Department of Soil Science, Ferdowsi University of Mashhad, 91775-1163 Mashhad, Iran.
Department of Soil Science, Ferdowsi University of Mashhad, 91775-1163 Mashhad, Iran.
Ecotoxicol Environ Saf. 2017 Oct;144:543-551. doi: 10.1016/j.ecoenv.2017.06.074. Epub 2017 Jul 5.
There is a gap of knowledge for the fate, effects and bioavailability of coated and uncoated ZnO nanoparticles (NPs) in soil. Moreover, little is known about the effects of soil properties on effects of NPs on plants. In this study, the availability ZnO NPs in two soils with different organic matter content (one treated with cow manure (CM) and the other as untreated) was compared with their bulk particles. Results showed that coated and uncoated ZnO NPs can be more bioaccessible than their bulk counterpart and despite their more positive effects at low concentration (< 100mgkg), they were more phytotoxic for plants compared to the bulk ZnO particles at high concentration (1000mgkg) in the soil untreated with CM. The concentration of 1000mgkg of ZnO NPs, decreased shoot dry biomass (52%) in the soil untreated with CM but increased shoot dry biomass (35%) in CM-treated soil compared to their bulk counterpart. In general, plants in the CM-treated soil showed higher Zn concentration in their tissues compared with those in untreated soil. The difference in shoot Zn concentration between CM-treated and untreated soil for NPs treatments was more than bulk particles treatment. This different percentage at 100mgkg of bulk particles was 20.6% and for coated and uncoated NPs were 37% and 32%, respectively. Generally, the distribution of ZnO among Zn fractions in soil (exchangeable, the metal bound to carbonates, Fe-Mn oxides, organic matter and silicate minerals and the residual fraction) changed based on applied Zn concentration, Zn source and soil organic matter content. The root tip deformation under high concentration of NPs (1000mgkg treatment was observed by light microscopy in plants at the soil untreated with CM. It seems that root tip deformation is one of the specific effects of NPs which in turn inhibits plant growth and nutrients uptake by root. The transmission electron microcopy image showed the aggregation of NPs inside the plant cytoplasm and their accumulation adjacent to the cell membrane.
土壤中涂层和未涂层氧化锌纳米粒子（NPs）的命运、效应和生物利用度存在知识空白。此外，人们对土壤性质对纳米粒子对植物影响的影响知之甚少。在这项研究中，比较了两种有机质含量不同的土壤（一种用牛粪处理，另一种未处理）中 ZnO NPs 的有效性与其块状颗粒相比。结果表明，涂层和未涂层的 ZnO NPs 比其块状颗粒更具有生物可利用性，尽管它们在低浓度（<100mgkg）下的效果更为积极，但与未经 CM 处理的土壤中的块状 ZnO 颗粒相比，它们在高浓度（1000mgkg）下对植物更具植物毒性。1000mgkg ZnO NPs 的浓度降低了未经 CM 处理的土壤中植物的地上干生物量（52%），但增加了 CM 处理土壤中植物的地上干生物量（35%）。与未经 CM 处理的土壤相比，CM 处理土壤中的植物组织中的 Zn 浓度更高。与未经 CM 处理的土壤相比，CM 处理和未处理土壤中 NP 处理的地上部 Zn 浓度差异更大。在 100mgkg 时，对于大块颗粒处理的差异为 20.6%，对于涂层和未涂层 NPs 处理的差异为 37%和 32%。一般来说，土壤中 ZnO 在 Zn 各组分中的分布（可交换的、与碳酸盐结合的金属、Fe-Mn 氧化物、有机物和硅酸盐矿物以及残余部分）会根据施加的 Zn 浓度、Zn 源和土壤有机质含量而发生变化。在未经 CM 处理的土壤中，用光学显微镜观察到植物在高浓度 NPs（1000mgkg 处理下的根尖变形。看来，根尖变形是 NPs 的一种特殊效应之一，它反过来又抑制了植物的生长和根对养分的吸收。透射电子显微镜图像显示 NPs 在内植物细胞质内聚集并在细胞膜附近积累。
