Responses of Total Flavonoid Yield in Erigeron Breviscapus (Vant.) Hand.–Mazz. to Enhanced UV-B Radiation

摘要

Responses of total flavonoid yield in Erigeron breviscapus (Vant.) Hand.-Mazz. to enhanced ultraviolet-B (UV-B, 280-315 nm) were studied through simulation experiment under greenhouse conditions. The supplemental UV-B radiation levels were 0, 2.5, 5.0 and 7.5 kJ·m-2, which were provided by UV-B lamps, simulating depletion of 10%, 20% and 30% stratospheric ozone at Kunming (25° N, 1950 m). At physiological maturity, total biomass and biomasses of leaf, stem, root and seed increased significantly (p< 0.05), whilst flower biomass increased significantly only under 7.5 kJ·m-2 UV-B radiation (p< 0.05). Chlorophyll content significantly decreased at 30 days of UV-B radiation (p< 0.05), but that subsequently increased significantly at 60 and 90 days (p< 0.05). UV-B radiation had sgnificant effect on MDA content (p< 0.05), and significant increase in PAL activity and total flavonoid content of leaf (p< 0.05). At physiological maturity, total flavonoid contents of various plant parts were different, highest total flavonoid content was observed in flower. Total flavonoid yield (dry mass ×total flavonoid content) of leaf, stem, root and seed significantly increased under UV-B radiation (p< 0.05), respectively, resulting in significant increase in total flavonoid yield of the whole plant. E. Breviscapus has greater UV-B resistance by significant accumulation of total flavonoid yield, which was contributed from higher biomass and higher total flavonoid content.