Abstract:In order to understand the effect of light quality on growth of Bletilla striata seedlings in vitro, the growth characters, activities of antioxidant enzymes and enzyme gene expression of B. striata seedlings under different light qualities were studied. The results showed that there were significant promoting effect on growth of B. striata under blue light and red light, but the effect of green light was not obvious. Except of CAT, the activities of APX, POD and SOD increased under different light qualities, in which the activities of APX and SOD were the highest under yellow light, and that of POD did under red light. The activities of antioxidant enzyme under green light were the lowest. The expression of antioxidant enzyme genes increased under blue light for 35-45 days. Therefore, red and yellow light could promote the height and rooting of B. striata, the activities of antioxidant enzyme increased overall under different light qualities, and the expression of antioxidant enzyme genes were the highest under blue light.