Page:Life Movements in Plants.djvu/227

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stimulus in retarding the rate of growth. The normal rate of growth of the bud of Urinum was 0'35 ft per second. On the application of electric shock of unit inten- sity for 5 seconds, the rate became reduced to 0'22 ,it per second. When the stimulus was increased to 2 units, the retarded rate of growth was 0'07 ,u, per second. When the intensity was raised to 4 units, there was a complete arrest of growth. In ﬁgure 72 is given records of a different experiment which show the eﬂ'ects of incr'asing intensity of stimulus in retardation of growth.

E but 0f Continuous stimulation» Io'J'lm'i/Iumt 70.“ The effect of continuous stimulation of increasing in- tensity will be seen in the record (Fin. 73), taken on, a

Fm. 73.~—Effcct of continuous electric stimulation of lncrwtsing inlmmity. The last record exhibits the actual shortenim; of the growing,' organ under strong stimulus.

moving plate. On application of continuous stimulus of increasing intensity an increased flexture was produced in the cone, which denoted greater retardation in the rate