Geotropic Response of Coleoptiles under Anaerobic Conditions ' Malcolm B . Wilkins

It has been reported recently that coleoptiles of Zea mays develop a geotropic response under anaerobic conditions (2). The geotropic response of a coleoptile arises from the differential growth of the upper and lower halves of the organ. At least 3 independent investigations have shown that in Avena sativa coleoptiles growth is totally arrested in the absence of 02 (1,6, 9). It is therefore difficult to reconcile the inhibition of growth under anaerobic conditions with the reported development of geotropic curvature. The geotropic responses in coleoptiles of Zea mays and Aventa sativa under anaerobic conditions have therefore been re-examined in an attempt to clarify this confused situation.