INHIBITION OF ETHYLENE SYNTHESIS IN MUNG BEAN HYPOCOTYL SEGMENTS BY THE PROTEINACEOUS INHIBITORS OF ETHYLENE SYNTHESIS

The effects of proteinaceous inhibitors of ethylene synthesis isolated from etiolated mung bean hypocotyls and from mung bean seeds were inv estigated using both indole-3-acetic acid (IAA)-treated and 1-aminocyc lopropane-1-carboxylic acid (ACC)-treated mung bean hypocotyl segments . These inhibitory proteins reversibly inhibited ethylene synthesis by IAA-treated mung bean segments. Similar reversible inhibitory effects were also observed for ethylene synthesis from ACC by the segments. T he inhibitory proteins had no effect on induction of ACC synthase by I AA. These results indicate that the inhibitory effects are caused by i nhibition of ethylene-forming enzyme activity.