RESUMO
Lead phytoextraction from salty soils is a difficult task because this process needs the use of plants which are able to tolerate salt and accumulate Pb(2+) within in their shoots. It has recently been suggested that salt-tolerant plants are more suitable for heavy metals extraction than salt-sensitive ones commonly used in this approach. The aim of this study was to investigate Pb-phytoextraction potential of the halophyte Sesuvium portulacastrum in comparison with Brassica juncea commonly used in Pb-phytoextraction. Seedlings of both species were exposed in nutrient solution to 0, 200, 400, 800 and 1000 µM Pb(2+) for 21 days. Lead strongly inhibited growth in B. juncea but had no impact on S. portulacastrum. Exogenous Pb(2+) reduced nutrients uptake mainly in B. juncea as compared to S. portulacastrum. Lead was preferentially accumulated in roots in both species. S. portulacastrum accumulated more Pb(2+) in the shoot than B. juncea. Hence, the amounts of Pb(2+) translocated at 1000 µM Pb(2+) were 3400 µg g(-1) DW and 2200 µg g(-1) DW in S. portulacastrum and B. juncea, respectively. These results suggest that S. portulacastrum is more efficient to extract Pb(2+) than B. juncea.
