State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, People's Republic of China.
Appraisal Center for Environment & Engineering Ministry of Environmental Protection, Beijing, 100020, People's Republic of China.
Environ Sci Pollut Res Int. 2018 Apr;25(10):9380-9390. doi: 10.1007/s11356-017-1157-x. Epub 2018 Jan 18.
Arbuscular mycorrhizal (AM) fungi play an important role in plant tolerance of heavy metal contamination. In this study, a pot experiment was conducted to illustrate the effects of the two AM fungi species Funneliformis mosseae (Fm) and Rhizophagus irregularis (Ri) on plant growth of Oryza sativa L. either with or without ethylenediamine tetraacetate (EDTA) addition and during exposure to five Cd concentrations (in the range of 0-5 mg kg). The results showed that Fm inoculation achieved greater mycorrhizal colonization and mycorrhizal dependency indexes than Ri inoculation. In addition, the effects of AM fungi on Cd biosorption and translocation in rice were also investigated in the presence of EDTA. Despite cooperative adsorption, the Freundlich isotherm could describe the biosorption effects of Cd on rice roots regardless of AM fungi inoculation or EDTA addition. Cd concentrations in mycorrhizal roots increased but decreased in mycorrhizal shoots in contrast to the control treatment. Although EDTA addition negatively inhibited the uptake of Cd to mycorrhizal shoots, lower translocation factor (TF) and bioconcentration factor (BCF) were still observed in treatments with EDTA compared to control treatment. Our findings suggest that Ri and Fm inoculation enhanced Cd immobilization in the roots, thus preventing Cd entry into the food chain during exposure to low and high Cd stress, respectively.
丛枝菌根（AM）真菌在植物耐受重金属污染方面起着重要作用。本研究通过盆栽实验，说明了两种丛枝菌根真菌摩西管柄囊霉（Fm）和无梗囊霉（Ri）在添加乙二胺四乙酸（EDTA）和暴露于五种 Cd 浓度（0-5mgkg）条件下对水稻生长的影响。结果表明，与 Ri 接种相比，Fm 接种实现了更高的菌根定殖和菌根依赖性指数。此外，还研究了 EDTA 存在下 AM 真菌对水稻中 Cd 生物吸附和转运的影响。尽管存在协同吸附作用，但 Freundlich 等温线可以描述 Cd 对水稻根系的生物吸附效应，无论是否接种 AM 真菌或添加 EDTA。与对照处理相比，菌根根中 Cd 浓度增加，但菌根地上部 Cd 浓度降低。尽管 EDTA 添加会负抑制 Cd 向菌根地上部的吸收，但与对照处理相比，添加 EDTA 的处理中仍观察到较低的迁移因子（TF）和生物浓缩因子（BCF）。我们的研究结果表明，Ri 和 Fm 接种增强了 Cd 在根部的固定，从而防止了在低 Cd 和高 Cd 胁迫下 Cd 进入食物链。
