Changes of SOD, CAT and POD Activities in Cucumber Leaves During Cold Damage

Three cucumber cultivars with different cold tolerances were used to study the changes of SOD, CAT and POD activities in Cucumber leaves during cold damage. The results showed that under the stress of low temperature, the cultivars presented the CAT and POD activities in their leaves that were consistent with their cold tolerances but the SOD activity against the cold tolerances. After the stress of low temperature, the three cultivars presented decreased activities of the three enzymes with the symptoms of cold damage appearing in their leaves, but Junyou 10, a cultivar with high cold tolerance, presented a relatively higher CAT activity. During their recovery period, the cultivars showed an insignificantly varying SOD activity; Junyan 4 with low cold tolerance and Junl 3 with medium tolerance presented a increased CAT activities while Junyou 10 presented a decreased CAT activities; all the three cultivars presented increased POD activities but Junyan 4 had a significantly higher POD increment than the other two cultivars did, which might relate to that POD was capable of catalyzing ROS generation.