Leaf-movements of Mimosa púdica in relation to light.

Abstract

Observations are made on induced "dark adaptation " of leaves during the daytime, their subsequent recovery in light, and their diurnal response to artificial illumination. Dark adaptation is defined as the process of reaching such a condition that the organism's sensitivity to light has attained a constant value as a result of prolonged subjection to darkness. This adaptation appears to be completed in thirty minutes, but further changes in light sensitivity occur after long periods (four hours) of darkness.
Application of β indolyl acetic acid to one side of the pulvini caused pronounced movements of the petioles and leaflets but the relation of the hormone to normal leaf motility is not known. -M.H.