Changes in total protein and protease activity in dehydrating recalcitrant sal (Shorea robusta) seeds

A rapid loss of viability was recorded in sal seeds when dehydrated below 36.7 % moisture content, at ambient conditions. Seed becomes non-viable at 6 days after harvest (dah). Gradual decline in total protein content due to corresponding increase in protease activity preceded loss of viability. Almost 43.7 % and 52.6 % loss in total protein content was observed on 3 dah in embryonic axis and cotyledon respectively of seeds showing 100 % viability. No protease activity was detected in the embryonic axis and cotyledon of freshly harvested viable seeds (0 dah). The protease activity was detected after 12 hrs of storage and increased sharply with peak levels on 6 dah (0.71 +/- 0.04 / min/mg protein) and 4 dah (0.16 +/- 0.01 / min/mg protein) in embryonic axis and cotyledon respectively. Later on the enzyme activity declined sharply in both the tissues. Enhanced protease activity in embryonic axes and cotyledons has been discussed with corresponding decline in total protein during desiccation induced loss of viability in sal seeds.