Soil contamination by mercury, which is one of the most toxic heavy metals due to its bioaccumulative capacity, poses a risk to the environment as well as health. The Almadén mining district in Ciudad Real, Spain is one of the most heavily-polluted sites in the world, making the soils unusable. Bioremediation, and more specifically phyto-rhizoremediation, based on the synergistic interaction established between plant and Plant Growth Promoting Rhizobacteria (PGPR), improves the plant's ability to grow, mobilize, accumulate, and extract contaminants from the soil. The objective of this study is to evaluate the plant growth-promoting ability of four PGPR strains (and mixtures), isolated from the bulk soil and rhizosphere of naturally grown plants in the Almadén mining district, when they are inoculated in emerged seeds of Lupinus albus, var. Dorado in the presence of high concentrations of mercury. After 20 days of incubation and subsequent harvesting of the seedlings, biometric measurements were carried out at the root and aerial levels. The results obtained show that the seeds treatment with PGPR strains improves plants biometry in the presence of mercury. Specifically, strain B2 (Pseudomonas baetica) and B1 (Pseudomonas moraviensis) were those that contributed the most to plant growth, both individually and as part of mixtures (CS5 and CS3). Thus, these are postulated to be good candidates for further in situ phyto-rhizoremediation tests of mercury-contaminated soils.

中文翻译：

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评估四种细菌菌株及其混合物的 PGPR 能力，在羽扇豆变种上测试。Dorado 幼苗，用于汞污染土壤的生物修复

汞是一种毒性最强的重金属之一，由于其生物蓄积能力而被土壤污染，对环境和健康构成威胁。西班牙雷亚尔城的阿尔马登矿区是世界上污染最严重的地区之一，导致土壤无法利用。生物修复，更具体地说是植物根际修复，基于植物和促进植物生长的根际细菌 (PGPR) 之间建立的协同相互作用，提高植物生长、动员、积累和从土壤中提取污染物的能力。本研究的目的是评估四种 PGPR 菌株（和混合物）的植物生长促进能力，这些菌株是从 Almadén 矿区自然生长的植物的大块土壤和根际分离出来的，当它们接种到羽扇豆变种 Dorado 在高浓度汞的情况下。经过 20 天的孵化和随后的幼苗收获，在根部和地上进行了生物特征测量。获得的结果表明，在存在汞的情况下，用 PGPR 菌株处理种子可以改善植物的生物特征。具体而言，菌株 B2 ( Pseudomonas baetica ) 和 B1 ( Pseudomonas moraviensis ) 是对植物生长贡献最大的菌株，无论是单独还是作为混合物的一部分 (CS5 和 CS3)。因此，这些被假定为对受汞污染的土壤进行进一步原位植物根际修复测试的良好候选者。