Cd-induced growth reduction in the halophyte Sesuvium portulacastrum is significantly improved by NaCl

The effects of Cd2+ and NaCl, applied together or separately, on growth and uptake of Cd2+ were determined for the halophyte Sesuvium portulacastrum L. Seedlings were cultivated in the presence of 50 or 100 mu mol L-1 Cd2+ alone or combined with 100 or 400 mmol L-1 NaCl. Data showed that alone, Cd2+ induced chlorosis, necrosis, and inhibited growth. Addition of NaCl to Cd2+-containing medium restored growth and alleviated the toxicity, however. NaCl also enhanced the amounts of Cd2+ accumulated in the shoots. All Cd2+ treatment reduced K+ and Ca2+ uptake and transport to the shoots. Accumulation of Na+ in the shoots was not affected by Cd2+, however. Thus S. portulacastrum maintained its halophytic characteristics in the presence of Cd2+. We suggest this halophyte could be used for phytoextraction of Cd2+ from salt-contaminated sites.