bluuebunny/crossref_metadata_2025 huggingface dataset:
Stomatal ontogeny of the vegetative and floral organs of some Papilionaceae
Authors: Shah GL , Gopal BV
Published: December 2005

The structure and development of stomata on the vegetative and floral organs of
Vigna unguiculata Walp., and the vegetative organs of Phaseolus radiatus L. and
P. aconitifolius Jacq. are described. Paracytic, anisocytic, and anomocytic stomata
are present on the same surface of different organs of the plants investigated except
on the stem and petiole of V. unguiculata, the bract of P. radiatus, and the petiole,
stipule, and stipel of P. aconitifolius where the last type is absent. Stomata with only
one subsidiary cell are found on the leaf, petiole, sepal, and petal of V. unguiculata.
Diacytic stomata occur on the stipel of P. radiatus and the stem, stipule, and stipel of
P. aconitifolius. Paracytic stomata are by far the commonest on each organ. The frequency
of different types of stomata on different organs in the plants investigated is
tabulated. The ontogeny of different kinds of stomata on each organ is mesogenous,
but the perigenous type may be found on the petal and pericarp of V. unguiculata and
the stipule of P. radiatus. The variation in stomata is due to: (a) a diversity in stomatal
types even on the same surface, and (b) an increase in the number of subsidiary cells.
The subsidiary cells divide, or additional subsidiary cells are derived from adjacent
epidermal cells. The present study also supports the inclusion of the species concerned
in the tribe Phaseolae.
Epidermal structure and ontogeny of stomata in vegetative and floral organs of Hibiscus rosasinensis L
Authors: Inamdar JA , Chohan AJ
Published: December 2005

The epidermal structure and ontogeny of stomata in vegetative and floral
organs of Hibiscus rosasinensis are described. The epidermal cells are polygonal isodiametric
or elongated and arranged irregularly or parallel to the long axis. The
anticlinal walls of the epidermis are thick, straight, arched, or rarely sinuous. The
surface of the cuticle shows parallel striations radiating from the guard cells or hair
bases. Six types of glandular and eglandular trichomes have been noticed. The mature
stomata are anisocytic, paracytic, or anomocytic. The development of anisocytic and
paracytic stomata is of the mesogenous or syndetocheilic type. The ontogeny of
anomocytic stomata conforms to the perigenous or haplocheilic type. The three types
of stomata occur on all the vegetative and floral organs of this plant except the anther
wall and the outer epidermis of the carpel. The developmental modes are constant from
organ to organ within the same plant.
The embryology of Kunzea capitata Reichb
Authors: Prakash N
Published: December 2005

The anther is tetrasporangiate and the development of its wall is of the Basic
type. Ubisch granules are formed on the surface of the tapetum at the signet-ring stage
of the pollen grains. The anther dehisces by longitudinal slits, and pollen grains are shed
at the two-celled stage.
The female archesporium is subepidermal and cuts off the primary parietal cell.
A six-layered parietal tissue is formed below the nucellar epidermis by the time megasporogenesis
is completed. The flowers are protandrous, and in any given bud meiosis
in megaspore mother cells follows that in microspore mother cells. Embryo sac development
is of the Polygonum type and the antipodal cells are ephemeral.
Cell formation in the nuclear endosperm commences at the micropylar end and
proceeds towards the chalaza. Embryogeny corresponds to the Onagrad type and no
evidence of polyembryony was found.
Both the integuments take part in the formation of the seed coat, in which the
cells of the outer layer of the outer integument are conspicuously elongated.
A comparison is made with the embryological findings in other myrtaceous plants.
Some aspects of the life history of Callistemon citrinus (Curt.) Skeels
Authors: Prakash N
Published: December 2005

Pollen development is irregular in native populations but regular in the cultivated
plants investigated. Development of the anther wall is of the Basic type and the
tetrasporangiate anthers shed their pollen at the two-celled stage through longitudinal
slits. The single vascular bundle of each stamen gives off two traces in the connective.
The ovules are anatropous, crassinucellar, and bitegmic. The swollen distal ends
of both integuments form the micropyle. The single archesporial cell cuts off a parietal
cell, and during megasporogenesis a one- to three-layered parietal tissue is formed
which collapses during the development of the embryo sac. Occasionally the megaspore
mother cell degenerates but in these instances the growth of the ovule is unimpaired.
The female gametophyte follows the Polygonum type of development, and
when mature is eight-nucleate and includes three ephemeral antipodal cells. Some abnormalities
pertaining to the number and arrangement of nuclei in the embryo sac
have been observed and hardly 4% of the ovules form fertile seeds. The seed coat is
formed from both the integuments. A hypostase is differentiated in the seed.
A further numerical contribution to the classification of the Poaceae
Authors: Clifford HT , Williams WT , Lance GN
Published: December 2005

A sample of 92 widely representative grass genera scored for 50 attributes was
subjected to the classificatory programmes MULTBET and MULTCLAS. Of these two the
former was accepted as the more useful in that it was the more successful in uniting
genera known to hybridize. It organized the genera into five groups here designated as
bambusoid, pooid, panicoid-phragmitoid, eragrostoid, and andropogonoid. On comparing
these in pairs and further combinations by means of a GROUPER analysis it was
found that leaf and fruit attributes were principally responsible and that spikelet attributes
contributed only slightly to the definition of groups. A principal coordinate
analysis of the same data separated the bambusoid genera from the remainder, which
were arranged in an elongated ellipsoid when considered in terms of the three largest
axes. Within the ellipsoid the pooid, panicoid-phragmitoid, eragrostoid, and andropogonoid
genera occupied discrete but contiguous regions. A GOWECOR analysis of the
data showed that the attributes most closely correlated with the three longest ordination
axes were those of the leaf and fruit. As with the GROUPER analysis, spikelet attributes
were of little importance.
The characterization of populations of Eucalyptus camaldulensis by chemical features
Authors: Banks JCG , Hillis WE
Published: December 2005

Samples of E. camaldulensis were collected from throughout its natural habitat
which covers most of Australia and represents a wide range of environments. Mature
leaves from 103 and seeds from 62 localities were examined as well as seedling leaves of
53 progenies. The 47 polyphenols from the different acid-hydrolysed tissues were
characterized chromatographically and a few identified. There was similarity between
all samples of the same type of tissue but nevertheless the specific occurrence of a small
number of compounds (four in mature leaves, three in the seeds, and one in seedling
leaves) and the variation in relative amounts of others enabled the localities to be
divided into six phytochemical provinces. These corresponded to the major river
drainage systems. The taxonomically important compounds from the mature leaves
were aromadendrin, kaempferol, a compound very similar to pelargonidin, and compound
20; from the seeds compounds 43, 44, and 47; and from the seedling leaves
compound 27. The mature leaves yielded the most significant data. The seeds and
seedling leaves provided useful supporting evidence. There was a strong correlation
between groupings based on morphological characters and those based on the polyphenol
composition. There were minor differences associated with environment particularly
between the tropical northern division and the temperate southern division. The
possible origin of trees planted in Israel is discussed.
The evolution and taxonomy of Calectasia cyanea R. Br. (Xanthorrhoeaceae) in terms of its present-day variation and cytogenetics
Authors: Anway JC
Published: December 2005

Calectasia cyanea R. Br. was collected at 48 sites throughout its range in southern South Australia and western Victoria, and in southern and western Western Australia. The eastern and western populations have been separated since Miocene times by various factors such as the sea, drought, soil conditions, and temperature. Ecological, morphological, chemical, palynological, and cytological features were studied to determine the variation within the populations. The close similarity of all populations of Calectasia in morphology, chemistry, pollen, and chromosome number indicated a stabilizing mechanism. This mechanism was found to be a cytological aberration of the ninth chromosome, which causes 20-30 % of the genetic material to be inherited as a supergene, thus maintaining a permanent, unchangeable heterozygosity. Two new varieties were recognized.
Floral morphology and the development of the gametophytes in Eucalyptus stellulata Sieb
Authors: Davis GL
Published: December 2005

Bud formation on new growth is a continuous process which extends from early
spring until midsummer, and at any time except during the winter months a wide range
of floral development is exhibited on each tree. The main flowering period in the
Armidale district is late summer to early autumn but sporadic flowering may occur at
any time.
The development of the single operculum and the floral parts is traced but, owing
to the prolonged period over which bud primordia are formed, stages of organogenesis
cannot be related to definite seasons. At the onset of meiosis the buds enlarge and
rupture the two fused bracts which enclose the inflorescence, and these are shed.
Embryo sac formation is of the Polygonum type and the components of the egg
apparatus undergo a threefold increase in size before anthesis. In more than half the
embryo sacs the endosperm mother cell becomes multinucleate and its subsequent
degeneration is followed by that of the egg apparatus. Such abnormal ovules continue
their growth and cannot be distinguished externally from those containing normal
embryo sacs.
The fertile pollen grains are two-celled when shed but a high proportion of
flowers produces only sterile pollen whose development has been arrested at the one-nucleate
stage.
Continuous measurements of radial variation in Eucalyptus pauciflora Sieb. ex Spreng
Authors: Green JW
Published: December 2005

Improvised dendrographs of the Fritts type were used to make continuous chart
records of radial variation in trees of Eucalyptus pauciflora at two altitudinal sites
where, in addition, concurrent observations were made of some environmental variables.
The total period of observation was 186 days, which was presumed to cover the main
growing season.
Continuous data were digitized by means of a stripchart converter and the
converted data used to replot curves and to extract daily values of variables.
Broadly sigmoid seasonal growth curves were found to be modified by a period of
reduced growth in the hottest part of summer, by irregular fluctuations apparently
related to precipitation, and by regular diurnal fluctuations.
Unreversed increases in radius immediately following some falls of rain suggested
that rapid cell growth occurred at times of high tissue hydration.
An attempt to find a general explanation of daily radial variation in terms of
certain environmental variables by means of multiple regression techniques was not
successful. The results reflected to some extent the effects of precipitation referred to
above, but the order of importance of significant variables was inconsistent between
trees and between altitudes.
Development of the secondary phloem of the primary root of Pisum
Authors: Zee S , Chambers TC
Published: December 2005

The divisional pattern of the cambium in giving rise to the secondary phloem and the associated changes in the fine structure of the cellular components from the initial to the morphologically mature sieve element have been described. The fine structure of the sieve element plastid is of particular interest in that it lacks a well-developed internal membrane system but contains two characteristic inclusion bodies, starch granules (which often break up into smaller units) and protein crystalloids (which invariably show subunits with either one- or two-directional periodicity). Electron microscope autoradiographs were made of cambial cells and their phloem derivatives in tissues exposed either to [3H]thymidine for 24 hr (followed by growth in the absence of tracer for 4 days) or to [3H]uridine for 2-12 hr without a further growth period. The [3H]thymidine labels were specifically lodged in the chromatin material of the cambial initials, the companion cells, the phloem parenchyma cells, and the young sieve elements. During sieve element maturation the [3H]thymidine label became less specifically associated with the chromatin material. The pattern of labelling of the [3H]uridine in addition to being associated with the nucleolus was also associated with the chromatin, the electron-lucent areas of the nucleus, and the cytoplasm of the young sieve element, the companion cell and the phloem parenchyma indicating that these cells were all active in RNA synthesis. In the sieve element the nucleolus disappeared at a very early stage of development. This was associated with a decrease in [3H]uridine incorporation into the nucleus. As the tonoplast of the sieve element disintegrated, [3H]uridine incorporation into both the nucleus and the cytoplasm stopped, which is interpreted as a cessation in RNA synthesis. At no stage in the development of the sieve element was [3H]uridine incorporated into the "slime" material.
Reproductive development in two species of Darwinia Rudge (Myrtaceae)
Authors: Prakash N
Published: December 2005

In Darwinia the floral parts are differentiated in a "calyx-orolla-gynoeciumandroecium"
sequence. In individual buds stages of microsporogenesis markedly precede
corresponding stages of megasporogenesis. The anther is tetrasporangiate with all
sporangia lying in one plane. The secretory tapetum is one- to three-layered within the
same microsporangium and a large number of Ubisch bodies are formed. The anthers
dehisce by minute lateral pores and an ingenious mechanism helps disperse the twocelled
pollen grains.
A basal placenta in the single loculus of the ovary bears four ovules in D. micropetala
and two in D. fascicularis. In both species, however, only one ovule is functional
after fertilization. The fully grown ovules are anatropous, crassinucellar, and bitegmic;
the inner integument forms the micropyle. The parietal tissue is most massive at the
completion of megasporogenesis but is progressively destroyed later. The embryo sac
follows the Polygonum type of developnlent and when mature is five-nucleate, the three
antipodals being ephemeral.
Following fertilization, the primary endosperm nucleus divides before the zygote.
Subsequent nuclear divisions in the endosperm mother cell are synchronous and lead to a
free-nuclear endosperm which becomes secondarily cellular, starting from the micropylar
end at the time the globular embryo assumes an elongated shape.
Embryogeny is irregular and the mature embryo is straight with a massive radicle
and a hypocotyl which terminates in two barely recognizable cotyledons. Sometimes the
minute cotyledons are borne on a narrow neck-like extension of the hypocotyl. A
suspensor is absent.
Both integuments are represented in the seed coat and only the outer layer of the
outer and the inner layer of the inner integuments, with their thick-walled tanniniferous
cells, remain in the fully grown seed. The ovary wall is demarcated into an outer zone
containing oil glands surrounded by cells containing a tannin-like substance and an
inner zone of spongy parenchyma. In the fruit this spongy zone breaks down completely
but the outer zone is retained.
The two species of Darwinia, while closely resembling each other in their
embryology, differ significantly from other Myrtaceae. However, no taxonomic
conclusions are drawn at this stage, pending enquiry into the life history of other
members of the tribe Chamaelaucieae.
The shoot apex and the ontogeny of axillary buds in Cuminum cyminum L
Authors: Shah JJ , Unnikrishnan K
Published: December 2005

The structure and plastochronic changes of the shoot apex, and the origin,
development, procambialization, and vascular relationships of the axillary bud in
Cuminum cyminium were investigated.
Pre-leaf initiation, leaf initiation, and post-leaf initiation phases of the shoot
apex are identified. The inflorescence is axillary. During flowering the main vegetative
shoot apex is semispherical, stratified, and devoid of any distinction between the central
and peripheral zones.
The vegetative axillary bud is differentiated from the peripheral zone of the
shoot apex at the second node. It is delimited by an arcuate shell zone which helps
in changing the apical position of the bud to foliar. The emergence of the bud is effected
by the meristematic activity of tunica and corpus cells. A single prophyll is formed at
right angles to the axillant leaf.
Usually the bud trace procambium is differentiated during prophyll initiation.
Occasionally it may be seen earlier, but not in connection with the earliest visible bud
meristem. There are four to six strands of the bud trace directly interconnecting not
only the strands of the prophyll and axillant leaf traces but also those of the second or
sometimes even the third bud leaf and the axillant leaf. The bud trace procambial
connection is formed by basipetal and acropetal differentiation of procambium in
which the bud meristem cells and vacuolated ground meristem cells below the bud are
involved. The cells of the peripheral zone of the bud apex below the prophyll primordium
procambialize in a basipetal direction. As a continuation from the strand of the axillant
leaf trace, the adjacent vacuolated ground meristem cells below the bud acropetally
differentiate into procambial cells in the direction of the basipetal procambium and
they make connection with it. All the strands of the bud trace are not simultaneously
developed.
The vegetative and inflorescence buds show varying vascular relationships
between the strands of the leaf traces and those of the bud traces. The node differentiated
during the vegetative phase of the plant is trilacunar and the one formed at flowering
time is tetra- or pentalacunar. The nature and number of bud trace strands, however,
suggest fundamental similarities between vegetative and inflorescence buds.
Soil temperatures and seed burial in relation to the performance of Heteropogon contortus and Themeda australis in burnt native woodland pastures in Eastern Queensland
Authors: Tothill JC
Published: December 2005

The factors underlying the increasing dominance of Heteropogon contortus
(bunch or black spear grass) as a result of regularly burning native pastures in eastern
Queensland have been investigated. In the subtropical environment of this experiment
the removal of ground cover by burning or other means significantly increased the
average maximum temperature of the surface soil. Burning favoured the germination
of buried H. contortus seed at a time when ambient temperatures were too low for this
to occur in unburnt situations. In late seasons and in the seasonally dry tropics insufficient
soil moisture would tend to limit growth and germination until ambient temperatures
are high, in which case the burning effect would be less pronounced.
The efficient seed burial mechanism of H. contortus places it at an establishment
advantage over other commonly associated species such as blue grasses (Bothriochloa,
Dichanthium) and others whose seeds remain largely in the surface litter. Fire destroys
much of this litter, the microhabitat for seed germination at ground level, and some of
the weaker perennial plants.
The implications of these results in relation to the increased dominance of either
H. contortus or Themeda australis (kangaroo grass) are discussed.
Growth of heath vegetation. III. Growth curves for heaths in Southern Austrailia: A reassessment
Authors: Jones R , Groves RH , Specht RL
Published: December 2005

Two growth curves are presented for above-ground portions of heath stands in
south-eastern Australia. These curves represent the drier and wetter limits of the
geographical range of heath in this region.
The growth curves do not necessarily indicate the maximum production of each
site. This may be influenced by the development (or invasion) of taller-growing species,
such as Banksia ornata, B. serrata, Eucalyptus baxteri, or Leptospermum Iaevigatum, at a
later stage in the pyric succession.
Amorphotheca resinae, gen. nov., sp. nov.: The perfect state of Cladosporium resinae
Authors: Parbery DG
Published: December 2005

A description is given of the isolation, development, and morphology of
Amorphotheca resinae gen. nov., sp. nov., the perfect state of the "kerosene fungus",
Cladosporium resinae. The Amorphothecaceae fam, nov. is proposed to accommodate
this genus, and its affinities within the order Eurotiales are discussed.
The validity of the name Cladosporium resinae, which is retained, is considered
as well as the significance of the ascal state and variation within the species.
Some systematic aspects of Mitchell grasses (Astrebla F. Muell.)
Authors: Jozwik FX
Published: December 2005

The systematics of the genus Astrebla were studied with use of morphological,
distributional, anatomical, and breeding characteristics. Results show that the genus is
a group of closely related but well-defined species. The occurrence of F1 interspecific
hybrids is strongly suggested from field observations and glasshouse plantings but
because of sterility in the F1 generation hybridization between species apparently plays
little part in continuing evolution.
Species distributions are closely correlated with the occurrence of cracking clay
soils and show large discontinuities. Although Astrebla pectinata, A. elymoides, and A.
Squarrosa are common on the Barkly Tableland A. lappacea is generally absent from
that area..
Internal and epidermal leaf anatomy indicates that Astrebla is related to the
chloridoid line of grasses.
Prevention of cross-pollination showed that all species are highly self-compatible.
Circumstantial evidence suggests that large-scale apomixis does not occur.
Environmental control of reproduction in Themeda australis
Authors: Evans LT , Knox RB
Published: December 2005

Seedlings and older plants of 30 ecological races of Themeda australis were
grown under controlled conditions to determine the effect of day length and vernalization
on their flowering and on the incidence of apomixis. The races ranged in origin from
latitude 6°S. in New Guinea to latitude 43°S, in Tasmania.
One race from New Guinea and several from the Northern Territory behaved
as strict short-day plants. The more southerly races, on the other hand, and several from
north Queensland were long-day plants. In some, long days were required for both
initiation and development of the inflorescence, in others apparently only for initiation.
Some races required long days as seedlings, but not as older plants. Races from drier
inland areas tended to be indifferent to day length in their flowering behaviour. At least
four races from the colder areas responded to vernalization.
Both the sexual and the aposporous reproductive pathways are described. Two
races were wholly sexual in their breeding system and two appeared to be almost entirely
aposporous, but most were versatile, displaying both sexual and aposporous reproductive
behaviour. In seven races there was some evidence that day length influenced the
reproductive pathway, short days causing increased apospory in all cases, regardless
of the day length requirements for flowering.
The structure of reaction wood as indicated by scanning electron microscopy
Authors: Scurfield G , Silva S
Published: December 2005

Scanning electron microscopy was used to investigate the structure of normal
and reaction wood of Cupressus arizonica Greene, Pinus canariensis C. Sm., and
P. radiata D. Don. The wood of P. radiata was examined before and after various
chemical treatments. These included chlorine water-sodium hydroxide, glacial acetic
acid-hydrogen peroxide, sodium hydroxide-sodium sulphide, 17.5 % sodium hydroxide,
78 % phosphoric acid, 72 % sulphuric acid, 1 % osmic acid, and 2% potassium permanganate.
The helical ribs of the S2 layer in reaction wood cells appeared to be multistranded.
Warts tended to become fewer and restricted to the grooves in the S2
layer during the change-over from normal to reaction wood cells. The origin and
chemical composition of the warts and associated membrane are considered.
A contribution to the life history of Angophora floribunda (Sm.) Sweet (Myrtaceae)
Authors: Prakash N
Published: December 2005

The flower buds of Angophora floribunda appear in the last week of November
and anthesis occurs in the middle of January the following year. There is no
prolonged resting phase at any stage during embryology and the seeds are shed
during late February to early March.
In floral development, the petals are the last structures to be formed. Early
anther development precedes corresponding stages in the ovules of the same flower,
but events in the ovules proceed more rapidly and meiosis occurs simultaneously
in the spore mother cells of both organs. The mature two-celled pollen grains are
shed when the ovules contain four-or eight-nucleate embryo sacs.
Many flowers bear anthers containing only sterile pollen grains, which occur
either singly or as tetrads. Various abnormalities in the development of the pollen
are reported, and the anthers containing sterile pollen neither develop fibrous bands
in the endothecium nor do they dehisce.
The ovules are bitegminal, crassinucellar, and hemianatropous. Occasional
bifurcation of the inner integument was observed and a hypostase differentiates at
the four-nucleate stage of the embryo sac. The embryo sac follows the Polygonum
type of development and is five-nucleate and four-celled when mature.
The endosperm is Nuclear in origin, and in about half the seeds examined a
granular unidentified substance accumulates in the embryo sac. The development
of the embryo is irregular and the seedlings bear a collar-like structure at the junction
of the hypocotyl and the radicle. The mature embryos are usually dicotyledonous
but rarely tricotyledonous.
The seed coat is formed exclusively by the outer integument; in the ripe seed
it consists of an outer epidermis of large, palisade-like, thin-walled, tanniniferous
cells and an inner crystalliferous layer.
Oil glands and ducts in Eucalyptus L'Hérit. I. The phloem and the pith
Authors: Carr SGM , Carr DJ
Published: December 2005

Most (94 %) of the known eucalypts have been examined for the presence of oil glands in vegetative tissues other than the mesophyll and the primary cortex of the stem. In certain species oil glands occur in the pith and, in a few cases, in the midrib as well. In others (series Corymbosae) oil ducts occur in the pith and in the midrib. In others again (Macrantherae Normales) glands are formed in the phloem of both root and shoot. As a general rule, species which have glands or ducts in the pith do not have glands in the phloem, and vice versa. The only exceptions are provided by nine species of the "eudesmioid complex" (defined below). Of eucalypt species, 58 % have no glands in either the pith or the phloem. It is believed that glands never develop in the primary cortex of the root but always in that of the shoot. The occurrence of glands in the pith or the phloem is constant in many species but others show great variability in the numbers of glands present. Possible explanations for the observed variability are suggested and further lines of investigation are indicated. The age of the tree at which glands first appear in the bark varies widely from one species to another and less widely within species; glands appear precociously in root bark. The age of the secondary phloem itself at which it produces glands also shows wide variations between species. In the Corymbosae the full development of the oil duct system is closely correlated with the ontogenetic juvenile-adult foliage change. The taxonomic implications of the presence or absence of glands in the pith and phloem are discussed. The characters have proved useful for field and herbarium identification. The presence or absence of pith glands is particularly valuable in dealing with Western Australian species.
Effects of moderate sheep stocking on plant populations of a Black oak-Bluebush association
Authors: Barker S , Lange RT
Published: December 2005

Investigations aimed at improving analysis and description of vegetation
changes during long-term stocking in arid areas are described. A hypothesis that
vegetation change will be patterned as is stocking pressure over an area is examined.
In arid areas, this implies radial gradients about a water point. An area of arid
zone vegetation was selected, described floristically, and sampled for species incidence
and density through an arc of 110° at ranges up to 2000 yd from a dam.
Significant linear regressions describe relationships for several species between
density and radial distance from water. Similarly a map can be constructed on an
analysis which shows the strengths and direction of influences on species incidence;
this pattern is concentric on the water point. It appears that vegetation changes
consequent on grazing agree with the original hypothesis, and are susceptible to
improved description by regression equations and other statistical analyses leading
to precise quantitative mapping.
The implications of these results are discussed.
Rhizobium affinities and phenetic relationships within the genus Stylosanthes
Authors: t'Mannetje L
Published: December 2005

Twenty-one accessions of seven Stylosanthes species were subjected to infection
with 25 Rhizobium strains. The introductions differed markedly in the number of
Rhizobium strains with which they could fix atmospheric nitrogen. Recommendations
for the best strains to use for each introduction are made. Rhizobium affinities, obtained
by a numerical analysis of the nitrogen yield of plant tops, are compared with relationships
between the hosts based on morphology, cytology, and flowering behaviour.
Although the two measures of affinity did not yield identical results, this study indicates
the usefulness of Rhizobium affinities in taxonomic studies in much the same way as
cytological and chemical information is used. The morphological and other differences
between introductions of S. guyanensis were further emphasized by their Rhizobium
affinities and it is concluded that four different taxa may be involved.
Light intensity and the growth of Eucalyptus seedlings. I. Ontogenetic variation in E. fastigata
Authors: Cameron RJ
Published: December 2005

Morphological and physiological variation associated with ontogenetic development
is described for E. fastigata and their significance in ecology is discussed. Juvenile,
intermediate, and adult leaf stages are identified. These differ in such morphological
characteristics as leaf orientation, shape, thickness, chlorophyll content, and anatomical
structure (including size, abundance, and distribution of stomata), all details which, in
juvenile and intermediate leaves at least, are modified by the light climate under which
the plants are grown. There are also significant physiological differences between
juvenile and intermediate growth stages, particularly as concern apical dominance and
rates of apparent photosynthesis, and modification of these by light climate. A comparison
of juvenile and intermediate leaves shows that the former possess a number of
features which should permit them to function better in conditions of low light intensity
but, contrary to such expectations, rates of apparent photosynthesis are higher in intermediate
leaves. That this is so is, it is suggested, due to differences in photosynthetic
enzyme activity, an hypothesis which has not been investigated.
The resistance of Pinus radiata to infection by Macrophoma pinea
Authors: Marks GC , Minko G
Published: December 2005

The resistance of wounds made on Pinus radiata to infection by Macrophoma
pinea was examined experimentally in the greenhouse and field. A study was made of
the anatomy of the epidermal tissues of the leader and stem, of injuries of different
ages, and of the recovery stages after inoculation.
There were many structural similarities between bark and wound periderm.
Both provided mechanical barriers to infection by M. pinea. Wound periderm began
to form 3-9 days after injury, and the mechanical barriers appeared after about 18
days. Wounds became resistant to infection after about 3-9 days, which suggests that
this resistance was associated with biochemical changes in the uninjured cells lining
the wound rather than with the appearance of the mechanical barrier.
Superficial injuries occluded rapidly. Wounds on fast-growing trees, however,
healed slowly when the cambium was injured; the rapid growth of the xylem continually
lifted the callus that was formed over the injury, providing new entry points for
M. pinea. This may explain the greater incidence of malformations on very productive
sites.
Adaptations in the genetic system of Australian arid zone Cassia species (Leguminosae, Caesalpinioideae)
Authors: Randell BR
Published: December 2005

Cassia is a large genus primarily of tropical and subtropical lowlands. However, one species group, series Subverrucosae of section Psilorhegma, has undergone a major development in the Australian arid zone, where it is a conspicuous element in the woody shrub flora. This species group is characterized by (1) widespread hybridization, involving most of the species of the complex over most of its area, (2) polyploidy, which occurs as an infraspecific and infravarietal phenomenon, with the highest frequency and at the highest levels recorded in the genus, and (3) apomictic reproduction through adventitious embryony. The occurrence of adventitious polyembryony in Cassia appears to be confined to series Subverrucosae and almost restricted to the polyploid forms. It is suggested that the balance between fitness and flexibility provided by these three features is an adaptation for the widely fluctuating environment of the arid zone. The diploid forms, which are parental to the complex, have relic occurrences in old moun- tain areas, and appear to be strongly reproductively isolated. Under conditions of fluctuating selection pressures, infraspecific polyploidy has had selective advantage in limiting the genetic effects of outbreeding. Polyploidy has also weakened isolation mechanisms and allowed extensive hybridization in populations colonizing the intervening plains. Adaptive biotypes have been maintained partly by the conservative effects of polyploidy but especially by the establishment of facultative apomixis, which allows continuous recombination concurrently with the fixation of successful genotypes. The equilibrium between recombination and conservation may shift in accordance with changes in habitat stability.
The cytology of Brachycome. I. The subgenus Eubrachycome: A general survey
Authors: Smith-White S , Carter CR , Stace HM
Published: December 2005

Chromosome number determinations and cytological observations are reported for 37 recognized taxonomic species and varieties, and for a number of undescribed species and chromosome races in Eubrachycome. Additionally, chromosome numbers are reported for six species of Metabrachycome and two species of related genera. A wide range of numbers has been found. It is inferred that x = 9 is the primitive base number in the group.
Eubrachycome has used various modes of chromosomal change, including polyploidy, amphidiploidy, decrease in base number, and the establishment of B. chromosomes. The present taxonomy of the group requires revision, taking into account cytological data. Primitive Eubrachycome was probably a mesic perennial. The evolution of desert species has involved reduction in chromosome number and the adoption of the annual habit, but other methods of desert adaptation have been available. Many species are chromosomally unstable, and may have been subject to catastrophic selection.
The physiology of growth in Subterranean clover. I. Seedling growth and the pattern of growth at the shoot apex
Authors: Williams RF , Bouma D
Published: December 2005

The shoot apex of Trifolium subterraneum L. is spirodistichous, with a divergence
angle of 160° and a phyllotaxis index of 2.
The vegetative plant is defined quantitatively in terms of lengths of successive
leaves, leaf areas, and dry weights of the leaves and all major plant parts for a 29-day
growth period. The selected environment gave very high values of net assimilation rate
(3 .0 mg cm-2 day-1for early growth).
The properties of the shoot apical system are further defined in terms of volumes
of meristematic and very young parts. The picture is extended by linking it with fresh
weight data for the leaves. To a remarkable extent the data, transformed to logarithms,
can be accounted for by arrays of linear regressions on time, the members of which show
decreasing slopes with increasing leaf number. However, the most instructive description
is obtained from an array of relative growth rate curves for successive leaves.
While the existence of one general pattern of leaf growth seems unlikely, there
is evidence for a marked increase in relative growth rate during leaf initiation. Exponential
growth in length seems to be fairly common in young leaf primordia, but
exponential growth in volume occurs in a variety of patterns in different plants. Attempts
to link these occurrences with events in vascular differentiation and thus with
the supply of substrate for growth have not been successful. It is suggested that
properties of the system as a whole may be relevant.
The physiology of growth in Subterranean clover. II. The dynamics of leaf growth
Authors: Williams RF , Rijven.A.H.G.C .
Published: December 2005

This study extends the account of the development of the fourth leaf of subterranean
clover. In particular, the four leaf constituents deoxyribonucleic acid,
ribonucleic acid, proteins, and cell wall materials are expressed on whole leaf and cell
bases.
Form change in the leaf is illustrated with perspective elevations for some early
stages.
Cell number increases exponentially until day 13, with a mean generation time
of 18 hr. The final number per leaf is c. 6.5 million, and deoxyribonucleic acid phosphorus
is estimated as 0.197 pg per cell.
The leaf is highly succulent, with a maximum water content of 478 % dry weight.
Soluble constituents are also high, with a maximum of 39 % of the dry matter.
The absolute amounts of ribonucleic acid phosphorus and protein nitrogen are
maximal on days 19 and 25 respectively, with losses of about 60% by day 36.
Cell wall materials increase from 8 to 57 % of the residual dry weight during a
period of 4 days prior to emergence. This is shown to be due to the concurrent
differentiation of the vascular system and the growth of 3000 leaf hairs.
Changes on a per cell basis are recorded, and the concept of relative growth
rate is used to extend the analysis of the data. Rates of production of one constituent
per unit of another are also presented and discussed.
The genesis of form in flax and lupin as shown by scale drawings of the shoot apex
Authors: Williams RF
Published: December 2005

Procedures for the preparation of perspective drawings from serial sections of
shoot apices and similar small structures are described, and the properties of the
projection are critically examined.
The procedures have potential value for morphogenetic studies, and examples
are given for shoot apices of flax and lupin. For lupin it is shown that the folioles
arise in an oblique circle at the top of the emerging petiole. After the median member,
they appear in pairs at unit plastochron intervals.
Rooting of stem cuttings of Eucalyptus: A rooting inhibitor in adult tissue
Authors: Paton DM , Willing RR , Nicholls W , Pryor LD
Published: December 2005

The available physiological evidence suggests that ontogenetic ageing of E.
Grandis seedlings involves a direct and quantitative association between decreased
rooting ability of stem cuttings and increased levels of a rooting inhibitor in the tissue
forming the base of the cutting. As detected by bioassay, this inhibitor is present only
in adult tissue, which very rarely forms roots from stem cuttings. It is absent in easily
rooted seedling stems of all Eucalyptus species tested, but it is also absent in the easily
rooted adult tissue of the exceptional species E. deglupta. The ability of seedling
cuttings of E. deglupta to root very easily in water provides an appropriate bioassay
for monitoring the presence of inhibitor in other Eucalyptus species.
Phellogen initiation in the stems of Eucalyptus camaldulensis Dehnh
Authors: Liphschitz N , Waisel Y
Published: December 2005

The induction of phellogen in E. camaldulensis stems by various environmental
factors was investigated.
High humidity and a continuous flush of oxygen were found to cause early
initiation of the phellogen. Light, temperature changes, or mechanical pressure did
not play an important role in the initiation of phellogen as long as they were applied
under dry conditions.
Oil glands and ducts in Eucalyptus L'Hérit. II. Development and structure of oil glands in the embryo
Authors: Carr DJ , Carr SGM
Published: December 2005

Oil glands are initiated in the cotyledons and hypocotyl of the eucalypt embryo
at a very early stage in its development, shortly after the "heart stage". The pattern
of development of these glands is remarkably uniform throughout the genus. The
gland is formed from a single epidermal initial which cleaves to form three tiers of
cells. The epithelial cells and some of the casing cells of the gland arise from the
innermost tier. A subepidermal cell also divides to add to the lower casing of the
gland. The programme of divisions of the gland initial appears to be completed
rapidly, well before seed maturation. No oil is secreted until a stage in germination
when the cotyledons begin to expand away from each other and turn green. The oil
cavity of the gland is formed schizogenously, i.e. is an intercellular space. Contrary
to the opinion generally accepted in the recent literature concerning eucalypt oil
glands, there is no resorption of cells, and the cytoplasm, nucleus, and cell wall of
each epithelial cell persist until senescence of the cotyledon. Aspects of the cytology of
the gland cells and other cells of the embryo are described. The walls separating
cells formed in early stages of gland development are tenuous, non-staining, and
remarkably deformable. In one species starch appears in all cells of the gland early in
germination but disappears before oil formation. Throughout seed maturation,
there are striking differences in the morphology of the nuclei of glands and those of
mesophyll cells, which are engaged in storing reserves. The formation of the oil
cavity is preceded by localized thickening of the cell walls of epithelial cells. Splitting
takes place probably by hydrolysis of the middle lamella at the locus of wall thickening.
The cytoplasm of the innermost casing cells appears to degenerate and these
cells may fill with polyphenolic materials. The outer walls of these cells and those
of some other cells of the gland become impregnated with substances such as suberin
or lignin which resist acid hydrolysis.
Complex hybridity in Isotoma petraea. III. Lethal system in Θ12 Bencubbin
Authors: Beltran IC , James SH
Published: December 2005

Analysis of selfed capsules of a ring of 12 (Θ12) complex heterozygote
confirms the presence of a balanced lethal system. One of the complexes, S' is two
interchanges removed from the primitive chromosome end sequence and when homozygous,
causes the abortion of seeds after differentiation of the testa has begun.
The other complex, Ne, is three interchanges removed from the primitive sequence
and the lethals in it operate, when homozygous, before the testa differentiates. Twin
hybrids from crosses between the Θ12 and an alethal structural homozygote exhibit
epistatic segregation ratios in their selfed capsules, demonstrating that the lethals
in the two complexes are not controlled by single loci. An hypothesis based on
relatively translocated internal chromosome segments is developed as the basis for
the evolutionary elaboration of the balanced lethal systems in I. Petraea complex
hybrids.
Pattern analysis of Scleropyll trees aggregated to different degrees
Authors: Westman WE , Anderson DJ
Published: December 2005

Pattern analysis data are presented for a number of tree species populations
sampled from two sites located in dry sclerophyll forest within the Ku-ring-gai Chase
park of New South Wales. The distributions proved to be predominantly contagious
or random, with regularity occurring only occasionally. Observed variations in the
degree of aggregation exhibited by a species were taken into account in interpreting
pattern analysis curves. The relation of pattern analysis data to sample quadrat data
fitted to known mathematical models is extremely variable, and it is shown that pattern
at block sizes other than the one under consideration may suppress the appearance of
deviations from randomness at block sizes which do show contagion when sampled with
randomly placed quadrats. The possible origins of contagious distributions in eucalypt
forest are briefly discussed.
Optical properties of leaves of some species in arid South Australia
Authors: Sinclair R , Thomas DA
Published: December 2005

Reflection and transmission spectra were measured for the leaves of a number
of species of South Australian arid zone vegetation, over the wavelength range 350-
1350 nm. Spectra were also obtained for several non-arid species for comparison.
Coefficients of reflection, transmission, and absorption of solar radiation were calculated
from these spectra, and also obtained from direct measurements made with a
specially constructed reflecting hemisphere.
The coefficients of reflection for the arid zone species covered a wide range of
values, and the group as a whole could not be clearly separated from the comparison
group on the basis of reflection or absorption coeficients. Of the species in the group,
Atriplex vesicaria had the highest coefficient of reflection, and also the lowest coefficient
of absorption.
The leaf waxes of the genus Eucalyptus L'Héritier
Authors: Hallam ND , Chambers TC
Published: December 2005

A survey of 315 species of the genus Eucalyptus demonstrated that the patterns of
leaf wax structure as revealed by means of electron microscopy can in some instances
aid the classification of this taxonomically complex genus. Within Eucalyptus there
are three main wax types: plates, tubes, and a mixed wax of both plates and tubes.
The degree of ornamentation of the margins of the plates can frequently be correlated
with taxonomic groupings or suggested evolutionary trends based on other lines of
evidence. Similarly tube waxes, depending on their branching pattern and arrangement
on the leaf surface, also proved useful as indicators of natural groupings of species. A
number of taxa known to be misfits on various morphological characters within the
most widely used classification of the genus (Blakely's "Key to the Eucalypts") are also
shown to be misfits on the basis of wax characters. Already recognized affinities of large
groups of species within the genus are supported by evidence from wax morphology.
A study of the chemistry of eucalypt waxes by means of infrared and ultraviolet absorption
spectroscopy confirms many of the results of the taxonomic study based on
wax morphology.