Abstract: The growth of 1-, 3-, and 5-year-old seedlings and young trees of Taxus chinensis var. mairei were studied under more than one year shading, and the contents of taxol and its precursor (10-deacetylbaccatin Ⅲ) in 5-yearold young trees of T. chinensisvar. maireiwere determined under different shading treatments. Light was one of the important environmental factors affecting the growth of young T. chinensis var. mairei individuals. Only under shading, 1-year-old seedlings grew up healthily and had a high survival rate; under full light, about 50% of 3-year-old young trees died; while 30% shading was suitable for the healthy growth of 5-year-old young trees. The contents of taxol and 10-deacetylbaccatin Ⅲ in 5-year-old young trees were higher under full light than under shading treatments. Different ages of T. chinensis var.mairei individuals required different shading conditions to maintain their healthy growth. For T. chinensis var. mairei, the most appropriate light condition for the biosynthesis and accumulation of taxol and 10-deacetylbaccatin Ⅲ was not fully identical with the most suitable light condition for growth.

Key words: Low light density, Long-term suboptimal temperature, Short-term low temperature, Photosynthesis, Growth speed, Cucumber