Effects of High Temperature on Antioxidant Enzymes and Lipid Peroxidation in Flag Leaves of Wheat During Grain Filling Period

On the basis of the phytotron, the effects of high temperature (daily average temperature 25, 30, 35 and 40°C, respectively) on antioxidant enzymes and lipid peroxidation in flag leaves of wheat at 50% relative air moisture during grain fastest filling stage [19-21 days after anthesis (DAA)] were studied. The wheat cultivars tested were Yangmai 9 with weak-gluten and Yangmai 12 with medium-gluten. Compared with 25°C, the higher the temperature was, the higher was the MDA content in flag leaves, while lower were the SOD, POD, and CAT activities. SOD and CAT activities in Yangmai 12 appeared to be more sensitive to high temperature than that in Yangmai 9. But POD activity in Yangmai 12 was less sensitive to high temperature. MDA content in Yangmai 12 was higher than that in Yangmai 9. The 1 000-grain weight declined with increase in temperature.