The Devils Lake world and inter-ocean. (Devils Lake, N.D.) 1915-1920, 1920-04-28
PLANT LIFE IS.
RULED BY LIGHT
U. S. Experts, After Experiments,
Advance Principle That Is
Revolutionary.
TEMPERATURE IS NEGLIGIBLE
Flowerino and Fruitine Period Of Prae.
ticaily Any Plant Can BE Controlled
by le%nothenino Day by Arti.
fetal Light.

Washington, d. C.-Government az
ricultural experts have discovered that
plant life seems to depend on light,
rather than temperature, for nourish-
ment and may be controlled by regu-
lating the hours of light and darkness.
The principle is revolutionary; but
1t rests on actual experiments, in which
1t was demonstrated that plants sub
jected to alternate periods Of light and
darkness in carefully determined pro-
portions could be brought to maturity
at any time of the year.
Greenhouse experiments" saws an
announcement by the department of
agriculture, prove that the. Towering
and fruiting period Of practically any
plant n be made to take place at any
time Of year by darkening the green
house IN the morning and evening, II
the day is too long, or by frightening
the day by artificial light II the day Is
too short.
Flowers That Bloom in Spring.
Spring flowers and spring crops
happen to be spring flowers and spring
crops because the days at the season
of their Towering and fruiting have
the proper number of hours Of day.
light"
The discovery may be of the highest
Importance in the future planning Of
cropping systems for different regions.
Eventually 1t may be found, accord
ing to w. w. Garner and H. A. Allard,
scientists in the bureau of plant indus
try, who conducted exhaustive expert
ments. that the animal organism also
is capable Of responding to the stimu-
lus Of certain day lengths. They be-
lieve that the migration of birds may
be an illustration, on the ground that
direct response to such q stimulus
would be more in line with modern
biological teachings than theories
which assume that birds go south"
as a matter Of instinct.
Experiments were conducted with a
large variety of plants. 1t was shown
conclusively that too little "sleep," or,
in other words too many hours of day
light, would prevent many plants from
even reaching the Towering and fruit
ing stage.
1t was found also that plants would
not reproduce except when exposed to
a favorable length of day, although too
much daylight for towering and fruit
ing might stimulate profuse vegetative
growth. A length Of day favorable
both to reproduction and growth re-
suits in the "ever-bearing" type of
fruits. II
BY employing dark chambers the sci
entists shortened or heightened the
life cycle of plants and forced some of
them to complete two cycles in one sea
son. Violets, which naturally bloom
only during the comparatively short
days of spring, when covered with
light-proof boxes for a time were made
to bloom again during the summer.
Biloxi soy beans exposed to the light
for only five hours a day Powered near
ly three months earlier than plants left
in the light all day, but attained only
about one-eighth of the height.
Temperatures Effect Slight.
Temperature appeared to exert no
influence in the tests. A striking H.
lustration Of the relative unimportance
of temperature was given in the fact
that plants kept in the dark for q part
Of the day underwent in midsummer
the changes that in nature come in the
fall and that, heretofore, have been at
tributed to lower temperatures. This
was true even when the dark houses
registered a higher temperature than
the outside atmosphere.
1.-The length Of the day." the depart
ment's announcement said, lis proved
to be the most potent factor in deter
mining the relative proportions be-
tween the vegetative and fruiting parts
of many crop plants. Indeed, fruiting
may be completely suppressed by a.
day too long or too short. This new
principle undoubtedly explains the. err
ratio. behavior which has been observed
with many crops when they are shifted
to different latftudes." '1