The nervous mechanism of plants / by Sir Jagadis Chunder Bose.

  • Bose, Jagadis Chandra, 1858-1937.
Date:
1926
Catalogue details

Licence: In copyright

Credit: The nervous mechanism of plants / by Sir Jagadis Chunder Bose. Source: Wellcome Collection.

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    transmitted with a considerable speed. After a period of rest the original ineffective stimulus was applied once more. The impulse was now found to be transmitted, the velocity being as high as 25 mm. per second. This enhanced conducting power began slowly to decline, and after an hour the velocity was reduced to 4 mm. per second. The application of a strong stimulus was once more found to confer enhanced conducting power, the velocity under the test-stimulus being increased from 4 to 25 mm. per second. The conducting path thus becomes canalised by stimulation. Experiment 29. Petiole of M. Spegazzinii.—A similar effect was strikingly demonstrated by this specimen, which was only moderately excitable and conducting. A stimulus of intensity of 1*5 from an induction-coil, applied below sub-petiole 3, failed to initiate any excitatory impulse. Stimulus of intensity 2 was similarly ineffective ; and it was only under an intensity of 2-5 that the impulse was effectively transmitted, causing the fall of sub-petioles 3, 2, and 1 (see fig. 13). After this the formerly ineffective stimulus of 1 - 5 was applied once more, and was now found to be effectively transmitted, causing the fall of all the sub-petioles. Summary Conduction of excitation takes place by means of the tubular cells in the phloem. The transverse septum between any two of the cells acts as a synapsoidal membrane. The characteristics of conduction across the synapsoidal membrane in the plant are similar to those across the synaptic membrane in the animal. Conduction is irreciprocal at the neuro-muscular junction. It is also irreciprocal at the junction of the plant-nerve with the contractile tissue of the pulvinus. Under minimal stimulus the conduction in the plant-