Page:Life Movements in Plants.djvu/271

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RESPONSES IN GROWING AND NON-GROWING ORGANS
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growing organ, I give a record (Fig. 88) obtained with a
Fig. 88.—Contractile response of growing organ under electric shock. Successive dots at intervals of 4″. Vertical lines below represent intervals of one minute. (Magnification 1,000 times.) growing bud of Crinum under the stimulus of electric shock above the critical intensity. The recorder gave a magnification of a thousand times. In Fig. 88, the normal growth elongation is represented as a down-curve. On the application of stimulus the normal expansion was suddenly reversed to excitatory contraction, the latent period of reaction was one second and the period of the attainment of maximum contraction (apex-time) was 4 minutes. The organ recovered its original length after a further period of seven minutes and then continued its natural growth elongation. Repetition of stimuli gave rise to successive contractile responses which are in every way similar to the mechanical responses of Mimosa pudica. The essential similarity of

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