College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi, 712100, China.
Department of Biology, College of Science, Taif University, P.O. Box 11099, Taif, 21944, Saudi Arabia.
Environ Res. 2023 Jan 1;216(Pt 4):114646. doi: 10.1016/j.envres.2022.114646. Epub 2022 Nov 2.
Microbial-assisted phytoremediation provides a green approach for remediation of metal contaminated soils. However, the impacts of mono and co-applications of lactic acid bacteria (LAB) on soil biochemical properties and phytoavailability of toxic metals in contaminated mining soils have not yet been sufficiently examined. Consequently, here we studied the effects of Lactobacillus plantarum (P), Lactobacillus acidophilus (A), and Lactobacillus rhamnosus (R) applications alone and in combination on soil enzyme activities and bioavailability and uptake of Cd and Zn by mustard (Brassica juncea) in a smelter-contaminated soil under greenhouse conditions. Among the studied bacteria, P was the most tolerant to Cd-and-Zn contamination. As compared to control, R increased the fresh and dry weight of mustard plants by 53.5% and 63.2%, respectively. Co-application of P + A increased the chlorophyll content by 28.6%, as compared to control. Addition of LAB to soil increased the activity of soil urease, alkaline phosphatase and β-D glucosidase increased by 1.86-fold (P + R), 1.80-fold (R) and 55.16% (P + R), respectively. Application of P + A + R enhanced catalase activity (19.3%) and superoxide dismutase activity (51.2%), while addition of A alone increased peroxidase activity (POD: 15.7%). Addition of P alone and together with A (P + A) enhanced Cd and Zn phytoextraction by mustard shoots up to 51.5% and 52.5%, respectively. We conclude that the single and/or co-application of LAB decreased soil pH, promoted plant growth, antioxidant and enzyme activities, and enhanced the phytoavailability of Cd and Zn in the studied contaminated soil. These findings might be an aid for enhancing the phytoremediation of Cd and Zn using LAB and mustard as a bioenergy crop, which may offer new ideas for field treatment of toxic metals contaminated soils.
微生物辅助植物修复为修复受金属污染的土壤提供了一种绿色方法。然而，单一和联合应用乳酸菌（LAB）对污染矿区土壤生物化学性质和有毒金属植物可利用性的影响尚未得到充分研究。因此，在这里，我们研究了在温室条件下，单独和联合应用植物乳杆菌（P）、嗜酸乳杆菌（A）和鼠李糖乳杆菌（R）对受冶炼厂污染土壤中土壤酶活性和 Cd、Zn 生物有效性以及芥菜（Brassica juncea）吸收的影响。在所研究的细菌中，P 对 Cd 和 Zn 污染的耐受性最强。与对照相比，R 分别使芥菜植物的鲜重和干重增加了 53.5%和 63.2%。与对照相比，P+A 的联合应用使叶绿素含量增加了 28.6%。LAB 的添加使土壤脲酶、碱性磷酸酶和β-D 葡萄糖苷酶的活性分别增加了 1.86 倍（P+R）、1.80 倍（R）和 55.16%（P+R）。P+A+R 的应用增强了过氧化氢酶活性（19.3%）和超氧化物歧化酶活性（51.2%），而单独添加 A 则增强了过氧化物酶活性（POD：15.7%）。单独添加 P 以及与 A 联合添加（P+A）可使芥菜地上部分对 Cd 和 Zn 的提取量分别增加 51.5%和 52.5%。我们得出结论，LAB 的单一和/或联合应用降低了土壤 pH 值，促进了植物生长、抗氧化和酶活性，并增强了受研究污染土壤中 Cd 和 Zn 的植物可利用性。这些发现可能有助于利用 LAB 和芥菜作为生物能源作物来增强 Cd 和 Zn 的植物修复，为受有毒金属污染土壤的田间处理提供新的思路。
