College of Environment and Safety Engineering, Qingdao University of Science and Technology, Qingdao, Shandong Province 266042, PR China; Agricultural College, Henan University of Science and Technology, Luoyang, Henan Province 471023, PR China.
Department of Plant and Microbial Biology, University of California Berkeley, California, USA.
Chemosphere. 2018 Oct;209:421-429. doi: 10.1016/j.chemosphere.2018.06.099. Epub 2018 Jun 14.
Both metals and metal-based nanoparticles (NPs) can easily accumulate in soil, posing risks for plants and microbes. However, the interaction between NPs and toxic metals coexisting in soil is not yet well understood. Here, we studied the combined effects of ZnO NPs and Cd on sweet sorghum inoculated with or without the arbuscular mycorrhizal (AM) fungus Funneliformis caledonium. Plants were grown in soil amended with ZnO NPs (50, 250, and 500 mg/kg), alone or in combination with 5 mg/kg Cd. The two higher doses of ZnO NPs inhibited plant growth, leading to synergistic toxicity with Cd. However, at the lowest dose, ZnO NPs were non-phytotoxic, displaying antagonistic interactions with Cd on plant growth. When added with high doses of ZnO NPs, Cd significantly increased root Zn concentrations, but decreased shoot Zn concentrations at the low dose. Conversely, all doses of ZnO NPs significantly decreased shoot and root Cd concentrations. Furthermore, high doses of ZnO NPs generally inhibited soil enzyme activities, but Cd addition showed no significant or even stimulative effects, and mitigated the inhibitory effects of ZnO NPs. AM inoculation increased plant growth and P nutrition, and soil enzyme activities. When the low dose of ZnO NPs was added alone or in combination with Cd, AM inoculation decreased shoot Zn concentrations. Our results reveal complex interactions between ZnO NPs and Cd on plant growth and nutrition, plant Zn and Cd accumulation, and soil enzyme activities, while AM inoculation can help diminish the adverse effects induced by ZnO NPs and Cd.
金属和基于金属的纳米粒子（NPs）都很容易在土壤中积累，从而对植物和微生物构成风险。然而，纳米粒子与土壤中共存的有毒金属之间的相互作用尚未得到很好的理解。在这里，我们研究了 ZnO NPs 和 Cd 对接种或未接种丛枝菌根（AM）真菌 Funneliformis caledonium 的甜高粱的联合影响。在添加 ZnO NPs（50、250 和 500 mg/kg）的土壤中种植植物，单独添加或与 5 mg/kg Cd 联合添加。两种较高剂量的 ZnO NPs 抑制了植物生长，导致与 Cd 产生协同毒性。然而，在最低剂量下，ZnO NPs 对植物生长没有毒性，表现出与 Cd 的拮抗相互作用。当添加高剂量的 ZnO NPs 时，Cd 显著增加了根部 Zn 浓度，但在低剂量下降低了茎部 Zn 浓度。相反，所有剂量的 ZnO NPs 均显著降低了茎和根中的 Cd 浓度。此外，高剂量的 ZnO NPs 通常抑制土壤酶活性，但 Cd 添加没有显著影响甚至具有刺激作用，并减轻了 ZnO NPs 的抑制作用。AM 接种增加了植物生长和磷营养以及土壤酶活性。当单独添加低剂量的 ZnO NPs 或与 Cd 联合添加时，AM 接种降低了茎部 Zn 浓度。我们的研究结果揭示了 ZnO NPs 和 Cd 对植物生长和营养、植物 Zn 和 Cd 积累以及土壤酶活性的复杂相互作用，而 AM 接种可以帮助减轻 ZnO NPs 和 Cd 引起的不良影响。
