Abstract: 【Objective】 Molybdenum is one of the essential micronutrients for plants. The present study was designated to explore the physiological mechanism of cold resistance enhanced by molybdenum in winter wheat.【Method】A pot experiment was conducted to investigate the effects of molybdenum on antioxidative enzymes in winter wheat (Mo efficient cv. 97003 and Mo inefficient cv. 97014) under low temperature stress. 【Result】The activities of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD) and ascorbate peroxidase (APX) increased and the production rates of free radicals decreased in Mo-treated winter wheat under low temperature stress. In Mo-treated winter wheat, with the prolongation of low temperature stress, the activities of the four antioxidative enzymes increased at first 2 or 4 days of low temperature stress, and then decreased or dropped drastically. The tendency in the activities of these antioxidative enzymes indicated that a valid cold acclimation experienced in the Mo-treated winter wheat and that molybdenum helped to maintain the higher level of cold resistance under the following durative low temperature stress. Genotypic differences in response of activities of molybdenum on antioxidative enzymes were found in Mo efficient cv. 97003 and Mo inefficient cv. 97014. The decrease rates of the SOD, CAT, POD and APX activities and the accumulative rate of free radicals for -Mo treatment in Mo inefficient cv. 97014 were higher than those in Mo efficient cv. 97003, which maybe one of the reasons why the cold injury happened frequently in Mo inefficient cultivar for the Mo deficient treatment. 【Conclusion】Molybdenum regulates reactive oxygen species (ROS) metabolism to affect the cold resistance of winter wheat.

Key words: Molybdenum, Winter wheat, Low temperature stress, Superoxide dismutase (SOD), Catalase (CAT), Peroxidase (POD), Ascorbate peroxidase (APX)