The Barre daily times. (Barre, Vt.) 1897-1959, 1920-12-11
LIGHT AND PLANT LIFE.
Sunshine Supposed to Be Necessary But
Possible to Haze Too Much.

1t has been agreed by all sorts OF
people from farmers to scientists that
sunlight is necessary for normal growth
of most kinds of plants. The farmers
discovered it through the appearance OF
sprouting tubes in the cellar and the
scientists by experiments which
brought about like results, but now the
scientists have gone . step further and
have learned that it is possible for
plants to have too much daylight, that
is to say, too many hours of sunlight
in comparison with the number of hours
of darkness
That explains, for instance, why
| some flowers blossom early in the
spring while others require a long pc
. Rod of light before their efflorescence,
but it also appears that the intensity
of the light has less significance upon
the growth of the plant than has been
supposed. Greenhouse experiments have
shown that the fswering and fruiting
period of any plant can be brought at
any period of the year by darkening
the greenhouse in the morning and eve
ming if the day is too long or by
lengthening the day by artificial light
if the day is too short.
Violets, for example, bloom during
the short days of early spring, but if
the plants are put in light proof boxes
at night and not uncovered until well
after sunrise the plants can be forced
TO bloom again in the summer. Thus
spring flowers and spring crops are
such because the days. at their season
OF Towering and fruiting, have the
proper number of daylight hours. So,
too, the early summer flowers and crops
must have a longer period of daylight.
The plant cannot attain TO reproduc-
ton except when it is exposed to a
favorable length of DAYS, but length
of day which is lunfavorable to repro
duction may be favorable to growth
and under such conditions the plant
continues its vegetative development
but produces no fruit.
Tests have been made with soy
beans, tobacco, wild aster, climbing
hempweed, beans, ragweed. radish, car
rot, lettuce. hibiscus, goldenrod, spin
ach, iris. buckwheat and various other
plants and all responded to it. Soy
beans were exposed to the light from
10 a. M to 3 p. m, from May 20 70
September 4, while other bean plants
terminated at the same time were
given the normal amount of daylight.
The first blossoms appeared on the
darkened plants on June 10, but none
appeared on those that were left in the
light until September T. The dark
house plants at the latter date were six
- oh HI lss..~
ing full daylight were 81 or IS inches
showing that the plans required a short
day and a long night for Towering and
seed bearing.
The length Of day, Il has been found
is more important than temperature
for the results were the same when the
Temperature was higher in the dark
house than in the open and plants that
were left in the dark for a part of The
hay underwent in midsummer the change
that in nature comes in the fall and
have been attributed to lower tempcra.
lure.
These scientists are discovering
something for the theory which theil
experiments develop shows why MANY
plants grow best near the northern I'm
Il Of their range for the long norther-
iay allows them 20 attain Their max
mum growth before the shorter dal
checks growth and starts reprOdue
Rive process. II may be found, 50 thes'
scientists think. that the annual organ
sm responds 20 the stimulus q Ger
ain day lengths and that the migra
tion cf birds j. an effect q IL The-'
nfen are Increasing knowledre--HA<s
"a Courant-