EFFECTS OF CADMIUM AND ZINC ON GROWTH AND METAL ACCUMULATION OF Mathiola flavida BOISS

Abstract

The effects of cadmium (Cd), Zinc (Zn), and Cd–Zn on growth and their accumulation in the Matthiola flavida shoots were investigated. A factorial experiment with two factors (Cd and Zn) concerning four concentrations of Cd (0, 5, 10 and 20 mg L -1 ) and four Zn concentrations (0, 10, 20 and 40 mg L -1 ) were carried out. The shoot and root biomass of M. flavida growing in CdZn medium decreased significantly (p<0.01) compared to the control. Growing in the presence of 20 mg L -1 Cd and 40 mg L -1 Zn, resulted in the highest decrease of root and shoot biomass and tolerance index compared to that at 5 mg L -1 Cd. At the highest Cd (20 mg L -1 ) and Zn (40 mg L -1 ) concentration, plant tolerance index was inhibited by 82 and 74%, respectively (P<0.01) compared with the control. The concentrations of Cd and Zn in the shoots of M. flavida were increased with increasing Cd and Zn concentration in the medium. Significant inhibitory effects of Zn on Cd concentration in the shoots occurred at levels above 10 mg Zn L -1 . On the other hand, the shoot Cd concentration of M. flavida in the combined Cd and Zn treatment group was reduced by 67.6%, relative to that of the Cd alone treatment group. Zinc concentrations in the shoots decreased with increasing rates of applied Cd. Therefore, we recognize M. flavida as a candidate for remediation of sites co-contaminated by Cd and Zn purposes in Iran, the more so because they are adapted to the local climate and soil conditions.