Microorganisms are used to alleviate heavy metal stress in plants cultivated in contaminated fields. However, the relevant mechanisms have been rarely explored. The goal of this study was to investigate effects of arbuscular mycorrhizal fungus Funneliformis mosseae and two Cd-resistant bacterial strains (Enterobacter sp. EG16 and Enterobacter ludwigii DJ3) on growth and Cd tolerance of tomato when applied with different inoculation strategies (single or dual) and Cd concentrations (50 and 100 mg kg-1). Better plant growth was observed in mycorrhizal alone or combined treatments. In F. mosseae and EG16 co-inoculation treatment, shoot and root dry weight were 119-154% and 91-173% higher than those of the control, respectively. Higher bacterial and mycorrhizal colonization rate and root Cd concentration were also found in this treatment. However, the decrease of shoot Cd concentration and translocation factor values indicated this treatment was effective in improving Cd tolerance of the host plants. In addition, the increase in soil pH and decline in bioavailable Cd in the rhizosphere might be partly involved in reduction of Cd accumulation in plants. Our results suggest that co-inoculation with suitable microorganisms is important in plant growth and tolerance to Cd in Cd-contaminated soil.

中文翻译：

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耐镉促进植物根瘤菌和漏斗形变菌对番茄（Lycopersicon esculentum L.）对镉的耐受性的影响。

微生物用于减轻在污染田地中种植的植物中的重金属胁迫。但是，相关机制很少被探索。这项研究的目的是调查当使用不同的接种策略（单次或双重接种）时，丛枝菌根真菌Funneliformis mosseae和两种对Cd耐药的菌株（Enterobacter sp。EG16和Enterobacter ludwigii DJ3）对番茄生长和对Cd的耐受性的影响。和Cd浓度（50和100 mg kg-1）。在单独或菌根治疗中观察到更好的植物生长。在F. mosseae和EG16联合接种处理中，枝条和根的干重分别比对照高119-154％和91-173％。在该处理中还发现较高的细菌和菌根定植率和根部Cd浓度。然而，芽中Cd浓度和转运因子值的降低表明该处理对提高寄主植物对Cd的耐受性有效。此外，根际土壤pH的升高和生物有效性Cd的下降可能部分与植物体内Cd积累的减少有关。我们的研究结果表明，与合适的微生物共同接种对植物生长和Cd污染土壤对Cd的耐受性很重要。