Abstract:Growth, N-fixation and heavy metal accumulation of Sesbania rostrata transplanted on acidified Pb/Zn tailings in Lechang, Guangdong Province, were investigated. Experiments were carried out by transplanting seedlings prepared with nutrition polybags of 9.5 cm in diameter and 10 cm height containing 1 kg soil (A), of 7.5 cm in diameter and 8 cm height containing 0.5 kg soil (B) and without polybag (C). The results showed that Sesbania rostrata succeeded to establish, grow and fix N on the tailings of pH 5-7, but failed to grow at pH<3. After transplanting on tailings for 84 days, the plant height (140-144 cm), basal diameter of stem (1.59-1.68 cm), individual biomass (36.6-38.8 g DW), dry matter production (5124-5432 kg hm-2) and nitrogen accumulation (77-107 kg hm-2) in treatments A and B were significantly higher than those in treatment C which were 117 cm, 1.35 cm, 20.2 g, 2828 kg hm-2, and 40 kg hm-2, respectively. The contents of Pb, Zn, Cu and Cd were highest in the roots followed by stems and leaves, and the amounts of the 4 heavy metals in whole plant were in the order Zn (186-221 mg kg-1) > Pb (96-145 mg kg-1) > Cu (17-30 mg kg-1) > Cd (3-4 mg kg-1). Transplanting seedlings with nutrition polybag could improve the growth and N-fixation, and markedly decrease heavy metals accumulation in S. rostrata. It is suggested that S. rostrata is a good pioneer species for bioremediation of the tailings.
