Department of Economic Plants and Biotechnology, Yunnan Key Laboratory for Wild Plant Resources, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China; Honghe Center for Mountain Futures, Kunming Institute of Botany, Chinese Academy of Sciences, Honghe, 654400, China.
Science and Technology Information Center, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China.
Environ Res. 2023 Dec 1;238(Pt 2):117270. doi: 10.1016/j.envres.2023.117270. Epub 2023 Sep 29.
Screening high Cd-accumulating plants and understanding the interactions between plants, rhizospheric microbes and Cd are important in developing microbe-assisted phytoremediation techniques for Cd-contaminated soils. In this study, the Cd tolerance and accumulation characteristics of Phytolacca americana L., P. icosandra L. and P. polyandra Batalin growing in acidic Cd-contaminated soil were compared to evaluate their phytoremediation potential. According to Cd concentrations (root: 8.26-37.09 mg kg, shoot: 2.80-9.26 mg kg), bioconcentration factors (BCFs) and translocation factors (TFs), the three Phytolacca species exhibited high Cd-accumulation capacities, ranked in the following order: P. icosandra (root BCF: 1.25, shoot BCF: 0.31, TF: 0.25) > P. polyandra (root BCF: 0.68, shoot BCF: 0.26, TF: 0.44) > P. americana (root BCF: 0.28, shoot BCF: 0.09, TF: 0.38). Phytolacca icosandra and P. polyandra can thus be considered as two new Cd accumulators for phytoremediation. Soil pH, available Cd (ACd) concentration and certain bacterial taxa (e.g. Lactobacillus, Helicobacter, Alistipes, Desulfovibrio and Mucispirillum) were differentially altered in the rhizospheres of the three Phytolacca species in comparison to unplanted soil. Correlation analysis showed that there were significant interactions between rhizospheric ACd concentration, pH and Lactobacillus bacteria (L. murinus, L. gasseri and L. reuteri), which affected Cd uptake by Phytolacca plants. The mono- and co-inoculation of L. murinus strain D51883, L. gasseri strain D51533 and L. reuteri strain D24591 in the rhizosphere of P. icosandra altered the rhizospheric pH and ACd concentrations, in addition to increasing the shoot Cd contents by 31.9%-44.6%. These results suggest that recruitment of rhizospheric Lactobacillus spp. by Phytolacca plants contributes to their high Cd-accumulating characteristics. This study provides novel insights into understanding the interactions between plants, rhizobacteria and heavy metals.
筛选高镉积累植物并了解植物、根际微生物和 Cd 之间的相互作用，对于开发用于 Cd 污染土壤的微生物辅助植物修复技术非常重要。本研究比较了在酸性 Cd 污染土壤中生长的美洲商陆、垂序商陆和多穗商陆对 Cd 的耐受和积累特性，以评估它们的植物修复潜力。根据 Cd 浓度（根：8.26-37.09mgkg，茎：2.80-9.26mgkg）、生物浓缩系数（BCF）和迁移系数（TF），这三种商陆均表现出高的 Cd 积累能力，按顺序排列如下：垂序商陆（根 BCF：1.25，茎 BCF：0.31，TF：0.25）>多穗商陆（根 BCF：0.68，茎 BCF：0.26，TF：0.44）>美洲商陆（根 BCF：0.28，茎 BCF：0.09，TF：0.38）。因此，垂序商陆和多穗商陆可以被认为是两种新的 Cd 积累植物，可用于植物修复。与未种植土壤相比，三种商陆的根际土壤 pH 值、有效态 Cd（ACd）浓度和某些细菌分类群（如乳杆菌属、螺旋杆菌属、拟杆菌属、脱硫弧菌属和黏液螺旋菌属）发生了不同程度的改变。相关性分析表明，根际 ACd 浓度、pH 值与乳杆菌属细菌（Lactobacillus murinus、Lactobacillus gasseri 和 Lactobacillus reuteri）之间存在显著的相互作用，这些相互作用影响了商陆植物对 Cd 的吸收。在垂序商陆的根际中单独或共同接种 L. murinus 菌株 D51883、L. gasseri 菌株 D51533 和 L. reuteri 菌株 D24591 会改变根际 pH 值和 ACd 浓度，并使植株地上部 Cd 含量增加 31.9%-44.6%。这些结果表明，商陆植物对根际乳杆菌属细菌的招募有助于其高 Cd 积累特性。本研究为深入了解植物、根际细菌和重金属之间的相互作用提供了新的见解。
