No abstract

The effects of exogenous genistein (GNT) on flavonoid content and antioxidase activity in Ginkgo biloba leaves were investigated. In particular, the flavonoids, chlorophyll, anthocyanins, and soluble sugar contents, as well as the enzymes included in flavonoid biosynthesis activities and antioxidant enzymes were measured. Leaves of one-year-old ginkgo seedlings were sprayed with 0 (control), 50, 100 and 150 μmol/L GNT. Results showed that 50, 100 and 150 μmol/L GNT significantly enhanced the intercellular CO 2 concentration, net photosynthetic rate, stomatal conductance, transpiration rate, and chlorophyll, soluble sugar and titratable acid contents in G. biloba. The contents of flavonoid and anthocyanins in the leaves of G. biloba treated with 50, 100 and 150 μmol/L GNT were significantly higher than of control. The results indicated that the key enzymes included in namely phenylalanine ammonia lyase, flavonoid biosynthesis, chalcone isomerase and chalcone synthase activities were markedly increased by GNT treatment. Likewise, application of GNT significantly enhanced the activities of ascorbate peroxidase, guaiacol peroxidase, catalase, and superoxide dismutase in G. biloba. These results suggest that foliar treatment with GNT may be effective measure of improving flavonoid content and beneficial antioxidant activity in the leaves of G. biloba.