Objective  Low temperature is the main limiting factor affecting cultivation of chewing cane (Saccharum officinarum L.) in north China. To investigate the physiological mechanisms of low temperature adaptation and physiological responses of chewing cane cultivars under low temperature stress, and provide a theoretical basis for chewing cane cold resistance germplasm screening and breed improvement.

Method  Six chewing cane cultivars seedlings were used as test materials to determinate the effect of low temperature stress on the seedlings using the indexes such as relative conductivity(REC), malondialdehyde (MDA), soluble sugar (SS), soluble protein (SP) and proline (Pro) contents and superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase(APX) activities in artificial simulation low temperature environment. Taking cold resistant coefficient of each physiological index of chewing cane leaves as the index to measure cold resistance capacity, and cold resistance of chewing cane cultivars were comprehensively evaluated using correlation analysis, principal component analysis and membership function analysis based on cold resistant coefficients of these indexes. Evaluations of cold tolerance of six chewing cane cultivars seedlings were made through fuzzy membership function analysis.

Result  With the extension of low temperature stress time, the REC, SS, SP and Pro contents of six chewing cane cultivar seedling leaves kept the overall rising trend, and the MDA content, the activities of SOD, POD, CAT and APX showed the trend of increasing at first and then decreasing. The cold tolerance order of comprehensive evaluation was ‘Guiguozhe1’>‘Badila’=‘Minyinhuangpiguozhe’>‘Baiyuguozhe’>‘Chuanzhe26’>‘Longheiguozhe’.

Conclusion  Membership function analysis is simple and accurate, which can be used as an effective method to identify cold hardiness of chewing cane. The adaptabilities of different chewing cane cultivars to long lasting low temperature are different. The cold resistance of chewing cane is not only related to its own genetic factors and physiological characteristics, but also closely related to the external environmental factors.