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...