Studies On Mechanism Of Desiccation Sensitivity And Free Radical Injury In Wampee Seeds

Wampee (Clausena lansium (Lour. ) Skeels) Seeds were chosen as materials in this thesis to study the mechanism of desiccation sensitivity in recalcitrant seeds. Studies were conducted firstly to explore the effective ways to reduce the desiccation sensitivity and establish a comparative system for analysing. The differences of free radical production, injury accumulation, free-radical-scavenging systems and cell ultrastructure were compared during dehydration of seeds with or without KCN treatment.The germination of wampee seeds were delayed by the treatment with ABA or Ca²⁺.But , the treatment, if combined with PEG ( —1. 5MPa) priming after drying, markedly enhanced vigour of wampee seeds. Treatment with teapolyphenol also increased vigour of seeds after drying. Pretreatment with KCN, a respiratory inhibitor, reduced the desiccation sensitivity of wampee seeds more effectively. The optimum concentration of KCN for application was 10 m mol/L. After KCN treating and drying under ambient air condition for 4 days to water content about 40±2% (fwb), the seed vigour index was two-fold higher than that of control,and for 6 days to water content about 30 ±2% (fwb), the seed vigour index was twenty-fold higher than control. At the later situation, over 35% KCN-treated seeds were able to germinate, whereas the control seeds almost lost their germinability. The analysis of electrolyte leakage showed that pretreatment with KCN delayed the mem-...