Li Qian, Fu Qingling, Islam Md Shoffikul, Zhu Jun, Hu Hongqing
College of Resource and Environment, Huazhong Agricultural University, Wuhan 430070, China.
College of Resource and Environment, Huazhong Agricultural University, Wuhan 430070, China; Department of Soil Science, University of Chittagong, Chattogram 4331, Bangladesh.
J Hazard Mater. 2025 Aug 15;494:138750. doi: 10.1016/j.jhazmat.2025.138750. Epub 2025 May 27.
Castor (Ricinus communis L.) has potential for phytoremediation of heavy metal-polluted soil due to its high accumulating capacity. In this study, four endophytic bacteria strains (TR16, TR18, TR21 and YS3), were used to investigate the effect of their individual and combined inoculations on castor's Cu/Cd uptake and the biochemical characteristics in the rhizosphere for two soils. Results showed that the highest Cu/Cd uptake by castor was obtained in treatments H1 and H2. Inoculation treatments significantly increased the activity of sucrase, acid and alkaline phosphatase in rhizosphere soil. Tartaric acid and dissolved organic carbon (DOC) levels significantly increased, enhancing soil Cu/Cd bioavailability. Strains TR18, TR21 and YS3 could be successfully colonized in rhizosphere soil. Endophyte inoculation increased the relative abundance of bacteria involved in soil nutrient cycling with varying effects. Root transcriptome analysis indicated that phenylpropane biosynthesis, glutathione metabolism, cysteine and methionine metabolism, and antioxidant enzyme activity play an important role in enhancing castor tolerance to heavy metal. TR21 inoculation could improve plant resistance to Cu/Cd in the root by regulating the synthesis of several secondary metabolites, including lignin, suberin, flavonol and coumarin, and that was beneficial to the sequestration of Cu/Cd in the castor root.
蓖麻（Ricinus communis L.）因其高积累能力而具有对重金属污染土壤进行植物修复的潜力。在本研究中，使用了四株内生细菌菌株（TR16、TR18、TR21和YS3）来研究它们单独接种和联合接种对两种土壤中蓖麻对铜/镉的吸收以及根际生化特性的影响。结果表明，在处理H1和H2中蓖麻对铜/镉的吸收量最高。接种处理显著提高了根际土壤中蔗糖酶、酸性和碱性磷酸酶的活性。酒石酸和溶解有机碳（DOC）水平显著增加，提高了土壤铜/镉的生物有效性。菌株TR18、TR21和YS3能够在根际土壤中成功定殖。内生菌接种增加了参与土壤养分循环的细菌的相对丰度，且效果各异。根系转录组分析表明，苯丙烷生物合成、谷胱甘肽代谢、半胱氨酸和甲硫氨酸代谢以及抗氧化酶活性在增强蓖麻对重金属的耐受性方面发挥着重要作用。接种TR21可以通过调节包括木质素、木栓质、黄酮醇和香豆素在内的几种次生代谢产物的合成来提高植物根系对铜/镉的抗性，这有利于蓖麻根系中铜/镉的螯合。
