The geotropic reaction and statolith movements following geostimulation of mung bean hypocotyls*

Characteristics of the geotropic response of de‐etiolated mung bean hypocotyls are presented. Geotropic sensitivity is not confined to the apical tissue but exists throughout the responding zone. The presentation time is estimated to lie between 0 and 30 s for this tissue. Anatomical features of the presumed geoperceptive tissues are described. Rapid sedimentation and cyclosis of statolith amyloplasts in living tissue are reported, which are fast enough not to preclude the possibility of receptor sites situated at or near the lateral wall of statocytes.