Abstract

Enhanced phytoextraction technologies have been proposed as an effective approach to the decontamination of heavy metals in soils. In this study, the application of ethylene diamine tetraacetic acid (0.5 and 1.0 g/kg EDTA) at preflowering stage depressed Rorippa globosa growth and Cd uptake, the dry biomass, Cd concentration and total metal accumulation (TMC) of shoots at the concentration of 1.0 g/kg EDTA resulted in 39.6, 3.1 and 41.0% reduction, respectively, relative to the control. In contrast, when EDTA was added at flowering and mature stages, it facilitated plant production and Cd absorption. Especially for 1.0 g/kg EDTA applied at mature stage, the maximum of shoot dry biomass, Cd concentration, TMC and remediation ratio (RR) were obtained, which were 4.7 g/pot, 210.3 mg/kg, 982.4 µg/pot and 1.6, respectively. Therefore, the moderate concentration of EDTA (1.0 g/kg) applied at optimal growing stage (mature stage) of R. globosa was more effective in increasing phytoextraction of Cd from contaminated soils.

Key words: EDTA, induced-phytoextraction, Cd-hyperaccumulator, Rorippa globosa.