Abstract: Changes in chloroplast membrane composition and membrane fluidity in wheat leaves exposed to 0kJ·m-2 (CK), 8.82kJ·m-2 (T1) and 12.6kJ· m-2 (T2) were studied. Ultraviolet-B radiation induced the degradation of photosynthetic pigments (including chlorophyll and carotenoids),an increase in MDA content and change in the fatty acid composition of chloroplast membrane and a decrease in IUFA. Compared with a control treatment ,both the activity of the Hill reaction and the fluidity of chloroplast membranes were reduced by ultraviolet-B exposure. The analysis indicated that membrane peroxidation might be one of the causes of chloroplast membrane damage induced by ultraviolet-B radiation.

Key words: Wheat (Triticum aestivum L. ), Ultraviolet radiation-B, Chloroplast membrane system, Membrane peroxid