Red Pine seedlings were grown in the potted soils with different acidity (pH=4.5,5.5,6.5,7.5,8.0) to investigate their physiological responses to soil pH,and futher to evaluate the soil pH feasibility. Dramatic physiological responses of Red Pine seedlings were detected under various soil pH treatments. Under soil pH 5.5,the seedling foliages grew best,with the lowest malondialdehyde content,ion leakage and soluble substance content,and the highest carotinoid content and antioxidant enzyme activities;With soil pH 7.5 and 8.0 treatments,the seedling needles developed poorest,with greater membrane lipid peroxidation and lower antioxidant enzyme activities,and the greater cell membrane injury and soluble substance content. Results suggested that Red Pine seedlings was mostly adapt to soil with pH of 5.5,followed by soils with pH of 4.5 and 6.5,and could hardly adapted to soil with pH of 7.5 and higher.
