Evening star., 1923-08-26

mentioned, the men in charge took up
another variety OF the soy bean.
called the Peking, and similar results
were obtained. thus proving that the
method employed fitted not only one
class Of beans but others.
4 y 4 y
EXPERIMENTS were then made
IL with the common wild aster, and
it was found that when the flower
was exposed to but seven hours OF
light daily. it was in bloom in thirty
six days instead of the usual 125.
The same result was obtained with
a variety of Lima bean that does not
ordinarily flower in Washington until
late in the fall. Under the improved
| methods it bloomed in twenty-eight
days. A common rasweed behave in
similar manner.
The chrysanthemun is a flower thar
usually makes its appearance about
the time that the football season
opens. and we have never looked for
it during the summer months. Now
, it can be made to bloom by shorten
ing the days Of sunlight, so we may
have the blooms to wear at base bal,
ga mes if We desire.
Old-time florists often bemoaned
! the fact that the highly colored poin-
settia could only be placed on sale
during the Christmas season, but now
the men who have reyolutionized the
plant industries can take this beauti-
full specimen and By reducing the
period of daylight to ten hours cause
it to develop in August.
There is a large group or plants
ip<, ~, 4
mer ANIMALS, which regularly flower
after midsummer as a result OF de
crease in the length of the day:
While relatively short days favor
Towering and fruiting in these plants.
long days are more favorable TO rapid
and extensive vegetatiye development
! Some of these plants, therefore, If
they receive the full benefit of the
long days Of summer, may reach giant
proportions before being brought into
the Towering condition. Thus We
can understand why it is that when
the farmer plants some crops too
early there is tendency toward ex-
cessive development Of leaf and stem.
with little Towering or fruiting.
, Late planting. on the other hand. may
lead to dwarfng in growth but abun-
Gant Towering and fruiting.
Let US look at the other side Of the
picture and see what can be accom-
plished b. giving longer periods o,
daylight TO those plants that need
: more than the ordinary amount OF
daylight or its counterfeit. If they
are to do things that are not don-
in the usual course OF growth. Il
striiti contrast with the group ct
plants already discussed is a second
group regularly towering in Lave
| spring or early summer. 1t is obri-
Gus that these plants do not require
short days to reach the Towering
! stage. On the contrary. it has been
! found that short days prevent. or az
J least greatly delay. towering o.
! fruiting. To this class OF plants be-
! long the so-called winter ANIMALS
! and many OF our common vegetables.
! Take the humble radish. The
Scarlet Globe variety. planted May L.
began to blossom June q. when OK
posed to the natural length Of day
! 4 similar planting. made at the same
, time. but allowed 10 receive only
seven hours of light. grew slowly and
formed no towering stem.
I * :: x =
| Tn cumming up the results, We find
i that IN summer the daily light
period is readily shortened by use OF
; dark chambers, into which the plants
are placed for a portion OF the day.
In this way, various plants may be
forced into Towering or fruiting out
of their natural season or plants
normally towering and fruiting in
summer may be prevented from doing
so.
! On the other hand, to initiate
! Towering out OF season in long-dar
plants during the short days OF win
ter. or TO prevent its occurrence IN
short day plants. It would be neces
sa;y to lengtflen the daily period OF
, illumination.
| The greenhouses in which the eX-
periments took place were fitted with
series OF 4o-watt electric lights.
evenly distributed overhead. so that
i the average intensity of about three
! to five candle power was obtained i'm
mediately above the soil surface. The
! electric light was used from sunset
| till about midnight each day. The
! intensity OF the light used seems in
, significant in comparison with day.
! ligzt. but, most striking results wer-
obtained. For comparison there wefe
plants grown in similar greenhouses
without the use of electric light
! These experiments have opened VI
| a wide field for experimentation and
study, and while at present it is pos
sible only to indicate broadly sope
of the directions in which it seems
! most likely that practical applica-
tion of the principles can be made,
yet enough work has been done tn.
demonstrate that correct interpre-
tation of the effects of length of day
upon plants will be great aid in-
! reaching a better understanding of
the causes which limit the natural
habitat of most plants. a problem
which has been difficult one to
solve.
To the farmer, the facts which have
been established will strongly en-
phasize the importance of accurately
knowing the correct season for plant
ing each OF his crops in order to Sc
cure the highest returns
The plant breeder should be able
to gain a better insight into some of
his problems, such as securing for
any particular region earlier or later
varieties. more fruitful or larger
growing forms and improved ever
bloomers and everbearers.
1t often happens that plant breeders
are unable to make crosses between
certain plants because of differences
in time of Towering of the two par
entail types. In such instances ar
tiGnial cnnfrn1 nf the daily Light