Changes in nucleic acid content and RNAse activity in desiccating recalcitrant sal seeds

Changes in nucleic acid and RNAse activity have been monitored in the desiccating recalcitrant sal seeds during storage. Desiccation of 100% viable seeds from 42.2 to 38.8% moisture content did not alter at all the germinability but further dehydration to 21.8% moisture content led to absolute loss of germination capacity. Dehydration of sal seeds was positively correlated with decline in amounts of DNA and RNA in the axes (DNA, r=0.97; RNA, r=0.97) and cotyledons (DNA, r=0.97; RNA, r=0.98). Higher stability of DNA (total loss 22%) compared to RNA (total loss 59%) was also established in our study. RNAse was not detected in undried seeds. Drying of sal seeds increased RNAse activity with maximum in axes (0.71/g fw) and cotyledon (0.31/g fw) of 30% viable seeds. Role of nucleic acids and RNAse during desiccation induced loss of viability in recalcitrant sal seeds are discussed.