Biochemical responses of two typical duckweeds exposed to dibutyl phthalate.

Effect of dibutyl phthalate (DBP) on physiologic and biochemical characteristics of two species of duckweed (Spirodela polyrhiza and Lemna minor) from Tai Lake in China was investigated. The results indicated that different degree of poisoning symptoms appeared on duckweeds after 7 days' exposure to different concentrations of DBP. With the increase of DBP concentration, content of chlorophyll and soluble protein decreased sharply, and activity of anti-oxidant enzyme systems including catalase (CAT), superoxide dismutase (SOD) and malondialdehyde (MDA) content increased significantly and decreased afterwards. With the concentration of DBP of 0.5 mg/L and 0.005 mg/L, SOD activity of Spirodela polyrhiza and Lemna minor reached peak value respectively, while CAT activity were maximum under the concentration of 1mg/L and 0.05 mg/L. It could be concluded that DBP can affect the growth of both Spirodela polyrhiza and Lemna minor, and the former has better endurance to exposure than the latter.