[Intraspecific differences in physiological responses of different wheat cultivars to enhanced UV-B radiation]

In this paper, field studies were conducted to determine the potential of alterations in physiology, and the intraspecific differences in sensitivity of 10 wheat (Triticum aestivum) cultivars to enhanced UV-B radiation. The supplemental UV-B radiation was 5.00 kJ x m(-2), simulating a depletion of 20% stratospheric ozone in Kunming area. The results showed that six of 10 tested wheat cultivars showed significant changes in total chlorophyll content, among which, chlorophyll a was strongly reduced, but chlorophyll b was reduced to a lesser extent, leading to a decrease in chlorophyll a/b ratio. The effects of UV-B on MDA and flavonoid contents also showed intraspecific difference. The MDA content of 5 cultivars was significant increased, while that of 2 cultivars was decreased. Four cultivars had significantly increased flavonoid content, but the flavonoid content in 2 cultivars was significantly decreased. The changes of chlorophyll and flavonoid contents were significantly correlated with the content of MDA(r = -0.78, P < 0.01 and r = -0.75, P < 0.05 respectively). There was a correlation between flavonoid and anti-UV-B radiation of wheat.