营养杯对长喙田菁在铅锌尾矿上的生长、固氮和重金属积累的影响

The Effects of Nutrition Polybag on the Growth, N-fixation and Heavy Metal Accum ulation of Sesbania rostrata Grown on Pb/Zn Tailings

摘要:

设置移栽时营养杯的有无及其大小作试验,研究长喙田菁在乐昌铅锌矿强酸化尾矿上的生长、固氮和积累重金属情况。结果表明,强酸性(pH<3)是限制植物定植的主要因素,在pH=5-7情况下,长喙田菁能在该尾矿库中定植、生长和固氮,表现出良好的适应性。未带营养杯移栽的长喙田菁在尾矿上生长84d,其株高117 cm、茎基部直径1.35 cm、单株生物量(干物质)20.2 g、单位面积生物量(干物质)2828 kg hm^-2、氮素积累量40 kg hm^-2；带营养杯移栽的上述各指标分别达到140-144 cm、1.59-1.68 cm、36.6-38.8 g、5124-5432 kg hm^-2和77-107 kg hm^-2,均显著高于未带营养杯处理的。长喙田菁根部铅、锌、铜、镉含量均最高,其次为茎,叶中最低；长喙田菁的4种重金属积累量为锌(186-221 mg kg-1)>铅(96-145 mg kg^-1)>铜(17-30 mg kg^-1)>镉(3-4 mg kg^-1)。带营养杯移栽能有效提高长喙田菁的产量和氮积累量,且明显降低其体内的重金属含量。试验证明长喙田菁是较理想的铅锌矿尾矿废弃地植被重建的先锋植物。

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.