The revolutions made by the plant-scripts led to the discovery of
certain new and unsuspected reactions in the life of plants, notably the
influence of variation of temperature in modifying thegeotropic
curvature. There are at least ten variables, which by their joint
effects give rise to over a thousand variations in the resulting
movement of plants. The effect of each of these different factors has
been isolated and a new theory propounded which offers a complete
explanation of the so called sleep movements. The life reactions of
plants to the various stimuli of the environment was most strikingly
illustrated by means of supersensitive Magnetic Crescograph. The plant
was shown to perceive the shock of light, to which it made an answering
signal, so also to the action of warmth and cold. And it was explained
how the various combinations of effects induced by environmental change
found diverse expressions in the movement of plants.
The scientific explanations offered for the opening and closing of the
water lily is that the flower is closed under sunlight and that the
opening takes place under darkness. But Prof. Bose has been able to keep
the lily awake even in day time by placing it in a cool place.
Simultaneous record of the movement of the flower and the thermograph of
daily variation of temperature proved conclusively that a rapid fall of
temperature in the evening brought about the opening of the flower, at
first slowly then rapidly, and by 10 p.m. the flower was fully expanded.
About 6 a.m. in the morning there is a rise of temperature, and the
reverse movement of closure sets in. The flower continues to close very
rapidly the sleep movement of closure is complete by about 10 a.m.
It will be seen how different flowers through their sensitiveness to
heat and cold execute movements of "sleep" or of "waking." Some of them
have the healthy habit of normal humanity to sleep at night and keep
awake at day-time. Others turn night into day, and make up for their
long night watch by sleeping it off at the day-time.
--_Amrita Bazar Patrika_, 25-1-1919.