Responses of wheat (Triticum aestivum L.) and maize (Zea mays L.) plants to cadmium toxicity in relation to magnesium nutrition

The infl uence of cadmium (Cd) on physiological processes in wheat (Triticum aestivum L.) and maize (Zea mays L.) plants exposed to either optimal mineral nutrition or the absence of magnesium (Mg) as well as the accumulation of cadmium and magnesium in plant organs were studied using the method of water culture in a greenhouse. Cd treatment reduced shoot fresh mass more strongly in Mg-supplied than in Mg-defi cient plants. Negative effect of Cd on photosynthetic activity was more pronounced in T. aestivum than in Z. mays plants. Cd treatment decreased leaf chlorophyll and carotenoid concentration in both Z. mays and T. aestivum, irrespective of the Mg supply. Cd was preferentially accumulated in the roots of both species. Catalase activity in T. aestivum leaves and roots was unaffected by Cd and Mg supply. Cd treatment did not affect Fe accumulation in the leaves of either species, while in the roots a considerable increase occurred, irrespective of the Mg nutrition. Higher tolerance of Z. mays and T. aestivum plants to Cd toxicity exposed to Mg defi ciency could partly be ascribed to the preservation of Fe nutrition.