Abstract: The changes of SOD activity, MDA content and tissue electrical resistance in rice seedlings were determined during the course of the treatment at low temperature (2℃). The decrease in SOD activity and the increase in MDA content were observed following the prolongation of the time at low temperature. There was a negative relation between SOD activity and MDA content. The tissue electrical resistance had a rise at first day, and then with a sharp fall, showing the occurrence of serious injury. As four kinds of free-radical acavengers were used to pretreat rice seedlings before cold treatment, the MDA content decreased unanimously, but increased with SOD inhibitor pretreatment to rice seedlings. According to these results, it is suggested that the free radicals did participate in the course of low temperature injury and showed that the peroxidation of membrane-lipids played an improtant part in low temperature injury.

Key words: Low temperature injury, Tissue electrical resistance, Superoxide dismutase, Lipid peroxidation