Physiological responses of water hyacinth, Eichhornia crassipes (Mart.) Solms,to cadmium and its phytoremediation potential

Authors: SUCHISMITA DAS, SUNAYANA GOSWAMI, ANUPAM DAS TALUKDAR

Abstract: Eichhornia crassipes is an abundant floating aquatic weed that has great potential for cadmium (Cd) remediation owing to its large biomass and relatively high tolerance and accumulation capabilities. This study was conducted with Eichhornia in 5, 10, 15, and 20 mg L^-1 CdCl₂ in a hydroponic system for 21 days, and the Cd concentrations in the roots, shoots, and leaves were estimated. The plant showed tolerance, but at high Cd concentrations declines in biomass, root length, and leaf area were observed. Leaves showed a progressive decline in chlorophyll, carotenoid, and soluble protein and a significant elevation in lipid peroxidation. Cd uptake gradually increased in all the plant tissues up to 15 mg L^-1 exposure, but at 20 mg L^-1 the accumulation declined. Shoot tissues accumulated more Cd than root and leaf tissues. The highest accumulation by the plant was 1927.83 μg g^-1 dry wt at 15 mg L^-1 Cd. The maximum leaf, shoot, and root bioconcentration factors were 179.05, 187.59, and 169.3, respectively, and the maximum translocation factor of 1.003 was observed at 5 mg L^-1 Cd. The root-to-leaf translocation of Cd was 100% efficient for all the doses of Cd exposure, except for 20 mg L^-1. The results of this study suggested that water hyacinth tolerated phytotoxic concentrations of up to 15 mg L^-1 and efficiently hyperaccumulated Cd in its above-ground tissues.

Keywords: Metal, rhizofiltration, macrophyte, hyperaccumulator, MDA, plant pigment

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