Perception of Gravity by Roots of Vicia Faba

Abstract

UNTIL recent years it was a generally accepted view that the region of perception of gravitational stimuli in roots was the extreme tip of the root. Cholodny,¹ however, performed experiments in which he replaced the root tip in maize by the tip of the coleoptile, and the fact that a positive curvature was still obtained suggested that the function of the root tip might not be so simple as had hitherto been supposed. More recently, Keeble, Nelson, and Snow² performed experiments in which positive geotropic curvatures were obtained when unstimulated root tips were stuck on to stimulated root stumps which had been decapitated before stimulation.