ABSCISSION: THE ROLE OF PROTEIN SYNTHESIS

Abscission of cotton Gossypium hirsutum L. var. Acala 4-42 cotyledonary node explants, coleus Coleus blumei Benth. nodal explants, and bean Phaseolus vulgaris L. var. Red Kidney primary leaf explants was inhibited by the protein synthesis inhibitors dactinomycin and cycloheximide. During the course of ethylene-enhanced abscission, C14L-leucine incorporation into a trichloroacetic acid-percipitable fraction of tissue homogenates occurred primarily in the separation zone of cotton explants. little or no enhanced incorporation was observed in the surrounding petiole and nodal tissue. In bean explants, the enhancement was primarily in the pulvinus tissue. These results support a hypothesis that in abscission the role of ethylene is to stimulate the synthesis of enzymes responsible for the separation of cells in the abscission zone.