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and the growth-rate fell almost immediately to 0.03 μ per second, or nearly to one-third the previous rate, the depression induced being thus greater than under condition of drought (Fig. 71).
TABLE XIV.—EFFECT OF ALTERNATE VARIATION OF TURGOR ON GROWTH (Zephyranthes).
| Condition of Experiment. | Rate of growth. |
Dry soil … … … … … … … … … … … … … … … … … … … … … … … … … … … … |
0.04 μ per second. |
Application of warm water … … … … … … … … … … … … … … … … … … … … … … … … … … … … |
0.20 μ per„ second.„ |
Steady growth after 1 hour … … … … … … … … … … … … … … … … … … … … … … … … … … … … |
0.08 μ per„ second.„ |
Application of KNO3 solution … … … … … … … … … … … … … … … … … … … … … … … … … … … … |
0.03 μ per„ second.„ |
From the series of results that have been given above, it will be seen that employing very different methods of turgor variation, the rate of growth, within limits, is enhanced by an increase of turgor. A diminution or negative 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 variation of turgor itself is also determined by that activity.
RESPONSE OF MOTILE AND GROWING ORGANS TO VARIATION OF TURGOR.
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 responsive movement of