Page:Life Movements in Plants.djvu/251

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RESPONSE OF SUB-TONIC TISSUES
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The normal retarding effect of electric stimulus on specimens in active state of growth was demonstrated in record given in Fig. 72, where the normal rate was found greatly reduced after stimulation.

Abnormal acceleration of growth under electric stimulus; Experiment 88.—For my present purpose I took a sub-tonic specimen of seedling of wheat, its rate of growth being as low as 0.05 μ second. After electric stimulation the rate was found enhanced to 0.12 μ per second, or about two and-a-half times. I give (Fig. 82) two records
Fig. 82.—Enhancement of rate of growth in sub-tonic specimens of wheat seedling. First series of record on stationary, second series (b) on moving plate. N, record before stimulation. S, after stimulation. obtained with two different specimens. In the first, the record was taken on a stationary plate (Fig. 82); the closeness of successive dots in N show the feeble rate of growth of the sub-tonic specimen, the wider spacing after stimulation, S, exhibit the induced enhancement of growth.

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