Effect of GA3 on ribonuclease activity in the embryos and endosperm of spring barley grain in the post-harvest dormancy period

Abstract

The effect of GA₃ on ribonuclease activity in the embryos and endosperm of barley seeds was investigated during dormancy and after its end. Incubation of dormancy grain with GA₃ stimulated its germination, increased the dry weight of the embryos and their protein content. Ribonuclease activity in seeds treated with GA₃ was considerably enhanced. The increase was more rapid and intensive in the embryos than in the endosperm. The action of GA₃ was most effective, particularly as regards the endosperm, on grain which had already passed through the stage of dormancy and had reached physiological maturity. This is evidence that the internal factor regulating the process of dormancy exerts a stronger influence on the activity of ribonuclease than does exogenic giberrellic acid.