两种土壤中氧化物纳米材料对微生物群落结构和功能的影响

发布时间：2018-03-28 07:10

本文选题：氧化物纳米材料　切入点：土壤微生物群落　出处：《东北师范大学》2017年硕士论文

【摘要】：由于氧化物纳米材料具有独特的化学和物理性质,从而被广泛应用。随着其应用越来越广泛,氧化物纳米材料将不可避免地被释放到土壤环境中。由于土壤微生物群落在地球上的许多生物地球化学过程中发挥重要作用,因此研究氧化物纳米颗粒暴露对土壤微生物群落的影响是至关重要的。为了表征其影响,我们以3种典型的氧化物纳米材料(CuO,SiO_2和Al_2O_3纳米材料)作为研究对象,模拟氧化物纳米材料进入土壤中的环境条件,探究了3种纳米材料在不同浓度(0.5,1.0和2.0 mg·g-1))、不同处理时间(15 d和30 d)下对两种土壤(黑土和盐碱土)的土壤酶活的影响,并且采用实时荧光定量PCR技术(qPCR)和高通量测序技术,探究了高浓度的氧化铜纳米材料在不同处理时间下对两种土壤细菌群落结构的影响,以期揭示氧化物纳米材料在不同尺度下与土壤微生物群落的相互关系,科学评估氧化物纳米材料的土壤环境生态及健康风险,从而为纳米材料泄露对土壤生态风险管理提供理论依据,进而推动纳米科技健康可持续发展。主要研究结果如下:(1)土壤酶活性对不同的纳米材料的敏感性不同。CuO纳米材料的毒性最大,紧随其后的是SiO_2纳米材料,Al_2O_3纳米材料对土壤酶活性的抑制作用最小。(2)纳米材料对土壤酶活性的影响呈现剂量依赖效应,随浓度的增加呈现增强效应。(3)Al_2O_3纳米材料对黑土脲酶抑制效应是短暂的,说明在培养过程中,土壤微生物群落可能产生了适应纳米材料处理的耐受机制。(4)SiO_2纳米材料对黑土磷酸酶的促进作用以及对黑土过氧化氢酶的抑制作用仅在纳米材料长时间(培养第30 d)暴露下出现,说明纳米材料对酶活的影响可能存在潜伏期。(5)与黑土相比,盐碱土的土壤酶活性更易受纳米材料的影响。(6)CuO纳米材料降低了盐碱土土壤细菌群落大小和多样性,但对黑土土壤细菌群落大小和多样性无显著影响。(7)CuO纳米材料改变了两种土壤类型中的土壤微生物群落组成,但物种组成有不同的变化。在盐碱土中,氧化铜纳米材料对土壤细菌群落的影响以抑制方式占主导,而在黑土中,氧化铜纳米材料对绝大多数细菌群落表现出了耐受效应和促进效应。
[Abstract]:Oxide nanomaterials are widely used because of their unique chemical and physical properties. Oxide nanomaterials will inevitably be released into the soil environment because soil microbial communities play an important role in many biogeochemical processes on Earth. Therefore, it is important to study the effects of oxide nanoparticles exposure on soil microbial communities. In order to characterize the effects, we studied three typical oxide nanomaterials, CuOSiO2 and Al_2O_3 nanomaterials. In order to simulate the environmental conditions of oxide nanomaterials entering into soil, the effects of three kinds of nanomaterials on the soil enzyme activity of two soils (black soil and saline-alkali soil) were studied under different concentrations of 0.5g ~ (-1) and 2.0 mg / g ~ (-1) and different treatment time (15 d and 30 d). The effects of high concentration copper oxide nanomaterials on the community structure of two kinds of soil bacteria were studied by real-time fluorescence quantitative PCR and high-throughput sequencing. In order to reveal the relationship between oxide nanomaterials and soil microbial communities at different scales, and to assess scientifically the soil ecological and health risks of oxide nanomaterials, Therefore, it can provide theoretical basis for soil ecological risk management by nanometer material leakage. The main results are as follows: 1) soil enzyme activity has different sensitivity to different nanomaterials. CuO nanomaterials have the greatest toxicity. The SiO_2 nanomaterials, Al2O3 nanomaterials, had the least inhibitory effect on soil enzyme activity. (2) the effects of SiO_2 nanomaterials on soil enzyme activity showed a dose-dependent effect. The enhancement effect was observed with the increase of concentration. The inhibitory effect of Al2O3 nano-material on urease in black soil was transient, which indicated that in the process of culture, The soil microbial community may have a tolerant mechanism adapted to the treatment of nanomaterials. The promoting effect of nano-materials on phosphatase in black soil and the inhibition of catalase in black soil appeared only after exposure to nano-materials for a long time (30 days of culture). The results showed that the effect of nanomaterials on enzyme activity might exist in incubation period. (5) compared with black soil, soil enzyme activity of saline-alkali soil was more susceptible to the influence of nanomaterials. CuO nanomaterials reduced the size and diversity of soil bacterial communities in saline-alkali soils. However, there was no significant effect on the size and diversity of bacterial community in black soil. CuO nanomaterials changed the composition of soil microbial communities in two soil types, but the species composition was different. The effect of copper oxide nanomaterials on soil bacterial communities was dominated by inhibition, while in black soil, copper oxide nanomaterials showed tolerance and promotion effects on most bacterial communities.
【学位授予单位】：东北师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB383.1;S154.3

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