Sir Jagadis Chunder Bose | Page 7

of the Botanical Section at Belfast, in his address, observed "Some very striking results were published by Bose on Electric Response in ordinary plants. Bose's investigations established a very close similarity in behaviour between the vegetable and the animal. Summation effects were observed and fatigue effect demonstrated, while it was definitely shown that the responses were physiological. They ceased as soon as the piece of tissue was killed by heating. These observations strengthen considerably the view of the identical nature of the animal and vegetable protoplasm."
Dr. Bose then brought out a systematic treatise embodying the results of his researches under the significant title of 'Response in the Living and Non-living.' He returned to India, in October, 1902.
GOVERNMENT RECOGNITION
After he had come back, from the Second Scientific Deputation, the Government of India conferred on him the distinction of Companion of the Order of the Indian Empire, in 1903, in recognition of his valuable researches.
PLANT LIFE AND ANIMAL LIFE
Next Dr. Bose, in natural sequence to the investigation of the response in 'inorganic' matter commenced 'a prolonged study of the activities of plant life as compared with corresponding functioning of animal life.'
ALL PLANTS ARE "SENSITIVE"
It was believed that so-called 'sensitive' plants alone exhibited excitation by electric response. But Dr. Bose, believing in continuity of responsive phenomena, used the same experimental devices, with which he had already succeeded in obtaining the electric response of inorganic substances, to test whether ordinary plants also--meaning those usually regarded as 'insensitive'--would or would not exhibit excitatory electrical response to stimulus. With the help of very delicate instruments, Dr. Bose demonstrated the very startling fact that not only every plant, but every organ of every plant gave true excitatory electric response--and that response was not confined alone to 'sensitive' plants like Mimosa.
Dr. Bose then proceeded to investigate whether the responsive effects which he had shown to occur in ordinary plants might not be further exhibited by means of visible mechanical response, thus fully removing the distinction commonly assumed to exist between the 'sensitive' and supposed 'non-sensitive.' Dr. Bose invented 'special apparatus of extreme delicacy,' which detected infinitesimal tremors, and showed that ordinary plants, usually regarded as insensitive, gave motile responses, which had hitherto passed unnoticed. His later investigation shows that "all plants, even the trees, are fully alive to changes of environment; they respond visibly to all stimuli, even to the slight fluctuations of light by a drifting cloud."[17]
'TROPIC' MOVEMENTS
Finding that the plants give, not only electric but motile response as well, to stimulus, Dr. Bose proceeded to study the nature of responses evoked in plants by the stimuli of the natural forces. He found that plants respond visibly, by movements, to environmental stimuli. But the movements induced--'tropic' movements--are extremely diverse. Light, for example, induces sometimes positive curvature, sometimes negative. Gravitation, again, induces one movement in the root, and the opposition in the shoot. Dr. Bose applied himself to find out whether the movements in response to external stimuli, though apparently so diverse, could not be ultimately reduced to a fundamental unity of reaction. As a result of a very deep and penetrating study of the effects of various environmental stimuli, on different plant organs, he showed that the cells on two sides are unequally influenced, on account of different external conditions, and contract unequally, and hence the various movements are produced--that the many anomalous effects, hitherto ascribed to 'specific sensibilities,' are due to the 'differential sensibilities'--differential excitability of anisotropic structures and to the opposite effects of external and internal stimuli--that all varieties of plant movements are capable of a consistent mechanical explanation. Dr. Bose's "latest investigations recently communicated to the Royal Society have established the single fundamental reaction which underlies all these effects so extremely diverse."[18]
EXTENDED APPLICATION OF MECHANICAL THEORY
With an extended application of his mechanical theory, Dr. Bose has gradually removed the veil of obscurity from many a phenomenon in plant life. The 'autonomous' movements of plants, for example, which remained enveloped in mystery, received a satisfactory solution at his hands.
'AUTONOMOUS' MOVEMENTS
It was believed that automatically pulsating tissues draw their energy from a mysterious "vital force" working within. By controlling external forces, Dr. Bose stopped the pulsation and re-started it and thus demonstrated that the 'automatic action' was not due to any internal vital force. He pointed out that the external stimulus--instead of causing, as was customary to suppose, an explosive chemical change and an inevitable run-down of energy--brings about an accumulation of energy by the plant. And with the accumulation of absorbed energy, a point is reached when there is an overflow--the excess of energy bubbles over, as it were, and shows itself in 'spontaneous' movements. The stimulus being strong a single response--a single twitching of the leaflets--is not enough to express the whole of the leaf's responsive energy and it yields a multiple response--it reverberates--it