Research Article
Hanen Zaier, Tahar Ghnaya and
Abstract
Lead is one of the most toxic metals in the environment and causes drastic morphological and physiological deformities in plants. Growth restriction, chlorosis and necrosis are usually accompanied with a large disturbance of the uptake of essential elements. The aim of this work is to study the effects of lead on mineral nutrient acquisition (Ca2+, K+, N), and their consequences on growth in two different species: halophytic (Sesuvium portulacastrum) and glycophytic (Brassica juncea). Seedlings were grown for 21 days in split-root conditions. One half of the root system was immersed in complete nutrient solution supplemented with 400 μM Pb(NO2)3, and the other half was immersed in a Pb2+-free medium, containing all nutrients or deprived of potassium or calcium or nitrogen. Using this approach, we demonstrated that lead interfere mainly with the absorption of Ca2+ by the roots, thus limiting the growth of plants and their ability to accumulate this metal. We propose that the increase of Ca2+ availability in soils could improve the growth of both species in the presence of lead. This would be essential for improving their utility for phytoremediation of this metal in contaminated soils.