施肥对高寒草甸地上地下生物群落营养限制类型及偶联关系的研究

发布时间：2018-07-05 08:21

本文选题：微生物群落 + 类群　；参考：《兰州大学》2017年硕士论文

【摘要】：地上地下生物群落的偶联不仅直接影响着生态系统的功能,更关系到未来全球气候变化及生态平衡。传统研究主要关注植物群落,近年来,生命科学技术方法的不断进步促进了微生物群落的研究,越来越多的研究集中到基于植物-土壤-微生物相互作用的地上地下生物群落偶联关系。青藏高原低温、高海拔、强辐射的独特生态环境使该区域长期处于寡营养状态,对全球气候变化较敏感。施肥作为一种草地生态系统管理模式在增加地上生产力的同时也会对生物群落及其参与的生态过程造成影响。因此,研究地上地下生物群落及其偶联关系对营养元素添加的响应能够对未来生态系统变化进行预测并为其保护措施提供理论指导。本研究通过高通量测序及荧光定量PCR相结合的方法解析微生物群落结构变化,构建了地上地下生物群落营养限制概念模型,通过SEM(Structural Equation Modeling)模型将地上地下生物群落进行耦合,研究青藏高原高寒草甸生态系统施加不同浓度氮肥(N)、磷肥(P)和氮磷肥(NP)的土壤中古菌和细菌群落的营养限制类型及两者与地上植物群落的偶联关系。主要实验结果如下:1.施肥对土壤微生物群落多样性的影响土壤古菌及细菌群落高通量测序结果显示,共测得182143条古菌序列分别属于355个OTU和276350条细菌序列分别属于6246个OTU,古菌与细菌群落多样性差异显著高于两者之间丰富度差异,土壤中细菌群落多样性较高。Thaumarchaeota(奇古菌门)主导土壤古菌群落,Proteobacteria(变形菌门)、Acidobacteria(酸杆菌门)和Actinabacteria(放线菌门)主导土壤细菌群落。高浓度NP和P添加分别会增加古菌群落α多样性和降低细菌群落α多样性。2.地上地下生物群落营养限制类型及其关系根据地上地下生物群落营养限制模型,古菌(21个OTU)、细菌(89个order/sub-order)及植物(21个物种)分别划分至十三种营养限制类型(分属五大类)。古菌群落营养限制类型相对单一,以P限制型类群占主导。细菌群落营养限制类型相对多元和平衡,以其他营养限制类群占主导。研究结果表明,群落和类群两个角度的营养限制类型有差异,植物群落属于N限制型,古菌群落属于P限制型,细菌群落无可划分类型。无论地下地上生物群落,P限制型类群均与AN:AP呈负相关,N限制型类群均与AN:AP呈正相关。植物与微生物营养限制类群相关性分析结果显示,植物群落对细菌群落的竞争力显著大于古菌,属于相似营养限制类型的地上地下生物群落显著正相关,因此施肥措施可缓解同类型植物及微生物之间的营养竞争。系统进化分析结果显示,古菌和细菌对营养元素的响应没有表现出显著发育信号。但古菌类群对单独P元素施加的响应表现出功能趋同,细菌类群对N施加响应值表现出显著的功能趋同。该现象归因于营养元素响应特征属于微生物简单特征,其进化没有保守性,易随环境发生改变。3.植物-土壤-微生物耦合关系植物-土壤-微生物耦合关系研究结果显示,N施加时古菌群落受植物群落的间接影响(λ=0.900),细菌则受施肥的直接影响(λ=-0.841)。古菌群落受P施肥的直接影响(λ=-0.612),NP共施肥时古菌(λ=0.621)及细菌群落均受施肥的直接影响(λ=0.462)。结果表明,不同施肥措施对地上地下生物群落的偶联关系有显著影响,其中P施肥直接作用于古菌群落,氮磷共施肥对古菌及细菌群落均为直接作用。
[Abstract]:The coupling of aboveground and underground biological communities not only directly affects the function of the ecosystem, but also relates to the global climate change and ecological balance in the future. The traditional research mainly focuses on the plant community. In recent years, the continuous progress in the methods of life science and technology has promoted the research of microbial community. More and more studies have focused on plant soil based on Soil - The unique ecological environment of low temperature, high altitude and strong radiation in the Qinghai Tibet Plateau makes the region be in oligotrophic state for a long time and is sensitive to global climate change. The ecological processes involved are affected. Therefore, the study of the responses of the aboveground and underground biological communities and their coupling relationship to the nutrient elements can predict the changes in the future ecosystem and provide theoretical guidance for the protection measures. This study analyzed the microbial community structure by the combination of high throughput sequencing and fluorescence quantitative PCR The conceptual model of the nutritional restriction of the aboveground and underground biological communities was constructed, and the SEM (Structural Equation Modeling) model was used to coupling the aboveground and underground biological communities to study the nutrient restriction types of the different concentrations of nitrogen fertilizer (N), phosphorous fertilizer (P) and nitrogen phosphate (NP) soil in the alpine meadow ecosystem of the Qinghai Tibet Plateau. The main experimental results were as follows: 1. the effect of Fertilization on the diversity of soil microbial community, the result of high throughput sequencing of soil palaebacteria and bacterial community showed that 182143 Archaea sequences belonging to 355 OTU and 276350 bacteria sequences were respectively 6246 OTU, and the Archaea and the bacterial community were more. The diversity of the samples was significantly higher than the difference between the two. The diversity of the bacterial community in the soil was higher.Thaumarchaeota (Archaea) dominated the soil palaeomycetes, Proteobacteria (Proteus), Acidobacteria (acid bacilli) and Actinabacteria (actinomycetes). The high concentration of NP and P added palaeomycetes, respectively. Alpha diversity and the reduction of bacterial community alpha diversity.2. on the ground and underground biological community nutrition restriction types and their relationships according to the nutrient restriction model of the aboveground biological community, palaeo (21 OTU), bacteria (89 order/sub-order) and plants (21 species) were divided into thirteen types of nutrition restriction respectively (belonging to five categories). The restrictive types are relatively single and dominated by P restrictive groups. The relative diversity and balance of the bacterial community are dominant. The results show that there are differences in the type of nutrition restriction between the two angles of the community and the group, the plant community belongs to the N restriction type, the palaeo community belongs to the P restriction type, and the bacterial community is not delimit. P restrictive groups were negatively correlated with AN:AP and N restricted groups were positively correlated with AN:AP. The correlation analysis between plant and microbial restricted groups showed that the competitiveness of plant community to bacterial community was significantly greater than that of paleo, which belonged to the subsurface subsurface biota of similar nutrition restriction type. The results of phylogenetic analysis showed that the response of the Archaea and bacteria to the nutrient elements did not show significant development signals. However, the response of the paleo groups to the individual P elements showed a functional convergence, and the bacterial group applied the response to the N. The phenomenon is attributed to the obvious functional convergence. The phenomenon is attributed to the nutrient element response characteristic of the simple microbial characteristics, its evolution is not conserved, and it is easy to change with the environment to change the plant soil microbial coupling relationship of.3. plant soil microbial coupling relationship. The results show that the palaeo community is influenced by the plant community at the time of N (lambda =0). .900), the bacteria were affected by the direct effect of fertilization (lambda =-0.841). The Archaea community was directly affected by the fertilization of P ([lambda] =-0.612). When NP was applied, the palaebacteria ([lambda] =0.621) and the bacterial community were directly affected by the fertilization ([lambda =0.462]. The results showed that the different fertilization measures had a significant influence on the coupling relationship between the aboveground and underground biological communities, and the direct effect of P fertilization. In the Archaea community, nitrogen and phosphorus co fertilization played a direct role in archaea and bacterial communities.
【学位授予单位】：兰州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S812

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