庞泉沟针叶林微生物群落结构与碳代谢功能特征

发布时间：2018-05-03 18:24

本文选题：庞泉沟自然保护区 + 微生物群落结构　；参考：《山西大学》2017年硕士论文

【摘要】：土壤微生物群落驱动土壤的碳、氮、磷、硫等物质的生物地球化学循环,在维持森林土壤碳汇和生态系统功能等诸多方面具有很重要的作用。本文通过分析环境与空间因素在森林土壤微生物群落构建中的作用以及功能微生物群落结构在碳存储及分解过程中的作用,旨在揭示温带森林土壤微生物群落构建机制以及针叶林土壤微生物驱动的碳循环机制,可以为区域森林生态系统管理措施的制定提供理论依据。山西省庞泉沟自然保护区位于吕梁山脉的关帝山腹地,主要保护对象是世界珍禽褐马鸡(Crossoptilon mantchuricum)以及以华北落叶松(Larix gmelinii var.principis-rupprechtii)、白gD(Picea meyeri)、青gD(Picea wilsonii)等天然次生林为主的栖息地。该区森林群落类型多样、结构差异明显,可以在小尺度范围内忽略气候因子的差异,研究森林植被类型和土壤因子对微生物群落结构和功能的影响,又可以利用不同的海拔高度研究气候因子的影响。本文基于16s r DNA和核糖体ITSⅠ的高通量测序技术研究了该地区的常绿针叶林[青gD和油松(Pinus tabulaeformis)]和落叶针叶林(华北落叶松)土壤中的细菌群落的结构以及落叶阔叶林[白桦(Betula platyphylla)红桦(Betula albosinensis Burkill)混交林]、常绿针叶林(青gD和油松)和落叶针叶林(华北落叶松)土壤中真菌群落的结构,并基于实时荧光定量PCR技术研究了该区常绿针叶林(青gD、白gD和油松)和落叶针叶林(华北落叶松)中参与土壤碳循环的固碳功能基因cbb M、淀粉酶基因amylase以及纤维素酶基因cellulase的丰度及时空动态,旨在揭示气候、环境因子和植物群落对微生物群落的结构和功能的调控机制。据此,制定科学的森林抚育和管理措施,通过人为改善森林土壤环境,优化土壤微生物群落结构,进而提高土壤碳汇,保持土壤碳库的稳定。本研究得出以下主要结论:(1)基于16s rDNA的高通量测序技术的结果表明:1)土壤含水率、C/N比、pH和土壤酶活性与土壤细菌群落结构显著相关。其中,变形菌门中的大部分类群和拟杆菌门更适于生活在酸性、湿度大、营养状况良好的土壤中,主要碳源是易分解碳;放线菌门、浮霉菌门和绿弯菌门则在碱性、干旱、营养贫瘠的土壤中更占优势,主要分解顽固性碳;2)地理距离与细菌群落的β多样性之间显著相关(R2=0.853),说明扩散限制对细菌群落结构有显著影响。综上所述,环境选择和扩散限制的共同影响,是本研究中不同针叶林土壤细菌群落结构和物种多样性显著差异的主要因素。(2)基于核糖体ITSⅠ的高通量测序技术的结果证明:1)5个样地中共有7个真菌门和33个优势真菌属;2)冗余分析结果表明:土壤pH、温度、含水率、全氮(TN)、铵态氮(NH4+-N)、全碳(TC)、蔗糖酶活性、脲酶活性、林下植被优势度和均匀度与土壤真菌群落结构显著相关;3)聚类分析和PCA分析结果表明,森林植被类型、土壤环境因子和林下植被对土壤真菌群落结构影响显著;4)空间变量(PCNM)分析结果表明,在局域尺度(local scale)上扩散限制对研究区域真菌群落构建的影响不显著。综上所述,本研究区森林土壤真菌群落结构主要受到环境选择的显著影响,这些环境因子包括土壤pH、温度、含水率、全氮(TN)、铵态氮(NH4+-N)、全碳(TC)、脲酶活性、蔗糖酶活性、林下植被优势度和均匀度、森林类型。(3)森林土壤微生物碳代谢特征1)土壤微生物碳代谢功能基因的季节动态4月份随着土壤温度的回升,土壤碳分解功能基因的丰度提高;7月份碳分解相关的功能基因丰度较低;4月和10月易分解碳功能基因的丰度占优势,5月易分解碳和顽固性碳功能基因的丰度大致相同。该区针叶林土壤微生物群落中碳分解基因的丰度大于固碳基因的丰度。2)土壤理化性质(pH和温度)、土壤营养状况(氮含量、脲酶活性、蔗糖酶活性)、土壤碳含量和森林类型,通过影响土壤微生物群落结构,决定碳代谢相关微生物的丰度,进而通过影响碳代谢功能基因的丰度来影响土壤碳代谢过程。(1)土壤pH和温度会通过直接影响土壤功能微生物的活性进而对土壤碳循环过程产生影响;(2)土壤氮含量和土壤酶活性主要是通过改变土壤肥力来影响土壤功能微生物的活性,进而影响土壤碳循环,并且,土壤氮含量对顽固性碳的分解能力影响较大;(3)土壤有机质和有机碳含量对土壤碳循环影响最大,不仅会直接对土壤中的功能微生物活性产生影响,还会通过调节土壤的pH和土壤酶活性(脲酶和蔗糖酶)而间接影响土壤微生物的活性,最终影响土壤碳代谢过程。并且土壤有机质的含量与土壤碳代谢功能基因丰度呈显著正相关,与易分解碳基因丰度/顽固性碳基因丰度(amylase/cellulase)呈显著负相关,说明随着土壤中有机质含量的增加,顽固性碳基因的丰度比易分解碳基因的丰度增长更快。(4)相同森林类型中的土壤碳代谢功能微生物群落结构相似,具有相似的土壤碳循环过程。
[Abstract]:Soil microbial communities drive soil carbon, nitrogen, phosphorus, sulfur and other biogeochemical cycles, which play an important role in maintaining forest soil carbon sequestration and ecosystem functions. This paper analyzes the role of environmental and spatial factors in the construction of microbial community in forest soil and the structure of functional microbial community in the forest soil. The role of carbon storage and decomposition is to reveal the mechanism of microbial community construction in temperate forest soil and the mechanism of carbon cycle driven by soil microbes in coniferous forests, which can provide theoretical basis for the establishment of regional forest ecosystem management measures. The Pang Quan gully natural conservation area in Shanxi province is located in the hinterland of Guandi mountain in the Lvliang mountains. The protection object is the world rare bird brown cheason (Crossoptilon mantchuricum) and the natural secondary forest, such as the Larix gmelinii var.principis-rupprechtii, the white gD (Picea meyeri), the green gD (Picea wilsonii) and so on. The forest community has many types and distinct structural differences, and the climate can be ignored in the small scale. The effects of forest vegetation types and soil factors on microbial community structure and function were studied, and the effects of climate factors could be studied at different altitudes. Based on the high throughput sequencing technology of 16S R DNA and ribosome ITS I, the evergreen coniferous forests in this area [green gD and pine (Pinus tabulaeformis)] were studied. The structure of the bacterial community in the soil of the deciduous coniferous forest (Larix Larix) and the deciduous broadleaf forest [Betula platyphylla (Betula albosinensis Burkill) mixed forest], the structure of the Fungi Community in the evergreen coniferous forest (green gD and Pinus tabulaeformis) and the deciduous coniferous forest (Larix Larix) soil, and based on the real-time fluorescence quantitative PCR Technology The abundances of carbon sequestration gene CBB M, amylase gene amylase and cellulase gene cellulase in the evergreen coniferous forest (green gD, white gD and Pinus tabulaeformis) and deciduous coniferous forest (Larix gmelinii) were investigated to reveal the structure and function of climate, environmental factors and plant communities on microbial communities. According to this, scientific forest tending and management measures are made to improve the soil microbial community structure by artificially improving the forest soil environment, and then to improve soil carbon sink and keep the stability of soil carbon pool. The following main conclusions are obtained: (1) the results of high throughput sequencing based on 16S rDNA show that soil moisture content, C/N ratio, pH and soil enzyme activity are significantly related to soil bacterial community structure. Most of the groups and bacteriobacteria in the Proteus doors are more suitable for living in acid, humidity, and nutritious soil, the main carbon source is carbon dioxide, actinomycetes, floating fungi and green Bens are in alkaline, arid, and barren soil. More dominant, mainly decomposition of refractory carbon; 2) significant correlation between geographical distance and bacterial community beta diversity (R2=0.853), indicating that diffusion restriction has a significant impact on the structure of bacterial community. In the summary, the common influence of environmental selection and diffusion restriction is the significant diversity of different coniferous forest soil bacteria community structure and species diversity in this study. The main factors of the difference. (2) the results of high throughput sequencing based on ribosome ITS I proved that 1) there were 7 fungal gates and 33 dominant fungi in 5 samples; 2) the results of soil redundancy analysis showed that soil pH, temperature, water content, total nitrogen (TN), ammonium nitrogen (NH4+-N), total carbon (TC), invertase activity, urease activity, vegetation dominance and uniformity under forest The results of cluster analysis and PCA analysis showed that forest vegetation types, soil environmental factors and understory vegetation had significant influence on soil fungal community structure, and 4) spatial variable (PCNM) analysis showed that diffusion restriction on local scale (local scale) had effect on the construction of fungal community in the study area. 3 Not significant. To sum up, the forest soil fungal community structure in this study area is mainly affected by environmental selection. These environmental factors include soil pH, temperature, water content, total nitrogen (TN), ammonium nitrogen (NH4+-N), total carbon (TC), urease activity, invertase activity, forest vegetation dominance and uniformity, forest type. (3) forest soil microbial carbon Metabolic characteristics 1) the seasonal dynamics of soil microbial carbon metabolism function gene in April, with the recovery of soil temperature, the abundance of carbon decomposition function genes in soil increased, the abundance of functional genes related to carbon decomposition in July was lower, and the abundance of carbon functional genes in April and October was dominant, and in May, carbon and stubborn carbon function genes were easily plentiful in May. The abundance of carbon decomposition genes in soil microbial communities in coniferous forests of this area is greater than that of carbon sequestration gene (.2). Soil physical and chemical properties (pH and temperature), soil nutrition status (nitrogen content, urease activity, invertase activity), soil carbon content and forest types, influence soil microbial community structure, determine carbon metabolism related microbiology. The abundance of objects affects soil carbon metabolism by affecting the abundance of carbon metabolism function genes. (1) soil pH and temperature will affect soil carbon cycle by directly affecting the activity of soil functional microorganisms, and (2) soil nitrogen content and soil enzyme activity are mainly influenced by soil fertility by changing soil fertility. Biological activity, and then influence soil carbon cycle, and soil nitrogen content has great influence on the decomposition ability of stubborn carbon. (3) soil organic matter and organic carbon content have the greatest influence on soil carbon cycle, which not only directly affect the activity of functional microorganisms in soil, but also regulate soil pH and soil enzyme activity (urease and urease). Invertase indirectly influenced soil microbial activity and eventually influenced soil carbon metabolism, and the content of soil organic matter was positively correlated with the abundance of soil carbon metabolism function gene, which was negatively correlated with the abundances of carbon gene abundances and the abundances of stubborn carbon (amylase/cellulase), indicating that the content of organic matter in the soil was with the content of organic matter. In addition, the abundances of the stubborn carbon genes increased faster than the abundances of the carbon genes. (4) the microbial community structure of soil carbon metabolism in the same forest types was similar, with similar soil carbon cycle process.

【学位授予单位】：山西大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S714.3

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