Page:Life Movements in Plants.djvu/222

192 and the, growth-rate fell almost. immediately to 0'03 {1. per second, or nearly to one-third the. previous rate, the depres- sion induct-d being thus greater than under condition of drought (Fig. 7 l

Condition of l‘lVllltl‘llllt‘lll. ‘ Rate of growth. l

2 Dry soil   0'05; ,1. per second. i Application of warm water ! 0°20 IL ,, ,, iSteady growth after I hour 0'08 [1. ,, ,, 1 iApplicaiion of KNUJ solution i 0'03 u ,, ,, l _ _ _ _ ___-_ w __¢____l

From the series of results that have been given aboVe, it will be seen that employing very different methods of tumor variation, the rate of growth, within limits, is en- hanced by an increase of turgor. A diminution or nega- tive variation of turgor, on the. other hand, brings about a retardation or negative variation in the rate. of growth. We should, in this connection, bear in mind the fact that, growth is dependent on protoplasmic activity, and the varia- tion of turgol‘ itself is also determined by that activity.

I have already described (p. 40) the effects of variation of turgor on the motile pulvinus of Mimosa. There is a strict correspondence between the reaponsive movement of