Developmental Aspects of Leaf Blade Hyponasty

Abstract

Nastic curvatures can be induced by indole-3-acetic acid (IAA) or transport inhibitors in the leaves of 4-day-old seedlings of Phaseolus vulgaris var. Pinto, but not in leaves of 10-day-old seedlings in which the capacity for differential growth is reduced. Although orientation to gravity influences the amount of curvature produced in response to IAA, gravity is not an essential stimulus for the development of the dorsiventral auxin transport system in the blade. The production of the planar leaf form follows the initiation of auxin production and is maintained by the development of a dorsiventral auxin transport system.