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

The e€ects of di€erent concentrations of lead nitrate on root, hypocotyl and shoot growth of Indian mustard (Brassica juncea var. Megarrhiza), and the 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 10ÿ5±10ÿ3 M. Root growth decreased progressively with increasing concentration of Pb2‡ in solutions. The seedlings exposed to 10ÿ3 M Pb exhibited substantial growth reduction and produced chlorosis. Brassica juncea has considerable ability to remove Pb from solutions and accumulate it. The Pb content in roots of B. juncea increased with increasing solution concentration of Pb2‡. The amount of Pb in roots of plants treated with 10ÿ4, 10ÿ3 and 10ÿ5 M Pb2‡ were 184-, 37- and 6-fold, respectively, greater than that of roots of the control plant. However, the plants transported and concentrated only a small amount of Pb in their hypocotyls and shoots, except for the group treated with 10ÿ3 M Pb2‡.