Organic acid assistance is one of the effective methods for phytoremediation of heavy metal contaminated soil. In this experiment, the addition of citric and glutaric acids was selected to improve the accumulation of cadmium and lead by Helianthus annuus L. Results showed that citric and glutaric acids elevated the growth of the plants and stimulated Cd/Pb uptake by plant in single Cd/Pb treatments, but glutaric acid showed inhibitory action on the uptake of metals in complex treatments. Organic acids impacted the translocation of Cd/Pb differently, and citric acids (30 mg·L-1) enhanced the translocation of Cd to aerial parts of the plants in Cd (5 mg·kg-1) and Cd (10 mg·kg-1) plus Pb treatments. Glutaric acid (30 mg·L-1) could promote the translocation factors in the complex treatments of Cd (5 mg·kg-1) with Pb (50, 100 mg·kg-1) added. The application of citric and glutaric acid could be conducive to increase floral growth when proper doses are used, and incorporation of these organic acids can be a useful approach to assist cadmium and lead uptake by sunflower. However, growth, bioaccumulation, and translocation of metals may differ due to the metals' property, kinds, and concentrations of organic acids.
Keywords: cadmium; lead; organic acids; phytoextraction; sunflower.