Lead accumulation, growth responses and biochemical changes of three plant species exposed to soil amended with different concentrations of lead nitrate

Lead (Pb) contamination of soil is a serious environmental problem, adversely affecting ecosystems, globally. Phytoremediation is an alternative to conventional methods of soil remediation. The success of phytoremediation depends on the identification of suitable native plant species with high biomass to deal with metal contamination. In the present experiment, response of Eclipta prostrata (L.) L., Scoparia dulcis L. and Phyllanthus niruri L. to increase in concentrations of PbNO3.5H(2)0 in the soil for a period of 30 days was tested to assess their suitability in phytoremediation. Pb accumulation in all the three plants was in a concentration-dependent manner. Although S. dulcis survived the soil metal concentrations, it exhibited a stunted growth; P. niruri was found susceptible to Pb toxicity; E. prostrata recorded a maximum uptake of 12484 gig dry weight in its root and 7229 mu g/g dry weight in its shoot, without any adverse impact on growth traits. Bioconcentration factor and translocation factor of the three plants were also calculated, which revealed that E. prostrata has Pb accumulation potential. Therefore, enzymatic antioxidant activities and transmission electron microscopic analysis were carried out to determine the physiological adaptation and tolerance of E. prostrata to Pb stress. Overall, E. prostrata is identified as a tolerant plant showing Pb hyperaccumulation tendencies with essential features for phytoextraction.