Progress of effects of light on plant flavonoids

As an important secondary metabolites of medicinal plant, flavonoids plays a very important role on itself including light protection and antioxidant. Light is one of the important environmental factors which impacts the secondary metabolites of plant and has a significant impact on biological synthesis of flavonoids. This paper reviews the recent progress of the effects of light on flavonoids on the plants focusing from light intensity and light quality, and summarizes briefly functions of the phenylalanine ammonia lyase (PAL) in plant secondary metabolism and the upstream key enzyme chalcone synthase (CHS) in flavonoid biosynthetic pathway.