Effects of Citric Acid or EDTA-Na2 on the Absorption Characteristic of Pb and Nutrient Elements of Lolium perenne L.

Abstract:

In order to understand the effects of citric acid or EDTA-Na₂ on the absorption characteristic of Pb and six nutrient elements of Lolium perenne L., the contents of Pb, N, P, K, Ca, Mg and Fe, as well as the dry weight, the root dehydrogenase activity and the membrane permeability in L. perenne with different treatments were studied. The results showed that the dry weight of L. perenne decreased, and root dehydrogenase activity and membrane permeability increased under Pb pollution, the changes in six nutrient elements contents in leaf and root varied, and Pb accumulated in both of leaf and root. Treated with low concentration of citric acid or EDTA-Na₂, there was a little influence on growth of L. perenne, and the Pb accumulation in leaf was low. However, treated with high concentration of citric acid or EDTA-Na₂, the growth of L. perenne not only showed serious inhibition, but also coursed imbalance of nutrients homeostasis, and the accumulation of Pb in leaf increased. Then, L. perenne could accumulate more Pb in leaf treated with 1 mmol L^-1 citric acid or 5 and 10 mmol L^-1 EDTA-Na₂. Therefore, it was suggested that suitable concentration of citric acid or EDTA-Na₂ could play certain role in control environment of Pb pollution.