Enzyme formation, cellular breakdown and the distribution of gibberellins in the endosperm of barley.

The α-amylase contents of the dorsal and ventral sides of the endosperm of barley grains increase approximately equally during germination. Aleurone tissue from all locations in the grain is equally able to make α-amylase in response to gibberellic acid, so the distribution of this enzyme reflects the distribution of endogenous gibberellins.Variations occurred in both the rate and pattern of cellular breakdown of the starchy endosperm. Generally breakdown progressed away from, and parallel to the scutellum, ultimately advancing faster adjacent to the aleurone layer. The "sheaf cells", above the furrow, were relatively resistant to enzymic breakdown. The results indicate that gibberellins are released generally from the scutellum and induce hydrolytic enzymes equally on the dorsal and ventral sides of the grain.