RELATIVE TOLERANCE AND PHYTOREMEDIATION CAPACITY OF DIFFERENT Brassica species UNDER LEAD STRESS

Abstract

The present study was carried out to investigate the metal accumulation and tolerance abilities of five Brassica species (B. compestris. B. napus. B.jllllcea, R. sativus and B. oleracea) seedlings exposed 10 four levels of lead (Pb) stress [0 mM. 0.25 mM. 0.5 rru'vland I mM Pb(NO,):) for six weeks. Of the Brassica species studied, Bi juncea accumulated the highest amount of Pb in a dose-dependent manner and in every casco the Pb coruent was higher in the roots than the shoots. Lead toxicity causes a severe impact on plant growth and biomass. All level of Pb stress reduced seedlings height fresh weight and dry weight in each varieties at 2. -'I and 6 weeks of age. In addition, leaf relative water content and SPAD value were also decreased with increase of stress concentration. But among the varieties, B. juncea showed lowe>! reduction of abovementioned parameters. Considering the growth and physiological performance B juncea is relatively tolerant species though il accumulated highest Pb in rOOIS and ShOOLS.So. B. junceo might be used as a 1001 of phytoremcdiation ill Pb polluted soil.