Six rice recombinant inbred lines with different heat tolerance and their parents,heat tolerant line 996 and heat sensitive line 4628 were treated with high temperature (9:00 - 1 7:00,37℃;1 7:00 - 9:00,30℃)and optimal temperature (9:00 - 1 7:00,30℃;1 7:00 - 9:00,25 ℃)in growth chambers.The effect of high temperature on antioxidant enzyme activities,membrane permeability,souble sugar content,heat stable protein content of anther, pollen grain and stigma viability were studied.The results showed the superoxide dismutase(SOD),catalase (CAT), p...