SOD and CAT activity of leaves of rhizomes were studied in six chrysanthemum cultivars in low temperature and cold tolerance were estimated via correlation and hierarchical cluster analysis.The analysis showed that SOD activity varied differently between six cultivars and CAT activity increased at first and then decreased.Higher correlation were presented between cold tolerance and changing rate of SOD activity during-14℃to-17℃,CAT activity during CK to-8℃and-11℃to- 14℃.The six cultivars were classified thr...