This paper dealt with the effects of Pb 2+,Cd 2+ and their combined pollution on the contents of chlorophyll,potassium and calcium in Thuidium cymbifolium.The results showed that except at 0.1 mg Cd 2+·L -1,the chlorophyll content decreased with increasing Pb 2+ and Cd 2+ concentrations,which was 18% of the control at 100 mg Cd 2+·L -1,and decreased by 48.6% at 200 mg Pb 2+·L -1.The potassium and calcium contents also decreased with increasing pollutants concentrations,being decreased by 61.1% at 100 mg Cd 2+·L -1.Cd 2+ had a stronger toxicity than Pb 2+,and the toxicity of their combined pollution was stronger than that of each pollutant.Pb 2+ could increase the toxicity of Cd 2+.
