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RESEARCHES ON IRRITABILITY OF PLANTS
VELOCITY OF TRANSMITTED IMPULSE IN PLANTS
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Detection of transmitted excitation by means of electromotive variation—Specific tissue for conduction of excitation—Hydro-mechanical theory of transmission of stimulus—Propagation of excitatory protoplasmic change—Physiological test—Automatic record of transmission-period—Conditions for obtaining constant velocity—Determination of velocity of transmission in Mimosa—Differential method of determining velocity—Constancy of results—Tabular statement of different determinations of velocity—Effect of intensity of stimulus on velocity of transmission—Effects on sub-tonic tissue and on tissue in optimum condition—After-effect of stimulus in enhancing conductivity—Effect of optimum condition—Disturbing action of leakage of exciting current—Effect of fatigue—Effect of temperature—Velocity of transmission in Biophytum and Averrhoa—Direction of preferential conduction |
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EXCITATORY CHARACTER OF TRANSMITTED IMPULSE IN PLANTS
The hydro-mechanical theory—Inconclusive character of the anæsthetic experiment of Pfeffer and scalding experiment of Haberlandt—Kühne's experiment showing transmission of excitation under intense stimulation in a rigored nerve—Error introduced by employment of excessive intensities of stimulus—Discriminative polar effect of current in excitation—Block of transmission of excitation by local application of cold—Restoration of normal conductivity by tetanising shock in tissue paralysed by cold—Electro tonic arrest of excitatory impulse—Action of various poisons in inducing block of conduction |
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THE POSITIVE RESPONSE
Two opposite kinds of responses, negative and positive—Excitatory contraction, negative turgidity variation, fall of leaf, and concomitant negative electric variation—Positive electric response—Positive or erectile mechanical response—Dual impulses under different forms of stimuli—Exhibition of positive and negative impulses by different plants—Conditions for obtaining positive response—Characteristics of
positive impulse—Masking and unmasking of positive effect—Laws of Direct and Indirect effects of stimulus |
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