Response of growth and Pb accumulation characteristics of plants with intercropping - to exogenous oxalic acid.

In order to study the effects of oxalic acids on plant growth and Pb accumulation in different parts of the plants of intercropping and , pot experiment was conducted to investigate the changes of oxalic acid contents of the plants and Pb accumulation through exogenous oxalic acid addition (0, 5, 25 and 50 mmol kg). The results showed the root biomass of intercropped and total biomass of increased by 3.22 folds and 2.97 folds with 5 mmol kg oxalic acid treatment. The oxalic acid contents of shoots and root secretions decreased by 86.5% and 44.3%, respectively. The BCF (bio-accumulation factor) and TF (translocation factor) of intercropping reduced under 25 - 50 mmol kg oxalic acid treatments. There were relationships between exogenous oxalic acid treatment concentrations and oxalic acid contents of shoots, root secretions. The Pb contents of shoots of and were related to exogenous oxalic acid additions and oxalic acid contents of shoots. In general, 5 mmol kg oxalic acid treatment, that can improve plant growth of intercropped and , which Pb translocation and accumulation of were promoted, whereas Pb accumulation of was inhibited with 25 - 50 mmol kg concentrations addition. This study will provide a basis for promoting the application of phytoremediation techniques and efficient crop production in heavy metal contaminated areas.