CONICET | Buscador de Institutos y Recursos Humanos

Heavy metal contamination in soils and the contact of these with plants generates a competition between the contaminating metals and the essential ones. Zinc (Zn) is an essential element for both plants and animals, in excess it causes alterations in important processes for the development of the organism. Cadmium (Cd) is a heavy metal without biological functions, in low concentrations it causes damage at cellular and molecular level. Because it has the same charge than essential metals, the plant absorbs Cd and Zn through the same transporters (IRT1-ZIP), generating interferences in the entry, transport and use of Zn. There is also competition with other cations such as Calcium (Ca) and Magnesium (Mg). The symptoms generated in plants by the presence of Cd and/or excess Zn, are similar: reduction of biomass, decrease in elongation and darkening of the main roots, chlorosis and necrosis of leaves, and changes in oxidative stress parameters. In our model, Glycine max leaves and roots were used, which after 10 days of development and adaptation to hydroponic conditions in Hoagland´s nutrient solution, were subjected to contamination with Cd and Zn, for 6 days. Zn was used at the concentrations of 0, 1.2, and 6.1 mM, with a constant concentration of 40 µM CdCl. Endogenous studies of the competitive capacity between Cd, Zn, Ca, and Mg were carried out to determine them when absorbed through the roots. Root and stem length and leaf area were determined, MDA was measured as an oxidative stress parameter and catalase (CAT) as an antioxidant enzyme. The results of the endogenous content in both leaves and roots showed that by increasing the concentration of Zn, the absorption of Cd decreased significantly (P