Preliminary Study on Changes of Accumulated Flavonoids Contents in Ginkgo Biloba Leaves

Flavonoids contents and biomass of Ginkgo biloba leaves at different growth periods and different ages leaves were determined and analyzed using spectrophotometry for the better development and utilization of Ginkgo biloba resources.The results showed that flavonoids contents accumulated in different periods presented saddle-shaped,that was,two peaks in April and July,and the highest in late July,and the lowest in middle June.Flavonoid contents decreased with the increase of age,and about in the 12th year decreased the fastest during the investigation period.Plant biomass gradually increased along with the growth ages,and the average growth rate(18.89%) in 5~8 growth ages was maximum value,and it reduced to 1.4% during 22~30 growth ages.Flavonoid content in young leaves was statistically higher than that in old ones.Therefore,the optimal combination was to collect young leaves of 5~8 years old Ginkgo biloba in late July to ginkgo leaf used in a better way to maximize the development and utilization of resources Ginkgo biloba.