The mechanical responses of sensitive plants also exhibit similar effects, i.e., a negative response under Direct, and positive response under Indirect stimulus.

In the responsive variation of growth, Direct stimulus induces a retardation, and Indirect stimulus an ac­cel­er­ation of the rate of growth.

The effects of Direct and Indirect stimulus on vegetable organs in general are as follows:

Direct stimulus induces negative variation of turgor, contraction, fall of leaf of Mimosa, electric change of gal­vano­metric negativity, and retardation of the rate of growth.

Indirect stimulus induces positive variation of turgor, expansion, erection of leaf of Mimosa, electrical change of gal­vano­metric positivity and ac­cel­er­ation of the rate of growth.

XVIII.—RESPONSE OF GROWING ORGANS IN STATE OF SUB-TONICITY

By

Sir J. C. Bose.