Abstract
The flavonoids are distributed in Bryophytes, Pteridophytes, Gymnosperms and Angiosperms, and about 5,000 kinds are reported. However, the functions and activities to plants and other organisms were hardly known. Only one phenomenon, i.e., the major contribution of flavonoids such as anthocyanins, flavones and flavonols to flower color as pollination, was well known in nature. Recently, some functions and acitivities of flavonoids, e. g., oviposition stimulants to butterflies of Aristolochiaceae and Rutaceae flavonoids, feeding stimulants to insects of Morus flavonoids, rhizobium induced agency of legume flavonoids, allelopathy and phytoalexins and so on, were reported. Moreover, it was proved that the translucent bracts and leaves of Himalayan Rheum nobile (Polygonaceae) selectively absorb UV-radiation by the flavonoids. In this lecture, I introduce the functions and activities of flavonoids in plants.
