Institute of Environmental Engineering, School of Metallurgy and Environment, Central South University, Changsha, 410083, China.
Hunan Research Academy of Environmental Sciences, Changsha, 410004, China.
Environ Sci Pollut Res Int. 2020 Feb;27(4):4294-4308. doi: 10.1007/s11356-019-07124-4. Epub 2019 Dec 12.
Woody plants have considerable application potential in the phytoremediation schemes, owing to their long-lived large biomass and prosperous root systems in heavy metal(loid)-contaminated soil. Under greenhouse conditions, the physiological response characteristics and phytoremediation possibility of Morus alba L. and its associated improvement of the bacterial and arbuscular mycorrhizal fungal (AMF) diversities in heavy metal(loid) co-contaminated soils were investigated. The results showed that the cultivated M. alba L. plant exhibited significant tolerance against the heavy metal(loid)s in co-contaminated soil and that the microbial diversities were improved notably. The contents of malondialdehyde (MDA) in M. alba L. leaves decreased with cultivation from 90 to 270 days, while the superoxide dismutase, peroxidase and catalase activities were maintained at normal levels to eliminate the production of lipid peroxides. The chemical compositions (e.g. amino acids, carbohydrates and proteins) in the root of M. alba L. fluctuated slightly throughout the cultivation period. Meanwhile, Cd, Pb and Zn were majorly concentrated in the M. alba L. roots, and the maximum contents were 23.4, 7.40 and 615.5 mg/kg, respectively. According to the polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analysis results, the influence of M. alba L. on the rhizosphere AMF community was greater than that on the bacteria community. Meanwhile, the bacterial and AMF Shannon diversity indexes in the contaminated soil were enhanced by 18.7-22.0% and 7.14-16.4%, respectively, with the presence of M. alba L. Furthermore, the correlations between the availability of As, Cd, Pb, and Zn and Shannon diversity indexes of the bacterial and AMF communities were significantly (p < 0.05) positive with the phytoremediation of M. alba L. Therefore, M. alba L. can be suggested as a potential plant candidate for ecological remediation and for simultaneously improving the activity and diversity of microorganisms in contaminated soils.
木本植物具有很大的应用潜力，可以用于植物修复，因为它们在重金属（类）污染土壤中具有长寿命的大量生物量和茂盛的根系。在温室条件下，研究了桑树及其相关的根际细菌和丛枝菌根真菌（AMF）多样性对重金属（类）复合污染土壤的生理响应特征和植物修复可能性。结果表明，在复合污染土壤中，栽培的桑树对重金属（类）表现出明显的耐受性，微生物多样性明显提高。随着栽培时间从 90 天到 270 天，桑树叶片中的丙二醛（MDA）含量逐渐降低，而过氧化物酶、超氧化物歧化酶和过氧化氢酶活性保持在正常水平，以消除脂质过氧化物的产生。桑树根系中的化学物质组成（如氨基酸、碳水化合物和蛋白质）在整个栽培期间波动较小。同时，Cd、Pb 和 Zn 主要集中在桑树根系中，最大含量分别为 23.4、7.40 和 615.5mg/kg。根据聚合酶链反应-变性梯度凝胶电泳（PCR-DGGE）分析结果，桑树对根际 AMF 群落的影响大于对细菌群落的影响。同时，桑树的存在使污染土壤中的细菌和 AMF Shannon 多样性指数分别提高了 18.7-22.0%和 7.14-16.4%。此外，As、Cd、Pb 和 Zn 的有效性与细菌和 AMF 群落的 Shannon 多样性指数呈显著（p<0.05）正相关，这表明桑树的植物修复作用。因此，桑树可以作为一种潜在的植物候选物，用于生态修复和同时提高污染土壤中微生物的活性和多样性。
