Effect of Organic Ligands on Accumulation of Copper in Hyperaccumulator and Nonaccumulator Commelina communis

Better understanding of copper uptake and accumulation regulation in plants is critical to the phytoremediation of copper contaminated soil. This study employed a 30-day pot experiment to assess the relationship between organic ligands and copper accumulation in plants. Hyperaccumulator and nonaccumulator varieties of Commelina communis were used, different organic ligands were applied, and the data of copper accumulation in shoots were collected. The six organic ligands included ethylenediaminetetraacetic acid and organic acids (formic acid, citric acid, malic acid, tartaric acid, and succinic acid). The results showed that organic ligands added to culture increased the copper accumulation both varieties. The results of the copper accumulation in shoots agreed with the study of the root uptake kinetics of copper influx. The addition of organic acids could increase copper accumulation in shoots because the copper influx in roots was increased. The results also indicated that the copper influx of hyperaccumulator roots was higher than that of nonaccumulator roots. This is one of the mechanisms by which a hyperaccumulator could amass large amounts of copper in its shoots. In this accumulation process, little effect on the leaf relative water content was in the hyperaccumulator and nonaccumulator of leaves and normal physiological condition of plants.