Effect of gibberellic acid on α-amylase and ribonuclease activities in rye endosperm after various periods of grain storage

Abstract

α-Amylase and ribonuclease activities were determined in embryoless rye half-seeds exhibiting different viaibility after various times of storage (2, 5 and 8 years). The half-seeds were incubated for 24, 48, 72 and 96 h with and without GA₃. α-Amylase activity in the endosperm of rye grain stored for 2 and 5 years and incubated without the hormone increased considerably, whereas in 8-year grain, practically incapable of germination, it remained almost unchanged. GA3caused a considerable increase of α-amylase activity in all the tested samples. In grain stored for 2 and 5 years the enzyme activity reached its peak under the influence of the hormone earlier than in the control samples. The differences in ribonuclease activity between the particular samples were less pronounced, and the reaction to the hormone much weaker. The results indicate that the reaction of rye endosperm to GA3depends on the physiological properties of the grain.