Abstract:Compared to variety Shanyou 63, super high-yielding hybrid rice Pei'ai 64S/E32 had higher activities of ascorbate peroxidase and glutathione reductase, higher antioxidant contents (Vc, total Vc, reduced glutathione, and β-carotene), and higher capacity of scavenging organic free radical, but less content of malondialdehyde (a product of membrane-lipid peroxidation) in flag leaves at late development stage. It was shown that the flag leaves of Pei'ai 64S/E32 at late stages have strong antioxidant capacity, which coincided with the lower degradation of chlorophyll and protein contents in this hybrid at late seed setting stage.