Perl, M., Agriculture Research Organization, The Volcani Centre, Bet Dagan, Israel
Luria, I., Agriculture Research Organization, The Volcani Centre, Bet Dagan, Israel
Gelmond, H., Agriculture Research Organization, The Volcani Centre, Bet Dagan, Israel

Examination of the initial rates of enzyme activities in various seed lots demonstrated that amylase, glutamic-pyruvic-transaminase, RNase, and glutamate decarboxylase follow the vigour profile, namely, an increase after 6 d of aging treatment followed by a decrease up to 48 d of aging time. Acid phosphatase, tetrazolium reduction, and [ 14C]leucine incorporation decline directly with the time of aging and no increase in those activities at 6 d aging could be observed. Proteinase is the only enzyme found so far that increases during accelerated aging. It is postulated that this enzyme may be the cause of the drop in all other enzyme activities and therefore may play an important role in the loss of seed vigour.Examination of the components released from seeds into water, and of the rates of their leakage, led to the conclusion that the efflux reflects severely damaged seeds rather than vigourless ones. © 1978 Oxford University Press.