黄土高原不同植被生态系统土壤微生物多样性及其影响因素研究

发布时间：2018-03-01 09:33

本文关键词： 黄土高原植被生态系统土壤性质土壤真菌土壤细菌　出处：《中国科学院研究生院（教育部水土保持与生态环境研究中心）》2015年硕士论文　论文类型：学位论文

【摘要】：黄土高原土壤侵蚀,植被破坏,土壤质量下降,严重威胁着人类赖以生存的土地资源。近年来开展了一系列的退耕还林(草)生态建设工程,对土壤质量的改善起到了至关重要的作用。本文选取黄土土丘陵区不同植被区典型植被类型区为研究对象,研究了不同植被生态系统下土壤基本理化性质、生态化学计量学特征、土壤微生物多样性等特征,以探讨植被恢复过程中不同植被生态系统下土壤微生物多样性变化。主要结论如下:(1)黄土高原从南到北,不同植被生态系统土壤性质差异显著,森林植被生态系统土壤全氮、全磷、有机质以及速效养分含量较高,沙区植被生态系统较低;森林植被生态系统pH值以及土壤容重较低,沙区植被较低。森林植被对土壤的改良作用明显,有助于养分的累积与土壤结构的改良。(2)黄土高原陕北地区土壤速效养分除速效磷外其他均随着纬度的增加逐渐减小,土壤pH与土壤容重从南到北逐渐升高。土壤有机碳、全氮、全磷含量均随着纬度的升高而降低,土壤有机碳与全氮的空间分布具有一致性。土壤的C:N比受气候变化影响较小,变异性小,在黄土高原随纬度的升高无明显的变化。相比土壤的C:N比,土壤C:P比、N:P比变异性较大,随着纬度的升高显著地下降。森林植被有利于土壤碳氮磷元素含量的累积,相对于高纬度地区,低纬度地区更容易缺磷;沙区及荒漠植被区土壤容重以及土壤养分含量较低,不利于植被的生长,其植被生长主要受N含量控制。(3)通过454高通量二代测序技术,测定黄土高原不同植被类型土壤细菌特征,研究结果表明:所有土壤样品共检测到36个门,84个纲,187个目。草原植被下的土壤细菌多样性最为丰富,森林植被区最小。土壤的理化性质对土壤细菌的相对丰度具有重要的影响。高通量测序所得序列分属于细菌的36个门,其中主要的门包括酸杆菌门(Actinobacteria)、变形菌门(Proteobacteria)、绿弯菌门(Chloroflexi)、放线菌门(Acidobacteria)、浮霉菌门(Planctomycetes)、芽单胞菌门(Gemmatimonadetes)、拟杆菌门(Bacteroidetes)、装甲菌门(Armatimonadetes)、未分类细菌(Bacteria_unclassified)、厚壁菌门(Firmicutes)、蓝藻菌门(Cyanobacteria),其中属于酸杆菌门(Actinobacteria)、变形菌门(Proteobacteria)、绿弯菌门(Chloroflexi)、放线菌门(Acidobacteria)、浮霉菌门(Planctomycetes)门的序列总和占所有序列的80%以上。森林植被生态系统主要以变形菌门(Proteobacteria)为主,沙区植被生态系统主要以酸杆菌门(Actinobacteria)为主。土壤pH、容重、土壤水分、有机质、总氮、总磷、微生物量碳、碳磷比、氮磷比是影响土壤微生物的主要因子。黄土高原细菌分布的空间分布具有生物地理学规律。酸杆菌门(Actinobacteria)在沙区植被生态系统中相对较多,主要受纬度的影响,变形菌门(Proteobacteria)在草原植被生态系统中出现较多。土壤总磷、土壤水分、有机碳及碳磷比是影响样品物种分布的最主要的因子。(4)对土壤真菌基因组ITS序列进行高通量测序,发现测序数据量合理,基本反映出实际样品的生物信息。一共检测到10个真菌门(Phylum)、28个纲(Class)、48个目(Order)、61个科(Familiy)、69个属(Genus)。真菌门包括:Ascomycota(子囊菌门)、Basidiomycota(担子菌门)、Chytridiomycota(壶菌门)、Glomeromycota(球囊菌门)。在门分类学水平上,主要优势均为子囊菌门(Ascomycota),担子菌门(Basidiomycota),壶菌门(Chytridiomycota)和球囊菌门(Glomeromycota)。影响子囊菌、担子菌的主要因素为土壤容重、土壤总磷、土壤含水量等因素。
[Abstract]:Soil erosion of the Loess Plateau, vegetation destruction, soil degradation, a serious threat to human survival of the land resources. In recent years carried out a series of returning farmland to forest (grass) ecological construction project, a key role in improving the quality of the soil. This paper selects the typical vegetation in different vegetation types in yellow soil in hilly area as the research object, study the ecosystem under different vegetation soil physicochemical properties, ecological stoichiometry, characteristics of soil microbial diversity, in order to restore the process of vegetation ecosystem under different vegetation soil microbial diversity. The main conclusions are as follows: (1) the Loess Plateau from south to north, the difference of soil properties in different vegetation the ecological system significantly, soil total nitrogen, total phosphorus in forest vegetation ecosystem, organic matter and available nutrient content is higher, the lower sandy vegetation ecosystem; forest vegetation The system pH value and soil bulk density low, sand vegetation is low. The improvement effect of forest vegetation on soil obviously, improved soil structure and nutrient accumulation of help. (2) the Loess Plateau soil available nutrients except available phosphorus were gradually reduced with the increase of latitude, soil pH and soil bulk density increased gradually from South to north. Soil organic carbon, total nitrogen and total phosphorus content were decreased with increasing latitude, soil organic carbon and total nitrogen are consistent. The spatial distribution of soil C:N than less affected by climate change and variability, in the Loess Plateau with increasing latitude. There was no obvious change in soil the C:N ratio of soil C:P ratio, N:P is larger than the variability, with the increase of latitude decreased significantly. Forest vegetation is conducive to the accumulation of soil carbon and nitrogen phosphorus content, relative to the high latitudes and low latitudes are more likely to phosphorus deficiency and sandy area; Desert soil bulk density and soil nutrient content is low, is not conducive to the growth of vegetation, the vegetation growth is mainly affected by the content of N. (3) through 454 high-throughput two generation sequencing technology, the determination of soil bacterial characteristics of different vegetation types in Loess Plateau, the results showed that all soil samples were detected 36, 84 classes, 187 orders. The grassland vegetation under the soil bacterial diversity is the most abundant, the smallest forest vegetation area. Has an important effect on the relative abundance of soil physical and chemical properties of soil bacteria. High-throughput sequence 36 belong to the bacteria, which mainly includes the door acidobacteria (Actinobacteria) (Proteobacteria), Proteobacteria, Chloroflexi (Chloroflexi), actinobacteria (Acidobacteria), planctomycetes (Planctomycetes), gemmatimonadetes (Gemmatimonadetes), Bacteroidetes (Bacteroidetes), Armatimonadetes (armored door bacteria ), unclassified bacteria (Bacteria_unclassified), Firmicutes (Firmicutes), cyanobacteria door (Cyanobacteria), which belong to the phylum acidobacteria (Actinobacteria) (Proteobacteria), Proteobacteria, Chloroflexi (Chloroflexi), actinobacteria (Acidobacteria), planctomycetes (Planctomycetes) sequence sum the door accounted for more than 80%. All sequences of forest ecosystem mainly Proteobacteria (Proteobacteria), desert vegetation ecosystem mainly acidobacteria (Actinobacteria). Soil pH, bulk density, soil moisture, organic matter, total nitrogen, total phosphorus, microbial biomass carbon, carbon phosphorus ratio, ratio of nitrogen to phosphorus is the main factor influencing soil microbial bacteria distribution of Loess Plateau. The spatial distribution of the biogeography law. Acidobacteria (Actinobacteria) are relatively abundant in desert ecosystem vegetation, mainly affected by latitude, Proteobacteria (Proteobacteria) There is more in the ecosystem of grassland vegetation. Soil total phosphorus, soil moisture, organic carbon and carbon phosphorus ratio is the effect of sample species distribution factors. (4) high flux sequencing on soil fungal genomic ITS sequence, we found that reasonable sequencing data, basic biological information reflects the actual samples were detected. 10 fungi (Phylum), 28 class (Class), 48 eyes (Order), 61 families, 69 genera (Familiy) (Genus). Fungi include: Ascomycota (Ascomycota), Basidiomycota (Basidiomycota), Chytridiomycota (Chytridiomycota), Glomeromycota (balloon the door in the door). Bacteria taxonomic level, the main advantages are Ascomycota, Basidiomycota (Ascomycota) (Basidiomycota), Chytridiomycota (Chytridiomycota) and Glomeromycota (Glomeromycota). The main factors influence Ascomycetes, basidiomycetes as soil bulk density, soil total phosphorus, soil moisture and other factors.

【学位授予单位】：中国科学院研究生院（教育部水土保持与生态环境研究中心）
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S154.3

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