Uptake and accumulation of lead by roots, hypocotyls and shoots of Indian mustard [Brassica juncea (L.)]

The effects of different concentrations of lead nitrate on root, hypocotyl and shoot growth of Indian mustard (Brassica juncea var. Megarrhiza), and t he uptake and accumulation of Pb2+ by its roots, hypocotyls and shoots were investigated in the present study. The concentrations of lead nitrate (Pb( NO3)(2)) used were in the range of 10(-5)-10(-3) M. Root growth decreased p rogressively with increasing concentration of Pb2+ in solutions. The seedli ngs exposed to 10(-3) M Pb exhibited substantial growth reduction and produ ced chlorosis. Brassica juncea has considerable ability to remove Pb from s olutions and accumulate it. The Pb content in roots of B. juncea increased with increasing solution concentration of Pb2+. The amount of ph in roots o f plants treated with 10(-4), 10(-3) and 10(-5) M Pb2+ were 184-, 37- and 6 -fold, respectively, greater than that of roots of the control plant. Howev er, the plants transported and concentrated only a small amount of Pb in th eir hypocotyls and shoots, except for the group treated with 10(-3) M Pb2+. (C) 1999 Elsevier Science Ltd. All rights reserved.