Effect of Different Intensity and Quality of Light on Accumulation of Triterpenoid in Birch (Betula platyphylla suk.) Seedlings

Betulin and oleanolic acid in bark of the white birh trees as the secondary metabolites of pentacyclic triterpenoid,have extensively pharmacological activities,which are the natural substances worthy of being empoldered in using for anti-cancer and anti-HIV.In this study,betulin and oleanolic acid content in different parts of birch seedlings which were treated by different intensity and quality of light,were analyzed.The results showed that with the comparion of control(white light),the accumulation of the two triterpenoids in their stem skin decreased under four kinds treatment of light quality include the red,yellow,blue,green.Oleanolic acid content in leaf of white birch treated by the green light and betulin content in leaf treated by blue light were significantly increased,which were 13.28 times and 1.959 time higher than that of control,respectively.In the growing season(from June to October),the highest contents of oleanolic acid and betulin in the stem bark was in August,which were higher than other months.The best shading treatment was 50% of natural light.Under the condition,oleanolic acid and betulin content in the stem bark were increased to 45.09 % and 30.50% higher than normal light,respectively.The contents of oleanolic acid and betulin in plants changed with the seasons.The research laid bases for seting up the cultivation technology of high efficient accumulation and metabolic regulation study of the triterpenoid substances of wihte birch.