Effect of organic acids on the availability of cadmium in wheat

Pot experiments were conducted to investigate the effect of various organic (carboxylic and amino) acids on the uptake and translocation of root-absorbed cadmium by wheat (Triticum vulgare) plants grown in sand and soil culture. Statistically significant increases in cadmium accumulation from cadmium treated plants in the presence of increasing concentration of organic acids suggest the existence of Cd-organic acid interactions in the soil-plant system resulting into the formation of organically bound cadmium which is mobile and plant available. Separate experiments were performed to synthesise and estimate the various forms of organically bound cadmium. The chemical nature of the organically bound form was ascertained by electrophoretic experiments. Amino acids were less effective in the mobilisation of cadmium compared to carboxylic acids. The results are discussed on the basis of the potential of organic acids to form complexes with cadmium.