DEVELOPMENT OF HYDROLYTIC ENZYMES IN GERMINATING GRAIN

Abstract

Studies of the order and rates of production of certain hydrolytic enzymes in the endosperm of germinating barley and in endosperm slices treated with gibberellic acid have shown that endo-β-glucanase formation precedes the formation of α-amylase which, in turn, precedes the formation of protease. A rise in acid phosphatase appears to take place shortly after the induction of endo-β-glucanase. Although the order of induction of the enzymes is the same in slices and in grain germinating without additives, enzyme production begins some ten hours earlier in the slices. The response of isolated aleurone to gibberellic acid is qualitatively similar to that of the endosperm slices, but, though there is appreciable formation of enzymes, secretion is very slight. This suggests that the effect of gibberellic acid on hydrolase synthesis can be distinguished from any effect on secretion. Preliminary hydration of endosperm slices induces a much more rapid response to gibberellic acid.