Cadmium-induced toxicity reversal by zinc in Ceratophyllum demersum L. (a free floating aquatic macrophyte) together with exogenous supplements of amino- and organic acids

This paper analyzes the detoxification mechanisms adopted by amino- and organic acids to alleviate Cd toxicity. In addition, with our published data on Zn-Cd interactions, the influence of Zn (200 mu M) supplements on the detoxification mechanisms of amino- and organic acids have also been studied. The experimental studies on metal uptake, lipid peroxidation levels, estimation of reduced and oxidized glutathione levels as well as gamma-glutamylcysteine synthetase activity in amino acid supplemented Cd treatments indicated glutathione-mediated detoxification system, which was also enhanced by Zn (200 mu M) supplements. However Zn did not aid in glutathione synthesis, but maintained the ratio of reduced and oxidized forms. The supplementation of organic acids to Cd treatments indicated detoxification through the mechanism of chelation. Zn seemed to be less influential on organic acids-mediated detoxification mechanism as compared to amino acid mediated detoxification system. (c) 2005 Elsevier Ltd. All rights reserved.