Changes of main secondary metabolites in leaves of Ginkgo biloba in response to ozone fumigation.

To investigate the effect of elevated O3 on the accumulation of main secondary metabolites in leaves of Ginkgo biloba L., four-year-old trees were exposed in open-top chambers with ambient air and the air with twice ambient O3 concentration in Shenyang in 2006. Elevated O3 increased the concentrations of terpenes, but decreased the concentrations of phenolics in G. biloba leaves. The results showed that secondary compounds from G. biloba leaves responded to the elevated O3 exposure in a different way when compared to previous studies which showed elevated O3 increased the concentrations of phenolics but had no effect on the terpenes in leaves of other deciduous trees. Furthermore, reduced synthesis of phenolics may decrease the resistance of G. biloba to O3 and other environmental factors. On the other hand, the induced synthesis of terpenes may enhance the antioxidant abilities in G. biloba leaves at the end of O3 fumigation.