Uptake and distribution of cadmium and micronutrients by bean cultivars exposed to cadmium levels

Abstract

To evaluate the effects of cadmium levels in nutrient solution on the uptake and distribution of Cd, Zn, Fe, Mn and Cu by bean plants (Phaseolus vulgaris L.), an experiment was carried out under greenhouse conditions, utilizing the cultivars Ouro Negro and Carioca. The Cd levels tested were: 0.0; 0.025; 0.05; 0.10 e 0.50 μg/mL applied in 4.8 L vases containing Clark nutritive solution with half the original ionic force at pH 6.0. For both cultivars, Cd contents in plants showed to increase with increased Cd levels in nutrient solution, with the roots accumulating more Cd than shoot. The Cd treatment resulted in decreased content of Zn and Mn in roots, with little or no effect on the contents of these elements in the shoot. The Cu contents in plants were apparently unaffected by the Cd levels in nutrient solution, except for the Cu content in roots of the Carioca cultivar. On the other hand, the Fe content was altered only in the roots of the Ouro Negro cultivar.