Abstract Phytoextraction of heavy metals by trees is less hazardous for human beings and animals than their extraction by agricultural crops from the contaminated sites. Therefore, phytoextraction potential of four tree species namely Eucalyptus tereticornis Sm. (eucalyptus), Leucaena leucocephala Lam. de Wit (subabul), Melia azedarach L. (dhrek), and Dalbergia sissoo Roxb. (shisham) to tolerate and extract lead (Pb) from soil at its six applied rates (0, 30, 60, 120, 180, and 240 mg Pb kg − 1 soil) was assessed after 18 months of their growth in a pot experiment. Dry matter (DM) yield of different tree components (stem, leaves, and roots), their Pb concentration, Pb uptake and available Pb in the soil before planting and after harvesting the plants were determined. Contamination indices namely transfer coefficient (TC) or bioaccumulation factor for shoots (BAFshoot), bioaccumulation factor for roots (BAFroot), translocation factor (TF), tolerance index (TI), and the remediation factor (RF) were also determined. The increasing Pb levels led to a significant decrease in total DM yield and in eucalyptus, subabul, dhrek, and shisham, it decreased by 38.9, 34.6, 23.3, and 23.5% at the highest level of applied Pb as compared to control (P ≤ 0.05). The Pb concentration in different plant parts increased significantly with increasing levels of added Pb (P ≤ 0.05). Subabul had significantly highest (0.25 − 100.9 mg pot − 1) removal of Pb at different applied Pb levels and therefore, subabul pots had the lowest amount of available soil Pb after harvesting of plants. Dhrek was observed to have highest (56.4 mg kg − 1 soil) upper critical level of available soil Pb whereas subabul had the greatest Pb extraction capacity from the soil. Contamination indices TF (1.35) and TI (0.88) were highest for dhrek but TC or BAFshoot (3.23), BAFroot (2.66), and RF (7.65%) were highest for subabul. Therefore, subabul can be used for phytoremediation of Pb-contaminated sites due to its more biomass and higher extraction of Pb from soil than the other tree species.

中文翻译：

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从铅污染土壤中植物提取铅的不同多用途树种的评估

摘要 树木从植物中提取重金属对人类和动物的危害比从受污染地点的农作物中提取的危害要小。因此，四种树种即Eucalyptus tereticornis Sm 的植物提取潜力。(桉树), Leucaena leucocephala Lam。de Wit (subabul)、Melia azedarach L. (dhrek) 和 Dalbergia sissoo Roxb。(shisham) 在盆栽试验中生长 18 个月后，评估了它们以六种施用率（0、30、60、120、180 和 240 毫克 Pb kg − 1 土壤）从土壤中耐受和提取铅 (Pb) 的能力. 测定了不同树木成分（茎、叶和根）的干物质 (DM) 产量、它们的 Pb 浓度、Pb 吸收和种植前和收获植物后土壤中的有效 Pb。还确定了污染指数，即转移系数 (TC) 或芽的生物积累因子 (BAFshoot)、根的生物积累因子 (BAFroot)、易位因子 (TF)、耐受指数 (TI) 和修复因子 (RF)。铅含量的增加导致总干物质产量显着下降，在桉树、亚布、dhrek 和 shisham 中，与对照相比，在施用铅的最高水平下，它分别下降了 38.9、34.6、23.3 和 23.5%（P ≤ 0.05）。植物不同部位的Pb浓度随着Pb添加量的增加而显着增加（P≤0.05）。Subabul 在不同应用铅水平下显着最高 (0.25 - 100.9 mg pot - 1) 去除铅，因此，在收获植物后，subabul 盆具有最低量的可用土壤 Pb。观察到 Dhrek 最高 (56. 4 mg kg − 1 土壤）有效土壤铅的上临界水平，而 subabul 从土壤中提取铅的能力最大。dhrek 的污染指数 TF (1.35) 和 TI (0.88) 最高，但 subabul 的 TC 或 BAFshoot (3.23)、BAFroot (2.66) 和 RF (7.65%) 最高。因此，subabul 可用于铅污染场地的植物修复，因为它比其他树种具有更多的生物量和从土壤中提取更高的铅。