Desiccating sensitivity of Litchi chinensis Sonn. seeds

On air-drying, daily loss of moisture content was directly proportional to the degree of loss of seed viability in four cultivars, viz. Deshi, Kasba, Purbi, and Early Bedana of Litchi chinensis Sonn. Their inability to withstand desiccation was the most pronounced in Early Bedana and the least in Deshi which may be due to cultivar differences. Moisture loss led to rising trend in starch and total sugar contents in these litchi cultivars. Both α-amylase and invertase enzyme activity exhibited parallel trends in each cultivar. However, in cultivars Deshi, Kasba and Purbi, these enzymes exhibited minimum activity whereas in cv. Early Bedana they increased considerably on the 4^th and 5^th day of air drying. Concurrently, soluble protein content underwent a rapid linear decline in Early Bedana whereas in Purbi and Kasba decline occurred at a relatively slow rate. On the other hand, in Deshi which retained greater viability, the protein content increased appreciably and was not adversely affected by moisture stress even after 72 hours of air-drying when IAA-oxidase activity declined to its minimum. This was in sharp contrast to Early Bedana exhibiting maximum loss of viability as indicated by no positive response with 2, 3, 5- triphenyltetrazolium chloride even after 12 hours of air-drying.