effects of different storage temperatures and times on germination and antioxidant responses of jatropha curcas seeds

the effects of different storage temperatures and times on germination rate, malondialdehyde (mda), superoxide dismutase (sod), peroxidase (pod) and catalase (cat) activities in jatropha curcas l. seed were investigated. the results showed that germination rates of seeds stored at room temperature and 4°c for 1 month was significantly higher than those stored for 3 months at -20 and -80°c. mda contents increased significantly for 1 and 3 months storage with decreasing temperatures. sod activity decreased gradually down to -80°c for 1 and 3 months storage. pod activity fluctuated slightly for 1 month, but increased apparently for 3 months storage with decreasing temperatures. cat activity declined rapidly as storage temperatures decreased, particularly for 3 months storage. a significant interaction of storage temperatures and times was found for the activity of sod and pod, and there was no significant interaction on germination rate, mda content, and cat activity. electrophoretic analysis showed that the observed changes of sod, pod and cat isoenzyme bands under different storage temperatures were consistent with the changes of enzyme activities assayed in extract solutions. these results suggested that sod, pod, and cat may be involved in regulating the level of reactive oxygen species under different storage temperatures and times.