STUDIES ON THE MECHANISMS OF ROOTLET INHIBITION IN DEVELOPING BARLEY EMBRYOS

Rootlet growth in developing barley embryos can be inhibited using var ious compounds. Little is known about the mechanism of action of these compounds, however. The inclusion of low concentrations of ethanol in the steep water inhibited rootlet growth markedly without affecting p roteolytic activity in the endosperm. Bromate inhibited both rootlet g rowth and proteolysis. This suggests that separate mechanisms exist fo r the control of root growth and proteolysis. Root growth was inhibite d progressively when alcohols of increasing carbon chain length were u sed, and similar concentrations of the corresponding aldehydes had eve n greater inhibitory effects. It is possible that the action of alcoho ls and aldehydes is on the membranes of the embryo root primordia. Thi s is supported by the observation that compounds able to disrupt membr anes, such as biological detergents and hop compounds, inhibit barley rootlet growth.