Characteristics of the process of enzyme release from secretory plant cells.

Secretion-the outward movement of molecules across the plasmalemma-of alpha-amylase by barley (Hordeum vulgare L. cv. Himalaya) aleurone layers is an energy-dependent process that is not directly dependent upon protein synthesis or RNA synthesis and does not appear to be under the direct control of gibberellic acid or abscisic acid. Release-the movement of the secreted alpha-amylase molecules through the walls into the surrounding medium-is apparently diffusion limited and is markedly dependent upon the presence of ions.