中文摘要：

重金属污染及生态修复是环境和生态领域研究的热点和难点。皇草是重要的纤维素生物燃料和电力植物。选用皇草作为重金属污染土壤的修复植物,探讨皇草对重金属的耐性机理和对重金属污染土壤的修复效果。结果表明：皇草的株高和干重在Ni、As、Zn、Pb处理中显著高于对照处理或者与对照处理没有显著差异,但在Cr处理中显著低于对照处理。皇草在Ni、As、Zn、Pb和低浓度Cr污染土壤均能生产大量的生物质,每季产25.55～28.51 t·hm（-2）鲜草和8.23～9.12 t·hm（-2）干草。皇草叶片中MDA和POD的含量随着Cr、Ni、As和Pb浓度的升高有所增加,但CAT和SOD的活性表现出相反的趋势。在Zn的2个浓度梯度下,皇草叶片中的CAT、POD和SOD的活性均随着Zn浓度升高而下降。从重金属在皇草各器官分布来看,Cr、As和Pb的浓度为根〉叶〉茎;Ni和Zn为根〉茎〉叶。从重金属在植物叶片中的形态来看,Cr、Ni、Zn和Pb的盐酸提取态的含量较高。从重金属在亚细胞分布来看,Cr、As和Pb在皇草叶片亚细胞组分分布为细胞质〉细胞壁〉细胞器,Ni和Zn在皇草叶片亚细胞组分分布为细胞器〉细胞质〉细胞壁。皇草对重金属的富集系数和转运系数均小于1,对重金属的提取量较低,但其耐性强、生物量大,适合应用于土壤重金属污染的植物稳定技术。

英文摘要：

The ecological restoration of heavy metal polluted sites is a hot topic in the fields of environmental sci- ence and ecology. King grass, which is an important energy crop for cellulosic biofuels and electric power plants, could also potentially be used as a remediation tool for heavy metal polluted soils. In this paper, the metal toler- ance mechanisms, metal accumulation tendencies, and phytoremediation efficiencies of king grass were studied in detail. The shoot lengths and dry biomass values of plants grown in treatments of Ni, As, Zn, and Pb were significantly higher than or the same as those of plants grown in control treatments, while plants grown in Cr treatments had shoot lengths and dry biomass values that were significantly lower than those of control plants. King grass could produce from 25.55 to 28.51 t · hm-2 of fresh biomass and 8.23 to 9. 12 t · hm-2 of dry bio- mass when grown in soils containing Ni, As, Zn, and Pb and low levels of Cr pollution. The content of MDA and the activities of POD in plant leaves increased with increasing concentrations of Cr（VI） , Ni, As, and Pb in the soil, while the activities of CAT and SOD showed the opposite trend. The biomarker activities in plant leaves de- creased with increasing Zn concentrations in soil. The concentrations of Cr, As, and Pb were the highest in the plant roots followed by the leaves and stems. The concentrations of Ni and Zn were the highest in plant roots fol- lowed by the stems and leaves. The analysis results for metal chemical forms showed that high proportions of thehydrochloric acid extraction fractions of Cr, Ni, Zn, and Pb could be found in plant leaves. The contents of Cr, As, and Pb in the leaf cells were the largest in vacuoles followed by cell wails and cell organs, whereas the con- tents of Ni and Zn in leaf cells were the largest in cell organs followed by vacuoles and cell walls. The bioaccu- mulation factor and translocation factor were both smaller than 1, and the metal extraction amounts were low; however, the metal tol