Hyperaccumulation of Lead by Roots, Hypocotyls, and Shoots of Brassica juncea

The effects of different concentrations of lead nitrate (10-5 to 10-3 M) on root, hypocotyl, and shoot growth of Indian mustard (Brassica juncea L. var. megarrhiza), and the uptake and accumulation of Pb2+ by its roots, hypocotyls, and shoots were investigated. Lead had no significant inhibitory effect on the root growth at concentrations of 10-5 to 10-4 M during the entire treatment, while at 10-3 M, Pb slightly inhibited the root and shoot growth. B. juncea has ability to take up Pb from solutions and accumulate it in its roots, and transport and concentrate it. The Pb contents in the parts of plants treated with 10-3 M Pb were greater than those of untreated plants, by factors of 230 in the roots, 170 in the hypocotyls, and 3 in the shoots.