Researches on Growth of Plants

Abstract

II. The General Principle Determining Tropic Movements. THE movements in plants under the stimuli of the environment—the twining of tendrils, the effect of tcmperature variation, the action of light inducing movements sometimes towards and at other times away from the stimulus, the diametrically opposite responses of the shoot and the root to the same stimulus of gravity, the night and day positions of organs of plants—present such diversities that it must have appeared hopeless to endeavour to discover any fundamental reaction applicable in all cases. It has, therefore, been customary to assume different sensibilities especially evolved for the advantage of the plant. But teleological argument and the use of descriptive phrases, like positive and negative tropism, offer no real explanation of the phenomena. I propose describe experimental results from which it will be possible to discover an underlying law which determines the various tropic movements in plants.