Life Movements in Plants, Volume I

by Jagadis Chandra Bose

TABLE XIII.—EFFECT OF INCREASED INTERNAL HYDROSTATIC PRESSURE (Kysoor).

Specimen.	Hydrostatic pressure.	Rate of growth.
	Normal	0.18 µ per second.
No. II	2 cm. pressure	0.20 µ "  "
	4 cm.  "	0.11 µ "  "
	Normal	0.13 µ "  "
No. II	1 cm. pressure	0.20 µ "  "
	3 cm.  "	0.18 µ "  "
	4 cm.  "	0.15 µ "  "

RESPONSE TO NEGATIVE VARIATION OF TURGOR.

I shall now describe the influence of induced diminution of turgor on the rate of growth.

Fig. 71.—Effect of alternate increase and diminution of turgor on the same speci­men: N, normal rate under drought; H, en­hanced rate under irri­ga­tion with warm water; N′, normal per­man­ent rate after irri­ga­tion; P, di­min­ished rate after plas­moly­sis (Zephyr­anthes).

Method of plasmolysis: Experiment 72.—Being desirous of demonstrating the responsive growth variations of opposite signs in an identical specimen under alternate increase and diminution of turgor, I continued the experiment with the same peduncle of Zephyranthes in which the growth ac­cel­er­ation was induced by irrigation with warm water. In that experiment the growth rate of 0.04 µ per second was enhanced to 0.20 µ per second after irrigation. A strong solution of KNO₃ was now applied at the root; 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 "  "
Steady growth after 1 hour	0.08 µ "  "
Application of KNO3 solution	0.03 µ "  "