Comparative effects of chelants on plant growth, cadmium uptake and accumulation in nine cultivars of Ramie (Boehmeria nivea)

Abstract

Chelate-induced phytoremediation has been considered as a promising measure for the remediation of heavy metal-contaminated soils. The plant growth and cadmium (Cd) accumulation in nine ramie cultivars pot-grown in Cd-contaminated soil were investigated following the application of ethylenediaminetetraacetic acid (EDTA) and ethylenediamine succinic acid (EDDS) at 5 mmol kg−1. Results showed that the application of chelants significantly affected the plant height and biomass with significant varietal difference. EDTA treatment resulted in reduced plant height and biomass in all cultivars tested, while EDDS application increased the plant height and aboveground biomass in most of the cultivars. Both chelants significantly increased the shoot Cd contents, being up to 60% and 54% more than those of control after EDTA and EDDS treatments, respectively. The chelants were found to reduce the root Cd content by 15% and 12% in EDTA- and EDDS-treated plants, respectively. They were found to significantly increase the value of translocation factor (TF), indicating that EDTA and EDDS can help Cd migrate from root to shoot. Cultivar Zhongzhu 1 showed a potential of extracting 0.104 t Cd ha−1. At the concentration of 5 mmol kg−1, EDTA treatment appeared to have greater impact on the plant growth and Cd accumulation than EDDS.