School of Geographic Sciences, Hunan Normal University, Changsha, 410081, People's Republic of China.
Rural Vitalization Research Institute, Changsha University, Changsha, 410022, People's Republic of China.
Environ Sci Pollut Res Int. 2022 Dec;29(59):89557-89569. doi: 10.1007/s11356-022-21711-y. Epub 2022 Jul 19.
Cadmium (Cd) pollution in farmland soils severely affects agricultural production safety, thereby threatening human health. Sedum plumbizincicola is a Cd and Zn hyperaccumulator commonly used for the phytoremediation of Cd-contaminated soil. This study was aimed to improve the remediation effect of S. plumbizincicola on Cd-contaminated farmland soil and provide a theoretical basis for the enhancement of endophytic bacteria in the repair of Cd-contaminated soil with S. plumbizincicola. Four kinds of endophytic bacteria, namely Buttiauxella, Pedobacter, Aeromonas eucrenophila, and Ralstonia pickettii, were used, and soil culture experiments and pot experiments were conducted to explore the effects of endophytic bacteria on soil Cd speciation and phytoremediation efficiency of Cd-contaminated farmland soils. Under the experimental conditions, after inoculation with endophytic bacteria, the soil pH was effectively reduced, content of weak acid-extracted Cd and oxidizable Cd increased, and content of reducible Cd and residual Cd decreased. Soil Cd activity was increased, and the availability coefficient of soil Cd increased by 1.15 to 6.41 units compared with that of the control (CK). Compared with CK, the biomass of S. plumbizincicola significantly increased by 23.23-55.12%; Cd content in shoots and roots of S. plumbizincicola increased by 29.63-46.01% and 11.42-84.47%, respectively; and bioconcentration factor was 2.13 to 2.72 times that of CK. The Cd removal rate of S. plumbizincicola monocropping was 48.25%. When S. plumbizincicola was planted with inoculating endophytic bacteria, the Cd removal rate in the soil reached 61.18-71.49%, which was significantly higher than that of CK (p < 0.05). The treatment with endophytic bacteria activated soil Cd, promoted the growth of S. plumbizincicola, increased its Cd content, and enhanced the phytoremediation of Cd-contaminated farmland soil. Therefore, endophytic bacteria can be used to improve the remediation efficiency of S. plumbizincicola in Cd-contaminated farmland soils.
农田土壤镉污染严重影响农业安全生产，进而威胁人类健康。菥蓂（Sedum plumbizincicola）是一种镉和锌的超富集植物，常用于修复镉污染土壤。本研究旨在提高菥蓂修复镉污染农田土壤的效果，并为利用菥蓂内生细菌增强土壤镉污染修复提供理论依据。本研究选用 4 种内生细菌，即 Buttiauxella、Pedobacter、Aeromonas eucrenophila 和 Ralstonia pickettii，进行土壤培养实验和盆栽实验，探讨内生细菌对镉污染农田土壤镉形态和植物修复效率的影响。在实验条件下，接种内生细菌后，土壤 pH 值有效降低，弱酸提取态镉和可氧化态镉含量增加，可还原态镉和残渣态镉含量减少。土壤镉活性增加，土壤镉有效系数比对照（CK）增加 1.15-6.41 个单位。与 CK 相比，菥蓂生物量增加 23.23%-55.12%，菥蓂茎叶镉含量增加 29.63%-46.01%和 11.42%-84.47%，生物浓缩系数增加 2.13-2.72 倍。菥蓂单种时的镉去除率为 48.25%。菥蓂接种内生细菌种植时，土壤镉去除率达到 61.18%-71.49%，显著高于 CK（p<0.05）。内生细菌处理激活了土壤镉，促进了菥蓂的生长，增加了其镉含量，增强了对镉污染农田土壤的植物修复。因此，内生细菌可用于提高菥蓂在镉污染农田土壤中的修复效率。
