Effect of low temperature stress on anti-stress physiological indexes of cabbage seedlings

In order to explore the different antioxidation of various cabbage seedlings under low temperature stress, two cold-resistant cultivars (173, 174) and two cold-sensitive cultivars (165, 166) were selected as experimental materials in this study to study the changes of physiological indexes related with cold tolerance. The resultes showed under the low temperature of 4℃, the soluble sugar of four cabbage varieties increased, and the increase rate of resistant cultivars was significant higher than sensitive ones. The soluble protein contents of 173 and 174 increased with the extension of treatment time, while 165 and 166 decreased in the late stage of low temperature treatment. Moreover, the trend of proline was similar. Under low temperature, the O'⨪₂ production rate and H₂O₂ contents showed increasing trend with the extension of treatment time. The activities of superoxide dismutase (SOD) showed increasing trend, 165 and 166 increase rate were significant lower than 173 and 174, while peroxidase (POD) and catalase (CAT) increased at first, and then decreased. This study concluded that there were significant differences in physiological responses between coldresistant varieties and cold-sensitive varieties, which provides a theoretical basis for further study on the physiological mechanism of cabbage seedlings against low temperature injury. (authors)