Page:Life Movements in Plants.djvu/234

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204
LIFE MOVEMENTS IN PLANTS


by wound, gives rise to greater and more persistent retardation of growth.

SUMMARY.

Mechani'al stimulus induces incipient contraction or re- tardation of rate of growth, the effect being similar to that induccd by electric _sti1nulus.

Stimulus by Contact or friction induces a retardation which is, relatively speaking, moderate. On the cessation of stimulus tho normal 'ntc of growth is restOrcd within an hour.

[ntcnsc stimulation caused by the wound givos rise. to grontcr and morn pvrsistont I'vtm'dn'iimi of growth.