The metabolism of aged seeds. The ribonucleolytic activity of rye grain embryos of different ages

Winter rye grain, harvested in various years and exhibiting clearly differing viability. was studied. Higher total ribonucleolytic activity was found in the post-ribosomal supernatant than in the ribosomes themselves. The ribonucleolytic activity of cytoplasmic ribosomes declined as the germination ability of the rye grain decreased. A similar relationship was observed in the post-ribosomal supernatant. Two additional, in comparison with fully viable grain, ribosome-associated RNase activities (pH 5.0 and 8.3) were found in the grain with the lowest (2%) viability