[Effect of exogenous iron on accumulation and chemical forms of cadmium, and physiological characterization in different varieties of tomato].
Pot experiments were carried out to investigate the influence of different iron (Fe) levels (0, 50, 100, 200 and 400 micromol.L-1) on the plant growth, activities of antioxidant enzymes, accumulation and chemical forms of cadmium (Cd) in tomato when exposed to Cd (10 mg.kg-1). The results showed that dry weights of fruit, roots, stem, leaf, and plant, and concentration and accumulation of Cd significantly differed between the two varieties of tomato tested. Dry weights of fruit, roots, stem, leaf, and plant increased in the presence of Fe. Activities of superoxide dismutase (SOD) of root in both varieties, and activities of catalase (CAT) of root in Yufenl09 deceased at first, and then increased with increasing levels of Fe, but activities of peroxidase (POD) of root in both varieties and activities of CAT of root in 4641 increased at first, and then reduced with increasing levels of Fe. Chemical forms of Cd in fruit of tomato were in the order of FR > FHCl > FE > FNaCl > FHAC > FW. All chemical forms of Cd obviously decreased after the application of adequate Fe compared to the control, while FHcI and FR of 4641, and the total extractable Cd, FE, FNaCl and FR of Yufenl09 increased at 400 micromol.L-1Fe treatment. Cadmium accumulations of tomato were in the order of leaf > stew > fruit > roots. Cadmium concentration in leaf, stem, roots and fruit of both varieties decreased by 7. 1% -25.3% , 30. 8% -50. 4% , 13.0% -45. 1% and 2.8% -11.7% in the presence of Fe when exposed to Cd, and the Cd concentration of fruit and Cd accumulations in plant were in the order of 4641 < Yufenl09 in the presence or absence of Fe.