[Objective]This study aimed at exploring the physiological properties of the known Cd hyperaccumulator Viola baoshanensis and the control plant Viola inconspicua to cadmium stress.[Method]After a hydroponic experiment carried in a greenhouse,plant Cd accumulations,root elongation rates,MDA contents,and antioxidant enzyme activities were determinined.[Result]Both Viola baoshanensis and Viola inconspicua showed high levels of Cd uptake growing in Cd-supplemented solution of 300 μmol/L for 12 d with Cd accumulations of 2 595 and 3 330 mg/kg in the shoots,respectively.In the cultural solution supplemented with 300 μmol/L of Cd,the root elongation rates were not affected and the MDA contents decreased significantly in Viola baoshanensis,while the root elongation rates were significantly inhibited and the MDA contents increased remarkably in Viola inconspicua,which indicated that Viola baoshanensis had the higher Cd tolerance.The superoxide dismutase（SOD）,peroxidase（POD）and catalase（CAT）activities of two Viola species were not linearly related to the middle and low Cd-supplemented concentrations（5,50 μmol/L）and had attained the tiptop in cultural solution supplemented with 100 or 300 μmol/L of Cd but declined in cultural solution supplemented with 500 μmol/L of Cd,suggesting that the contribution of antioxidative enzymes was limited to the Cd tolerance of Viola plants.The Viola inconspicua showed a strong adaptability to the middle and low concentrations of Cd.[Conclusion]Viola species could be used as potential plant resources for the phytoremediation of agriculture areas polluted with low and even middle levels of Cd.
