RESUMO
Chelating agents can increase the bioavailability of heavy metals and enhance their enrichment in plants. The effects of different concentrations of biodegradable chelating agent L-glutamic acid N, N-diacetic acid (GLDA) on the remediation of heavy metal-contaminated soil by super-enriched plant Trifolium repens were investigated by pot experiments with Cd-contaminated soil. Results show that low-dose GLDA could significantly promote the growth of Trifolium repens, and the biomass of Trifolium repens was the highest at 2.5 mmol·kg-1-GLDA, which was 1.30 times that of the control group. Different concentrations of GLDA can increase Cd content of various parts of Trifolium repens. In general, the treatment effect of 5 mmol·kg-1 GLDA was ideal. In this scenario, the root, aerial parts, and whole Cd content were 3.57, 4.69, and 4.67 times of the control group, respectively. GLDA can significantly increase the available Cd content in soil, promote direct absorption at the Trifolium repens roots, and provide better transport to the aerial parts. The prediction model obtained by fitting the linear relationship between physical and chemical properties of soil indicates that GLDA and Trifolium repens Cd content can provide references for the future research of soil-Trifolium repens enrichment. Studies have shown that the biodegradable chelating agent GLDA has potential applications for enhancing phytoremediation of heavy metal Cd contaminated soil.
