Effects of different concentrations of Pb²⁺(0,0.25,0.50,1.00,2.00 mmol·L^-1) on contents of Pb,chlorophyll and malondialdehyde (MDA),activities of antioxidant enzymes (SOD,CAT and POD) and subcellular structure in the leaves and roots of Typha orientalis Presl were studied in this experiment.The results indicated that:(1)with the increase of exogenous Pb²⁺ concentrations,Pb accumulation in roots and leaves were significantly higher than that of the control,and Pb contents in roots were significantly higher than those in leaves,which had significant positive correlation with exogenous Pb²⁺ concentrations.(2)Both contents of chlorophyll a and chlorophyll b in leaves increased first and then decreased,which both reached the peak value in 0.50 mmol·L^-1 Pb²⁺ treatment.(3)There was no significant change of MDA contents in leaves compared with the control,whereas MDA content in roots significantly declined.(4)In leaves,superoxide dismutase (SOD) activity reached the peak value in 1.00 mmol·L^-1 Pb²⁺ treatment and then decreased compared to the control,which was always higher than that of control.However,peroxydase (POD) and catalase (CAT) activities in Pb²⁺ treatment groups were all lower than that of control group.In roots,superoxide dismutase (SOD) activity decreased significantly compared to the control except 1.00 mmol·L^-1 Pb²⁺ treatment.Catalase (CAT) and peroxydase (POD) activities reached their peak values in 0.25 mmol·L^-1 and 0.50 mmol·L^-1 Pb²⁺ treatments,respectively,and then decreased with the increase of exogenous Pb²⁺ concentration.(5) By means of transmission electron microscope technology,it was observed that Pb²⁺ induced damages of cell ultrastructure:chloroplast envelope was damaged,thylakoid swelled and broke in leaves cells;in leaf and root cells,mitochondria were vacuolated and the envelope was broken;nuclear membrane was damaged,nucleolus lost and chromatin condensed.It was concluded that Pb²⁺ stress induced imbalance of physiological metabolism and irreversible damage of subcellular structure.This research could provide theory basis for the specific mechanism of Pb²⁺ stress at the molecular level and application of Typha orientalis Presl in heavy metal pollution repair.