Response of Indian mustard (Brassica juncea arawali) plants under nickel stress with special reference to nickel phytoextraction potential

The objective of present paper was to evaluate nickel phytoextraction capacity of Indian mustard plants (Brassica juncea arawali) with and without chelant application. The chelants chosen for the study were ethylene diamine tetraacetic acid (EDTA) and salicylic acid (SA). Seeds of Indian mustard were sown in nickel contaminated soils with nickel concentrations from 100 to 800 mg/l as nickel nitrate. Plants were harvested at four stages. Various morphological parameters, biochemical parameters and nickel phytoextraction potential of plants were studied. It was found that seed germination and percentage survival of Indian mustard reduced with increasing concentration of Ni. Addition of SA enhanced germination and survival of B. juncea, while EDTA played negative role. Plant growth parameters like numbers of branches and leaves, root length and shoot length decreased with increased concentrations of Ni. In general, EDTA decreased all morphological parameters, whereas SA stimulated them. EDTA treated plants showed 83-90% higher Ni accumulation compared to control for the applied Ni doses of 100-800 mg/l respectively. The Ni metal accumulation order was Ni+EDTA>Ni+SA>Ni. EDTA proved to be more efficient chelant than SA for Ni removal from contaminated soil