space.

NASA’s research with plants in space is dedicated to systematic studies that explore the role gravity

plays at all stages in the life of higher plants. Research focuses on the interaction of gravity and other

environmental factors with plant systems, and uses hypergravity, simulated hypogravity, and

microgravity as tools to advance fundamental knowledge of plant biology. Results of the research

contribute to NASA’s efforts to further human exploration of space and to improve the quality of life on

Earth through applications in medicine, agriculture, biotechnology and environmental management.

NASA's plant science research questions focus on five objectives:

• to explain the basic mechanism whereby plants perceive, transduce, and

respond to gravitational force (example: comparisons of seedling vs. older

plant responses to gravity);

• to understand the role of gravity and microgravity in developmental and

reproductive processes in plants (examples: flower development and

wood formation);

• to learn how metabolic and transport processes are affected by gravity

and microgravity (examples: photosynthesis and long and short distance

sugar transport);

• to analyze interactions of microgravity with other important parameters

of space (examples: cosmic radiation and electromagnetism); and

• to study the role of plants within recycling life support systems for space

exploration (examples: carbon dioxide production and oxygen

revitalization).
7

Knowledge of physiology, cell biology, biochemistry and molecular biology of plants coupled with

biotechnology advances contributes to our fundamental knowledge of plants and provides impetus for

a new era of plant investigations. The opportunity to experiment at a micro level of gravity provides a

new dimension that enables interdisciplinary plant research to answer important questions about the

plant’s reception of the gravity signal, the plant’s biochemical interpretation of that signal, and how

that interpretation causes a developmental reaction. It appears that this reaction system, in general,

interacts with receptor systems that detect both internal and external signals. It is for this reason

that understanding the role of mechanical signals, such as gravity, assumes such significance for

plant science: these investigations could begin to reveal the precise control mechanisms involved in

dictating plant form, structure, and function.

Understanding how basic processes can be manipulated and put into use in new ways that develop

new products and increase productivity is the basis for biotechnological applications in agriculture,

horticulture, and forestry. For example, understanding the interaction between gravity and light could

be the basis for genetic engineering of plants resulting in increased crop productivity while minimizing

the required growing space. Application to horticulture could include the ability to control plant form,

and forestry could benefit from faster methods of regeneration of lost forest areas.

Before the first lunar outpost, the

proposed Mars base, and other future

missions from planet Earth can become

realities, numerous scientific and

technological problems remain to be

solved. None of these problems is more

important than that of supporting human

life in space. Extended duration human

exploration missions will require life

support capabilities beyond those now

available. A solution is to develop

technologies that integrate physical and

chemical processes into a dynamic,

recycling life support system.

Studying plants in space will provide the scientific information necessary for development of such a

life support system. Plants will be a primary component of atmospheric regeneration: carbon dioxide

exhaled by humans will be taken up by plants and used in photosynthesis, in the process returning

oxygen and food to the crew. Plants are also important in water regeneration. The productivity of

plants relative to the input of energy (light) can be increased by using such techniques as carbon

dioxide enrichment and hydroponics. To achieve a controlled life support system, ground-based

research in growth chamber facilities will be conducted along with plant investigations in the

microgravity environment of space flight.

Why study plants in space? The discoveries made, lessons learned, and technologies developed from

these investigations will benefit those of us on planet Earth as we unlock and utilize gravity’s

mysteries to enhance our journey into space.
8

Microgravity

Contributed by Greg L. Vogt (Crew Educational Affairs Liaison, NASA Johnson Space Center).

Gravity is an attractive force that is a fundamental property of all matter. Whether an object is a

planet, a feather or a person, each exerts a gravitational force on all other objects around it.

Physicists identify gravity as one of the four types of forces in the universe (the others are strong and

weak nuclear forces and electromagnetic force).

The strength of the attraction between two objects is directly proportional to the product of the masses

of those objects and inversely proportional to the square of the distance between the centers of mass of

those objects: in other words, the larger the objects the stronger the attraction between them and the

greater the distance between the objects the weaker the attraction. When measured at the surface of

the Earth, the acceleration of an object acted upon only by Earth's gravity is commonly referred to as

"1 g" or "unit gravity." This acceleration is approximately 9.8 meters per second squared (m/s2).

On Earth, gravitational force is important in providing orientation and guidance to many forms of life

including plants. For example, plants orient themselves with gravity so that shoots grow up and roots

grow down and water and nutrients are transported through the plants against the pull of gravity.

Although gravity is a force that is always with us, its effects can be greatly reduced by the simple act

of falling. NASA uses the term "microgravity" to refer to the condition that is produced by a "free fall."

The diagram at the right illustrates

how a condition of microgravity is

created. Imagine riding in an elevator

car to the top floor of a very tall

building. At the top, the cables

supporting the car break, causing the

car and you to fall to the ground. (In

this example we discount the effects

of air friction on the falling car.)

Since you and the elevator car are

falling together, you feel like you are

floating inside the car. In other

words, you and the elevator car are

accelerating downward at the same

rate. If a scale were present, your

weight would not register because the

scale would be falling too. You would

be experiencing free fall or what

astronauts call "microgravity." The ride

is lots of fun until you get to the bottom!

The term microgravity can be interpreted in a number of ways, depending upon context. The prefix

"micro-" (μ) is derived from the original Greek "mikros," meaning "small." By this definition, a

microgravity environment is one that will impart to an object a net acceleration that is small compared

with that produced by the Earth at its surface. Another common usage of micro- is found in

quantitative measurement, such as the metric system, where micro- means one part in a million. In

practice, net accelerations will range from about one percent of the Earth's gravitational acceleration

(aboard aircraft in parabolic flight) to about one part in a million (aboard the Space Shuttle orbiter).

normal

weight

heavier

than

normal

lighter

than

normal

no

measured

weight

lighter

than

normal

no measured

weight

heavier

than

normal

normal

weight
9

NASA uses airplanes, drop towers

and small sounding rockets to

create a microgravity environment

for experimental purposes. In

each facility, an experimental

payload is put into free fall that

lasts from a few seconds to several

minutes. Eventually, free fall ends

because the object will impact on

the Earth's surface.

When scientists want to conduct

experiments in microgravity for

longer durations – days, weeks,

months or even years – it is

necessary to travel into space and

orbit Earth. Having more time

available for experiments means

that slower processes and more

subtle effects can be investigated.

Today, the Space Shuttle and

special satellites are the space

facilities that provide opportunities

for these microgravity experiments. The International Space Station will soon be an important

additional means of accomplishing such investigations.

Microgravity Activity

You can demonstrate a microgravity environment and the effects of freefall in the classroom. Collect

an aluminum soft drink can, a nail, about 12 ounces of water and a waste basket.

Orbiter Orientation

To obtain the most consistent microgravity environment in

space, the Space Shuttle orbiter is oriented in a tail-down

position. This is called the "gravity gradient mode." The tail of

the orbiter is closer to the Earth and feels a stronger pull of

gravity than does the more distant nose of the orbiter.

The difference in the strength of

the attraction between the nose

and tail has a stabilizing effect on

the attitude of the orbiter. This

means that the on-board crew is

able to keep the orbiter stabilized

with fewer corrective firings of the

reaction control rockets (thrusters).

Each firing produces an acceleration

that interferes with the microgravity

environment of the Space Shuttle.

During the fall, no force is at work pulling the water out of the hole. The water and the can fall at the

same rate, just as in the falling elevator example. The water is in the condition of microgravity,

experiencing free fall (Vogt and Wargo, Eds., 1992).

The Collaborative Ukrainian Experiment provides many unique opportunities for understanding the

effects of gravity and microgravity on plants.

Punch a small hole in the lower side of the can with

the nail, about 0.75 cm up from the bottom. Hold the

can with one end so that your thumb covers the hole.

Keeping your thumb tightly covering the nail hole, fill

the can with water and position the waste basket

below. You may wish to stand on a chair to gain a

higher can altitude.

Slide your thumb off the hole so that a stream of

water is visible to all. Then drop the can. The water

stream stops. Why?

In free fall, gravity's local effects are reduced.
10

The Life Cycle of AstroPlants

What are AstroPlants? AstroPlants are a special form of the species Brassica rapa (Wisconsin Fast

Plants), a member of the mustard or cabbage family Cruciferae. Crucifers are distinguished by

characteristic flowers with four petals in the form of a cross or crucifix. Other forms of Brassica rapa

include turnips, Chinese cabbage, pak choi and canola. Some related crops in other Brassica species

are cabbage, broccoli, collard, cauliflower and mustard.

Life Cycle Concepts and Questions Life Cycle Concepts and Questions

Beginning the Life Cycle: Growth, Development and Flowering

Germination is the awakening of a seed (embryo) from a resting state. It involves the harnessing of

energy stored within the seed and is activated by components in the environment. Growth represents

increase in size, number and complexity of plant cells and organs. Environment and genetics play

fundamental roles in regulating growth. The energy for growth comes from photosynthesis.

Flowering is the initiation of sexual reproduction. The generation of male and female gametes (sperm

and eggs) is one of the primary functions in flowering. The plant prepares for pollination by producing

flowers. Each part of the flower has a specific role to play in sexual reproduction. The flower dictates

the mating strategy of the species.

• What are the main components of the environment necessary for germination?

• How does the seedling orient itself?

• What enables the emerging plant to shift its dependency from stored energy to the energy from light?

• What is the role of the environment in regulating plant growth?

• How do plants grow?

• How does a plant know when to produce leaves and when to produce flowers?

• Why does a plant have flowers?

Pollination

Pollination is the process of mating in plants. In flowers, pollen is delivered to the stigma through a

wide range of mechanisms that insure an appropriate balance in the genetic makeup of the species.

In brassicas, pollen is distributed by bees and other insects. The flower is the device by which the

plant recruits the bee. Bees and brassicas have evolved an interdependent relationship.

• How do flower parts function to influence mating behavior?

• How does the flower recruit the bee?

• How does pollination occur?

• How does the flower discriminate between self and nonself in the mix of pollen?

Double Fertilization and Post-Fertilization Events

Fertilization is the final event in sexual reproduction. In higher plants, two sperm from the pollen

grain are involved in fertilization. One fertilizes the egg to produce the zygote and begin the new

generation. The other sperm combines with the fusion nucleus to produce the special tissue

(endosperm) that nourishes the developing embryo. In some plants endosperm nourishes the

germinating seedling. Fertilization also stimulates the growth of the maternal tissue (seed pod or fruit)

supporting the developing seed.

• What is unique about fertilization in flowering plants?

• What is endosperm and what is its relationship to the embryo?

• How does an embryo develop into a seed?

• How does the maternal parent contribute to the developing embryo?
11

P = parent O = offspringP = female =maleP = male & female

A

0 1

B

2

3

C

4

7

D

9 11

E

F

13 15

G

18

H

28-35

I

>35

J

20

15

10

5

0

Stage

Embryo

200X 100X 200X 100X 80X 40X 20X 10X 1X

Days after planting

2 +

globular heart torpedo walking stick mature

Plant height in centimeters A. quiescence (P) B. germination (P) C. growth and development (P) D. gametogenesis (P)

+

&

E. flowering andpollination (P)

F. gamete maturation (P)

3 ,2

3 + endosperm (P)

 + embryo (O & P)

G. double fertilization (P)

H. fruiting (P)H. embryogenesis (O)

Growth of Rapid-cyclingBrassica rapa, Rbr

I. senescence (P)I. seed ripening (O & P)

J. death (P)J. quiescence (O)

A. quiescence (P)

B. germination (P)

C. growth and

development (P)

D. gametogenesis (P)

= female = male

= female & male

P = parent O = offspring

Growth of AstroPlants

5

0

20

15

10

F. gamete maturation (P)

G. double fertilization

H. fruiting (P) and

embryogenesis (O)

J. death (P) and

quiesence (O)

200X 100X

200X 100X 80X 40X 20X 10X 1X

torpedo

globular

walkingstick full size heart

EMBRYO

A

0 1 2 3 4 7 9 11 13 15 18 28-35 > 35

B

C

D

E

F

G

H I

J

STAGE

Days after Sowing

Plant Height (in centimeters)

&

(P)

I. senescence (P) andseed ripening (O)

E. flowering and pollination (P)

+ embryo (O & P)

2 +

+

3 , 2

2 + endosperm (P)
12

Stages in the Life Cycle of AstroPlants: Concepts of Dependency Stages in the Life Cycle of AstroPlants: Concepts of Dependency

• independent of the

parent and many

components of the

environment

• dependent on

environment and

health of the individual

• dependent on

environment

• dependent on healthy

vegetative plant

• dependent on pollen

carriers; bees and

other insects

• dependent on

compatibility of pollen

with stigma and style

• dependent on

compatibility and

healthy plant

• interdependency

among developing

embryo, endosperm,

developing pod and

supporting mature

parental plant

• seed is becoming

independent of the

parent

• seed (embryo) is

independent of parent,

but is dependent on

the pod and the

environment for

dispersal

• suspended growth of

embryo

• awakening of growth

• roots, stems, leaves grow

rapidly, plant is sexually

immature

• gametogenesis —

reproductive [male

(pollen) and female (egg)]

cell production

• pollination — attracting

or capturing pollen

• gamete maturation

• germination and growth of

pollen tube

• union of gametes

• union of sperm (n) and

egg (n) to produce diploid

zygote (2n)

• union of sperm (n) and

fusion nucleus (2n) to

produce endosperm (3n)

• embryogenesis — growth

and development of

endosperm and embryo

• growth of supporting

parental tissue of the

fruit (pod)

• withering of leaves of

parent plant

• yellowing pods, drying

embryo

• suspension of embryo

growth, development of

seed coat

• drying of all plant parts,

dry pods will disperse

seeds

Stage State Condition Dependency

• quiescence

(dormant

embryo)

• germination

• growth and

development

• flower bud

development

• flowering

• mating

• pollen growth

• double

fertilization

• developing

fruit

• developing

endosperm

• developing

embryo

• senescence of

parent

• maturation

of fruit

• seed

development

• death,

desiccation

• seed quiescence

A. seed

B. germinating

seed

C. vegetative

growth

D. immature

 plant

E. mature plant

F. mature plant

G. mature plant

H. mature parent

plant plus

embryo

I. aging parent

 plant plus

 maturing

embryo

J. dead parent

plant plus seed
13

Understanding the Environment

Three broad categories of environmental components interact

to influence all life: 1) physical, 2) chemical and 3) biological.

Understanding the many environmental factors and how they

interact with each other to influence life is essential for good

investigative science and is the key to successful experimenting

with AstroPlants. In space life science investigations such

as the CUE, scientists and engineers have worked together

to develop technology that will create an environment to

support normal plant growth within the hostile external

environment of space.

Some environmental factors influence plant growth more

than others. If one or more factors is reduced or increased

such that normal functioning is disrupted, that factor is said

to be limiting. When a factor that can be quantified becomes

limiting, its observed effects can also be quantified.

The Physical Environment The Physical Environment

Light

Appropriate lighting is perhaps the most critical component of a plant's growing environment. Plants

use energy from various regions of the visible spectrum to perform a number of functions essential to

their growth and reproduction. Some seeds require red light to activate germination. Blue light is

important for regulating elongation of stems and in guiding the direction of plant growth. Red and

blue are the primary energy levels used for photosynthesis, whereas red and far red are important in

the regulation of leaf expansion and certain pigment production systems.

Light for AstroPlants is

produced by fluorescent

lamps which emit a mix of

photons in the visible

range that appear as

white with warm (red) or

cool (blue) tones in the

mix. The quantity of

photons reaching a

surface is known as

irradiance or photon flux

density and is measured

in micromoles (μM) or

microEinsteins (μE) of

photon flux per square

meter per second.

Irradiance of greater than 200 μEm-2s-1 is ideal for AstroPlants. Less than 100 μEm-2s-1 is inadequate.

As with other electromagnetic forces and gravity, the inverse square relationship applies to light. That

is, if the distance between the source of light and the receiving surface doubles, the intensity of the

irradiance diminishes by a factor of four.

Life

Processes

and Systems

Physical

Chemical Biological

Physical

Environment

Chemical

Environment

 Biological

Environment

Life

Processes

and Systems

VIOLET BLUE GREEN YELLOW ORANGE RED

380 430 500 560 600 660 750

VISIBLE LIGHT

gamma rays

wavelength

x-rays

<0.1nm 100nm

uv infrared

<1 meter

radio waves

(thousands of meters)

wavelength (nanometers)

gamma rays x-rays uv infrared radio waves

VISIBLE LIGHT

VIOLET BLUE GREEN YELLOW ORANGE RED

380 430 500 560 600 650 750

wavelength (nanometers)

wavelength <0.1nm 100nm <1 meter (thousands of meters)

Spectrum of electromagnetic radiation.
14

If you are using the standard four-foot Fast Plants light bank, you can

use either eight 40 watt cool white or six of the newer 32 watt high

efficiency bulbs which will require different fixtures than the 40

watt bulbs. Six 32 watt Sylvania Octron® 4100K FO32/741 bulbs

spaced within two feet will produce ideal lighting for AstroPlants.

Fluorescent "circle" lamps can be suspended above and will

adequately irradiate the plants growing within a circle of 30 cm

diameter (12 inches). The Wisconsin Fast Plants Program has had

the most successful growth under 30 or 39 watt circular or "folded"

circular bulbs.

Reflectors made from aluminum foil or reflective mylar (available from fabric or stationery stores)

greatly increase the irradiance reaching the plants, particularly those around the edges of the lamps.

Aluminum foil "curtains" (15 cm x 25 cm) taped on the lamp fixture to hang down to about the soil

level will contribute to uniform lighting across the plants.

Formula for growing successful AstroPlants — LIGHTING LIGHTING : LIGHTING 

g

o

4

2

2

* red alert - male sterility induced

getting warm - male and female

reproductive capability reduced

ideal - most plants will flower

on time

plants develop more slowly

plants develop very slowly

* temperatures under

light banks

>30 ̊C / 86 ̊F*

22 / 72

18 / 64

Temperature Temperature

The temperature of the AstroPlants' growing

environment will have an important influence on the

growth of your plants. Temperatures that are too high

or too low can affect the timing of developmental events

such as seedling emergence and flowering. Optimal

temperature is between 22 ̊C and 28 ̊C (72 ̊F to 82 ̊F).

Tip:

- Temperatures can be monitored under each

bank using hi-low thermometers. Note

fluctuations in the room temperature and

variation in temperature among light banks.

Tips:

- Keeping the AstroPlants under constant 24 hour light will

produce the most satisfactory results. Be sure to make

arrangements (with custodians, etc.) so light banks are not

turned off at any time.

- Bulbs should be kept 2 cm to 3 cm above the top of the

experimental Plant Growth Chamber lid (page 32). Ideally the

growing tips of the plants should be kept 5 cm to 10 cm from

the lights. The height of the Plant Growth Chamber (PGC) lid

will keep your seedlings about 15 cm from the bulbs. This is

adequate provided reflective curtains are used.

+ use reflective

foil curtains

+ keep top of PGC lid

2 to 3 cm from the lights = eight 40 W bulbs or six

32 W high efficiency bulbs,

lighting 24 hours a day

Healthy Healthy

AstroPlants

28 / 82
15

Gravity and Microgravity Gravity and Microgravity

Of the many environmental factors that impact on life, gravity is one that exists on Earth with the

greatest constancy (page 8). Gravity is an environmental factor that is difficult to vary experimentally

without the support of space technology. Microgravity is what the CUE experiments are all about!

The Soilless Root Medium

In the CUE-TSIPS activities, a mixture of one part peat moss and one part vermiculite, known as

peatlite, serves as the root medium that anchors the plant roots, providing support for the stem and

leaves. Physical characteristics of the root medium must be such as to provide adequate capillary

wicking of water to the absorptive surfaces of the root hairs and epidermal cells, yet there must also

be adequate channeling within the matrix of the root medium to enable air exchange for oxygen

diffusion to the growing roots. Under conditions of unit gravity, peatlite provides ideal capillarity and

air channeling for AstroPlants.

The Chemical Environment The Chemical Environment

Water

Water functions in many ways in plants, serving as the

primary solvent supporting life's metabolic processes,

generating turgor pressure (water pressure) for cell

enlargement and growth, maintaining ionic

balance and providing cooling via transpiration.

Water is also the source of hydrogen

reducing power when it is split by light

energy in photosynthesis. Water enters

the plant primarily through the root

epidermis and hair cells, traveling

through intercellular space and cortical

cells to the xylem tissue where it is

distributed throughout the plant.

Within the root zone, water is found

adhering to soil particles as a continuous

film created through the cohesive forces

of the water molecules. The adhesive

forces that attract water molecules to the

surfaces of soil particles and plant root

cells pull the water into the minute

channels within the soil and plant

tissues via capillarity.

In the PGC, capillary wicking material is

used to pull water from a reservoir to the

root medium which has strong capillary

properties. There is an unbroken

continuity of water from the soil into and

throughout the plants (see figure at

right). Through this water course, the

plant also gains access to inorganic

nutrients. On Earth, gravity acts as a

vertical counter force opposing the cohesive

forces of water and adhesive forces of capillarity.

soil

air

root hair

soil

soil soil

air

capillary mat

platform base

upward

movement

of water in xylem

transported water

vapor through

stomata

capillary wick

film can wick pot

increased

distance of

soil to water

surface

increases

tension capillary flow capillary wick

water transpired

through stomata

soil

soil soil

air

air

increased

distance of

soil to water

surface

increases

tension

capillary mat

platform base

capillary flow capillary wick

upward capillary flow

of water in xylem

water in

reservoir

soil

capillary wick

film can wick pot
16

Atmospheric Relative Humidity Atmospheric Relative Humidity

The atmospheric relative humidity of a classroom can affect the rate of

transpiration and water uptake by plants. Under low relative humidity there

can be rapid water uptake from the reservoirs. When reservoirs run dry,

capillarity is broken and plants will desiccate and die. When plants begin to

wilt, it is an indication that transpiration is exceeding water uptake. In some

climates this occurs when there has been a rapid drop in atmospheric

relative humidity. In these cases plants usually adjust by reducing

transpiration and regaining their turgor pressure.

If wilting persists when using the PGC, check the reservoir and examine the

capillary wicks and matting to be sure they have not dried out and broken

the capillary connection between roots and reservoir.

If the atmospheric relative humidity is very high (>95% RH), mature anthers in

flowering AstroPlants may fail to open (dehisce) to expose their pollen. This

occurs when plants are grown in closed containers in which the relative

humidity builds up. It can be remedied by circulating air over the plants

with a fan; mature anthers will then usually dehisce within a few minutes.

Inorganic Nutrients

In addition to the elements carbon, oxygen and hydrogen which make up the main structure of

organic compounds in plants, 13 other elements are required to support the range of metabolic

processes that constitute life. Six elements – nitrogen, potassium, calcium, phosphorus, magnesium

and sulfur – are known as macronutrients because they are required in relatively greater quantities

than the seven micronutrients – iron, chlorine, copper, manganese, zinc, molybdenum and boron

(Raven, Evert and Eichorn, 1992).

In the CUE-TSIPS experiments, inorganic nutrients are added to the root media as Wisconsin Fast

Plants Nutrient Solution (page 96). Nutrients can also be added as commercially available fertilizer,

such as Peters® 20-20-20 N-P-K (page 96).

Atmosphere Atmosphere

Ambient air contains nitrogen (78%), oxygen (21%), hydrogen and helium (<1%). Carbon dioxide in air

is approximately 350 parts per million and is the primary source of carbon incorporated into organic

molecules via photosynthesis. In closed systems such as the Space Shuttle orbiter, where humans

and other organisms are respiring, CO2 may build up to toxic levels. Plants have the potential role in

space flight of extracting CO2 from the air and converting it into edible biomass. In the Space Shuttle

orbiter, CO2 levels are carefully monitored and excess removed from the atmosphere by chemical

trapping in filters.

Formula for growing successful AstroPlants — NUTRITION : NUTRITION : NUTRITION :

water + air + = Healthy Healthy

AstroPlants

inorganic nutrients

(6 major and 7 minor)
17

The Biological Environment The Biological Environment

Types of Organisms

There can be many types of organisms associated with the plant's environment, from algae to insects.

These organisms may reside together in various symbiotic relationships, from mutually beneficial to

parasitic (one partner benefits) and even pathogenic (one partner harms the other). Some symbioses

may be strictly neutral. Controlling undesirable organisms in the plants' environment requires

continuous attention. Possible residents include:

• various soil microflora (bacteria, fungi) and microfauna

(nematodes, worms, insect larvae) which may colonize

the root zone or rhizosphere;

• phytophagous (plant-eating) arthropods which may be

found on stems, leaves and flowers (mites, thrips, aphids,

leaf-eating beetles, moth and butterfly larvae);

• the larvae of fungus-eating (mycophagous) flies which may exist in large numbers, emerging

from the root medium and water mat as small black gnats; and

• various algal populations which may live on the moist root media, capillary wicking material

and in the nutrient solution reservoirs. Most common are blue-green algae (cyanobacteria) on

root media and mat surfaces and green algae in reservoirs.

Controlling Undesirable Organisms

Fungi and Bacteria: Fungi and bacteria rarely attack the above-ground parts of plants as long as the

relative humidity is less than 95% and there is good air flow. The best control for fungi and bacteria is

sanitation. Be sure to use pathogen-free root media – most commercially available peatlite mixtures

are sanitized and pathogen-free. Keep the root media well aerated and drained by not packing it in the

growing containers. After growing, it is important to rinse, then soak all pots, reservoirs, capillary

mats and wicks for at least 30 minutes in a 10% chlorine bleach solution. Do not reuse root media.

Insect Pests: The continuously illuminated plants can be attractive

to many insects, especially at night. Daily surveillance and removal of

insects is good practice. Sticky yellow pest control cards work well to

trap incoming insects and flies emerging from the soil. The sticky

strips available from garden stores can be cut and stapled to bamboo

grilling skewers and mounted in film cans filled with sand and placed

among the plants. These are very effective for white flies, aphids,

fungus gnats and thrips.

If colonies of aphids, white flies or thrips appear or evidence of larval

feeding is observed (holes chewed in leaves or flowers), plants may be

sprayed with insecticidal soap or another safe chemical control agent.

Read labels carefully before applying chemicals. Surveillance and

careful removal by hand is the best control practice.

Algae: The most common residents with AstroPlants are algae. Most

do not affect plant growth but can become unsightly and occasionally

will build up in reservoirs and wicking to consume nutrients and

retard water flow. Algae growth can be suppressed by adding copper

sulfate (CuSO4•5H2O) to the nutrient solution at a final concentration in

the reservoir of between 50 and 100 parts per million (milligrams/liter).

4 cm

10 cm

2

y

s

a

s

b

g

s

f

f

s

4 cm

10 cm

bamboo

grilling

skewer

film can

filled with

sand

sticky

strip

stapled

around

skewer
18

CUE-TSIPS Science and Technology

Science begins when a person of any age is curious about something and begins to question and

explore the relationships of a phenomenon to his or her understanding of the world. The scientific

process begins with an observation and questions and proceeds through a process of inquiry involving

exploration, investigation, experimentation and analysis, and communication and persuasion. That

process engages the creative energy of the individual and leads to deeper understanding, a sense of

pleasure and increased self-worth. Even young children quite naturally say: "Look what I found!"

Dr. Mary Musgrave and Dr. Antonina Popova are successful scientists who are curious about the

growth of plants in space. Their interest is broad, but the questions they are asking in the CUE are

very specific. They are successful as scientists because they pay a great deal of attention to the details

of the questions they ask and to the design and execution of the experiments they have run to test

their questions. They are both analytical and critical in their approach to the science they do; before

they accept an answer to their questions, they want rigorous proof that there are not more plausible

alternatives. Indeed, many scientists believe that they come closest to an understanding of what is

true through an exhaustive quest which seeks, yet fails, to disprove a hypothesis. This chapter deals

with many of the essentials that will lead you and your students through the discipline and pleasure

of good science.

As the result of microgravity experiments run on previous missions from the former USSR, from the

Russian, Ukrainian and U.S. space programs, in which the gravitational force was about one million

times less than on Earth, Drs. Musgrave and Popova have observed various abnormal growth and

developmental phenomena in plants. The CUE B-STIC experiments are designed to address aspects of

the more specific question: what developmental events during pollination, fertilization and embryo

development fail to occur normally in the microgravity environment?

Science is All About Questions Science is All About Questions

As you and your students proceed with the CUE-TSIPS activities, you will be progressing through the

stages illustrated in the Science Exploration Flowchart (page 20). The following questions are

designed to assist you. Remember the power of writing as an assistance to learning. Have your

students pose questions and answers, document ideas and diagram relationships.

1. What do you observe?

2. What is your question about your observations? What is the question

you are exploring?

3. How would you convert the question into an assertion, which is the

idea you are experimentally testing (your hypothesis)?

- Can you also write this as a null hypothesis in which you may state the

hypothesis having the opposite, or null, outcome?

4. What variable will you change in your tests? What is your treatment?

What potential variables will remain constant?

5. What are your control treatments? How will each serve as a control?

6. How many observations for each result are enough? Is n = 1 enough to be

representative? If not, what is enough? Why?
19

7. Is there any special experimental design of the treatments and/or

replicates needed in the experiment?

8. What equipment, tools, etc., will you need for your experiment?

- Draw your experimental set-up.

9. What form will your observations take? How will you describe

or measure your observations?

- Use descriptors, comparators, scales and quantitative estimates.

Identifying a need

You have a problem

Defining the need

Describing the problem

Inventing a solution: Inventing a solution:

Designing, describing, drawing

Can you think of a way

to solve the problem?

Constructing the invention: Constructing the invention:

Making and describing, accessing and

assessing resources as needed

Can you construct a tool,

equipment or method

to solve the problem?

Testing the invention: Testing the invention:

Effectiveness, efficiency,

accuracy, precision

Will your invention work?

Verifying the test

of the invention: of the invention:

Effectiveness, reliability

How well did it work?

Communicating the results

Technology Innovation Flowchart

How will you tell others

of your invention?

10. How will you record or tabulate

your data?

11. How will you organize your data?

How will you display your data?

- Use statistical summarization.

12. What is your conclusion relative

to your hypothesis? What further

conclusions can you draw from

your analysis of your experiment?

13. What other questions come to

your mind as the result of this

experiment?

14. What is the next experiment that

you plan to run? Why?

The Science-Technology Partnership The Science-Technology Partnership

As students design and execute experiments the

need for technological assistance from tools and

equipment is ever-present, from the moment of

the first observation to the time when new

insight is shared with someone across the ocean

or across the classroom. Technological

innovation, like science, follows a logical

progression, resulting in a successful invention

and its application to a need or problem.
20

Design of the Experiment — Testing the Hypothesis Design of the Experiment — Testing the Hypothesis

The heart of science activities lies in the design and execution of the experiment developed to test a

hypothesis. It is in this phase of the process of science that technology plays an essential role. To

conduct any experiments, technological requirements will arise and will need to be addressed. If the

question and hypothesis have been carefully thought out and refined to be experimentally testable,

then the design and execution of the experimental phases should yield satisfactory results. As you

plan your experimental design, consider the following:

• Keep focused on the

question and

hypothesis.

• Think of the simplest

way, both in the design

and in the equipment

needed, to run the

experiment.

• Alter one variable

(treatment) with each

experiment and analyze

the results.

• Always run control

treatments for each

experimental treatment

such that for each

variable in the

experimental treatment

there is an adequate

basis for interpreting

the information from

the treatment.

• The careful choice and

execution of the control

treatments is as

important in the

experiment as that of

the experimental

treatments.

• Information from the

control treatments

serves as the basis for

determining whether

information from the

experimental variables

is valid and, thus

guides the researcher

in conclusions as to the

validity of the hypothesis.

Testing the hypothesis

Develop an experiment to test the hypothesis

Choose the variable(s) and control(s)

Conduct the experiment

Collect and analyze data

"ODMRODA"

Forming a hypothesis

What is your idea about an answer

for your question?

Do you have a question

about what you observed?

Making observations

What do you observe?

Collect

background

information.

Back to the

beginning!

Science Exploration Flowchart

Asking questions

Evaluating the hypothesis

Was the hypothesis verified?

Did you answer the question?

Communicating the results

How could you investigate

your idea?

Have you communicated your

results to other people?
21

Execution of the Experimental Investigation Execution of the Experimental Investigation

Below are some of the activities involved in the experimental investigation of an hypothesis. For your

investigations, use :

MM

RR

D

O

D

O

A

Observe and Describe:

Using your eyes and other tools to assist in observation (lenses,

microscopes, etc.) together with insight from your brain, observe

various phenomena or characteristics associated with the

experiment and determine the way that you will describe them.

Measure and Record :

Using tools and devices (eyes, brain, rulers, scales, comparators

and experience), measure (quantify) and record numeric and

descriptive characteristics as data. Estimate, count or compare

what you observe while adhering to an understanding of the

precepts of accuracy and precision.

Organize and Display:

Organize and display recorded data in various ways (tables, charts,

graphs, diagrams, drawing, photographs, videos, audios,

multimedia, etc.) that will provide insight into phenomena

associated with the experiment.

Analyze:

Observe the data displays (tables, graphs, etc.) for comparisons

among treatments, including controls. Apply statistical analysis to

the data that provides information from which to derive and

develop inferential insight that will be useful in the evaluation of

the hypothesis.

D

O

A

O

D

"ODMRODA"
22

Observing and Describing Observing and Describing

Observation is frequently assisted by tools such as lenses, microscopes and other devices that amplify

what we see, hear or detect chemically. In living organisms, characteristics which are observed

constitute the phenotype. Phenotype is the genetically and environmentally determined appearance of

an organism. Variation in the phenotype among individuals of the same grouping is a fundamental

attribute of life.

In order to be useful in an experiment the phenotype must be described using terms that are widely

understood and easily communicated. For these reasons scientists have agreed upon various

standards or descriptors to describe characteristics in the natural world. Descriptors take many forms

(Table 1). The choice of how to describe what you observe is important, because it will determine the

kinds of descriptors used and establish the basis for recording, analyzing and communicating results.

Descriptors Method of description Examples

number 1. direct count 1. hair on margin of first leaf

2. comparator scale 2. very hairy = 8-9 on a

scale of 0 = no hair to

9 = very many hairs

size 1. use of a tool to measure 1. height of a plant in mm

(estimate dimension),

e.g. ruler, calipers

2. comparator scale 2. short, medium, tall

compared to a range of

measure

color 1. visual comparison using 1. no purple (anthocyanin)

standard color chart or color in plant

scales

2. describe with words using 2. very light yellow-green

hue, lightness and leaves

saturation

shape 1. descriptive language 1. leaf margin lobed edge

(often Latin)

2. comparator charts 2. leaf spoon-shaped

Table 1: Table 1: Examples of descriptors. Table 1: 

Measuring and Recording Measuring and Recording

Size, Scale and Magnification: "Compared to What?" Size, Scale and Magnification: "Compared to What?"

It is at the time of observing that students will understand the notions of size, scale and magnification.

Some of the CUE-TSIPS activities require that students become familiar with observing, drawing to

scale and measuring under magnification. To help them view specimens and understand the

magnification, dissection strips and dissection cards have been developed as tools for use in the

CUE-TSIPS activities.
23

0 1 2 3 4 5 cm

0 1 2 3 4 5 cm

0 1 2 3 4 5cm

0 1 2 3 4 5cm

Much of the emphasis in the supplemental activity "Getting Acquainted with a Seed" (page 67) is

designed to familiarize students with the use of lenses and scales. As they draw and measure what

they observe under different magnifications, students will begin to understand size relationships.

Drawing to scale requires practice and sharpens students' hand-eye coordination and sense of

perspective and scale. This understanding will be useful to them as they undertake more detailed

dissection of AstroPlants embryos.

Making and Using Dissection Strips

0 1 2 3 4 5 cm

0 1 2 3 4 5 cm

0 1 2 3 4 5cm

0 1 2 3 4 5cm

Once the strips are finished, they are ready for use.

Begin by cutting a piece of clear 2 cm adhesive tape to be

about 3 cm long. Fold over about 0.75 cm of this piece of

tape to make a tab. Stick this tabbed piece of tape to the

dissection strip, with the tab at the end of the strip.

0 1 2 3 4 5 cm

0 1 2 3 4 5 cm

0 1 2 3 4 5cm

0 1 2 3 4 5cm

Cut a piece of clear double-stick tape. Place this

piece near the top edge of the dissection strip so that

the end of the piece overlaps the tabbed piece of tape

by a few millimeters.

Dissection strips can be made by copying the black line master

(page 100) onto a transparency sheet. The copied transparency

sheet can be stuck, printed side down, to a "do it yourself"

laminating sheet or piece of clear contact paper, and then the

individual strips can be cut out. Using the laminating sheet or

contact paper as a sealer protects the printing from being pulled

off during use of the strip, so strips can be reused.

On the dissection card (page 99) are spaces for measuring and recording observations. Each card has

two circular fields for sketching what is observed in the field of view delineated by the microscope or

film can magnifier.

Specimens for dissection are placed on the double-stick

tape. Once your specimen is in place, the specimen

and strip can be placed under a dissecting microscope

or a film can magnifier (page 97) to make observations.

double-stick

tape

tabbed

tape

tabbed

tape

film can

microscope

0 1 2 3 4 5 cm

0 1 2 3 4 5 cm

0 1 2 3 4 5cm

0 1 2 3 4 5cm

Once a dissection has been completed, the dissected

specimen may be taped in a student notebook or removed

from the strip by pulling up on the tabbed piece of tape.

As this piece of tape is removed it will pull off the used

double-stick tape and the strip will be ready for a new

dissection. Alternatively, a second dissection strip may be

placed over the first to preserve your specimen.

0 1 2 3 4 5 cm

0 1 2 3 4 5 cm

0 1 2 3 4 5 cm

0 1 2 3 4 5 cm
24

Dealing with Variation: The Nature of Normal Dealing with Variation: The Nature of Normal Dealing with Variation: The Nature of Normal

Measurable differences will be found among individuals in a group or population. It is therefore

important to know how much variation in a particular phenotype (observable trait) might be expected

so that it can be determined whether the variation observed experimentally may be viewed as normal

for that population. Normal would be defined as that range of potential phenotypes that a population

would exhibit in a specified range of environmental conditions.

The species Brassica rapa, of which AstroPlants are a specially bred stock, is inherently genetically

variable. Within a population of AstroPlants one can observe considerable phenotypic variation in

some traits such as plant height or intensity of purple stem color. For this reason, it is important to

determine what is a normal range of phenotypes for AstroPlants.

Organizing and Displaying Data: Graphical Representation Organizing and Displaying Data: Graphical Representation

When, for example, the heights of a

population of 48 AstroPlants are

measured in millimeters at Day 10 and

recorded (Table 2), considerable variation

can be noted. Height is measured from

soil level to shoot apex.

The "Stem and Leaf Table" The "Stem and Leaf Table"

Simply listed as a set of 48 numbers,

relatively little information can be gained

from them other than to note that they

are variable. An easy way to begin to

organize the numbers is to put them into

what is commonly known as a stem and

leaf table (Table 3).

To do this, note that each number is

broken into "tens" and "digits." Examine

each number, breaking it into its tens

and digits, e.g., 48 becomes 4 (tens) and

8 (digits). Make a vertical column "stem"

listing from zero to 9 that represents the

tens. Then enter the digit from each

number in the horizontal row "leaf"

corresponding to the appropriate ten or

stem position; e.g., 48 is listed as an 8

in row 4 in Table 3. Numbers in the

range from 10 to 19 go in the "1" row,

while numbers in the range from 20 to

29 go in the "2" row, etc.

Considerable information about the population of 48 plants begins to become apparent from the stem

and leaf table. For example, it can be observed that the most plant heights in this data set fit into the

"4" stem. The numbers representing the plant heights in the population are a set of size 48 (n = 48).

digits, "leaf"

tens, 0

"stem" 1 8

2 7, 5, 1

3 3, 0, 2, 9, 7, 3, 9, 5, 2, 6

4 8, 3, 0, 7, 3, 9, 1, 4, 5, 5, 5, 1, 0, 8

5 0, 2, 3, 4, 9, 5, 7, 6, 1, 5, 2, 0

6 2, 0, 6, 8

7 2, 6, 3

8 4

9

Table 3: Table 3: AstroPlant height data from Table 2 organized into a Table 3:

stem and leaf table.

33 40 32 59 18 45 73 21

49 52 60 55 33 56 32 52

50 84 54 25 57 45 68 41

43 53 43 76 49 39 36 50

62 27 66 39 41 51 55 41

30 47 72 37 44 35 45 48

Table 2: Table 2: Height, in mm, of 48 AstroPlants measured Table 2:

at Day 10 (hypothetical data).
25

The Frequency Table

The set of 48 plant heights can be organized into groupings or classes representing a specified range of

values or class interval (i). In this example the class interval is 10 mm: i = 10 mm. The number of

plants having heights within a particular class interval (e.g., 20 to 29 mm) is the class frequency (fi).

The relative frequency of a class is determined by looking at the number of measurements in a class

(fi) relative to the number of measurements in the entire data set (n): fi/n.

With the above information the set n = 48 can be arranged in a frequency table by counting and

recording the numbers in each class (fi) and calculating the proportion of numbers in each class to the

total set (fi/n). The relative frequency of the class interval 20 to 29 mm in the example set of 48 plant

heights is fi/n = 3/48 = 0.06.

The Frequency Histogram

The relationship among the numbers in each class can be more effectively visualized by displaying

them as a frequency histogram in which the data are treated as two variables, x and y, and plotted in

relation to each other in a two-dimensional graph with the x and y axes at 90 ̊ to each other.

The first variable, the class interval (i), was chosen

to be i = 10 is the independent variable as it was

predetermined by choice. The independent

variable is arrayed on the x or horizontal axis just

as it appears in the frequency table (Table 4).

The second variable is the class frequency (fi) and

is known as the dependent variable because the

number in the particular class (i) depends on the

class chosen and is arranged and plotted on the

y or vertical axis of the graph. When plotting the

x and y axes of a graph it is important to consider

the size or scale of a unit on each axis so that an

effective symmetry is achieved in the presentation

of the graph. Figure 1 is a frequency histogram of

the data from the frequency table, Table 4.

The relative frequency (fi

/n) from the frequency

table can also be plotted as a relative frequency histogram. In this case the x-axis remains the same as

in the frequency histogram and the y-axis is arrayed in units of decimal fractions. The appearance of

the relative frequency histogram is similar to the frequency histogram, however what is being

portrayed is the relative proportion of a class size in relation to the set.

Choosing the proper class interval can be important to the process of analyzing and understanding the

information that is codified in the data set of plant height measurements. If the chosen class interval

is too small or too large, certain relationships among the individuals within the set will not be evident.

0 10 20 30 40 50 60 70 80 90

0 1 3 10 14 12 4 3 1 0

0 0.02 0.06 0.20 0.29 0.25 0.08 0.06 0.02 0

class interval, i

class frequency, fi

relative frequency, fi/n

Table 4: Table 4: Frequency table of heights, in mm, of 48 AstroPlants at Day 10, grouped in classes of 10 mm intervals Table 4:

and relative frequency of each class.

n = 48, i = 10

Note: relative frequency fractions should add up to 1, rounding numbers in this example reduced this to 0.98.

15

10

5

0

0 0 20 30 40 50 60 70 80 90

Height classes (10 mm intervals)

- x-axis

- independent variable

- class interval i = 10

Figure 1: Figure 1: Frequency histogram of heights, Figure 1:

in mm, of 48 AstroPlants at Day 10,

grouped in class intervals of 10 mm.

10

15

5

0

Number of plants per class- y-axis- dependent variable- class frequency, fi

0 10 20 30 40 50 60 70 80 90 100
26

For example if a class interval of i = 25 rather than i = 10

were chosen then the frequency histogram would appear

as in Figure 2 or if a class interval of i = 2 were selected

the frequency histogram would appear as in Figure 3.

The Normal Curve

The outline of a frequency histogram roughly depicts

a curve known as a frequency curve. Frequency

curves can assume various different shapes.

Interpretation of the shapes can give insight into

underlying phenomena conditioning the expression

of the phenotype's contribution to the curve. For

instance, the data on plant height recorded in the

data chart (Table 2), organized in a frequency table

(Table 4), and displayed in the frequency histogram

(Figure 4) depicts what is referred to as the normal

distribution curve or the normal curve. A bell-shaped

normal distribution is commonly observed for many

phenomena and is the basis for certain kinds of

statistical summarization and interpretation.

Organizing and Displaying Data: Numerical Representation Organizing and Displaying Data: Numerical Representation

r

Range

There are various ways of describing or summarizing the variation in heights of the 10

day old AstroPlants recorded in Table 2 and displayed in Figure 4. One way is in terms

of range (r). Range extends from the shortest plant to the tallest plant and is defined as:

"r = the difference between the largest and smallest numbers in a set of data." Here

again the stem and leaf diagram is useful in identifying the range, r = 84 - 18 = 66 mm.

The range identifies the upper and lower limits of a data set and is helpful in

determining the limits of the x-axis on a graph. When measuring a population of

AstroPlants over several days of growth it is interesting to observe what happens to the

range of plant heights. Does the range stay the same, decrease or increase? Why?

30

20

10

0

0 25 50 75 100 0 25 100 50 75

Height classes (25 mm intervals)

0

10

20

30

Number or plants per class

Figure 2: Figure 2: Frequency histogram of Figure 2:

heights, in mm, of 48 AstroPlants at Day

10, grouped in class intervals of 25 mm.

4

0

0 10 100 20 30

3

2

1

40 50 60 70 80 90

4

3

2

1

0

Number of plants per class

0 10 20 30 40 50 60 70 80 90 100

Height classes (2 mm intervals)

Figure 3: Figure 3: Frequency histogram of heights, in mm, of 48 Figure 3:

AstroPlants at Day 10, grouped in class intervals of 2 mm.

15

10

5

0

0 0 20 30 40 50 60 70 80 90

15

10

5

0

0 10 20 30 40 50 60 70 80 90 100

Height classes (10 mm intervals)

Number of plants per class

Figure 4: Figure 4: Frequency histogram of heights, Figure 4:

in mm, of 48 AstroPlants at Day 10,

grouped in class intervals of 10 mm.
27

Mean, Median and Mode: Measures of Center Mean, Median and Mode: Measures of Center

Another way to summarize the variation represented in a set is in terms of averages.

Continuing with our example, the average or arithmetic mean (x) is the sum of the

measurements divided by the total number of measurements, n:

x = ∑i xi/n = (x1 + x2 + xn)(1/n)

When phenotypes are distributed normally, the mean can be a useful way of

summarizing or representing the set. The mean or average is a way of representing a

data set using a single number. In our example the mean is:

x = (x1 + x2 + xn)(1/n) = (2212)(1/48) = 47.13

Another way of identifying a central point in the data set is to identify the median

(md), or middle value of a set. The median is the highest value divided by two, in our

example:

md = 84/2 = 42

Notice that the median differs from the mean by approximately 5 mm

(47 - 42 = 5).

Yet another way of representing the data set with a single number is to use the mode

(mo). The mode is the measurement with the highest frequency. Again, by

scrutinizing each "leaf" of the stem and leaf diagram, you will observe that the

number 45 mm appears three times. All others appear less frequently. This would

be the mode for our example:

mo = 45.

x

md

mo

As is characteristic with normally distributed data,

the mean, median and mode tend to be in proximity.

With some natural phenomena which are not

normally distributed there may be more than one

mode, hence the terms bimodal and trimodal (Figure

5). In other distributions the mode may be widely

separated from the mean and median (Figure 6).

mode

mean

median

x

y

x

y

Figure 6: Figure 6: Example of a frequency curve with Figure 6:

widely spread mode, mean and median.

median

Figure 5: Figure 5: Example of a bimodal frequency curve. Figure 5:

median

x

mean

mode 1

mode 2 y

mode 1

x

y

mean median
28

number in set n = 48

range r = 66 mm

mean x = 47.13 mm

standard deviation s = 14.27 mm

Standard Deviation and Variance

Although the mean is probably the most useful value in representing a set of measurements, the mean

does not give an indication of the way in which the values of the set are distributed around the mean.

In other words, how the shape of the bell in the normal frequency curve appears. The standard

deviation (s) is a statistical notation that provides an indication of whether the measures of phenotype

are widely distributed around the mean. When s is relatively high the normal curve is broad; when s

is low the curve is relatively narrow, or tightly distributed around the mean (Figure 7).

Figure 7: Figure 7: Example of normally distributed Figure 7:

frequency curves depicting high A and low B

standard deviations.

x

A, low s

B, high s

mean

y

SB SA

A, low s

mean

x

y

Statistical Summaries

For our data set of 48 height measures of 10 day old AstroPlants, the summarized statistical data are

given in Table 5.

From the statistical summaries and graphical

displays of the data sets you and your students will

be able to better understand the variation that will

become evident in all aspects of the CUE-TSIPS

investigations. Throughout, the activities of

measuring and recording, organizing and displaying

are important. In order to communicate your

observations, results and conclusions effectively

with others, it is important that you compare the

same sorts of data in the same terms of reference. The CUE-TSIPS activities have been designed so

that your students will be able to share their data with others and generate discussion of their results.

Data Sheets and Tables

Data sheets or tables need to be organized so as to receive descriptive information in a logical and

orderly manner that will minimize the likelihood of entry errors and that will aid in later

summarization and analysis. For each activity, examples of student and class data sheets have been

provided. With most of the experiments, the data sheets also contain columns for data summation

and statistical analyses. Calculators with graphical capabilities may be useful to students in

analyzing data.

Table 5: Table 5: Statistical summary of height data Table 5:

of 48 AstroPlants from Table 2.

sB sA

B, high s

The standard deviation is the square root of the variance (s2), which is the sum of

the squared deviations of each value from the mean x divided by n-1, the set size

minus one.

Though the standard deviation is

a tedious calculation to make

with a pencil and paper, most

hand calculators with a

statistical capability will have

functions that automatically

provide the mean (x), variance

(s2) and standard deviation (s).

s2 = ∑i (x1 - x)2

 n-1

s
29

Day das dap Subject Areas Activity

T minus – – - construct the life support

4-2 weeks system (light bank)

T minus – – - prelude to planting - "Getting Acquainted with a Seed"

10 days (page 67)

T minus – – - germination - Germination activity: "Launching

7-5 days the Seed" (page 74)

T minus – – - constructing the PGC - students make and assemble the

5-1 days Plant Growth Chambers (page 35)

CUE-TSIPS Mission Calendar

The CUE-TSIPS Mission Calendar is arranged to follow along with the timing of the experiments being

performed on the CUE Space Shuttle mission in October, 1997. To establish the "real-time" schedule,

count back from the day of launch, once scheduled and confirmed by NASA, to find the start date.

Teacher Preparation

Time Activity

May to August, 1997 - construct or order light bank (get supplies for light bank from

hardware store)

- purchase AstroPlants seeds (page 94)

- purchase peatlite root medium (page 94)

- purchase salts for Wisconsin Fast Plants Nutrient Solution or

commercial fertilizer (page 94)

August to September, 1997 - assemble materials for the student Plant Growth Chambers

(page 32)

- purchase other recommended supplies, including a hi-low

thermometer (page 14) and pest control cards (page 17)

"Day" refers to the ordered timing of activities. In the "Day" column, "T" stands for "terminal," a term

used by NASA to indicate time of launch. The abbreviation "das" stands for "days after sowing." The

abbreviation "dap" stands for "days after pollination."

Beginning with Day 14, each activity is given a span of days rather than a specific day. The timing of

these activities depends on the rate of growth and development of your plants, depending specifically

on the day that your students pollinate. For these activities, follow the "dap" designation, performing

each at the appropriate number of days after pollination.

Countdown to Launch Countdown to Launch

Remember that the bean icon indicates that an activity can be completed with seeds from

plant types other than AstroPlants. These activities are part of the supplemental sections

and do not need to be performed as part of the central CUE-TSIPS experiments.
30

Day das dap Subject Areas Activity

Day 0 0 – - planting - sow seed, place complete PGCs

under lights (page 35)

Day 1 1 – - orientation, tropism - tropism activity: "How do Plants

 Know Which Way to Grow" (page 79)

Day 2 2 – - orientation, tropism - tropism activity: "Do Plants Prefer

 the Blues?" (page 86)

Day das dap Subject Areas Activity

Day 3 3 – - growth, development - each student notes number of emerged

plants, records number on AstroPlants

Growth Group Data Sheet (page 41)

 - revisit gravitropism chamber

Day 5 5 – - orientation, tropism - revisit gravitropism chamber

 - revisit phototropism chamber

Day 7 7 – - growth, development - thin to two plants per film can wick pot

- each student measures plant height,

records data on AstroPlants Growth

Group Data Sheet

Day 11 11 – - growth, development - each student measures plant height,

records data on AstroPlants Growth

Group Data Sheet

Day 12 12 – - pollination - make beesticks (page 46)

Day 14 14 – - growth, development - each student measures plant height,

records data on AstroPlants Growth

Group Data Sheet

Launching the Seed Launching the Seed

Life in Orbit Life in Orbit

Reproduction in Orbit Reproduction in Orbit

Day das dap Subject Areas Activity

Day 14-16 14-16 0 - growth, development - each student notes day of first open

- pollination flower, records day on AstroPlants

Growth Group Data Sheet

- each student removes the most apical

(top) flower on two plants, makes floral

strip, measures and records pistil

length on Floral Clock Student Data

Sheet (page 51), numbers open flowers

- each student pollinates all open

flowers, terminalize plants (pinch off

all but open flowers 1-4)

- record stigma position in flowers 1-4

on Floral Clock Student Data Sheet
31

Day 17-20 17-20 3 - growth, development - each student measures pistil length on

flowers 1-4, records data on Floral

Clock Student Data Sheet

Day 21-22 21-22 6 - double fertilization, - each student measures pistil length on

embryogenesis flowers 1-4, records data on Floral

Clock Student Data Sheet

- AstroPlants embryo dissection, record

data on Ovule and Embryo Student

Data Sheet (page 65)

Day 23-24 23-24 9 - double fertilization, - each student measures pistil length on

embryogenesis flowers 1-4, records data on Floral

Clock Student Data Sheet

- AstroPlants embryo dissection, record

data on Ovule and Embryo Student

Data Sheet

Day 26-28 26-28 12 - double fertilization, - each student measures pistil length on

embryogenesis flowers 1-4, records data on Floral

Clock Student Data Sheet

- AstroPlants embryo dissection, record

data on Ovule and Embryo Student

Data Sheet

Day 35-37 35-37 21 - double fertilization, - each student measures pistil length on

embryogenesis flowers 1-4, records data on Floral

Clock Student Data Sheet

- AstroPlants embryo dissection, record

data on Ovule and Embryo Student

Data Sheet

- remove plants from water

Day 43-45 43-45 28 - harvest seeds

- test seed for viability in bottle cap

seed germinator (page 75)

Day das dap Subject Areas Activity

Reproduction in Orbit, continued Reproduction in Orbit, continued
32

Getting Started

Engineering of life support systems in space flight involves designing, building and operating the

equipment that creates, monitors and regulates those components of the environment that are

essential for normal plant growth.

To participate in the CUE-TSIPS activities, you and your students will create a growing environment

for the plants. In groups of four, students will construct Plant Growth Chambers (PGCs) and start the

life cycle of their AstroPlants in Activities One and Two.

Constructing the PGC Constructing the PGC

Introduction

The CUE-TSIPS growing system has been designed to simulate the conditions

under which plants will be grown pre-flight and in-flight on the Space Shuttle mission.

The system uses readily available, low-cost materials with which students can construct

their own Plant Growth Chambers.

Each group of students will need one PGC for

experimental plants. Control plants will be grown

separately in additional PGCs. For pollination and

fertilization activities, each class will need at least

16 extra plants (two PGCs) to serve as controls.

Time Frame

Teachers may choose to have their students

construct PGCs prior to the start of the CUE-TSIPS

activities or use the "CUE-TSIPS Mission Calendar"

to time the construction with the Shuttle mission.

Working in groups of four, construction of the PGC

components (lid and base) would take about one 50

minute class period. Assembly of the components once

students are ready to plant will take about 15 minutes.

Learning Objectives

This activity is largely technology-based. In participating in this activity students will:

• learn to construct experimental equipment; and

• make accurate measurements.

I. PGC Lid Construction

Materials

• transparent acrylic sheet, 2 mm (1/8") thick (comes in various dimensions, illustrated as a sheet

70 cm x 80 cm), or other clear plastic sheets (e.g., report covers, overhead transparencies, etc.)

• cutter for acrylic sheet (such as Red Devil®) and/or scissors for plastic sheets

• 2 cm wide clear adhesive tape

• fine tipped permanent marker

• metal or wood file, or sand paper

PGC PGC

Space Shuttle

Plant Growth Chamber

flight units (PGCs).

A C T I V I T Y 1 A C T I V I T Y 1
33

Procedure

1. Use a marker to mark the cut lines on the

acrylic sheet as shown. For other types of

clear plastic make appropriate measures

and cuts.

Each PGC lid includes pieces in the

following dimensions:

- two pieces 20 cm x 21.5 cm (front and

back panels), and

- two pieces 20 cm x 5.6 cm (side panels).

A 70 cm x 80 cm acrylic sheet can be cut

as shown at right to yield pieces for four

PGC lids.

2. Cut the acrylic sheet with the cutter (or

with a circular table saw with a hardened

blade). Peel off the protective plastic film.

Caution: Acrylic sheet cutters and saws are very sharp and should be used with care.

Tips:

- Smooth off sharp edges of the cut acrylic pieces using a file or sand paper.

- For thin plastic sheets, cut the front panel to be shorter to access plants.

3. Assemble the PGC lid as follows:

- Use two pieces of clear adhesive tape to attach the back panel to one of the side panels. Place

one piece of tape about 2 cm from the top and one about 4 cm above the bottom edge on each

side-back joint.

- Use two pieces of tape to attach a side panel to the other side of the back panel. Again, place one

piece about 2 cm from the top and the other about 4 cm above the bottom edge. Three of the

four panels should be taped together at this point.

20 cm 20 cm 20 cm 20 cm

80 cm (32")

(scrap)

21.5

cm

21.5

cm

5.6 cm

5.6 cm

70 cm

(28")

(scrap) (scrap) (scrap)

80 cm (32")

20 cm 20 cm 20 cm 20 cm

21.5

cm

5.6 cm

5.6 cm

- Tear off two additional pieces of

tape. On each piece, fold over

one end about 1 cm to make a

flap. Place one of these two

pieces of tape on each side of the

front panel, with the flap end on

the front panel. By peeling back

these pieces, the front panel can

be removed and replaced,

allowing easy student access to

the plants inside the PGC.

- If using thin plastic sheets,

support them by taping panels to

bamboo grilling skewers at the

corners. The skewers can be

poked into the styrofoam film can

wick pot holder (page 35).

21.5 cm open for

g and light

5.6 cm

20 cm

bottom is open

to fit over plants

bottom is open to

fit over plants

21.5 cm top is open for

cooling and light peel back

flap of

tape to

open front

scotch

tape

(scrap) (scrap) (scrap) (scrap)

21.5

cm

5.6

cm

20 cm

70 cm

(28")
34

1 cm

3 cm

II. PGC Base Construction

The basic growing system utilizes peatlite (peat moss:vermiculite, 1:1) as the root medium, and a

capillary wicking system to provide water and nutrients to the plants in film can wick pots. Although

the peatlite medium and film can wick pot system is not being used in the Space Shuttle Plant Growth

Chambers, it is recommended as the most reliable system in which AstroPlants can be grown.

Materials

• two plastic drawer organizers (22 x 7.6 x 5.1 cm), the first to be a base which will hold the film can

wick pots and the second to act as a reservoir

• four 35 mm black film cans for wick pots

• capillary wicking material

• styrofoam block (2.5 cm thick, 21 cm long x 5.5 cm wide), cut from builder's insulating foam

Procedure

1. Melt or drill an approximately 5 mm diameter hole in the center of the bottom of each film can.

Caution: Melting plastic produces noxious fumes; perform this step in a well-ventilated area. Wear

safety goggles if using a drill.

6. From 2.5 cm (1 inch) thick insulating styrofoam, measure and cut, with a fine blade saw (hacksaw

or utility saw), a rectangular block 21 cm long by 5.5 cm wide. Rough edges where the styrofoam

is cut may be smoothed with sandpaper.

5. With a hot soldering iron or large hot

nail melt two 2 cm slots in the bottom

of one of the drawer organizers to

accommodate the capillary wick; this

organizer will become the base for the

growing system.

Caution: Melting plastic produces noxious

fumes; perform this step in a well-ventilated area. (view from top)

slot "platform base" (2 cm long)

slot

(2 cm long) "platform base"

5.5 cm

21 cm

capillary mat

21 cm

4. From the capillary wicking material, cut a

capillary mat to fit the bottom of one of the

drawer organizers (21 cm x 5.5 cm).

capillary mat

30 cm

ill i k ti k

30 cm

capillary wick strip

3. From the capillary

wicking material,

cut a wick strip to

be 30 cm long and

1 cm wide, with

tapered ends.

1 cm

diamond

wick

2. From the capillary wicking material, cut four diamond wicks (3 cm x 1 cm),

with tapered ends, for the film can wick pots.

(view from above)

3 cm
35

7. With a pen and a film can, trace four equally spaced circles on the top surface of the styrofoam

block (this block will hold the film can wick pots).

8. Using a 33 mm (1.25 inch) circular "keyhole" cutter in an electric drill, cut four holes equally

spaced in the styrofoam block. Alternatively the hot flamed rim of a Pyrex® test tube (18 to 22 mm

diameter) may be used to melt the four holes. Other forms of film can wick pot holders, such as

wooden blocks, are satisfactory.

Caution: Melting styrofoam produces noxious fumes; perform this step in a well-ventilated area.

Wear safety goggles if using a drill.

33

mm

5.5 cm

(view

from

top)

33

mm

(view

from

above)

5.5 cm

21 cm

holes (33 mm diameter)

2.5 cm

(view

from

side)

21 cm

(view

from

side)

holes (33 mm diameter)

A C T I V I T Y 2

Planting AstroPlants in the PGC Planting AstroPlants in the PGC

Introduction

After constructing the PGC lid and base, students are ready to begin planting.

Planting can be timed with the flight experiments by following the "CUE-TSIPS Mission

Calendar" (page 29). Once seeds have been planted, the AstroPlants life cycle is underway.

Time Frame

With an assembled PGC (lid and base), planting and placing the completed PGCs under lights will take

less than one 50 minute class period.

Learning Objectives

In participating in this activity students will:

• understand the importance of capillarity in

providing a continuous supply of water and

nutrients to the plants (see "Water," in

"Understanding the Environment," page 15);

• learn the importance of the physical

characteristics of the peatlite root medium in

providing a suitable environment for normal

root growth and function; and

• understand the role of water in activating the

process of seed germination.

Materials

• PGC lid and base, reservoir, film can wick pots and capillary wicks and mat (from Activity 1)

• 16 AstroPlants seeds

• forceps for handling seed

• peatlite root medium and horticultural vermiculite

• nutrient solution, such as Wisconsin Fast Plants Nutrient Solution or commercially available

fertilizer (page 96)

• white lab tape

"Though I do not believe

that a plant will spring up

where no seed has been,

I have great faith in a seed.

Convince me that you have a seed there,

and I am prepared to expect wonders."

- Henry David Thoreau,

The Dispersion of Seeds, 1860
36

Procedure

1. Collect and assemble the components of the PGC lid and base along with the other materials

required for this activity. Each group of three to four students should plant in one PGC.

Additional PGCs for control plants can be planted by volunteers or the teacher.

2. On Day 0, wet the four diamond wicks and insert one saturated diamond halfway through the hole

in the bottom of each film can. The emerging ends of the wicks will make contact with the

capillary mat.

3. Wet the long capillary wick and mat. Feed the wick through the slots in the base platform so that

a length of 5 cm is emerging from each slot, hanging below the base. Place the wet capillary mat

over the wick in the bottom of the tray, make sure there are no air pockets trapped in the mat.

4. Fill each film can wick pot with slightly moistened peatlite, to the rim, tapping lightly to settle the

peatlite. Remove the excess peatlite above the pot rim. Do not press down on the peatlite.

Carefully moisten the peatlite by watering from above until the wick drips. The peatlite will settle

slightly to a few millimeters below the rim of the can.

5. Place four seeds in the form of a cross at the rim of the pot. Cover the

seeds to the film can rim with horticultural vermiculite and gently water

again from above.

6. On a piece of white lab tape placed just below the rim, label each film

can with a student number (1 to 4). Carefully place each film can into

its hole in the styrofoam holder. Place the styrofoam and film cans into

the base platform drawer organizer, on top of the wet capillary mat.

seeds

(view

from top)

9. Carefully place the assembled lid of the PGC into the base platform, with the walls outside of the

foam. Label each PGC appropriately (date and time of sowing, seed stock, student names, student

group number, etc.).

10. Place the PGC with film can wick pots under lights.

Note: The time that the seeds are moistened begins the timing of the growth cycle. From this point on

time is taken as days after sowing or "das."

7. Add about 2 cm depth, approximately 200 ml, of

Wisconsin Fast Plants Nutrient Solution to the

second drawer organizer (without slots), to act as

the reservoir.

If a commercial liquid fertilizer is used (e.g., Peters®

20-20-20), fill the reservoir with a 2 cm depth of

water. Add fertilizer solution at the soil surface at

the rate of 4 ml per film can wick pot on Days 3, 7,

14, 21 and 28 (page 16). Do not put the fertilizer

solution in the water reservoir.

8. Place the base platform drawer organizer into the

second reservoir drawer organizer, with the wicks

beneath it. The water or nutrient solution will be

carried via capillary action into the film can wick

pots and to the plants.
37

Growth, Development and Flowering

Concepts Concepts

Growth represents increase in size, number and complexity of plant cells and organs. Both

environment and genetics play fundamental roles in regulating growth. The energy for growth in

plants comes from photosynthesis and respiration. Variation within a population is related to

variation in both the genetic constitution and the growth environment of the individuals.

Questions Questions

• What is the role of the environment in regulating plant growth?

• How do plants grow?

• How does a plant know when to produce leaves and when to produce flowers?

Background Background

The environment is created by the interaction of physical (light, temperature, gravity), chemical (water,

air, minerals) and biological components (microbes, larger organisms). When environmental

conditions are favorable, plant growth occurs. Following the emergence of the germinating seedling

from the soil, growth of the plant continues through developmental stages in which new plant parts –

leaves, stem and flowers – are produced from the growing point known as the shoot apical meristem.

Further growth is observed as the increase in size of the new leaves, stems and flowers.

In AstroPlants, growth is most dramatic in the 10 to 12

days between seedling emergence and the opening of the

first flowers. During this period, students may explore

important concepts that will help them understand

growth and development.

Each part of the plant performs important functions in

the life cycle. The roots anchor the plant in the soil so

that it doesn’t wash or blow away. The roots also

provide the means by which plants obtain water and

minerals from the soil. The stem supports leaves and

flowers and ensures that these parts are in the best

position to perform their special tasks. The stem also

transports water and minerals from the roots, and food

manufactured in the leaves, to other plant parts.

The leaves are positioned to capture sunlight. In the

process of photosynthesis, energy from sunlight is

trapped by the green chlorophyll in leaves. This energy

is used to manufacture food [carbohydrates (CHO)] by

combining the carbon (C) and oxygen (O) from carbon

dioxide (CO2) in the air with hydrogen (H) which is

transported from the roots as water (H2O).

Flowers contain many specialized parts that are formed

to ensure that the seed of the next generation of plants

will be produced and then dispersed to new locations for

growth (Raven, Evert and Eichorn, 1992).
38

Tracking Variation within the Normal Growth and Tracking Variation within the Normal Growth and

Development of a Population of AstroPlants Development of a Population of AstroPlants

Introduction

With four students working as a team with one PGC, each student will be responsible for

two plants in a subpopulation of eight. Students will sow four seeds in each film can wick pot

and place them in an environment conducive to germination, growth and emergence. After plants

emerge students will select two of the four plants and track their growth and development by

measuring plant height at specified days after sowing (das).

Data collected by students on their plants will become part of a class data set, which will be organized,

summarized, analyzed, plotted and displayed so that students may gain a better understanding of the

normal variation within a population of AstroPlants as they grow and develop.

Question: How much variation is exhibited within and among subpopulations of AstroPlants grown

under standard environments in classrooms across the United States and Ukraine?

Sample Hypothesis: A normal amount of variation will exist.

Design

• Subpopulations of AstroPlants are grown in classroom PGCs, specified growth parameters (height,

etc.) are measured and summarized results compared with other subpopulations and with

experimental subpopulations grown in microgravity on the Space Shuttle orbiter.

• Students will record data on their AstroPlants Growth Group Data Sheet (page 41).

• It is important for each class to have at least 2 sets of 4 film can wick pots in extra PGCs to serve

later as unpollinated control plants. Plant and maintain the extra PGCs in the same manner as

the experimental PGCs, being careful to avoid pollen transfer once the control plants are in flower.

Time Frame

A period of 16 days from the sowing of seed is required for the growth of the AstroPlants and the

completion of the activity. Class time required daily will vary depending on the developmental stage of

the plants and the activity.

Learning Objectives

In participating in this activity students will:

• learn about plant growth by observing the emergence of seedlings, observing and measuring

increases in plant size and in number, size and complexity of plant parts;

• understand the role of environment in regulating plant growth;

• observe, measure and analyze variation in growth and development among individuals in a

population of plants;

• consider the use of statistical and graphical representation of growth and development within a

population; and

• understand that growth in plants represents an ordered sequence of developmental events which

vary between individuals of a population within limits that are defined as "normal" (see page 26).

Materials

• white lab tape

• metric ruler

• black fine-tipped marking pen

• PGC with seeded film can wick pots, three days after sowing (Day 3)

A C T I V I T Y 3
39

Procedure

1. On Day 0, students planted AstroPlants and placed the experimental and control PGCs under

recommended lights (Activity 2, page 35).

2. By Day 3, seedlings will have emerged. At the time of sowing, film cans were numbered for

students 1 to 4. Refer to the AstroPlants Growth Group Data Sheet and record the number of

seedlings that have emerged from each film can wick pot.

3. On Day 7, thin the plants in each film can wick pot by carefully snipping off two of four plants at

soil level with fine scissors. Number the remaining two plants on the white tape label of each pot.

Each team of four students should have plants numbered from 1 to 8 according to the AstroPlants

Growth Group Data Sheet.

4. On Day 7, each student should measure the

height of his/her two plants (in millimeters)

and record the measurements on the group's

AstroPlants Growth Group Data Sheet.

Note: Measure height from the soil to the

apex as indicated in the illustration, not to

the highest part of the leaf.

At this time students will have generated a group

data set. Teachers may wish to have students

practice some simple organization and analysis

activities on the group data and have students enter

data into a class population data set.

5. Continue to observe the developing plants. As the plants grow, they will draw increasingly more

liquid from the system; be sure to check reservoirs daily and fill as needed.

Around Day 9 students will notice the first appearance of small flower buds in the apex of the

growing shoot. Within these buds the tissues that lead to the production of the male and female

sex cells are differentiating.

Over the next six days the buds will enlarge as male gametes develop within the anthers and as

female gametes develop within the ovules of the pistil (page 43).

6. On Day 11, each student should again measure and record the height of his/her two plants.

Notice that the plants are beginning to elongate more rapidly. All of the leaves on the main stem

have formed and flower buds are more prominent.

7. Sometime between Day 12 and Day 14, flowers on individual plants will begin to open. For each

plant, record the number of days after sowing (das) when the first flower opens.

8. A final measurement of height should be made on Day 14, even if some plants are not in flower.

After all of the students' data are in and recorded, it is a good time to observe and discuss the

variation within plant population growth over time.

9. Following Day 14, many of the flowers will be opening on the plants, awaiting pollination. The

pollination activity (Activity 4, page 46), should be carried out on Day 15 or Day 16, or when most

plants have been in flower for two days. The timing of pollination may vary depending on the

environment in which the plants have been growing.

plan

so

plant height

apex

soil level
40

Concluding Activities and Questions

Combine the group data into a class data summary using the AstroPlants Growth Class Data Sheet

(page 42). See "CUE-TSIPS Science and Technology" for a review of data analysis (page 18).

If available, use data analysis software to create graphical and statistical summaries of class data.

Notice how the various statistical notations (range, mean and standard deviation) change over time

from sowing. Have students consider the following:

- From a class frequency histogram and statistical summary, does the measured plant character of

height exhibit a normal distribution within the class population as hypothesized?

- Are their individual plants shorter than the average in the population? Or taller?

- Do their individual plant heights fall within one or two standard deviations of the class mean?

Would they consider their plant heights to be normal? Why or why not?

- How many plants in the population fall within one or two standard deviations of the class mean?

- Are there any "abnormal" plants?

- There are many other ways that students could measure growth and development. Height is only

one. Can they come up with others?

Classes can submit the AstroPlants Growth Class Data Sheet to the Wisconsin Fast Plants Program

and then check the WFP World Wide Web site to see where their plant growth data fit into the data set

from the larger population of plants grown for CUE-TSIPS in the United States and Ukraine (see page

for addresses).

i
41

Date das Character/Activity Character/Activity Plant Measurements Statistics

Students: Students: Student 1 Student 1 Student 2 Student 3 Student 4 n r x s

3 indicate number of

seedlings emerged

7 thin to 2 plants/film can,

number plants

Plant Number Plant Number 1 2 3 4 5 6 7 8

7 plant height (mm)11 plant height (mm)14 plant height (mm)

day to first open flower (das)

AstroPlants Growth Group Data Sheet AstroPlants Growth Group Data Sheet

Environment

Student Name 1 Irradiance: no. of bulbs distance of plants from bulbsStudent Name 2 wattage of bulbs or μEm-2s-1 measured under bulbs

Student Name 3 Average daily temperature of growing environment:  ̊CStudent Name 4 Nutrient used: WFP nutrient solution Specify other:

Root medium used: Peatlite Specify other:

Group Number Seed type: AstroPlants Specify other:

Plants grown in PGC? yes / no

das = days after sowing, n = number of measurements, r = range (maximum minus minimum), x = mean (average), s = standard deviation
42

Statistics Statistics

Group n r x s Group n r x s

Group 1 Group 7Group 2 Group 8Group 3 Group 9Group 4 Group 10Group 5 Group 11Group 6 Group 12

Date EnvironmentTeacher Name Irradiance: no. of bulbs distance of plants from bulbs

School Name wattage of bulbs or μEm-2s-1 measured under bulbs

School Address Average daily temperature of growing environment:  ̊C

Nutrient used: WFP nutrient solution Specify other:

School Phone ( ) Root medium used: Peatlite Specify other:

Email Address Seed type used: AstroPlants Specify other:

Plants grown in PGC? yes / no

AstroPlants Growth Class Data Sheet AstroPlants Growth Class Data Sheet

How to use this Class Data Sheet: How to use this Class Data Sheet:

This Class Data Sheet can be used for the teacher or students to compile data from one measured character (e.g., plant height, Day 7)taken by groups of students who have completed the AstroPlants Growth Group Data Sheet. This Class Data Sheet can be submittedto the Wisconsin Fast Plants Program to be included in a compilation of statistics from other classes.

Variable Measured Date Measured das of Measurement

* taken from AstroPlants Growth Data Sheetsdas = days after sowing, n = number of measurements, r = range (maximum minus minimum), x = mean (average), s = standard deviation

Group Data* Group Data*

Statistics n r x s

Class Data
43

Pollination

Concepts Concepts

Pollination is the process of mating in plants; it is the precursor to double fertilization. In flowers,

pollen is delivered to the stigma through a wide range of mechanisms that insure an appropriate

balance in the genetic makeup of the species. In brassicas, pollen is distributed by bees and other

insects. The flower is the device by which the plant recruits the bee. Bees and brassicas have evolved

an interdependent relationship.

Questions Questions

• What is the effect of microgravity on pollination?

• What will be the pollen vector in space? Can a bee fly in microgravity?

Background Background

What is a flower? In human eyes it is something to enjoy, with color and fragrance. For many plants,

flowers are vital organs of reproduction containing both male and female gametes. For bees and other

nectar-feeding animals, flowers are a source of food.

Symbiosis is the close association of two or more dissimilar organisms. Such associations can be

beneficial to both organisms (mutualistic) or detrimental to one (parasitic). Symbiotic relationships

among species occur frequently in nature. When the two or more species in symbiosis evolve in

response to each other, they are said to coevolve. Under close examination each symbiotic

relationship stands out as an example of miraculous complexity which has emerged. The coevolution

of bees and brassicas, each dependent upon the other for survival, is such a relationship.

The Flower The Flower

Most flowers have the same basic parts,

though they are often arranged in different

ways. The five main parts of a flower are the

sepals, petals, stamens, pistil and nectaries.

The sepals are the green leaflike structures

at the base of the petals that protect the

developing flower. The petals are the colored

leaflike structures within the sepals.

The stamen has two parts, the anther and

the filament. The anther contains the pollen

grains, which contain the male gametes.

The pistil usually has three parts, the stigma

(which receives the pollen), the style (the neck

below the stigma) and the carpel (or ovary).

AstroPlants flowers have two fused carpels,

separated by a thin membrane. The carpels house

the ovules, which contain the female gametes.

Sugar-rich nectar is secreted by the specialized nectary tissues strategically located in the flower to

ensure that nectar-gathering animals will receive pollen from anthers and transmit it to stigmas.

pedicel

sepal

petal

nectary

receptacal

ovule

anther

filament

stamen

(male)

pistil

(female)

stigma

style

carpel filament







stamen

(male)

anther

ovules

receptacle

nectary

pedicel

sepal

petal

 style





pistil

(female)

stigma

carpel
44

Investigations of a Gametic Kind Investigations of a Gametic Kind

The Developmental Clock The Developmental Clock

At about Day 7 in the AstroPlants life cycle, you may have looked

down on your plants from the top view and noticed a tightly

packed whorl of buds, some of which were larger than others.

Each successively smaller bud represented a time interval in the

developmental clock of AstroPlants, later marked by the

appearance of new flower buds on the shoot.

As your AstroPlants begin to flower, normally the lowest flower on

the shoot opens first, followed by the next highest and so forth.

By recording the time when the first flower opens and counting the

number of successive flowers that open in the intervening 24 hours,

you can calculate the average time between successive developmental

events that initiate a flower on the shoot apical meristem.

• Can you calculate the number of hours between successive

flowers on your AstroPlants?

• How many flowers would you predict will open between the time

your first flower opens and when you pollinate your plants?

When is a Flower Open? When is a Flower Open?

The answer to this question is not always as straightforward as it might appear. As you observe the

progression of flowers opening, you will notice that as the buds swell the sepals are pushed apart by

the enlarging anthers and emerging yellow petals. Eventually the petals (which are slightly rolled) fold

outward about halfway up their length, flattening and spreading to reveal their bright yellow color. At

this time you might conclude that the flowers were open.

From the perspective of mating, a flower is open

when it is capable of providing and receiving pollen.

Thus, not until the anthers on the filaments of the

stamens open up (dehisce) and release their pollen

is a flower functionally open.

The shedding of pollen is known as anthesis. When

you observe a succession of flowers at the shoot

apex of your AstroPlants you will observe whether

anthesis has occurred by noting the release of the

powdery yellow pollen from the anthers. A hand

lens can be helpful in detecting anthesis.

Sometimes a flower is inhibited from male function by excessive heat or genetic male sterility. As

mentioned in "Understanding the Environment" (page 13) anthers may fail to dehisce at very high

relative humidities. This problem can usually be corrected in a few minutes by circulating air over the

plant with a fan.

Gametogenesis ogenesis ogenesis ogenesis ogenesis

The production of sperm and eggs involves a fundamental sequence of events that characterizes most

higher plant and animal life. In plants, meiosis precedes gamete formation and establishes the initial

events of sexual reproduction by exchanging and sorting the genes on the chromosomes into the

vehicles of genetic transmission and reception that we call gametes: the eggs and sperm.

er

ding pollen–

esis

Anther NOT

shedding po

anther NOT

shedding pollen

anther

shedding pollen —

anthesis
45

In AstroPlants the developmental process known as microsporogenesis occurs in the developing

anthers when the first flower bud of the apical whorl is about one millimeter in diameter and leads to

the production of pollen. Within the anthers specialized tissues undergo meiosis to form the

microspores that eventually become pollen grains. Pollen is the immature stage of the

microgametophyte, which does not become fully mature until it germinates on a stigma and forms a

pollen tube containing two sperm cells and a tube nucleus (see page 53).

At about the same time as the anthers are developing, tissues within the developing pistil of the

immature flower bud give rise to a series of ovules. Within each ovule meiotic divisions in the process

of megasporogenesis lead to the production of megaspores. Through the process of megagametogenesis the megaspore develops into a mature megagametophyte or embryo sac (Raven, Evert and

Eichorn, 1992).

These developmental processes may be subject to perturbations resulting from microgravity, and

therefore are be included as part of the CUE experiments.

The Flower and The Bee: Pollination The Flower and The Bee: Pollination

Brassica pollen is heavy and sticky – unable to be easily wind-borne. For brassicas, bees are

marvelously coevolved pollen transferring devices (vectors).

Bees depend on the flower for their survival. Sugars in the nectar provide carbohydrates to power

flight and life activities. Pollen is the primary source of proteins, fats, vitamins and minerals to build

muscular, glandular and skeletal tissues. A colony of bees will collect as much as 44 to 110 pounds of

pollen in a season.

A worker bee foraging for pollen will hover

momentarily over the flower and use its

highly adapted legs for pollen collection

(see illustration). The bee's three

pairs of legs are evolved to comb

pollen from the bee hairs and

pack it into the pollen basket

for transport to the hive.

Each foreleg is equipped with

an antenna cleaner, a deep

notch with a row of small

spines, which is used to

brush pollen from the

antennae. Using the large

flat pollen brushes on the

midlegs, the bee removes the

pollen from its head, thorax

and forelegs. The pollen is

raked off the brushes by the

pollen combs and packed into

the baskets by the pollen press.

Bees are members of the insect family Apidae, which are unique in that their bodies are covered with

feather-like hairs (setae). The bright yellow flower petals act as both beacon and landing pad for the

bees, attracting them to the flower and guiding them to the nectaries. The bee drives its head deep

into the flower to reach the sweet nectar secreted by the nectaries and brushes against the anthers

and stigma. Quantities of pollen are entrapped in its body hairs.

pollen

basket

po

co

po

pre

pollen

brushes

ntena

eaner

BEE LEGS pollen

basket

pollen

comb

pollen

press

pollen

brushes

antenna

cleaner

FORE-LEG MID-LEG HIND LEG
46

As the bees work from plant

to plant, pollen on the bee

setae is carried from flower

to flower. The transfer of

pollen from the anther to

the stigma is known as

pollination. When pollen is

transferred from one plant

to another, the process is

called cross-pollination.

As the bee forages, crosspollination occurs and

genetic information is widely

transferred. Some pollen

grains are deposited on the

sticky surface of each stigma

and each compatible pollen grain

sends a tube through the style to the

ovule to complete fertilization. Within three days

of fertilization, petals drop and the pistil begins to elongate to form a pod as the seeds develop inside.

Are We Compatible? Are We Compatible?

For AstroPlants and many other brassicas, the act of pollination does not insure fertilization and seed

formation. Some brassicas contain recognition compounds called glycoproteins which are unique to

each plant. These compounds enable the plant to recognize "self," resulting in the abortion of the

plant's own pollen. This genetically controlled prevention of fertilization with "self" pollen is called selfincompatibility. Only "non-self" pollen is able to germinate and effect fertilization.

In order for pollen germination and fertilization to occur, pollen must travel from one brassica plant to

the stigma of a different brassica plant in the process of cross-pollination. Bees take care of this

problem naturally as they move from plant to plant in search of nectar and pollen. AstroPlants are

therefore cross-compatible and self-incompatible.

A C T I V I T Y 4 Making Beesticks, Pollinating and Observing Pollen Making Beesticks, Pollinating and Observing Pollen

Introduction

As their plants come into flower, students need to be prepared to pollinate. The act

of pollination is the prelude to the beginning of a new generation that starts with

double fertilization. In preparation for pollination of their plants, students will need to

understand the developmental biology leading to the production of male and female gametes

(sperm and egg) and the concepts associated with the coevolutionary relationships between

flowers and their pollinators.

It is unknown whether natural pollen vectors on Earth, such as bees, flies

hummingbirds and bats, are capable of flight or transit between and among flowers

in conditions of microgravity. For this reason, in the B-STIC experiment, the CUE

mission's Payload Specialist will be simulating the flight of a bee using an artificial

pollination device to transfer pollen among the AstroPlants flowers.

Question: Question: How is effective pollination carried out?

anther (shedding pollen)

nectaries bee proboscis

bee abdomen

bee thorax bee thorax

anther (shedding pollen)

nectaries bee proboscis
47

Sample Hypothesis: ample Hypothesis: The transfer of adequate numbers of viable, compatible pollen from the anthers of

one plant to the stigmas of another plant will result in effective pollination.

Design

• With a beestick as the vector, pollen is collected from the anthers of various plants and transferred

to the stigmas of other plants.

• Students will record data on their Floral Clock Student Data Sheet (page 51).

• It is important for each class to have at least two extra sets of four film can wick pots (16 plants)

in PGCs to serve as unpollinated control plants. The extra PGCs should have been planted along

with and maintained in the same manner as the experimental PGCs.

Time Frame

A period of 16 days from the sowing of seed is required for the growth of the AstroPlants and the

completion of the activity. Making beesticks will require about 15 minutes and should be done one to

two days prior to pollination. Observation of the bee and a lesson on the relationship of bees and the

AstroPlants flower in pollination could take one 50 minute class period. The pollination will require

one 50 minute class period.

Learning Objectives

In participating in this activity students will:

• understand flowering as the sexually mature stage of plant development;

• understand where and how ovules and pollen originate (male and female gamete formation);

• explore the parts of the flower and the role that each part plays in reproduction;

• observe the reproductive tissues of plants, including pollen and stigma, under magnification;

• understand the interdependent coevolutionary relationship of bees and brassicas; and

• begin the process of reproduction in their AstroPlants by performing a pollination using a beestick,

setting the stage for future developmental events.

Materials

• flowering AstroPlants (Day 14 to 16)

• forceps

• two dissection strips (page 23)

• 2 cm wide clear adhesive tape

• dried bees

• toothpicks

• glue (e.g., Duco® Cement)

• hand lens or microscope

Procedure: Making Beesticks

1. One to two days prior to pollination, students should make

beesticks. While making beesticks the teacher may wish to have

students observe the anatomy of a bee, focusing on the legs and

proboscis, to reinforce an understanding of the design (role and

function) of the bee in relation to the flower.

2. Carefully remove the legs, head and abdomen of the dried

bee, leaving the fuzzy thorax. Pollination can be performed

with "whole bee" beesticks as well.

3. Place a drop of fast-drying glue on the tip of a toothpick.

Carefully push the toothpick into the top of the thorax of the

bee. Remove the wings. Let the beesticks dry overnight.
48

Procedure: Setting the Floral Clock

1. At a time between Day 14 and Day 16 when five or more flowers are open on

each plant in the PGC, cross-pollinate all open flowers on each plant with a

beestick by gently rolling the bee thorax back and forth over the anthers of

flowers of several plants until yellow pollen can be observed on the hairs.

2. Take the top open flower of the first plant and carefully remove it with a forceps. Place it on the

sticky tape of a dissection strip.

3. While observing with a hand lens or microscope, carefully remove the flower parts, noting their

relative positions on the receptacle, making sure not to damage the pistil. Refer to the

illustration on page 43 for help in identifying the floral parts. You and your students may want to

test the nectaries for the presence of glucose (write to Wisconsin Fast Plants for the activity "The

Hunt for Glucose - A Flower's Treasure").

4. Slip the ruler on a second dissection strip (without tape on it) under the first strip. Each student

should measure the length of the pistil from the receptacle to the top of the stigma and record the

pistil length on his/her Floral Clock Student Data Sheet (page 51).

5. Remove the top open flower of the second plant, measure the length of the pistil and record the

data on the Floral Clock Student Data Sheet in the column under the number of the second plant.

- With higher powered microscopes students could

observe magnified views of pollen trapped on the

stigmas of dissected flowers or on a beestick.

- While pollinating, students might also observe the

pollen trapped on the tape of a dissection strip.

- Alternatively, look at the pollen on the stigmas or

on the beestick with a hand lens.

- A beestick with pollen can be rolled over the sticky

tape on the dissection strip. Observation under a

magnifier will reveal pollen attached to the bee setae.

6. Note that flowers on the plants are produced and open in a sequence spiraling up the flower stem.

Starting with the next flower down from the one that you removed, number the remaining flowers

as 4, 3, 2 and 1 as shown in the illustration on page 49, with number 1 being the oldest flower.

- With a sharp pair of fine scissors, carefully snip off all additional remaining flowers below flower

number 1 (including side shoots), leaving only the four open flowers that have been numbered.

- Snip off the developing apical flower shoot and buds above the four remaining open flowers. This

is known as terminalizing the plant.

Moving to other plants and repeating the

rolling motion over the anthers and the

stigma of each pistil, students should make

sure to deposit pollen collected on the

beestick on to the stigma of each flower.

Students from one group may wish to "fly"

their bees to flowers of other groups. Buzz!

magnified

pollen grains on

bee setae
49

7. Returning to the four remaining flowers, note the

position of the stigmas relative to the tall anthers.

Is the stigma below (-1), equal to (0) or above (+1)

the tall anthers? Record this information for each

flower of both plants on the Floral Clock Student

Data Sheet.

- Is there a relationship between flower age and

the position of the stigma relative to the level of

the four tall anthers?

8. Be sure to measure the length of the uppermost open flower of each plant in the set that was

grown for the unpollinated controls. Data for the unpollinated control sets should be recorded on

a separate Floral Clock Student Data Sheet.

9. Before leaving the plants be sure that each of the remaining stigmas has been adequately

pollinated by the beestick. Can you see any pollen on the stigmas? Check with a hand lens.

-1 0 +1

FLOWER #1: FLOWER #1:

follow pistil

development

SIDE SHOOT: SIDE SHOOT:

remove and

discard

FLOWER SHOOT AND

UNOPENED BUDS: UNOPENED BUDS:

remove and discard FLOWER #5: FLOWER #5:

remove for dissection, measure

pistil (STEP 2, ACTIVITY 2)

FLOWER #2: FLOWER #2:

follow pistil

development

FLOWER #4: FLOWER #4:

follow pistil

development

FLOWER #3: FLOWER #3:

follow pistil

development
50

Concluding Activities and Questions

The completion of pollination sets the floral clock at "0 dap" (days after pollination). Activities 5 and 6

in the section "Double Fertilization and Post-Fertilization Events" involve observing, recording and

analyzing pistil development as an indication of successful pollination. In participating in these

activities students will complete their Floral Clock Student Data Sheets. After completing Activity 4,

have students consider the following:

- What is the relative importance of each flower part in relation to pollination and sexual

reproduction? Are some parts more important than others? Why?

- Does the pistil continue to elongate after the

flower is functionally open? Even if the flower is

not pollinated?

- How many flowers on average open each day once

the first flower has opened?

- What is the average amount of time (in hours)

between the development of one flower and its nearest neighbor?

Extensions

For activities on observing and experimenting with pollen germination in vitro under the microscope

and on observing compatible and incompatible pollen-stigma interactions and pollen tube growth in

the style and ovaries, write to Wisconsin Fast Plants for the activities "Pollen Germination" and

"Pollen-Stigma Interactions and Pollen Tube Growth."

With a separate third set of plants, try self-pollinating and compare the amount of seed produced with

the seed produced by the cross-pollinated plants.

"People from a planet without flowers

would think we must be mad with joy...

to have such things."

- Iris Murdoch
51

Plant No. Plant No. Plant No. Plant No. Plant No. Plant No.

Date dap Character/Activity Character/Activity Measurements Measurements

0 pistil length top flower (mm)

number pollinated flowers

Flower/Pod Number Flower/Pod Number 1 2 3 4 n r x s 1 2 3 4 n r x s

0 note position of stigma

above, at or below anthers(+1, 0, -1)*pistil length (mm)pistil length (mm)pistil length (mm)est. no. developing seeds (#)pistil length (mm)pistil length (mm)harvest & count seeds/podviability test (+ / -)

Environment

Student Name Irradiance: no. of bulbs distance of plants from bulbsPlant Type: (circle one) wattage of bulbs or μEm-2s-1 measured under bulbs pollinated unpollinated Average daily temperature of growing environment:  ̊C

Nutrient used: WFP nutrient solution Specify other:Root medium used: Peatlite Specify other:

Group Number Seed type: AstroPlants Specify other:

Plants grown in PGC? yes / no

Floral Clock Student Data Sheet Floral Clock Student Data Sheet

dap = days after pollination, n = number of measurements, r = range (maximum minus minimum), x = mean (average), s = standard deviation

* when noting stigma position: +1 = above anthers, 0 = at level of anthers, -1 = below the level of anthers

The dap column is left blank on this data sheet because the timing of activities depends on the rate of development in each students' plants. For aguide of approximate dap, see the "CUE-TSIPS Mission Calendar" (page 29).

Statistics Statistics
52

Statistics Statistics

Group n r x s Group n r x s

Group 1 Group 7Group 2 Group 8Group 3 Group 9Group 4 Group 10Group 5 Group 11Group 6 Group 12

Floral Clock Class Data Sheet Floral Clock Class Data Sheet

Group Data

Statistics n r x s

Class Data

Variable Measured Date Measured dap of Measurement

Date EnvironmentTeacher Name Irradiance: no. of bulbs distance of plants from bulbs

School Name wattage of bulbs or μEm-2s-1 measured under bulbs

School Address Average daily temperature of growing environment:  ̊C

Nutrient used: WFP nutrient solution Specify other:

School Phone ( ) Root medium used: Peatlite Specify other:

Email Address Seed type used: AstroPlants Specify other:

Plants grown in PGC? yes / no

How to use this Class Data Sheet: How to use this Class Data Sheet:

This Class Data Sheet can be used for the teacher or students to compile data from one measured character (e.g., pistil length, 14 dap)taken by students who have completed the Floral Clock Student Data Sheet. Each group of students should compile summarystatistics for the group's eight plants. These statistics should then be entered in the chart below. From the Group Data chart, theclass data can be derived. This Class Data Sheet can be copied and submitted to the Wisconsin Fast Plants Program to be included ina compilation of statistics from other classes.

dap = days after pollination, n = number of measurements, r = range (maximum minus minimum), x = mean (average), s = standard deviation
53

Double Fertilization and

Post - Fertilization Events

Concepts Concepts

Fertilization is the event in sexual reproduction which follows pollination. In higher plants, two sperm

are involved in fertilization, reaching the ovule via a pollen tube from the germinating pollen grains.

One sperm fertilizes the egg cell within the embryo sac to produce the zygote and begin the new

generation. The other combines with the fusion nucleus to produce the endosperm, a special tissue

that nourishes the developing embryo. Fertilization also stimulates the growth of the maternal tissue

(seed pod or fruit) supporting the developing seed. In AstroPlants the fertilized egg cell develops

through various stages over the next 20 days until it becomes a mature quiescent embryo, the seed.

Questions Questions

• What is the effect of microgravity on fertilization and embryo development?

• Will the maternal parent be affected by microgravity? Will fruits develop?

Background Background

What happens between fertilization and seed harvest? After pollination, each compatible pollen grain

adhering to the stigma sends through the style a pollen tube which carries two male gametes (sperm)

to the ovule, where the egg and other cell nuclei are housed in the embryo sac. One sperm unites with

the egg cell (n) to produce a zygote (2n) which

becomes the embryo. The second sperm (n)

unites with the diploid fusion nucleus

(2n) to form the triploid endosperm

(3n), the energy source for the

developing embryo. This process

is known as double fertilization.

Within two to three days after

fertilization, the pistil begins

to elongate and swell to

accommodate the enlarging

ovules. The sepals and petals

wither and drop off, having

completed their functions.

Within the ovules, the embryos

differentiate and enlarge through

a series of developmental stages,

known collectively as embryogenesis.

Enlarging also within the ovule is

the endosperm. In the latter stages

of embryo development in brassicas,

the nutrient reserves in the endosperm

are used by the embryo and the space

that was filled by the endosperm is

occupied by the enlarging embryo.

compatable

pollen

papilla cells

of stigma

pollen tube

callose plug in

empty tube

embryo sac

(female

gametophyte)

ovule

endosperm

nucleus (3n)

zygote

nucleus (2n)

incompatable

pollen

empty pollen

grain

sperm nuclei

tube nucleus

ovary cavity

central cell with 2

polar nuclei which

fuse to give 2n

fusion nucleus

egg cell (n)

pollen tube

entering the

micropyle

male

gametophyte

(germinating

pollen)

compatible

pollen

papilla cells

of stigma

pollen tube

callose plug in

empty tube

ovule

endosperm

nucleus (3n)

zygote nucleus

(2n)

central cell with two

polar nuclei which

fuse to give 2n

fusion nucleus

tube nucleus

sperm nuclei

empty pollen

grain

germinating pollen

(microgametophyte)

incompatible

pollen

ovary cavity

egg cell (n)

pollen tube

entering the

micropyle

embryo sac

(megagametophyte)

vascular strands
54

In cereal crops, such as wheat, rice and corn, endosperm is not used by the enlarging embryo and

remains a major portion of the seed as a starchy energy source for the germinating seedling.

Through the development of the seed, the plant has solved the problem of packaging its new

generation to survive until favorable conditions for growth return. As the seed matures, the walls of

each ovule develop into a protective seed coat and the entire ovary becomes a fruit (seed pod). In

AstroPlants, embryos mature into seeds in 20 days after successful pollination.

Measuring Time on the Floral Clock Measuring Time on the Floral Clock

Introduction

One of the primary aspects of the questions that Dr. Musgrave and Dr. Popova are

asking relates to embryogenesis, the orchestrated sequence of developmental events

within the ovule and supporting maternal tissues that ultimately leads to the development

of a viable seed (see "Mission Information," page 92). The failure to produce significant

quantities of viable seed in past missions raises the question as to whether normal embryogenesis

is affected in microgravity. In order to ask this question, an understanding of normal embryogenic

events in AstroPlants is important.

Successful embryo and endosperm development is accompanied by rapid elongation and enlargement

of the pistil which serves as supportive nourishing maternal tissue. There is a strong interdependency

between the developing embryos, endosperm, ovule and maternal tissues of the pod: it is believed that

hormones produced by the developing embryos and endosperm regulate the growth and expansion of

maternal tissue (Stage G in the life cycle, page 12). When either embryo or endosperm fails in its

development, ovule development also ceases and pod enlargement may be slowed.

At the same time vigorous pod development supported by a healthy plant is necessary for the

developing embryo and endosperm in the ovule. Seed failure can result if the maternal plant comes

under excessive environmental stress, as from excessive heat, water stress or nutrient deprivation.

Fertilization in sexually reproducing organisms represents the onset of the next generation. Following

double fertilization in plants, the most visible event is the rapid wasting of all those flower parts which

are no longer needed by the plant. Sepals, petals and stamens wither and fall. Nectaries dry up. At

the same time, within a few hours of fertilization, the pistil with its complement of fertilized ovules

begins rapid development.

This activity provides students with an opportunity to follow the results of student pollination by

measuring the increasing length of the pistil at regular intervals until mature seeds are formed and

harvested. Upon harvest, viability of the seeds will also be tested. In Activity 6, students dissect pods

at various stages of development in order to investigate the stages in embryogenesis.

Students will discover and document what constitutes normal embryo development in AstroPlants

through observation and drawing. An important part of this investigation is to determine whether the

students results will correspond with the data from the B-STIC experiments.

Question: Question: What are the indicators of normal fertilization and post-fertilization development that follow

successful pollination?

Sample Hypothesis: Sample Hypothesis: Flower parts other than the pistil wither. The pistil enlarges to become a pod

containing developing seed. At maturity the pod and seeds dry. Viable seeds germinate.

A C T I V I T Y 5
55

Design

• At specified intervals following pollination, measure the length of the pistil, observe developing

embryos and endosperm and estimate the number of developing embryos. At maturity, harvest

seed and verify viability with germination test. As a control follow the development of pistils of the

unpollinated control plants.

• Students will record observations and measurements on the Floral Clock Student Data Sheet

(page 51).

Time Frame

A period of 36 days from the sowing of seed is required for the growth of the AstroPlants and the

completion of this activity. The time required each class period will vary according to the observations

or measurements being made. Time will be required on seven separate days through the course of

this activity, specified in the procedure.

Learning Objectives

In participating in this activity students will:

• learn to make observations and accurate measurements of pistil enlargement;

• understand the role of pollination and compatible pollen germination as a precursor to double

fertilization (Stage F, page 12);

• understand that following double fertilization a complex sequence of interdependent developmental

events occurs over a period of 20 days that results in the production of viable seed for a new

generation in the spiral of life (Stages F, G, H and I, page 12);

• understand the unique nature of double fertilization in higher plants in which embryo and

endosperm are interdependent specialized tissues within the ovule that function in normal seed

development (Stage G, page 12);

• understand the interdependent relationship of developing maternal tissue and developing fertilized

ovules (Stage G, page 12);

• understand that the development of a viable seed requires a healthy (environmentally nonstressed) plant during the period of growth in which the fertilized ovules are developing into seed.

Materials

• flowering AstroPlants, post-pollination

• dissection strips (page 23)

• fine scissors

• fine-tipped forceps and fine dissecting needles (e.g., tuberculin syringes with #23 or #25 needles)

• clear double stick tape

• 2 cm wide clear adhesive tape

• seed envelope

• glass microscope slide

• water and dropper

• sharp cutting blade

Procedure

1. At 3 dap (days after pollination) students will notice that the flower parts

that were important in pollination have withered and fallen from the plant.

- Using a dissection strip without tape as a ruler, carefully measure the

length of each expanding pistil, recording its length to the nearest

millimeter in the appropriate column of the Floral Clock Student Data

Sheet according to its position number. Remember the highest number

(4) is the most apical (top) flower.

stigma

receptacle

pistil

length
56

2. Repeat Step 1 at 6 dap and 9 dap.

3. Students will notice that the pods at 9 dap, in addition to elongating, have swollen around what

appears to be developing seeds or ovules (Stage H in the life cycle, page 12).

- Carefully hold the plants up to the light. Can you see the outlines of the developing ovules

within the pods?

- Estimate the number of developing seeds in each pod. Record the information on your Floral

Clock Student Data Sheet. At harvesting you will be able to verify your estimations by counting

the seed.

4. If students are not doing Activity 6 (embryo dissection), each pair may sacrifice one pod from one

of their plants in order to observe the developing embryos within the ovules at 9 dap.

- With two needles, hold and squeeze the first ovule, cutting into it with one needle. A tiny green

object should squirt out along with some cloudy material (the endosperm).

- With a hand lens or microscope, observe the object. Does it look like any of the illustrated

embryos on page 64? Which stage?

- If you didn't succeed with the first one, try another ovule.

- If you have a microscope, observe the ovule under higher magnification, then draw it.

- With a dropper place a very small drop of water over the ovules on the dissection strip.

- Proceed by choosing a pod in which several ovules are visible. Carefully snip it

off with a fine scissors.

- Cut the pod in half with a sharp blade and give one half to each student. Place

each half on the sticky tape of another dissection strip.

- Holding one end of the half-pod, use a

sharp needle to pry it open along its length

to expose the ovules which look like tiny

green grapes. With the needle or forceps,

detach two or three ovules from the pod

and place them in a cluster on the sticky

tape of the dissection strip. Put the pod

aside on wet paper toweling to stay fresh.

didissection needles ssection needle

water drop ovule

cut

pod

ovules

dissection needle

ovules

dissection needle

l

w

starchy en

green green embryo e

water drop

starchy endosperm

ovule wall
57

5. At 12 dap, repeat Step 1 and record the data on the Floral Clock Student Data Sheet.

- By this time, the plant's lower leaves may be starting to turn yellow or even wither and dry. This

is the normal succession in the life cycle of the plant, particularly if it is supporting a number of

pods with developing seeds.

- If a plant fails to develop any seeds, it will frequently remain green and continue to produce

flowers from side shoots developing in the axils of leaves. This should be the case in the

unpollinated control plants, if a plant has been severely stressed so that embryogeny has failed

or if it is genetically or phenotypically sterile (incapable of producing offspring).

6. At 21 dap, plants are now approaching maturity. Normally AstroPlants embryos have fully

developed by 18 to 20 dap, at which time stem and pods of the aging parent plant begin to turn

yellow along with the leaves and the seed coat begin to turn brown (Stage I in the life cycle,

page 12). This is the time that water can be withheld from the plants to encourage seed ripening.

- At 21 dap, students should take a final pistil length measurement.

- Empty the water from the reservoir and remove the capillary mats. Keep the plants under the

lightbank and let them dry.

7. In about a week, or when the pods are dry, harvest the seeds from each of

your pods onto separate loops of sticky tape. Record the plant and pod

number on the tape.

- Count and record the number of seeds for each pod on the Floral

Clock Student Data Sheet.

- Did the number of seeds in each pod agree with the estimates you

made at 9 dap?

- As you harvest, notice any unusual seed. If these are of interest

with you, tape them to a card where they can be examined or

germinated later.

- Two days later, record the seed viability on the Floral Clock

Student Data Sheet. On the data sheet, "+" indicates a viable seed

and "-" indicates a nonviable seed.

- Combine all the other seed in a bulk and store it in a seed or coin

envelope within a sealed container with indicator silica gel (drying

compound, see page 94). Seed stored dry and cool in a refrigerator

or freezer will stay viable for many years.

8. Take a sample of two seeds from each pod and test their viability in a bottle cap seed germinator

according to the instructions on page 75.
58

Concluding Activities and Questions

After setting the floral clock with the pollination activity (Activity 4), students have followed the course

of reproductive development by observing and measuring pistil enlargement and seed production and

completing the Floral Clock Student Data Sheet. Combine the student data into group data, and then

into a class data summary using the Floral Clock Class Data Sheet (page 52). See "CUE-TSIPS

Science and Technology" for a review of data analysis (page 18).

If available, use data analysis software to create graphical and statistical summaries of class data.

Notice how the various statistical notations (range, mean and standard deviation) change over time

from pollination. Have students consider the following:

- From a class frequency histogram and statistical summary, does the measured plant character of

pod length on a particular day exhibit a normal distribution within the class population?

- Do individual pod lengths for each day fall within one or two standard deviations of the class

mean? Do students consider their post-fertilization events to be normal? Why or why not?

- Are there any "abnormal" seeds? They may be tested for viability.

- From a graph of the average rate of increase in pod length over time, is there a period in postfertilization development in which the increase in pod length is fastest?

- Is there a relationship between the number of developing seed and pod length?

- How do graphs of pod length increase over time compare between the pollinated and unpollinated

sets of plants?

Classes can submit the Floral Clock Class Data Sheet for both experimental and unpollinated control

plants to the Wisconsin Fast Plants Program and then check the WFP World Wide Web site to see

where their plant growth data fit into the data set from the larger population of plants grown for CUETSIPS in the United States and Ukraine (see page for addresses).

Extension

For an activity investigating the role of plant hormones in the regulation of pod enlargement, write to

Wisconsin Fast Plants for "Hormone-Induced Parthenocarpy in Rapid-Cycling Brassica rapa."

i
59

A C T I V I T Y 6

vascular

nucellar tissue (region of strands

nutrient transfer from

maternal to endosperm)

cellular

endosperm

ndosperm

ns starch

at early

stick stage

days)

nteguments

ll layers)

integuments dry down to

form the seed coat (testa)

inner integuments

(several cell layers

aleuro

of end

conta

mic

sus

fun

aleurone

(outer layer of

endosperm, often

contains pigment)

Embryogenesis: Going for the Globular Embryogenesis: Going for the Globular!

Introduction

Following double fertilization, four complex processes are triggered. The ovary wall

and related maternal structures rapidly grow to become the fruit tissue (the pod)

surrounding the developing seeds. Each ovule within the fruit enlarges to accommodate

the developing endosperm and embryo. The various outer cell layers of the ovule (integuments)

eventually become the seed coat. Within the embryo sac, the triploid endosperm nuclei divides

very rapidly to form the nutrient-rich, starchy liquid endosperm. The liquid endosperm provides

nutrients to the developing embryo.

Since fertilization, the zygote has undergone several mitotic divisions. The first few divisions produced

a strand of eight cells known as the suspensor, which is attached to the embryo. The suspensor

orients the developing embryo within the ovule and is thought to serve as an “umbilical cord,” as it

passes nutrients from the endosperm to the embryo cells. The basal cell of the suspensor anchors the

developing embryo and orients the embryonic root tip near the micropyle, a hole in the integuments

where the pollen tube

entered. At the tip of the

suspensor, repeated cell

divisions give rise to the

very young globular

embryo (page 64).

Immersed in the nutrientrich endosperm, the

embryo develops rapidly.

By Day 7, the embryo

becomes flattened and

bilaterally symmetric with

two lobes which will

become the cotyledons.

This is the heart stage.

As its development

continues, the embryo

elongates into the torpedo

stage. At this stage the

embryo produces

chlorophyll and becomes

green. Elongation of the

embryonic hypocotyl

separates the root apical

meristem from the shoot

apical meristem, which is

hidden between the

embryonic cotyledons.

As the embryo enlarges it consumes space formerly occupied by the endosperm. To package the

enlarging embryo, the cotyledons fold around the hypocotyl, now curved within the ovule; this is the

walking stick stage. By Day 20, the walls of the ovule (the integuments) harden and become the seed

coat (testa) and the embryo within desiccates to become a seed (Stages I and J, page 12). As

maturation proceeds within the enlarged folded embryo, the starch reserves within the embryonic

cotyledons are converted to lipids as the final form of energy storage.

outer integuments

(4 to 5 cell layers)

nucellar tissue (region of

nutrient transfer from

maternal to endosperm)

vascular

strands

funiculus

Developing Brassica Ovule

inner integuments

(several cell layers)

micropyle

cellular

endosperm

liquid endosperm

(contains starch

grains)

embryo at early

walking stick stage

(Day 12 to 14)

integuments dry down to

form the seed coat (testa)

suspensor
60

There are many questions that remain unanswered in developmental embryology – perhaps you and

your students can answer some of them.

Questions

• What is the normal sequence of embryo development within the ovules of AstroPlants?

• Can your students identify the various stages in the developmental continuum from embryo to

mature seed?

• Can your students record, draw to scale and estimate the relative sizes of the embryo at various

stages of development?

Sample Hypothesis: Sample Hypothesis: Normal embryogenesis proceeds rapidly within the developing seed from a singlecelled zygote through recognizable stages of increasing size and complexity ending in a dried seed.

Design

* At specified intervals following pollination, remove embryos from ovules, draw to scale various

stages and measure embryo sizes. Construct a developmental chart of embryogenesis.

• Students will record observations and measurements on the Ovule and Embryo Student Data

Sheet (page 65).

Time Frame

A period of 36 days from the sowing of seed is required for the growth of the AstroPlants and the

completion of Activities 5 and 6. The time required for the embryogenesis activity will vary depending

on the amount of class time spent in dissecting embryos. A minimum of two 50 minute class periods

is recommended, one for students to practice and develop their dissection and drawing skills and one

or more to examine and record the stages of embryogenesis. The number of periods spent on embryo

dissection depends on the timing of the dissections students wish to make.

Learning Objectives

In participating in this activity students will achieve the learning objectives presented for Activity 5

(page 55). In addition, students will:

• learn to dissect embryos from ovules in developing pods, improving their hand-eye coordination;

• learn that embryogenesis is a continuum of development from a very small spherical group of cells

to a complex multidimensional, multicellular organism;

• learn how an embryo can enlarge within the limited confines of the ovule and become "packaged"

in preparation for desiccation and quiescence as a seed (Stage I of the life cycle, page 12);

• learn to make accurate descriptive observations of specimens under the microscope, draw carefully

"to scale," and record and analyze data obtained from the drawings;

• learn to construct a model embryonic development that can be compared to the development that

occurs in plants grown in microgravity.

Materials

• fresh or fixed pods of AstroPlants at various stages of development

- for a range of embryo stages suitable for initial dissection, ovules sampled between 6 and 12

days after pollination are best, these should provide stages between heart and walking stick

- after developing dissection skills, sample ovules from plants 3 to 6 days after pollination

- see page 98 for instruction on fixing pods

• dissecting microscope with 20 to 40X magnification

• fine-tipped forceps and fine dissecting needles (e.g., tuberculin syringes with #23 or #25 needles)

• dissection strips (page 23)

• 2 cm wide clear adhesive tape

• clear double stick tape

• fine scissors or cutting blade

• water and dropper
61

Procedure

1. At the desired day after pollination (dap), students should use fine

scissors to remove one pod from one of their two plants. Place the

pod on the sticky tape of the dissection strip aligning it longitudinally

on the scale.

2. Measure and make a drawing of the pod "to scale" in a lab notebook.

3. Using the dissection needles or a sharp blade, cut along one seam of

the pod where the two carpels are fused. Pry open the pod to reveal

the ovules aligned within the carpel; each ovule is attached to the

vascular strands by its funiculus. You will also see a thin paper-like

septum separating the ovules in each carpel.

4. Observe the opened pod with a hand lens or under a dissecting microscope. In a lab notebook,

make a drawing "to scale" of what you observe.

5. Remove an ovule from the opened pod with fine forceps or dissecting needles, keeping a portion of

the funiculus attached to the ovule. Then transfer the ovule onto the sticky tape on a dissection

strip. Measure and record the length of the ovule next to the first circle on the Ovule and Embryo

Student Data Sheet.

6. With a pipette, transfer a small drop of water to cover the ovule on the sticky tape of the dissection

strip. Alternatively a drop of iodine potassium iodide (IKI) staining solution (page 98) can be used

in the dissection, in which case any cells or tissues containing starch will turn blue or purple.

7. Place the opened pod with remaining ovules on moist paper toweling in a covered petri dish. This

will keep it fresh for further sampling.

8. Place the dissection strip under a dissecting microscope and observe the ovule, noting the

funiculus attachment and the micropyle.

- If the ovule is illuminated from below, students may be able to see the indistinct embryo within

the ovule. This will depend on the stage of embryo development.

ovules ovules

F

I

fun

e

ovule

micropyle funiculus

ovule

- Make a second incision perpendicular to the first and

using dissection needles gently pull open the integuments.

Embryos at 9 dap will generally be visible once the seed

coat is open.

niculus

ovule

9. With needles make an incision across the ovule at the

end opposite the funiculus. As this cut is made, the

embryo may float out into the water along with the

cloudy starchy liquid endosperm.

ovule

funiculus

SECOND

INCISION

FIRST

INCISION
62

INC

funic

em

ovule

en

integ

INCISION

embryo

funiculus

ovule

endosperm

integuments

INCISION

INCISION

- If the embryo is not visible, slowly and carefully

remove small pieces of the integuments,

working toward the micropylar end.

Young embryos in the heart and globular

stages are found surrounded by a funnel

of aleurone and nucellar tissue from the

torn embryo sac. The young embryo is

immersed in cellular endosperm and is

anchored by the suspensor in the

integuments at the base of the funnel.

- Continue to carefully tease out the

embryo and, if possible, its attached suspensor.

10. Once the embryo has been removed, students may wish to increase the magnification under the

microscope for viewing and drawing.

- Under an appropriate magnification, slide a second dissection strip under the one holding the

embryo in the water drop.

- Align the magnified image of the scale of the second dissection strip across the horizontal

diameter of the field of view of the microscope.

11. Draw in the magnified scale on the horizontal line of the first circle on the Ovule and Embryo

Student Data Sheet. Be as accurate as possible in the spacing between the scale marks.

- Draw a scale bar at the top or bottom of the circle representing the distance of 1 mm or some

fraction (0.5, 0.25, 0.1) of the magnified millimeter scaling. Indicate the distance represented

by the bar on the drawing.

12. Observe the embryo and accurately draw it to scale within the same circle as the scale bar.

13. Identify and record the stage of embryo development (globular, heart, torpedo, etc.).

- Either from the drawing or directly, measure and record the length of the embryo, excluding

the suspensor. Record the magnification of your microscope.

14. Calculate the magnification of the drawing using the following method:

- Measure and record the actual distance in millimeters between the two ends of the scale bar in

the circle of the drawing of the embryo (e.g., 21 mm).

- Divide this measurement by the distance in millimeters represented by the scale bar in the

circle to give the magnification of the scale bar and drawing (e.g., 21 mm/0.5 mm = 42X).

15. Dissect ovules from pods of different dap making drawings and length measurements of the

difference stages of development, using the remaining circles on the Ovule and Embryo Student

Data Sheet. If students have "spare" ovules at one developmental stage, they can share them

with other students or exchange them for ovules at different stages of development.

Suggested dissection times include 6, 9, 12 and 17 to 20 dap. If dissections are made in a

potassium iodide staining solution, note the presence or absence of starch in the ovule at

different stages.
63

Concluding Activities and Questions

In completing Activity 6, students will have taken their AstroPlants through a complete life cycle, from

sowing the seed on Day 0 to harvesting the seed for the next generation. Analyze the data taken on

the Ovule and Embryo Student Data Sheets. Have students consider the following:

- Students as a group or as a class may construct a developmental graph or chart depicting the dap

on the x-axis and the length of the embryo, size and stages on the y-axis, similar to what has been

done for the growth of AstroPlants on page 11.

- Students may use the embryo lengths of various developmental stages as a quantitative indicator

of development (page 64).

- How much does the embryo enlarge from the time it is a globular until it is mature?

- What are the relative sizes of the various stages in embryogenesis? With what will you compare

those sizes?

- In what stages of embryogenesis is the embryo enlarging most rapidly? What is your evidence?

- What becomes of the endosperm? Is there any stage in embryogenesis at which starch is not

present in the ovule?

Extension

The embryo dissection activity can also be performed using pods that have been harvested and "fixed"

in an acetic alcohol fixative on specified days after pollination. Fixed pods can be stored for future

use. See page 98 for an acetic alcohol fixative recipe and safety information.

Practice makes perfect . . . embryos!

Embryo dissection can be challenging for students, especially when the embryos are at

the early stages of development. Prior to beginning the dissection of your experimental

embryos, you and your students should practice dissecting embryos at different stages.

Have students plant several film can wick pots of AstroPlants, timed to be different ages the

day or two before your class begins its experimental dissections. Pollinate these plants well:

the more pods, the more practice!
64

*embryos not drawn to scale; sizes are samples, measured on embryos from wild type plants (AstroPlants embryos may be slightly smaller)

KEY

BC = basal cell C = cotyledon EP = embryo proper RAM = root apical meristem

SAM = shoot apical meristem S = suspensor TC = terminal cell

Z= zygote P = pro-embryo G = globular H = heart T = torpedo W= walking stick FS = full size

ZYGOTE

(Day 0)

2-CELL EMBRYO

T

B

FULL SIZE

EMBRYO

(Day 10-11)

WALKING

STICK

(Day 9)

EP

S

EARLY

PRO-EMBRYO

(Day 2) H

LATE

PRO-EMBRYO

(Day 3)

S

PC

PD

H

EARLY

GLOBULAR

(Day 4)

S

PC

PD

H

MID

GLOBULAR

(Day 4)

Day 4:

0.03 mm

Day 5:

0.047 mm

S

LATE

GLOBULAR

(Day 5-6)

Day 2:

~100 μm

Day 12:

0.967 mm

Day 10:

0.748 mm

Day 9:

0.446 mm

Z

P

G

H

T

FS

W

Embryo Development

in AstroPlants*

Day 8:

0.377 mm

Day 7:

0.1 mm

Day 7:

0.073 mm

C

H

PD

PC

S

S

EARLY HEART

(Day 6-7)

EP

S

EP

S

HEART

(Day 7)

EARLY

TORPEDO

(Day 7-8)

TORPEDO

(Day 8)

RT

S

SAM

PC

RAM

S

EARLY

WALKING STICK

(Day 8)

S

EP

TC

BC

Z

P

ZYGOTE

(Day 0)

S

EARLY

GLOBULAR

(Day 4)

S

Day 4:

Day 2: 0.03 mm

~ 100 μm

Embryo Development

in AstroPlants*

EARLY

PRO-EMBRYO

(Day 2)

EP

S

S

EP

LATE

PRO-EMBRYO

(Day 3)

S

Day 5:

0.047 mm

G

MID

GLOBULAR

(Day 5)

LATE

GLOBULAR

(Day 5 to 6)

Day 6:

0.073 mm

T

S

C

EARLY HEART

(Day 6 to 7)

Day 7:

0.1 mm

H

HEART

(Day 7)

S

EP

S

EARLY

TORPEDO

(Day 7 to 8)

TORPEDO

(Day 8)

S

EP

Day 8:

0.377 mm

Day 9:

0.446 mm

Day 12: Day 12:

0.967 mm

Day 10: Day 10:

0.748 mm

FS

W

WALKING

STICK

(Day 9)

EARLY

WALKING STICK

(Day 8)

S

RAM

SAM

TWO-CELL EMBRYO

FULL SIZE

EMBRYO

(Day 10 to 11)
65

Ovule and Embryo Student Data Sheet Ovule and Embryo Student Data Sheet

Student Name Date

dap

scale bar length

ovule length

stage letter

embryo length

magnification

 of drawing

magnification

 of microscope

dap

scale bar length

ovule length

stage letter

embryo length

magnification

 of drawing

magnification

 of microscope

dap

scale bar length

ovule length

stage letter

embryo length

magnification

 of drawing

magnification

 of microscope

dap

scale bar length

ovule length

stage letter

embryo length

magnification

 of drawing

magnification

 of microscope
66

Germination

Concepts Concepts

Germination is the awakening of a seed (embryo) from a resting state. It involves the harnessing of

energy stored within the seed and is activated by components in the environment.

In the metaphor of the mission, the seed is pointed in the correct position and ready for launch.

Germination, like launch, involves the bringing together of essential chemicals, hydrogen and oxygen,

to generate energy that will be directed toward expanding and propelling the two growing points of the

germinating seed outward (upward and downward if guided properly).

Questions Questions

• What are the main components of the environment necessary for germination?

• How does the germinating seed go about harnessing its stored energy and using the environment?

• How does a germinating seed 'know' which way to grow?

• What developmental events enable the emerging plant to shift its dependency from stored energy to

the energy from light?

Background Background

Germination is the beginning of growth of a plant from a previously dormant seed which contains the

embryo. Germination begins when the seed takes up water (imbibition) and the seed coat cracks.

An embryonic root (radicle) emerges from the seed and develops root hairs that bring in water and

nutrients. In AstroPlants, an embryonic stem (hypocotyl) elongates, pushing the seed leaves

(cotyledons) upwards through the soil. As they emerge from the soil the cotyledons expand. The

cotyledons serve as an energy source until true leaves form. These events happen on Days 1, 2 and 3

of the AstroPlants life cycle (see page 11). For germination to take place, water and oxygen are needed

and the temperature must be suitable.

With germination water is the "on" switch. Water taken up by the dry seed hydrates the cytoplasm,

activating enzymes, solubilizing substrates, loosening the structural fabric of walls and providing

pressure that enlarges the cells, resulting in expansion and growth. Oxygen, another essential

ingredient, combines

with hydrogen from the

stored oil reserves in the

embryonic seed leaves

and fuels the metabolic

combustion that powers

life processes. Rapid

development of the fine

root hair cells vastly

increases the surface

area of the root,

facilitating the uptake of

water that drives the

elongation of the

hypocotyl, which pushes

the seed leaves and

shoot meristem upward

through the soil.

H2O, O2, 22 ̊C, – light

seed

coat

soil level

Germination in Brassica rapa

0 HOURS 0.5 - 6 6 - 12 12 - 24 24 - 36 36 - 48

DRY SEED HOURS HOURS HOURS HOURS HOURS

seed

coat

light

soil level

H2

O, O2, 22 ̊C

Germination in AstroPlants
67

On Earth, orientation during germination is provided by gravity. Roots respond positively to gravity by

growing downward (positive gravitropism), while shoots respond negatively by growing upward

(negative gravitropism). Prior to emerging from the soil into the light, the germinating brassica

seedling is dependent on the energy reserves stored in the seed leaves. Seeds of other plant species

may also store carbohydrates, starch (cereals) or protein (legumes, beans).

Upon emergence from the soil and triggered by the light, the cotyledons expand, casting off the

protective seed coat, turn green and become photosynthetically active. At this point the "plant"

becomes independent of the stored reserves and dependent on the energy of light. Launch has been

successful! The solar panels (cotyledons) have been deployed. The future success of the mission

depends on keeping the panels oriented and operational to gather light energy which is converted

through photosynthesis to chemical energy for growth, flowering and reproduction.

The following activity will provide students with insight into the various stages of germination and give

them an introduction to the phenomena associated with orientation. Remember, one of the big

questions about the microgravity environment is: how will plants know which way to grow?

Getting Acquainted with a Seed Getting Acquainted with a Seed

Introduction

In this activity students become acquainted with the anatomy and biology of seeds.

They will use lenses and scales and make drawings to scale. Students will measure

and calculate magnifications and they will begin to understand relationships among these.

They will organize and summarize their data and, as they do so, they will be developing the

understanding and skills needed to undertake more detailed investigations on the reproduction of

AstroPlants in space.

Questions

• On a seed, which way is up?

• Does a seed “know” which way to grow? If so, how does a seed “know” which way to grow?

• When planting a seed, is there a best way to orient the seed?

• In microgravity is there a best way to orient the seed?

Time Frame

This activity will take two or more 50 minute class periods. During the first period students will make

a dissection strip and become familiar with its use in conjunction with magnifying lenses and

microscopes for observing, measuring and recording data from seeds. The dissection, organization,

analysis and discussion of student and class data could take another period. Further periods can be

spent graphing and statistically analyzing data.

Learning Objectives

This activity is designed to strengthen students' observational and quantitative skills. In participating

in this activity students will:

• learn to use magnifying lenses, microscopes and dissecting tools for detailed observation;

• measure scales with rulers;

• draw to scale, with accuracy and precision to understand scale and magnification;

• learn features of the external anatomy of seeds that are associated with certain features of the

internal anatomy of seeds; and

• estimate the amount of water required to be taken up by seeds in order to initiate germination.

A C T I V I T Y 7
68

Materials

• dissecting microscope with 20 to 40X magnification

• two dissection drawing cards with two 50 mm circles (page 99)

• two dissection strip (page 23)

• fine dissection needles, e.g., tuberculin syringes with #23 or #25 needle, or #8 sewing needle

• forceps to handle seed

• pencil with eraser for sketches

• Student Seed Data Sheet (page 72)

• Class Seed Data Sheet (page 73)

Procedure: Comparing Size edure: Comparing Size edure: Comparing Size dure: Comparing Size ure: Comparing Size

1. Have students place a pinto bean and a brassica seed (or other similar sized seed) on the sticky

tape on a dissection strip. Roll them around until they are over the millimeter scale oriented with

the long axis along the scale.

2. Measure to the nearest half or quarter millimeter the length of each kind of seed and record each

estimate as a decimal (e.g., 6.25 mm). Record the measurements in Row 1 on the Student Seed

Data Sheet (SSDS), with the brassica in Column 1 and pinto bean in Column 2. Enter these data

in Rows 1 and 2 of the Class Seed Data Sheet under the appropriate student column number.

- Calculate what fraction of the pinto bean length is the

brassica seed length. Enter the result on SSDS, Row

2, Column 1 as a fraction.

- Calculate how many times longer the pinto bean is

than the brassica seed. Enter the result on SSDS,

Row 2, Column 2 as a decimal.

- Proceed as if both seeds are spherical with diameters

equivalent to their lengths and calculate their

volumes. Enter the volumes on SSDS, Row 3,

Columns 1 and 2.

- Express the volume of the brassica seed as a decimal of the volume of the bean on SSDS, Row 4,

Column 1. How many times larger in volume is the pinto bean? Enter this number on SSDS,

Row 4, Column 2.

3. Place a film can magnifier or hand lens over the seeds and the scale.

- Observe and re-measure the magnified images of the length of each seed, estimating to the

nearest quarter millimeter.

- Record the lengths on the SSDS under Row 5, Columns 1 and 2 for magnified measures. Also,

record these lengths in Rows 3 and 4 of the Class Seed Data Sheet under the appropriate

student column number. Note on the SSDS, Row 5, the magnification of the viewing lens.

- With the aid of a magnifier, were students able to measure the seed more accurately? Describe

in writing why you were or were not.

• two brassica seeds or any other similar-sized seed (e.g., turnip, alfalfa or lettuce), one set

that has been presoaked in water for 1 to 3 hours, then placed on moist paper towel

• two pinto bean seeds, one dry and one presoaked for 4 to 12 hours

• 5X hand lens

"From the leaves and downs,

and beards of plants,

we come at last to the seeds;

and here indeed seems to be

the cabinet of nature,

wherein are laid up its jewels..."

- Robert Hooke, 1667
69

Procedure: Orientation of the Seed — Which Way is Up?

1. While each seed is on the dissection strip, roll it around with a needle or pencil point and observe

its shape and features.

2. Can students determine which way is up on the seed?

For this a point of view is needed.

- On Earth bottom is usually directed down or in the

direction of the gravitational force (toward the center

of the Earth). Up is opposite.

- Front can be arbitrarily determined as that view

which presents most visible detail. Can students find

the front of their seeds?

side front

side back

bottom

top

side

Procedure: Drawing to Scale — Measuring and Magnification

1. With the seeds still on the dissection strip and using a hand lens or film can magnifier on the

dissection strip, align the millimeter scale across the horizontal diameter of the circular field of

view of the lens.

- Encourage students to relax, have them keep both eyes open, but training their eye and brain to

concentrate on the scale and the seeds. This will take some practice.

2. Using the left circle on the first dissection card, with a sharp pencil lightly sketch in the magnified

scale on the horizontal center line of the circle. Encourage students to be as accurate as possible

in drawing and spacing the millimeter scale marks (see page 74 for a sample dissection card).

- Now near the bottom of the circle draw a line or scale bar that is the length or

some fraction of the length between two magnified millimeter scale marks (e.g.,

10 mm, 1 mm, 0.5 mm, etc.). Indicate on the scale bar and on the card the

length represented by the scale bar.

3. Students should make an accurate drawing to scale of the front view of the brassica seed,

recording as much detail of the hilum and surrounding area as they can observe.

4. Now roll the brassica seed around on the tape. With the aid of a

magnifier, a darker circular area with a small lighter area in it

will be seen. This is the remains of the funicular attachment.

5. Looking at the front view of the seeds, can you tell which

direction is up and which is down?

- To answer this question students will need to observe and

record details of their seeds under greater magnification using

the dissection strip, a microscope and a dissection card for

drawing to scale, estimating object sizes and calculating the

magnification of the drawing.

hilum or

funicular scar

brassica

seed

bean

seed

3. On the pinto bean, a distinctive oval light area on the seed coat will be observed. This is the hilum

and is the scar where the developing seed was attached through the funiculus (like an umbilical

cord) to the maternal tissue of the carpel or ovary. If the hilum is facing you, this is front.

hilum or

funicular scar

BRASSICA

SEED

top

front

side back

bottom

1 mm

PINTO

BEAN
70

- On the dissection card note:

- the object (e.g., the pinto bean)

- the magnification of the lens (e.g., 5X, 10X, etc.)

- the length represented by the scale bar (e.g., 1 mm, 0.5 mm, 0.25 mm, etc.)

- the actual length of the scale bar in millimeters

- an estimate of the length of the seed in decimal fractions, and

- a calculation of the magnification of the drawing from the scale bar measures.

4. Repeat the same procedure with the pinto bean on a second dissection card.

5. Now with the same seeds, place the strip under a dissecting microscope or lens with magnification

between 10X and 40X.

- On the second circle of each dissection card, repeat the accurate drawing of the magnified

millimeter scale and seeds and note how enlarged the scale marks have become.

- In estimating the dimensions of the seeds, measure from the centers of the scale marks.

- At the higher magnification, not all of the pinto bean will

fit into the field of view. In this case, just draw to scale

the details of the hilum area, observing the location of the

micropyle, a minute hole in a depression at one end of the

hilum and opposite the end with two small raised pearshaped structures.

The micropyle is the hole in the ovule integuments

through which the pollen tube passes on its way to

double fertilization of the egg and polar nuclei (see the

illustration on page 53).

6. Still using the higher magnification, students should complete the drawings of the scales and

seeds in the right-hand circles of the two dissection cards.

- Students should calculate the magnification of their drawings.

- Students should enter the estimated length of their brassica seed measured from their drawing

at the high power magnification on the Student Seed Data Sheet, Row 6, Column 1, indicating

the magnification of the lens used, and on the Class Seed Data Sheet, Row 5.

be

kened

wn area

ular m

bra

BRASSICA

SEED

The micropyle is also the weakest area in the

seed coat, or testa, which splits under pressure

from the emerging root tip.

In brassica seeds, the micropyle is less

conspicuous than in the bean, but appears as a

minute raised area adjacent to the darkened

circular area of funicular attachment.

funicular

scar

darkened

brown area

micropyle

micropyle

hilum

field of view

PINTO BEAN
71

Procedure: On the Front View — Which Way is Up?

1. Returning to the question of which way on the front view of the seed is up, take a pinto bean and a

brassica seed that have been soaking in water for one to four hours. Dry off the excess water and

place them on the dissection strip next to the dry seeds that have been measured.

2. Observe, measure and record the length of each soaked seed on the Student Seed Data Sheet, Row

7, and on the Class Seed Data Sheet, Rows 6 and 7. Then, as with the dry seeds, calculate the

volumes and enter them in SSDS, Row 8, Columns 1 and 2.

3. Calculate the average volume increase of the brassica seed upon soaking. Enter this calculation in

the SSDS, Row 9, Column 1. Repeat for the pinto bean and enter the calculation in the SSDS,

Row 9, Column 2.

- What causes the increase in seed volume? Is the increase in seed volume due entirely to water

uptake (imbibition)? How can this question be tested?

4. Under magnification examine the front views of the soaked seeds, comparing them with the

drawings of the dry seeds. Has anything changed? Can the hilum and micropyle still be seen?

5. Keep the location of the micropyle of the soaked pinto bean in view. With a sharp dissection

needle cut through the testa around the hilum, peeling back the seed coat to expose the white or

pale cream embryo. As this is done students will see the rounded tip of the embryonic root

pointing towards the micropyle. Make a front view drawing of the embryo in the orientation with

root tip pointing down.

Concluding Activities and Questions

In completing Activity 7, students will have made detailed observations of seeds which will provide

them with further insight into plant biology and prepare them for further experimentation, including

Activity 8, "Launching the Seed." If available, use data analysis software or a calculator to create

graphical and statistical summaries of student and class data. Have students consider the following:

- How much variation was measured among the lengths of the pinto beans? Or of the brassica

seeds? Is the variation distributed normally?

- Does the measurement of data differ when gathered from the unaided eye, with the assistance of a

magnifier or from a drawing? How do measurement data differ when gathered by each method?
72

Row Character/Activity Character/Activity Column 1 Column 1 Character/Activity Character/Activity Column 2

1 Length of dry brassica seed as Length of dry pinto bean as

measured by eye (mm) measured by eye (mm)

2 Ratio of brassica seed length to Ratio of pinto bean length to

pinto bean length (fraction) brassica seed length (decimal)

3 Brassica seed volume, assuming Pinto bean volume, assuming

seed is spherical (mm3) bean is spherical (mm3)

4 Ratio of brassica seed volume to Ratio of pinto bean volume to

pinto bean volume (decimal) brassica seed volume (decimal)

5 Length of dry brassica seed Length of pinto bean as measured

as measured with X lens (mm) with X lens (mm)

6 Length of dry brassica seed from

 X drawing (mm)

7 Length of soaked brassica seed (mm) Length of soaked pinto bean (mm)8 Volume of soaked brassica seed, Volume of soaked pinto bean,

assuming seed is spherical (mm3) assuming seed is spherical (mm3)

9 Increase in brassica seed volume Increase in pinto bean volume

caused by soaking (percentage) caused by soaking (percentage)

Date Seed Types: Column 1: brassica or other similar-sized seedStudent Name Column 2: pinto bean

Student Seed Data Sheet Student Seed Data Sheet
73

DateTeacher Name

Class Seed Data Sheet Class Seed Data Sheet

Student Data** Student Data** Statistics

Row Measurement* Measurement* 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 n r x s

1 Length of dry brassica seed

(SSDS Row 1, Column 1)

2 Length of dry pinto bean

(SSDS Row 1, Column 2)

3 Length of dry brassica seed

measured with X lens(SSDS Row 5, column 1)

4 Length of dry pinto bean

measured with X lens(SSDS Row 5, Column 2)

5 Length of dry brassica seed

from X drawing(SSDS Row 6, Column 1)

6 Length of soaked brassica

seed (SSDS Row 7, Col. 1)

7 Length of soaked pinto

bean (SSDS Row 7, Col. 2)

* these measurements were recorded on the Student Seed Data Sheet in the Row and Column indicated, and should be transferred to the

appropriate Student Data columns

** this Class Seed Data Sheet will hold data from up to 16 students
74

Sample dissection card recording observations and measurements made on brassica seeds.

complete items

below:

magnification

of lens: X

length represented

by scale bar:

 mm

actual length of

scale bar:

 mm

estimated length

of object:

 mm

calculated

magnification of

drawing:

=

= X

Dissection Card

Name Date

1. Draw a magnified scale on the horizontal axis

of the field.

2. Accurately draw scale bar

indicating length.

3. Draw the object in view

to scale.

Object is:

1. Draw a magnified scale on the horizontal axis

of the field.

2. Accurately draw scale bar

indicating length.

3. Draw the object in view

to scale.

complete items

below:

magnification

of lens: X

length represented

by scale bar:

 mm

actual length of

scale bar:

 mm

estimated length

of object:

 mm

calculated

magnification of

drawing:

=

= X

Object is:

50 mm 50 mm

Willy Doit 8 - 6 - 96

brassica seed

5

10

14

1.5

14 / 10

1.4

brassica seeds

seed micropyle

scale marks

scale bar

14 / 1

1.6

14

14

1

30

Launching the Seed Launching the Seed

Introduction

From the activity "Getting Acquainted with a Seed," students found that on brassica

seeds the tip of the embryonic root points down toward the micropyle, near a darkened

circular area on the seed coat associated with the attachment of the seed to the maternal

ovary by way of the funiculus. Follow the steps below to begin to explore the interaction of

germination and orientation.

Question: Question: Question: For a brassica or other seed, which way is down? Or up?

Sample Hypothesis: Sample Hypothesis: The dark spot near the micropyle is down – brown is down.

Sample Null Hypothesis: Brown is up.

Design:

• Germinate seeds oriented in different directions. Observe and record initial and later direction of

root emergence from seed. Alter orientation of seedlings, predict, observe and record responses.

• Observations are recorded on the "Launching the Seed Student Sketch Sheet," (page 77).

A C T I V I T Y 8

10 mm

scale bar

seeds

1 mm
75

• Design Tip: You may want to begin this activity on a Monday, so that your germination will occur

during the week when students can make observations. Alternatively, students may set it up and

observe it at home.

Time Frame

Students will be able to construct their seed germinator and place their seeds within one 50 minute

class period. This activity is designed for the student to observe their germinators over a two to three

day period. Data are collected as drawings and a written discussion. Time for observations should be

five to ten minutes on each of three consecutive days.

Learning Objectives

In participating in this activity students will:

• determine whether their understanding of seed anatomy from Activity 7 is correct and their

hypothesis regarding seed orientation is verified, namely that the micropyle is the down orientation

in brassica seeds; and

• understand that plant roots reorient in the direction of their growth to conform with the direction

of the gravitational force.

Materials

• two soda bottle caps (film can lids will also work)

• kitchen plastic wrap

• paper toweling

• four brassica or other similar-sized seeds (lettuce, turnip, or alfalfa)

• forceps for handling seed

• hand lens

• elastic band

Procedure

1. Cut two layers of paper towel into circles that will fit into the bottom of a soda bottle cap.

2. Place the towel in the cap and moisten it with water. Pour off any excess water.

3. Orient the four seeds in north-south-eastwest positions on the moist towel surface,

making sure that the brown micropyle area

(spot) is pointing toward the center of the cap

(Figure 1).

4. Make a mark on the bottle cap that indicates

the direction of north, or up.

5. Cover the open cap with plastic wrap and

secure the wrap with an elastic band. Trim

off excess wrap with scissors.

6. Position the "bottle cap seed germinator" so

the seeds are in a vertical orientation by

standing it in a second bottle cap (Figure 2,

page 76).

7. Make a drawing of the seeds in the bottle cap germinator, including the orientation of the brown

micropylar area toward the center of the circle. Use the "Circle 1" on the Launching the Seed

Student Sketch Sheet.

p

paper

l

70 ̊,W

w

90 ̊,

360 ̊/0 ̊,N

soda bottle

cap stand

seeds with

micropyles

pointed to center

mark for North

wet paper

towel

270 ̊, W 90 ̊, E

180 ̊, S

360 ̊/0 ̊, N

Figure 1: Figure 1: Front view of bottle cap seed germinator. Figure 1: 

soda bottle

cap
76

8. If students carry their bottle cap seed germinator

home with them, they can observe it every few

hours. Be sure to keep it in the vertical position

with the proper north-south-east-west orientation.

9. When the roots begin to emerge, record the

direction of the emerging root from each seed with

a second drawing on the Sketch Sheet (Circle 2).

You may wish to use a hand lens.

10. Continue to observe the germinating seeds being

sure that the paper towel is kept moist. Note

the appearance of the fine, fuzzy root hairs and

the extension of the hypocotyl.

11. After 24 to 48 hours, make a third drawing depicting the direction of the roots and hypocotyl

and illustrating the root hairs, cotyledons and seed coat (Circle 3).

12. Then reorient your bottle cap seed germinator in some way that will give you more information

on seed orientation. Make another drawing that predicts how the seedlings will look after 12 or

24 hours in this new orientation (Circle 4). Observe them from time to time – do you notice

anything happening?

14. Twelve or 24 hours after reorientation, draw the seedlings on the Sketch Sheet (Circle 5).

Has anything changed? Compare the outcome of the orientation with what you predicted in your

last drawing.

15. Have students write about what they have learned on the Sketch Sheet.

Concluding Activities and Questions

In this activity students will have observed the effects of the Earth's gravity in reorienting the direction

of roots in the direction of the gravitational force. They will also have observed that shoots orient

against the direction of the gravitational force, bending and growing upward. This should raise a

discussion around the questions:

- In microgravity which direction will roots and shoots grow?

- Is there a guiding force for root growth in the absence of gravity? Could you generate a hypothesis

and experiment to carry this question farther? Hint: What would happen if you ran this

experiment on a centrifuge?

- What might be the possible influence(s) of light in this experiment?

see

wet

sosoda bottle cap d

soda bottle

cap stand

seed

Figure 2: Figure 2: Side view of bottle cap seed germinator. Figure 2: 

wet paper towel

elastic band

clear

plastic

wrap
77

Launching the Seed Student Sketch Sheet Launching the Seed Student Sketch Sheet

Circle 1: Circle 1:

Sketch

and

label your

bottle cap

seed germinator

at time of placement of seeds.

Circle 2: Circle 2:

Sketch

and

label your

bottle cap

seed germinator

as the roots emerge from the seeds.

Circle 3: Circle 3:

Sketch

and label

your bottle

cap seed

germinator 24 to

48 hours after placement of seed.

Circle 4: Circle 4:

Sketch

and label

your bottle

cap seed

germinator with

your prediction of the effects of

reorientation on your seedlings.

Circle 5: Circle 5:

Sketch

and label

your bottle

cap seed

germinator 12 or

24 hours after reorientation to

compare with sketch in Circle 4.

Write about what you have learned about germination and orientation.
78

Orientation and Guidance

Concepts Concepts

Rooted in the ground, plants, unlike most animals, are unable to relocate themselves in their

environment from their fixed position. They are, however, capable of movement and of orienting

themselves so as to optimize their capacity to access the environmental components essential to their

life. Plants orient themselves to light and gravity through tropism. Plants use guidance systems which

sense and respond to gravity (gravitropism) ensuring that roots anchor plants and access water and

that shoots emerge into the light. Plants then use light to activate energy-capturing photosynthesis.

Light also guides the development of leaf expansion (photomorphogenesis), stem bending and

elongation (phototropism), and pigment production (chlorophyll and anthocyanin).

Questions Questions

• How does a seedling orient itself?

• How does a plant grow up?

• Why does the shoot grow up and the root down?

Background Background

Plants like many other organisms, including humans, use both gravity and light to provide them with

orientation and guidance in their environments. Rooted in the ground, plants are unable to move, but

they are able to grow and bend toward or away from various stimuli in what is known as tropism.

Roots exhibit positive gravitropism and shoots negative gravitropism. Whereas shoots are also

positively phototropic (bend or grow toward a source of light), plants and humans rely heavily on

gravity for orientation. We are especially aware of the verticality of our orientation as we lean forward

or lift a heavy object.

The perception of the horizontal is mostly afforded us by light through sight. Our awareness of a

horizon provides us with an essential sense of where we are in space. Just shut your eyes for a few

moments and you come to realize how important 'horizontality' is to our orientation. The effects of the

horizon on your sensory stability can be best experienced in movies of stunt aircraft flights or on roller

coasters where the horizon is constantly changing. In the absence of sight, gravity and other sensory

systems (sound, smell, touch) provide compensation in our orientation.

In the absence of light, plants rely on gravity for orientation. This leads to an interesting question for

plant biologists: in the environment of microgravity and in the absence of light, are there other ways

that a plant can become oriented? This and other questions will be under investigation in the CUE.

In the microgravity of the orbiting Space

Shuttle, humans and plants do not perceive

the force of Earth’s gravity. Astronauts and

cosmonauts orient visually on the many

structures within the orbiter. In space,

plants also must orient using light. Just

how plants orient themselves to the light is

still under intensive study by plant

physiologists. Perhaps the best place to do

such studies on phototropism is in the

Space Shuttle and on the International

Space Station, where the confounding influence

of gravity as a guiding force is minimized.

"...[in plants] we know that there is always movement

in progress, and its amplitude, or direction, or both,

have only to be modified for the good of the plant in

relation with internal or external stimuli."

- Charles Darwin,

The Power of Movement in Plants, 1880
79

Seedlings of various plants, including AstroPlants, are excellent model organisms with which to

investigate the influence of light on tropic bending. As presented in the section on light in

"Understanding the Environment" (page 13), visible light includes a spectral range of wavelengths from

400 nanometers to about 750 nanometers, ranging from ultraviolet through blue, green, yellow,

orange to red. Plants use different colored molecules to capture various wavelengths and use that

energy for different functions, including photosynthesis, phototropism, and photomorphogenesis.

Complex biochemical processes known as signal transduction pathways translate the energy

transferred from light into various physical and physiological manifestations of growth and

development.

The gravitropic response in plants is conditioned by a signal transduction pathway that is thought to

be largely controlled by a group of growth promoting hormones called auxins, and by inhibitors of

auxins. When a plant is turned on its side, auxins stimulate elongation in the cells on

the lower side of the shoot, causing it to bend up (against gravity), but in the roots,

cells on the upper side elongate causing the roots to grow down (with gravity).

In phototropism, an unequal distribution of auxins

and inhibitors on the side of the plant away

from the light stimulates cell enlargement

on the "dark" side of the plant and results

in the plant bending toward the light. Much

has yet to be learned about how the force of

gravity actually acts in the mechanism of tropism in plants.

In Activity 8 on brassica seed germination (page 67), students will have observed the strong combined

influences of gravity and light on seedling orientation and growth. However, the relative roles of each

of these environmental factors on the direction of seed growth were not clearly defined. To approach

this challenge, it will be necessary to separate experimentally the influences of each factor, light and

gravity, on tropic responses. The following activities on gravitropism and phototropism will help

students to understand how plants orient themselves and also how complex the interpretation of

experiments into tropism can become.

Gravitropism: Gravitropism: Gravitropism:

How do Plants "Know" Which Way to Grow? How do Plants "Know" Which Way to Grow?

Introduction

This activity utilizes the "film can gravitropism chamber" in just one of many experiments

that can be designed to answer a large number of questions that students may ask relating to

the question: How do plants “know” which way to grow?

Begin by making the assumption that on Earth, in the absence of light, plants sense and respond

(orient) to the gravitational force of 1 g (unit gravity).

Question: Question: Question: How responsive is the germinating seedling to Earth's gravity?

Sample Hypothesis: Sample Hypothesis: The AstroPlants seedling hypocotyl will respond rapidly and continuously,

exhibiting negative gravitropism at least over a 72-hour period.

A C T I V I T Y 9
80

Design

• Seeds are germinated in the dark over several days and are observed and measured for their

directions of growth. At specified intervals of time, orientation is altered progressively by 90 ̊ of

rotation through 360 ̊ of rotation.

• At each orientation, growth response is recorded on the Gravitropism Data Sheet (page 85).

• The experiment is designed so that it can be run either at home or in class.

Time Frame

Construction of and placing seed within the film can gravitropism chamber will require one 50 minute

class period. Observation and data taking will require time on the day of chamber construction and

the two following days, approximately 15 minutes per day at specified intervals.

Learning Objectives ning Objectives ing Objectives ng Objectives ng Objectives

In participating in this activity students will:

• learn that seedling hypocotyls (shoots) orient strongly in the direction opposite to the direction of

the force of gravity;

• understand that the tropic response in seedlings is rapid and occurs in the absence of light;

• construct a simple piece of experimental equipment from low-cost materials; and

• develop spatial-temporal skills by predicting what seedling orientations will be in each of the four

positions of the film can gravitropism chamber at each reorientation.

Materials (per group of four students)

• 35 mm black film can with lid

• two extra film can lids

• clear double stick tape or double stick mounting tape

• white masking or lab tape, 2 cm wide

• four grid strips, 0.5 cm x 4 cm pieces cut from millimeter square graph paper photocopied onto

overhead transparencies

• four wick strips, 1 cm x 4.5 cm strips of soft paper toweling

• one floral foam disc, 28 mm diameter, 2 to 4 mm thick

• four brassica or other medium-sized seeds (turnip, lettuce or alfalfa)

• water bottle

• forceps to handle seed

• ultrafine permanent black marker

Preparation

• Making grid strips:

- Photocopy millimeter square graph paper onto an overhead transparency sheet.

- Cut the sheet along the lines to make strips with the dimensions 0.5 cm x 4 cm.

- Grid strips can be reused after rinsing, soaking for 20 minutes in a 20%

bleach solution, then rinsing again and drying on paper toweling.

• Making wick strips:

- Fold a square sheet of kitchen paper toweling to form an

eight layered rectangle.

- With scissors, trim end and folds to make a rectangle with

the dimensions 4.5 cm x 10 to 12 cm.

- Cut wick strips from the rectangle by cutting 1 cm strips.
81

• Making germination strips:

- Hold a wick strip with a grid strip aligned on top of it. Moisten the wick strip.

- As the wick strip becomes moist through capillary

action, the grid strip will adhere to it through the

adhesive forces of the water. Together the wick and

grid strip make a germination strip.

- The wet germination strip will adhere to the inner wall of the film can gravitropism chamber.

• Making plastic seed forceps:

- Cut a strip 1 cm x 10 cm from a piece of the flat side of a heavy plastic food or detergent bottle.

- Bend the strip in half and crimp the fold lightly between your thumb and forefinger.

- With scissors, trim edges to points of desired taper and precise alignment.

- Place a triangle of electrical tape on the inner surface of one of the forceps tips by taping on a

square and trimming of the excess tape with scissors. The tape will cushion the seeds and

prevent them from slipping from the forceps.

blac

elec

black vinyl

electrical tape

• Making floral foam discs:

- Prepare discs by cutting foam cylinders with a Fuji® brand "film can foam cylinder cutter" created

by cutting off the bottom of a Fuji® film can and beveling the outside edge with a knife.

cut outside

bevel with

knife

cylinder

cutter

cylinder

cutter

It is important to use clear Fuji® film cans for

this step because the foam cylinders and

foam discs will have a diameter of 28 mm

required to fit inside the tropism chamber.

- Cut foam cylinders by carefully pressing the cylinder cutter

completely through a dry floral foam block.

- With a flat knife slice discs of foam 2 to 4 mm thick

from the cylinders.

cut outside

bevel with knife
82

270 ̊ 90 ̊

0/360 ̊

NT W270 ̊ 90 ̊E

ilm can

d f f

Procedure

1. Each student or group of students should

construct a film can gravitropism chamber.

- On each extra film can lid place a 3 cm strip of

double stick tape and then attach the lids to the

outside wall of the film can so that each lid is

opposite the other.

- Mark the film can using an ultrafine tipped

permanent marking pen to draw arrows on the

film can lid and one of the mounted lids as in

Figure 1 to indicate "FRONT".

- With the front facing you, stick a white label on

the right side of the chamber and draw a

compass on the label, marked with angles of

0 ̊/360 ̊, 90 ̊, 180 ̊ and 270 ̊, corresponding to

north, south, east and west (Figure 2).

- As indicated in the right side view drawing of

Figure 3 (page 83), put in arrows indicating a

counterclockwise direction or rotation.

2. Place the floral foam disc in the bottom of the

film can.

3. With a water bottle, add enough water to

saturate the floral foam and just a little more

free water in the bottom.

4. Dip the end of a germination strip into the

bottom of the can, touching the water until it

wicks up some of the free water.

- Align the germination strip vertically inside

the film can, with grid strip against the inner

wall and the wick strip overlapping it and

adhering to the wall.

- You may tilt the film can to encourage the free water to ascend the wick strip and speed the

adhesion of the wick to the wall.

5. Align the germination strip with the front orientation of the chamber. At this stage you may let the

strip extend above the rim of the film can chamber.

6. Repeat the procedure with the other germination strips, aligning them to create four strips

opposite each other aligned at 90 degree angles, as illustrated.

7. Now remove one strip pair from the chamber and with your finger or using seed forceps to pick up

one seed, place it about 2 cm down the strip. The seed will adhere to the wet paper towel.

8. With a forceps or a pencil point align the seed so the micropyle points down (this hinges on what

was learned in the Activities 7 and 8).

FRONT

film can lid

FRONT

floral foam

Figure 1: Figure 1: Front view of film can gravitropism chamber. Figure 1: 

film can lids

seeds on

germination

strips

white lab tape

with markings

showing

direction of

chamber

rotation

film can lid

film can lid

270 ̊ W 90 ̊ E

N

0/360 ̊

180 ̊

S

floral foam disc

with water

Figure 2: Figure 2: Side view of film can gravitropism chamber. Figure 2: 
83

3.

2. 4.

1.

FRONT

10. Replace the strip with seed to its original

position in the can, but this time push the

germination strip down so that the bottom

of the wick strip connects with the wet floral

foam disc and the top of the strip is below

the rim of the film can chamber. It is critical

that the top is below the rim, or when the

chamber is closed, the moisture from inside

will "wick" out of the can.

11. Repeat steps 8 to 10 until all four seeds are

on the four wick strips in the chamber.

12. Make a final check on the amount of water

in the bottom of the chamber.

- If there is excess free water, gently tip the

chamber and let the extra water drip out, making sure not to wash off the seeds.

13. Gently place the film can lid on, sealing the chamber. Be sure that the arrow on the lid is

aligned with the arrow on the front cap of the chamber.

- As indicated in Figure 3, each strip has a numbered position, 1 to 4: 1 is front, 3 is back, 2 is

left and 4 is right.

14. Put a white tape label on the top lid of the film can with the following information recorded: your

name, the date (e.g., 10-1-97), the time on a 24 hour clock (e.g., 13:00 hours), and the symbol

"0 ̊" indicating the initial orientation of the chamber (upright). Add the information from the

chamber label into the first three columns on the Gravitropism Data Sheet. Germination in the

absence of light has begun at hour zero.

15. Place the chamber in the upright, 0 ̊/360 ̊ position, where a relatively uniform temperature

between 22 ̊C and 30 ̊C can be maintained. Under your light bank is ideal.

16. Be prepared to observe your chambers every 12 to 24 hours, noting any elongation of the

seedling hypocotyls.

- When the seed and seedlings are observed, keep the lid open only for as long as necessary.

- If a seedling has fallen off of its wick strip, it may be placed back gently, picking it up with a

forceps. If a seedling's root is growing off of the wick strip, it can be gently pressed to the wick

where its root hairs will attach firmly. If it looks like more water is needed, add a few drops to

the foam disc.

17. Sometime between 24 and 48 hours, depending on the temperature, the seedling hypocotyls

will be between 1 cm and 2 cm long. Make a drawing of the vertical seedling on each strip in the

appropriate box in the first row of the Gravitropism Data Sheet. Record the date, time (on a 24

hour clock) and total cumulative hours from hour zero.

18. At this time rotate the chamber by 90 ̊. As the chamber is rotated, think about the possible

outcome of reorienting the four seedlings.

- What will the seedling on each strip look like after 12 to 24 hours? Students should make a

drawing on the Gravitropism Data Sheet of how they predict each seedling will appear.

film can lid

seed on

germination

strip

Figure 3: Figure 3: Film can gravitropism chamber, Figure 3: 

view from above.

FRONT

film can lid

number of strip and

seed position

Willy Doit

10-1-97

13:00 hrs

0 ̊
84

19. Record the date, time and total cumulative hours of your first 90 ̊ rotation on the Gravitropism

Data Sheet, and each rotation thereafter.

20. After 3 to 12 hours or 24 hours (3 to 6 is best), observe the chamber. Mark the time and date

on the Data Sheet and next to the predicted sketch, make a quick but accurate sketch of how the

plant on each strip appears.

- The chamber should then be rotated another 90 ̊ to the 180 ̊ position. A predictive drawing

should be made on the Data Sheet and after 3 to 12 hours, repeat the cycle of observation,

drawing and rotation. Be sure to record the date, time and total cumulative hours.

21. Continue rotating, observing and drawing until the chambers have completed 360 ̊ of rotation.

Would students like to try to keep it going? Have them try it!

22. When the rotations have been finished carefully remove each strip with its seedling attached and

make a final drawing.

- Stretch out the seedling to straighten it, then accurately record the length of the hypocotyl

from the hypocotyl from the cotyledon to the root hypocotyl junction above where the root hairs

first appear.

- On the Gravitropism Data Sheet, record the length of the hypocotyl in millimeters.

Concluding Activities and Questions

In this activity students will have observed the effects of gravity in orienting the growth of seedlings.

Have students consider the following:

- Discuss the outcome of the experiment relative to the original hypothesis. Was the hypothesis

verified? How strong is your evidence? Were you able to successfully predict how the seedlings

would respond to successive reorientation of the chamber?

- What is the average length of the hypocotyls in your chamber after X hours of germinating in the

dark? You fill in the X!

- How long is it possible for a hypocotyl to grow in the dark?

- Is there a limit to how long it would grow? If there is, what is it?

- When it is elongating, how is the hypocotyl actually growing longer? By what mechanism?

- Is there a limit to how much bending a hypocotyl can undergo?

- What would the orientation behavior of the seedlings be like in microgravity?
85

Environment

Student Name 1 Temperature Range:  ̊CStudent Name 2 Average Daily Temperature of Growing Environment:  ̊CStudent Name 3Student Name 4

Gravitropism Data Sheet Gravitropism Data Sheet

Germination Strip Position Number Germination Strip Position Number

Date Time Total Hours from Rotation 1 2 3 4

(24 hr clock) (24 hr clock) Hours Last Rotation Angle predicted observed predicted observed predicted observed predicted observed

length of hypocotyl after hours: mm mm mm mm

0 0

90

 180

 270 360
86

Phototropism: Do Plants Prefer the Blues? Phototropism: Do Plants Prefer the Blues?

Introduction

This activity will deal mainly with phototropism, illustrating how plants use

various colors of light for different tasks. Unlike the gravitropism activity in which

light was excluded, experiments in the classroom on Earth are done in the ever-present

1 g force. This fact can provide fascinating questions and design challenges for students.

Question: A Phototropic Riddle

If you were a plant

Or a plant were you,

Which hue would you choose

To tie your shoe?

Is it red, green or blue?

Sample Hypothesis: Sample Hypothesis:

My leaves are green,

Could it be green?

Or is it the red?

I’ll guess blue,

And test if it’s true.

Design

• Give germinating seedlings a choice of red, green or blue light, each coming from a different

direction, and see if they bend toward one color more than toward the others.

Time Frame

Construction of the phototropism chamber will take approximately half of one 50 minute class period.

The observational activities will take place over a period of 60 to 72 hours, with the actual time of

observation and recording data requiring about 15 minutes at each interval.

Learning Objectives

In participating in the activity students will:

• learn to construct their own experimental equipment from low-cost materials;

• learn to set up a simple experiment, make a prediction and observe results; and

• understand that blue wavelengths of visible light affect the bending of plants more than red or

green, demonstrating the partitioning of various energy levels of light to different growth functions.

Materials

• 35 mm black film can with lid

• one floral foam disc, 28 mm diameter and 2 to 4 mm thick

• three grid strips, 0.5 cm x 4 cm (page 49)

• three wick strips, 1 cm x 4.5 cm, made of soft paper toweling (page 49)

• three brassica or other medium-sized seeds (turnip, lettuce or alfalfa)

• water bottle

• forceps to handle seed

• hand-held hole punch

• 2 cm wide clear adhesive tape

• 2 cm wide black vinyl electrical tape

• three 1.5 cm squares, 1 each of red, green and blue transparent plastic mylar (Roscolux® films red

#26, green #89 and blue #69, work well) or colored acetate from art stores or theatre departments

A C T I V I T Y 10
87

Procedure

1. With a hand-held hole punch, make three windows about 1.5 cm from

the rim of the black film can at approximately 120 degree intervals.

2. Use a 10 cm strip of clear adhesive tape to cover each window with a

red, green and blue square.

3. As with the gravitropism chamber, place a floral foam disc in the

chamber and wet it with water.

4. Set up three germination strips. The germination strips should be

aligned vertically, each spaced between two windows (Figure 4). Be

sure that the germination strips are below the chamber rim and that

there is sufficient, but not excess, water in the floral foam disc.

5. Place a seed, oriented with micropyle down, 2 cm down on each strip.

6. Snap the lid tightly onto the film can and place

the phototropism chamber under a light bank

where light will enter all three windows.

7. Make a top view drawing of your chamber,

predicting how the plants will appear after 48 to

72 hours of germination.

8. After 48 to 72 hours, open the lid and indicate

whether or not your prediction is to be accepted

or rejected. As evidence, draw what you observe

and compare it with your prediction.

Concluding Activities and Questions

In this activity students will have observed the effects of light in orienting the growth of seedlings in

the presence of gravity. Have students consider the following:

- Within the mix of colors making the white fluorescence of your plant lights, which color tells the

plant which way is up? Is this the same for humans? Are you sure?

- What has been the influence of gravity on the phototropic response? How would the seedlings

respond to light if this experiment were carried out in microgravity?

- What will happen to the seedlings if you darken the windows? What will happen if you darken

only the blue window?

- Recently plant physiologists have isolated minute amounts of a yellow molecule called flavochrome

that absorbs blue light and is active in the signal transduction pathway that transmits energy from

the blue light to the bending response.

b

red window

blue window

seed on

germination

strip

red window

green

window

Figure 4: Figure 4: Film can phototropism chamber, Figure 4:

view from above.
88

Phototropism: How Little Light Will Bend a Seedling? Phototropism: How Little Light Will Bend a Seedling?

Introduction

On Earth gravity is present in the quantity of 1 g (unit gravity). The quantity of

light on the other hand can vary enormously from very large quantities of irradiance in

the order of 8000 μEm-2s-1 in sunlight at noon to vanishingly small amounts. With the

chamber that you and your students constructed in the phototropism activity, it is easy to

investigate the effects of light quantity on bending of seedlings.

Question: Question: How much light is needed to bend a seedling?

Hypothesis: Hypothesis: You provide an amount. Then find out!

Design

• Groups of students will use a set of film can phototropism chambers to vary the quantity (intensity

and duration) of unidirectional light reaching seedlings and measure the responses over time. This

experiment can be run at home to facilitate observation and data collection.

• Students will record observations and measurements on the Phototropism Data Sheet (page 91).

Time Frame

Construction of the phototropism chamber will require approximately half of one 50 minute class

period. The experiment will run 96 hours from the time seeds are placed in the chamber, with

observations and measurements made at specific intervals. The time required for the measurements

will be approximately 15 minutes at each interval.

Learning Objectives

In participating in this activity students will:

• learn to construct their own experimental equipment from low-cost materials;

• apply simple geometry to the determination of the experimental variables of light quantity

impacting a seedling; and

• learn to interpret complex interactions involving three variables, including three-dimensional

graphing of data representing two independent variables (time and quantity of light) and one

independent variable (angle of plant bending).

Materials (per group of four students)

• four 35 mm black film cans with lids

• four floral foam discs, 28 mm diameter x 2 to 4 mm thick

• four grid strips, 0.5 cm x 4 cm (page 43)

• four wick strips, 1 cm x 4.5 cm, made of soft paper toweling (page 43)

• four brassica or other similar-sized seeds (turnip, lettuce or alfalfa)

• water bottle

• forceps to handle seed

• 2 cm wide clear adhesive tape

• 2 cm wide black vinyl electrical tape

• scissors

• four 1.5 cm squares of aluminum foil

• fine needles or pencil point for making holes in aluminum

• dissection strips (page 23)

• hand lens

• hand-held hole punch

• small plastic protractor or Tropism Response Measuring Card (page 90)

A C T I V I T Y 11 A C T I V I T Y 11
89

Procedure

1. On each of four black film cans, use a hand-held

hole punch to make a single hole of 6 mm diameter

1.5 cm from the rim and cover it with a clear strip of

tape to make a window.

2. Taking a 1.5 cm square of aluminum foil, puncture

the center of the foil with a very fine needle to make a

circular hole (aperture of 1 mm diameter).

3. On a second square of foil, use the needle to puncture

an aperture of about 2 mm diameter. On a third

square puncture an aperture of 6 mm (Figure 5).

4. On a fourth foil square, make no aperture.

5. Measure the actual diameter of each aperture with

the aid of a hand lens and ruler, estimating to a

fraction of a millimeter, enter the diameter on the

Phototropism Data Sheet. Calculate the area of each

window and enter it on the data sheet.

6. With clear tape, mount each foil square over the window on a different film can phototropism

chamber, so that now there are four chambers each with a window of differing aperture diameter

(0 aperture, 1 mm, 2 mm and 6 mm).

7. Cover each of the windows with a 3 cm strip of black vinyl tape that has a 5 mm length folded back

on itself to produce a tab so the tape can be easily removed.

12. After removing the window covers, open the lid of each chamber and observe the orientation of

the seedlings.

- Remove each germ strip with its seedling. Lay each down on a Tropism Response Measuring

Card as shown in Figure 7. Draw a line indicating the angle of bending from the vertical, 0.

- Carefully return the germination strip and the seedling to the original position in the chamber

and replace the cap.

8. As in the gravitropism experiment, set up each

chamber with a wet floral foam disc in the bottom

but this time with a single germination strip with

one seed located 2 cm down the strip.

9. Place the germination strip and seed opposite the

window (Figure 6).

10. Set the chambers under the light bank with the

windows in a position to receive light when the

black tape window covers are removed.

11. Let germination proceed in the dark for 36 to

48 hours, then remove the window covers.

Figure 6: Figure 6: Film can photoropism chamber, Figure 6:

view from above.

Figure 5: Figure 5: Side view of tropism chamber, and Figure 5:

aluminum foil squares with varying apertures.

aper

seed

germ

strip

flora

disc

1 mm

aperture

seed on

germination

strip

2 mm

floral foam

disc

6 mm

black tape

window

foil ape

seed on

germination

strip

window with aluminum

foil aperture

black tape
90

13. With a protractor on the Tropism Response

Measuring Card, determine the angle of

bending for each seedling and enter the data

on the Phototropism Data Sheet under T1.

Note the number of hours that have passed

between the time the seeds were placed and

the time of measurement.

14. Repeat steps 12 and 13 at each of three

additional time intervals: 6, 24 and 48

hours after removing the window covers.

Record the high, low and average ambient

temperatures during each time period.

Tropism Response Measuring Card

Concluding Activities and Questions

In this activity students will have observed

the effects of light quantity on the growth

and development of seedlings in the

presence of gravity. Have students consider

the following:

- From the Phototropism Data Sheet, plot

a line graph with aperture diameter on

the x-axis and degrees of plant response

from the vertical (0) on the y-axis, with

each line representing a different time of

exposure to light. On another graph,

plot a second set of four lines with time

of light exposure on the x-axis and the

degrees of response from the vertical (0)

on the y-axis, with each line representing

a different quantity of light. How do the

two line graphs compare?

- This experiment represents two

independent variables (time and quantity

of light) and one dependent variable

(angle of plant bending). These could be

displayed graphically in a threedimensional graph with axes x, y and z.

Try plotting this graph; some computer

software programs have this capability.

- Discuss the observed phototropic

responses from the standpoint of the

interaction of light direction and quantity

(as aperture) as an opposing horizontal

force at an angle of 90 ̊ to the constant

vertical force of gravity.

- What do you think the response data from this experiment would look like if it were carried out in

the microgravity of the Space Shuttle?

9

90 80

100 70

110 60

120 50

130 40

140 1500

30

160

20

170

10 0

180

100 110

80 70 120

80 130

50 140

40 150

30

160

20

170

10

180

0

90  ̊

0  ̊

0

<θ ̊=54

ding

9

0  ̊

O = 54  ̊

point of bending

from vertical

90  ̊

Figure 7: Figure 7: How to Figure 7:

measure angle of

bending from vertical.
91

Phototropism Data Sheet Phototropism Data Sheet

Angle ( Angle (O) at Hour of Light Exposure

Chamber Chamber Aperture Area of Area of T1 T2 T3 T4

Aperture # Diameter (mm) Diameter (mm) Aperture (mm2) hr hr hr hr

hi lo avg

10 0

2

3

4

ambient temperature during time period ( ̊C):

hi lo avg hi lo avg hi lo avg

Environment

Student Name 1 Temperature Range:  ̊C

Student Name 2 Average Daily Temperature of Growing Environment:  ̊CStudent Name 3Student Name 4
92

Mission Information*

Microgravity effects on pollination and fertilization Microgravity effects on pollination and fertilization

Experiment Acronym: B-STIC

Principal Investigators: Dr. Mary Musgrave (United States) and Dr. Antonina Popova (Ukraine)

Hardware: PGF

A particularly sensitive time in the life cycle of a plant growing in microgravity seems to be the

transition from the vegetative to the reproductive phase. In previous spaceflight experiments, most

plants grown full term in space failed to produce any seed at all, and in one experiment in which seeds

were produced, the seed quality was very poor. Dosimetry reading taken in flight have failed to explain

this ubiquitous sterility in terms of radiation load, thus some developmental failure during plant

reproduction seems to be triggered by the microgravity environment itself. Reproductive events in

angiosperms have a number of stages which could potentially be influenced directly by gravity.

Microsporogenesis (the production of pollen), megasporogenesis (the production of egg cells),

pollination and fertilization are all complex developmental events. Brassica rapa, a compact plant with

a short life cycle, is ideal for such studies.

Close comparison of pollination and fertilization processes in microgravity with ground controls has

not been possible before this experiment because we have not been able to control when pollination

occurs. It is only through the availability of a trained participant for in-flight activities that controlled

pollination and in-flight fixation of pollinated flowers will be possible. This will yield important

information on pollen germination and maturation in microgravity, pollen-stigma interactions, pollen

tube growth, fertilization and early embryo development.

Two plant populations are involved in this study. One population will be launched at the pre-flowering

stage of growth. A second population will be seeds at time of launch. Using a pollination kit, the

Payload Specialist will perform daily pollinations on the first population, and will mark the flowers

pollinated with color-coded wire loops. The pollination wands will be stored with desiccant for

subsequent viability assays on pollen. Several pollinated flowers will be fixed in-flight for microtubule

studies, but the bulk of the flowers will be returned fresh for extensive processing on the ground.

From the first population of plants which will be launched at the pre-flowering stage, siliques will be

obtained. For high quality microscopy it will be necessary to dissect out the developing ovules prior to

in-flight fixation. A small portion of the siliques will be placed in tissue culture for embryo rescue

techniques.

From the second population of plants which were seeds at time of launch, flower buds will be

obtained. In vivo tests on these buds will include pollen viability (fluorescein diacetate staining),

pollen germination, pollen tube growth through the stigma (aniline blue staining), and staining for

stigma esterases. Flower buds will be scored for size prior to dissection and processing for

microscopy. In many ways, study of this single event in a plant life cycle integrates the many

outstanding questions in gravitational biology.

* adapted from CUE Experiment Requirements Document (ERD), draft version (6/13/96)
93

Front Elevation of PGF: Front Elevation of PGF:

View of six Plant Growth Chambers

(PGCs) and the Control Panel.

Plant Growth Chambers (PGCs): Plant Growth Chambers (PGCs):

On STS-87, plant specimens will be contained in six

identical PGCs. The PGCs are designed for easy

loading and unloading into the Plant Growth

Facility (PGF), and are designed to be

doubled or possibly tripled in width.

PGF and PGC Schematics and PGC Schematics
94

Sources of Supplies

Acrylic Sheets

The 2 mm thick, clear acrylic sheets of various size dimensions (e.g., 70 cm x 80 cm) are available

from hardware and building supply stores.

AstroPlants Seed

Seed from the stock of Wisconsin Fast Plants known as "AstroPlants" can be purchased from Carolina

Biological Supply Company (2700 York Road, Burlington, NC 27215, tel: 800-334-5551).

Bees

Honeybees can be obtained from local beekeepers, or commercially from Carolina Biological Supply

Company (2700 York Road, Burlington, NC 27215, tel: 800-334-5551).

Capillary Wicking Material Capillary Wicking Material Capillary Wicking Material

Capillary wicking material is used in the CUE-TSIPS peatlite growing system. Pellon is available from

fabric stores. WaterMat® is available local garden supply centers or from Florist Products (2242 N.

Palmer Drive, Schaumburg, IL 60173, tel: 1-800-828-2242).

Chemical Fixatives

The components for mixing chemical fixative solutions are available from chemical supply companies;

these components can be ordered for preparing solutions to fix brassica pods, embryos and ovules. A

recipe for acetic alcohol fixative solution is included on page 98.

Drawer Organizers

Drawer organizers can be purchased at discount houseware stores.

Nutrient Solution Chemicals

The components for the Wisconsin Fast Plants nutrient solution can be ordered from commercial

chemical supply companies. This solution is a modified Hoagland's basal salt mixture with the macroand micronutrients as described by Hoagland and Arnon (1950). Hoagland's mixture is available

premixed in volumes of 1 liter and 10 liters from Sigma Chemical Company (P.O. Box 14508, St. Louis,

MO 63178, tel: 800-835-3010). A recipe for Wisconsin Fast Plants Nutrient Solution is included on

page 96. Liquid fertilizers such as Peters® are available from garden supply stores.

Film Cans

Both 35 mm black and clear film cans can be obtained in large quantities from film processing outlets

or camera stores. The cans are usually discarded, so ask that they be saved.

Floral Foam

Floral foam is available from florist supply stores.

Indicating Silica Gel Indicating Silica Gel Indicating Silica Gel

Type III indicating silica gel changes color from blue to pink above 20% relative humidity. Silica gel is

available in various quantities from Sigma Chemical Company (P.O. Box 14508, St. Louis, MO 63178,

tel: 800-835-3010) and Aldrich Chemical Company (1001 West Saint Paul Avenue, Milwaukee, WI

53233, tel: 800-558-9160).
95

Iodine Potassium Iodide Staining Solution

The components for the nutrient solution can be ordered from commercial chemical supply companies

such as Sigma Chemical Company (P.O. Box 14508, St. Louis, MO 63178, tel: 800-835-3010).

Directions for mixing the solution and staining specimens is included on page 98.

Lenses

Double convex lenses for film can magnifiers are available from various suppliers, including Hamilton

Bell (30 Craig Road, Montvale, NJ 07645, tel: 800-526-0864).

Light Banks

Materials for constructing light banks are available from hardware and building supply stores, or a

light system can be ordered from Carolina Biological Supply Company (2700 York Road, Burlington,

NC 27215, tel: 800-334-5551).

Microscopes

Illuminated hand-held microscopes are available in magnifications of 30X and 100X from local Radio

Shack stores.

Mylar

Colored mylar filters (for the phototropism activity) are available from entertainment or theatre supply

stores or directly from Roscolux.

Peatlite

Commercially available as JiffyMix® or Terra-lite Redi-earth®, peatlite mixtures can be obtained from

garden supply stores.

Styrofoam Sheets

Builder's insulating styrofoam can be purchased as large sheets from building supply stores.

* Note: The listing of proprietary names in this section is not an endorsement of the products.

The brand names listed are suggestions only.
96

Wisconsin Fast Plants Nutrient Solution Wisconsin Fast Plants Nutrient Solution

Four stock solutions are made in 2-liter dispensing plastic soda bottles. Wisconsin Fast Plants

Nutrient Solution is used in the reservoirs for continuous irrigation, mixed in the proportions listed.

This nutrient solution is a modified half-strength (0.5X) Hoagland's solution. As an alternative to

mixing the stock solutions and preparing the solution, premixed Hoagland's can be purchased from

Sigma Chemical Company and diluted to half-strength for use in the CUE-TSIPS activities.

Stock Solutions

• Stock Solution 1: Mixture

- Add gram amounts to distilled water to make 1.8 liters of stock solution:

1.0 M KNO3 (potassium nitrate) 182 grams

0.2 M KH2PO4 (potassium phosphate monobasic) 49 grams

0.4 M MgSO4•7H2O (magnesium sulfate) 177.5 grams (or 86.6 grams anhydrous)

• Stock Solution 2: Calcium Nitrate

- Add gram amounts to distilled water to make 1.8 liters of stock solution:

1.25 M CaNO3 (calcium nitrate) 531.4 grams

• Stock Solution 3: A-Z (micronutrients)

- Add gram amounts to distilled water to make 100 ml, then put 45 ml solution in 2-liter bottle, fill

to 1.8 liters using distilled water (discard excess):

H3BO3 (boric acid) 2.9 grams

MnCl2•4H2O (manganese chloride) 1.8 grams

ZnSO4•7H2O (zinc sulfate) 0.2 grams

CuSO4•5H2O (copper sulfate) 0.08 grams

H2MoO4•H2O (molybdic acid) 0.09 grams

• Stock Solution 4: Iron

- Dissolve gram amounts in 400 ml of distilled water by heating to 80°C for one hour; let cool

slightly and add distilled water to reach total volume of 1.8 liters:

FeSO4•7H2O (iron sulfate) 2.5 grams

Na EDTA (ethylene diamine tetraacetic acid) 3.3 grams

Wisconsin Fast Plants Nutrient Solution

To make half-strength Wisconsin Fast Plants Nutrient Solution, mix the following quantities of the four

stock solutions and add distilled water to make a total volume of one liter:

2.0 ml Mixture (Stock Solution 1)

2.5 ml Calcium Nitrate (Stock Solution 2)

2.0 ml A-Z (Stock Solution 3)

2.0 ml Iron (Stock Solution 4)

Peters® Fertilizer Solution Fertilizer Solution

Peters® Professional brand fertilizer solution (N-P-K 20-20-20, with minor elements) can be made in a

dispensing plastic soda bottle. To mix the solution, dissolve one soda bottle cap of the Peters® crystals

per liter of distilled water.
97

Film Can Magnifier Film Can Magnifier

A simple hand lens can open the world of micro-exploration for a student. Through the use of an

inexpensive lens, a film can and soda bottle cap, students can make their own magnifier.

Materials

• one clear film can (such as those made by Fuji®)

• one plastic soda bottle cap

• one double convex glass lens, 28 mm in diameter (Tip: Use a lens with a focal length of 59 mm;

you can use smaller lenses but drill correspondingly smaller holes in the film can.)

• 17 to 20 mm diameter Pyrex test tube or wood bit with spurs

• propane torch or Bunsen burner

Procedure

1. Drill or melt a 20 mm hole in a plastic soda bottle cap and in the bottom of a clear film can. To

melt the hole, heat the lip of a Pyrex test tube in a propane torch or Bunsen burner flame.

Carefully push the heated end of the tube through the cap and can.

Caution: Melting plastic can give off noxious fumes, perform this step in a well-ventilated area or

under a hood.

2. Use scissors to trim off the small protruding rim of the cap so that it fits into the film can.

3. Drop the lens into the drilled film can. Push the drilled soda bottle cap into the can until it holds

the lens snugly in place against the film can. The focal length of this lens will bring an object into

focus at the open edge of the film can.

Tips and Suggestions

• A local film processing outlet or camera store is a good source for film cans. Ask that the cans be

saved for you, since they are usually discarded.

• You can thread a string through two small holes made in

the film can and wear the magnifier as a necklace.

• The hand lens can be used as a bug bottle by placing

a bug in the can and replacing the lid.

For Dissections

• You can melt two larger holes in the side of

the can to be used as access ports.
98

Chemical Fixative Chemical Fixative

To mix a fixative solution, combine 75 ml 95% ethanol and 25 ml glacial acetic acid for a total volume

of 100 milliliters

Store the fixative solution in an airtight container. Use caution when mixing chemicals.

At the desired developmental stages, remove pods from AstroPlants. Place the pods in an airtight

container. Add a depth of the chemical fixative to cover the pods. Seal and label the container with

the date and the age of the pods. Pods can be stored for many years at room temperature in acetic

alcohol fixative.

Use forceps to remove pods from the fixative and transfer them into a container of at least 100 ml of

water for at least three minutes. Pods can then be safely handled with fingers or forceps. Wash hands

thoroughly after working with the fixed pods.

Acetic alcohol fixative solution can be poured down a sink and followed with water for disposal. Check

with lab supervisors for any special instructions.

Iodine Potassium Iodide (IKI) Staining Solution Iodine Potassium Iodide (IKI) Staining Solution

To mix an iodine potassium iodide (IKI) staining solution, dissolve 2 g of KI in 100 ml distilled water.

Then dissolve 0.2 g of iodine in the KI solution. Store the solution in an airtight container.

Starch will appear blue to black within a few minutes of staining. Newly formed starch may appear

red to purple.
99

Black Line Masters

complete items

below:

magnification

of lens: X

length represented

by scale bar:

 mm

actual length of

scale bar:

 mm

estimated length

of object:

 mm

calculated

magnification of

drawing:

=

= X

Dissection Card

Name Date

1. Draw a magnified scale on the horizontal axis

of the field.

2. Accurately draw scale bar

indicating length.

3. Draw the object in view

to scale.

Object is:

1. Draw a magnified scale on the horizontal axis

of the field.

2. Accurately draw scale bar

indicating length.

3. Draw the object in view

to scale.

complete items

below:

magnification

of lens: X

length represented

by scale bar:

 mm

actual length of

scale bar:

 mm

estimated length

of object:

 mm

calculated

magnification of

drawing:

=

= X

Object is:

50 mm 50 mm

Dissection Card Dissection Card

Use this card for activities in which students make observations, drawings and measurements.
100

Dissection Strips Dissection Strips

Photocopy this page onto an overhead transparency sheet. Stick the transparency sheet to a "do it

yourself" laminating sheet or piece of clear contact paper, printed side down (this will protect the

printing from being pulled of during use of the strip). Cut out the dissection strips. Use the strips for

the activities in the pollination and fertilization sections.

0 1 2 3 4 5 cm

0 1 2 3 4 5 cm

0 1 2 3 4 5 cm

5 cm 4 3 2 1 0

0 1 2 3 4 5 cm

0 1 2 3 4 5 cm

0 1 2 3 4 5 cm

5 cm 4 3 2 1 0

0 1 2 3 4 5 cm

0 1 2 3 4 5 cm

0 1 2 3 4 5 cm

5 cm 4 3 2 1 0

0 1 2 3 4 5 cm

0 1 2 3 4 5 cm

0 1 2 3 4 5 cm

5 cm 4 3 2 1 0

0 1 2 3 4 5 cm

0 1 2 3 4 5 cm

0 1 2 3 4 5 cm

5 cm 4 3 2 1 0

0 1 2 3 4 5 cm

0 1 2 3 4 5 cm

0 1 2 3 4 5 cm

5 cm 4 3 2 1 0

0 1 2 3 4 5 cm

0 1 2 3 4 5 cm

0 1 2 3 4 5 cm

5 cm 4 3 2 1 0

0 1 2 3 4 5 cm

0 1 2 3 4 5 cm

0 1 2 3 4 5 cm

5 cm 4 3 2 1 0

0 1 2 3 4 5 cm

0 1 2 3 4 5 cm

0 1 2 3 4 5 cm

5 cm 4 3 2 1 0

0 1 2 3 4 5 cm

0 1 2 3 4 5 cm

0 1 2 3 4 5 cm

5 cm 4 3 2 1 0

0 1 2 3 4 5 cm

0 1 2 3 4 5 cm

0 1 2 3 4 5 cm

5 cm 4 3 2 1 0

0 1 2 3 4 5 cm

0 1 2 3 4 5 cm

0 1 2 3 4 5 cm

5 cm 4 3 2 1 0
101

NASA Space Life Sciences

Suggested Resources for Study of Plants

Websites

The following Internet addresses will provide users with links to the NASA Specialized Centers of

Research and Training (NSCORTs) that focus on plant research and to NASA Life Sciences websites

that include lessons and information on plants.

NSCORT in Gravitational Biology:

http://www2.nscu.edu/unity/lockers/project/ncsu-nscort/public/homepage.htm

NSCORT in Plant Biology

Co-sponsored by NASA and the National Science Foundation

http://trna.chem.yale.edu/pss/

Plant Growth Imaging Homepage

http://hideo.biosci.ohio-state.edu/

NSCORT in Bioregenerative Life Support

http://www.rci.rutgers.edu/~biorengg/njnscort

Web of Life

This site is designed as an open door to activities of public interest sponsored by NASA's Life Sciences

Division.

http://webolife.arc.nasa.gov

OR email to: UL_outreach@mail.arc.nasa.gov

NASA Headquarters Homepage

http://www.hq.nasa.gov

Office of Life and Microgravity Sciences and Applications Homepage

http://www.hq.nasa.gov/office/olmsa

Kennedy Space Center Homepage

http://www.ksc.nasa.gov/ksc.html - Select Biomedical Homepage, Select Space Biology

Johnson Space Center Homepage

http://www/jsc.nasa.gov - Select search, type word "plants"

Ames Research Center Advanced Life Support (CELSS)

http:brad.arc.nasa.gov/Project/CELSSExplanation.html

Additional Websites

The AstroPlants

http://fastplants.cals.wisc.edu/ap.html

Wisconsin Fast Plants Information Documents

http://fastplants.cals.wisc.edu
102

Books

Bowman, J., Ed. 1994. Arabidopsis, An Atlas of Morphology and Development. Springer-Verlag, Inc.

(New York).

Buchmann, S.L. and G.P. Nabhan. 1996. The Forgotten Pollinators. Island Press (Covelo, CA).

Darwin, C. 1880. The Power of Movement in Plants. J. Murray Publishing (London).

Hart, J.W. 1990. Plant Tropisms and Other Growth Movements. Unwin Hyman Publishing (London).

Kearns, C.A. and D.W. Inouye. 1993. Techniques for Pollination Biologists. Colorado University Press

(Niewot, CO).

National Council for Agricultural Education. 1994. Using Fast Plants and Bottle Biology in the

Classroom. National Association of Biology Teachers (Reston, VA).

Proctor, M., P. Yeo and A. Lack. 1996. The Natural History of Pollination. Harper Collins (London).

Suge, Hiroshi. (editor) 1996. Plants in Space Biology. Institute of Genetic Ecology, Tohoku University.

Ragnavan, V. 1986. Embryogenesis in Angiosperms: A Developmental and Experimental Study.

Cambridge University Press (New York).

Raven, P.H., R.F. Evert and S.E. Eichorn. 1992. Biology of Plants. Worth Publishers (New York).

Vogt, G.L. and J.J. Wargo, Eds. 1992. Microgravity. National Aeronautics and Space Administration

(Washington, D.C.).

Journal Articles

Evans, M.L., Moore, R., Hasenstein, K.H., 1986 How roots respond to gravity. Scientific American

254: 112–119.

Reiser, L. and R. Fischer. 1993. The ovule and embryo sac. The Plant Cell 5:1291–1301.

Russel, S. 1993. The egg cell: development and role in fertilization and early embryogenesis. The

Plant Cell 5:1349–1359.

Salisbury, F.B. 1993. Gravitropism: Changing Ideas. In Offprints from Horticultural Reviews, Volume

15, pp. 233–278.

Salisbury, F.B. and B.G. Bugbee. 1988. Space farming in the 21st Century. 21st Century Science

and Technology 1:32–41.

West, M. and J. Harada. 1993. Embryogenesis in higher plants: an overview. The Plant Cell

5:1361–1369.

Williams, P.H. 1986. Rapid-cycling populations of Brassica. Science 232:1385–1389.

Yeung, E. and D. Meinke. 1993. Embryogenesis in angiosperms: development of the suspensor. The

Plant Cell 5:1371–1381.
103

Wisconsin Fast Plants Information Documents

(Documents available from the Wisconsin Fast Plants office or at http://fastplants.cals.wisc.edu.)

Wisconsin Fast Plants. 1987. "Around the World with Brassicas" Wisconsin Fast Plants (Madison, WI).

Wisconsin Fast Plants. 1994. "Hormone-Induced Parthenocarpy in Rapid-Cycling Brassica Rapa."

Wisconsin Fast Plants (Madison, WI).

Wisconsin Fast Plants. 1996a. "The Hunt for Glucose—A Flower's Treasure." Wisconsin Fast Plants

(Madison, WI).

Wisconsin Fast Plants. 1990. "Pollen Germination." Wisconsin Fast Plants (Madison, WI).

Wisconsin Fast Plants. 1996b. "Pollen-Stigma Interactions and Pollen Tube Growth." Wisconsin Fast

Plants (Madison, WI).
104

NASA Educational Resources

NASA On-line Resources for Educators provide current educational information and instructional

resource materials to teachers, faculty, and students. A wide range of information is available,

including science, mathematics, engineering, and technology education lesson plans, historical

information related to the aeronautics and space program, current status reports on NASA

projects, news releases, information on NASA educational programs, useful software and graphics

files. Educators and students can also use NASA resources as learning tools to explore the

Internet, accessing information about educational grants, interacting with other schools which

are already on-line, and participating in on-line interactive projects, communicating with NASA

scientists, engineers, and other team members to experience the excitement of real NASA projects.

Go to these resources through the NASA Education Home Page:

http://www.hq.nasa.gov/office/codef/education

or, for more information, E-mail:

comments@spacelink.msfc.nasa.gov

NASA Television (NTV) NASA Television (NTV) is the Agency's distribution system for live and taped programs. It offers the

public a front-row seat for launches and missions, as well as informational and educational

programming, historical documentaries, and updates on the latest developments in aeronautics and

space science. NTV is transmitted on Spacenet 2 (a C-band satellite) on transponder 5, channel 9, 69

degrees west with horizontal polarization, frequency 3880 megahertz, audio on 6.8 megahertz; or

through collaborating distance learning networks and local cable providers.

Apart from live mission coverage, regular NASA Television programming includes a News Video File

from noon to 1:00 pm, a NASA History File from 1:00 to 2:00 pm, and an Education File from 2:00 to

3:00 pm (all times Eastern). This sequence is repeated at 3:00 pm, 6:00 pm, and 9:00 pm, Monday

through Friday. The NTV Education File features programming for teachers and students on science,

mathematics, and technology, including the NASA. . .On the Cutting Edge Education Satellite

Videoconference Series. The videoconferences include NASA scientists, astronauts, and education

specialists presenting aeronautics and Earth & space science topics of interest to teachers and students

of grades 5-12. The series is free to registered educational institutions. The videoconferences and all

NASA Television programming may be videotaped for later use.

For more information on NASA Television, contact:

NASA Headquarters, Code P-2, NASA TV, Washington, DC 20546-0001

Phone: (202) 358-3572

Home Page: http://www.hq.nasa.gov/office/pao/ntv.html

For more information about the Education Satellite Videoconference Series, contact: Videoconference

Producer, NASA Teaching From Space Program, 308 CITD, Room A, Oklahoma State University,

Stillwater, OK 74078-8089

E-mail: edge@aesp.nasa.okstate.edu

Home Page: http://www.okstate.edu/aesp/VC.html
105

IF YOU LIVE IN: Precollege Officer Educator Resource Center

Alaska Nevada Mr. Garth A. Hull NASA Educator Resource Center

Arizona Oregon Chief, Educational Programs Branch Mail Stop 253-2

California Utah Mail Stop 204-12 NASA Ames Research Center

Hawaii Washington NASA Ames Research Center Moffett Field, CA 94035-1000

Idaho Wyoming Moffett Field, CA 94035-1000 Phone: (415) 604-3574

Montana Phone: (415) 604-5543

Connecticut New Hampshire Dr. Robert Gabrys NASA Educator Resource Laboratory

Delaware New Jersey Chief, Education Office Mail Code 130.3

District of Columbia New York Mail Code 130.3 NASA Goddard Space Flight Center

Maine Pennsylvania NASA Goddard Space Flight Center Greenbelt, MD 20771-0001

Maryland Rhode Island Greenbelt, MD 20771-0001 Phone: (301) 286-8570

Massachusetts Vermont Phone: (301) 286-7206

Colorado North Dakota Ms. Billie A. Deason NASA Educator Resource Room

Kansas Oklahoma Education Team Lead Mail Code AP 2

Nebraska South Dakota Education & Information Services Branch - AP 2 NASA Johnson Space Center

New Mexico Texas NASA Johnson Space Center 2101 NASA Road 1

2101 NASA Road 1 Houston, TX 77058-3696

Houston, TX 77058-3696 Phone: (281) 483-8696

Phone: (281) 483-2462

aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa

NASA Educator Resource Center Network

To make additional information available to the education community, the NASA Education

Division has created the NASA Educator Resource Center (ERC) network. ERCs contain a wealth

of information for educators: publications, reference books, slide sets, audio cassettes, videotapes,

telelecture programs, computer programs, lesson plans, and teacher guides with activities. Because each NASA field center has its own areas of expertise, no two ERCs are exactly alike. Phone

calls are welcome if you are unable to visit the ERC that serves your geographic area. A list of the

centers and the geographic regions they serve starts at the bottom of this page.

Regional Educator Resource Centers (RERCs) Regional Educator Resource Centers (RERCs) offer more educators access to NASA educational materials. NASA has formed partnerships with universities, museums, and other educational institutions to

serve as RERCs in many states. Educators may preview, copy, or receive NASA materials at these

sites. A complete list of RERCs is available through CORE.

NASA Central Operation of Resources for Educators (CORE) NASA Central Operation of Resources for Educators (CORE) was established for the national and

international distribution of NASA-produced educational materials in audiovisual format. Educators can obtain a catalogue and an order form by one of the following methods:

• NASA CORE

Lorain County Joint Vocational School

15181 Route 58 South

Oberlin, OH 44074

• Phone (216) 774-1051, Ext. 249 or 293

• Fax (216) 774-2144

• E-mail: nasaco@leeca8.leeca.ohio.gov

• Home Page: http://spacelink.msfc.nasa.gov/CORE
106

IF YOU LIVE IN: Precollege Officer Educator Resource Center

Florida Dr. Steve Dutczak NASA Educator Resource Laboratory

Georgia Chief, Education and Services Branch Mail Code ERL

Puerto Rico Mail Code PA-ESB NASA Kennedy Space Center

Virgin Islands NASA Kennedy Space Center Kennedy Space Center, FL 32899-0001

Kennedy Space Center, FL 32899-0001 Phone: (407) 867-4090

Phone: (407) 867-4444

Kentucky Dr. Marchelle Canright NASA Educator Resource Center

North Carolina Precollege Officer for Langley Research Center

South Carolina Mail Stop 400 Virginia Air and Space Center

Virginia NASA Langley Research Center 600 Settler's Landing Road

West Virginia 17 Langley Boulevard Hampton, VA 23669-4033

Hampton, VA 23681-0001 Phone: (757) 727-0900 x 757

Phone: (757) 864-3313

Illinois Minnesota Ms. Jo Ann Charleston NASA Educator Resource Center

Indiana Ohio Acting Chief, Office of Educational Programs Mail Stop 8-1

Michigan Wisconsin Mail Stop 7-4 NASA Lewis Research Center

NASA Lewis Research Center 21000 Brookpark Road

21000 Brookpark Road Cleveland, OH 44135-3191

Cleveland, OH 44135-3191 Phone: (216) 433-2017

Phone: (216) 433-2957

Alabama Louisiana Mr. William Anderson NASA Educator Resource Center

Arkansas Missouri Director, Education Programs Office for Marshall Space Flight Center

Iowa Tennessee Mail Code CL01 U.S. Space and Rocket Center

NASA Marshall Space Flight Center P.O. Box 070015

Huntsville, AL 35812-0001 Huntsville, AL 35807-7015

Phone: (205) 544-8811 Phone: (205) 544-5812

Mississippi Dr. David Powe NASA Educator Resource Center

Manager, Educational Programs Building 1200

NASA John C. Stennis Space Center NASA John C. Stennis Space Center

P.O. Box 508 Stennis Space Center, MS 39529-6000

Iuka, MS 38852-0508 Phone: (601) 688-3338

Phone: (601) 423-7452

Mr. David Seidel NASA Educator Resource Center

Precollege Officer Mail Stop CS-530

Mail Stop CS-530 NASA Jet Propulsion Laboratory

NASA Jet Propulsion Laboratory 4800 Oak Grove Drive

4800 Oak Grove Drive Pasadena, CA 91109-8099

Pasadena, CA 91109-8099 Phone: (818) 354-6916

Phone: (818) 354-6916

California (mainly cities near Dr. Marianne McCarthy NASA Educator Resource Center for

Dryden Flight Research Facility) Education Specialist NASA Dryden Flight Research Facility

P.O. Box 273, MS D4839A 45108 N. 3rd. Street East

NASA Dryden Flight Research Facility Lancaster, CA 93535

Edwards, CA 93523-0273 Phone: (805) 948-7347

Phone: (805) 258-2281

Virginia and Maryland's Mr. Keith Koehler NASA Goddard Space Flight Center

Eastern Shores Public Affairs Specialist Wallops Flight Facility

Wallops Flight Facility Education Complex/Visitor Center Bldg. J-17

Wallops Island, VA 23337 Wallops Island, VA 23337-5099

Phone: (804) 824-1597 Phone: (804) 824-2297 / 2298
107

EG-1997-02-113-HQ

4. How did you use this teacher's guide?

Background Information Critical Thinking TasksDemonstrate NASA Materials DemonstrationGroup Discussions Hands-On ActivitiesIntegration Into Existing Curricula Interdisciplinary ActivityLecture Science and MathematicsTeam Activities Standards IntegrationOther: Please specify:___________________________________________________________

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Teachers and Students Investigating Plants in Space:

A Teacher's Guide with Activities for Life Sciences

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