Effects of molybdenum on antioxidative enzymes in winter wheat under low temperature stress

中国人. 揭示钼提高冬小麦抗寒力的生理机制。采用盆栽试验的方法，以冬小麦钼高效品种97003和钼低效品种97014为材料，研究了在低温胁迫下施钼对冬小麦叶片抗氧化酶活性影响。低温处理2、4和6 d时施钼均显著提高了超氧化物歧化酶（SOD）、过氧化氢酶（CAT ）、过氧化物酶（POD）和抗坏血酸过氧化物酶（APX）活性，显著降低了2个冬小麦品种叶片中超氧阴离子产生速率；施钼后，随着低温胁迫时间的延长，2个冬小麦品种叶片中4种抗氧化酶活性均先升高而后呈下降或突降趋势，说明施钼能使冬小麦通过正常的低温锻炼过程，有利于植株在经受更长时间低温胁迫时维持较高的抗寒力；钼对冬小麦钼高、低效品种叶片中抗氧化酶活性的影响存在基因型差异，与钼高效品种相比，钼低效品种缺钼处理叶片SOD、CAT、POD和APX等抗氧化酶活性下降幅度更大，活性氧自由基积累速率更大，这可能是钼低效品种在缺钼条件下更易受到低温伤害的原因之一。钼通过调控活性氧代谢过程来影响冬小麦的抗寒力。

英语. 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. 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. 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. Molybdenum regulates reactive oxygen species (ROS) metabolism to affect the cold resistance of winter wheat.