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川西亚高山土壤微生物垂直分布格局及影响因子
Alternative TitleVertical distribution pattern and impact factors of soil microbe on the subalpine, Western Sichuan Plateau
刘丹
Subtype博士
Thesis Advisor刘国华
2018-06
Degree Grantor中国科学院生态环境研究中心
Place of Conferral北京
Degree Name理学博士
Degree Discipline生态学
Keyword细菌,真菌,海拔梯度,土壤剖面,多样性 Bacteria,Fungi, Elevation Gradient, Soil Profile,Diversity
Abstract

      土壤微生物地理分布格局目前是生态学上的研究热点。沿海拔的垂直水热分配在一定程度上可以反映沿纬度梯度上的水平水热分配,山地生态系统短距离上的环境差异利于微生物的空间分布研究。山地生态系统中植物和大型动物的垂直分布格局早有研究,并且有一定的规律可循。然而,土壤微生物的垂直分布规律尚未明确。微生物的垂直分布不仅是海拔梯度上的还是不同土壤深度上的。研究土壤微生物垂直分布规律,有利于生态学理论的发展。并且土壤微生物的高变异性使得其可用于预测环境变化条件下生态系统功能结构的变化。

      本研究采用测序方法,对川西亚高山海拔梯度上和剖面上的土壤细菌和真菌的群落组成和多样性差异进行研究并分析其影响因子。同时,对地上植被和土壤微生物的关系做了进一步的梳理。研究结果如下:

    1、研究区土壤细菌主要以酸杆菌门、变形菌门、放线菌门、绿弯菌门、疣微菌门、拟杆菌门和浮霉菌门等为主。与其他研究结果相比,本研究中的酸杆菌门相对丰富度较高,这可能与那都山偏酸性的土壤有关。土壤总的细菌多样性沿海拔呈典型的“U”型格局,酸杆菌、变形菌门、放线菌门、绿弯菌门、疣微菌门等优势门类的多样性沿海拔变化趋势与总的细菌群落多样性变化趋势相似均为“U”型格局。这种微生物多样性沿海拔的“U”型格局在自然界中不常见,并且与地上植被多样性沿海拔的分布格局完全不同。表明了土壤细菌的地理分布规律可能与地上植被有所不同。另外,当所有因子单独分析时,土壤pH和总氮对细菌群落的贡献率分别为7.4%和6.01%。当所有因子综合分析时,土壤pH、总氮和总碳总共对细菌群落的贡献率为19.12%。本研究中,土壤pH沿海拔增加也呈显著的“U”型格局,并且细菌多样性随土壤pH的增加呈显著线性增加。土壤pH在中间海拔较低可能是由于中间海拔的土壤淋溶作用较强所致。随海拔增加土壤黏粒含量呈显著的单峰格局,这进一步证明了中间海拔土壤强烈的淋溶作用。

    2、研究区土壤真菌以担子菌门、接合菌门、子囊菌门、壶菌门和球囊菌门为主,这和其他环境中的土壤真菌类群相似。担子菌门较高的丰富度可能与它分解山地生态系统的复杂木质素有关。土壤真菌多样性在3000米海拔的土壤中最高而在3700米海拔的土壤中最低,但土壤真菌多样性沿海拔增加没有显著的变化趋势。本研究于前人的不同研究结果表明山地真菌多样性沿海拔可能并没有统一的变化规律。距离线性结果表明土壤真菌物种丰富度和系统发育多样性受土壤pH(23.72%和24.25%)和总氮(22.33%和13.01%)影响。土壤真菌物种丰富度和系统发育多样性随土壤pH增加呈线性增加趋势,同时子囊菌门、担子菌门、壶菌门和球囊菌门多样性也随土壤pH增加呈线性增加趋势。这与前人研究结果一致,进一步证明了土壤养分和土壤pH对真菌群落的重要作用。

    3、那都山棕色针叶林土壤剖面上细菌多样性在淀积层最高而在枯枝落叶层最低,同时细菌特有种的种类也是在淀积层最多而在枯枝落叶层最少。淀积层的细菌特有种主要来自于绿弯菌门、浮霉菌门、放线菌门和酸杆菌门。绿弯菌门是厌氧生物,更容易在低氧含量的淀积层生存。棕色针叶林土壤剖面上的细菌群落主要受土壤总氮(11.87%)和土壤pH(10.43%)影响。那都山棕色森林土壤剖面表层土壤pH最低,淀积层土壤pH值最高。淀积层较高的土壤pH促使受酸胁迫的细菌繁殖,因此淀积层细菌多样性较枯枝落叶层细菌多样性较高。而土壤总氮主要是对淀积层参与脱氮和固氮过程的微生物起着重要的作用。

    4、相较于细菌多样性而言,真菌多样性在棕色森林土壤剖面的变化不显著,这可能是由于细菌和真菌对环境变化的敏感性相关。枯枝落叶层特有真菌的比例高于腐殖质层、淋溶层和淀积层,这可能是由于真菌可利用有机物的多样性和质量在枯枝落叶层较高。枯枝落叶层特有真菌主要来自于子囊菌门、担子菌门和壶菌门。棕色针叶林土壤剖面上的真菌群落主要受灌木(8.04%)和草本(6.74%)影响,乔木对真菌的作用不显著可能是因为在6个采样点地上乔木种类基本一致。

    5、不同植被类型下, 20-30厘米土壤细菌多样性在杜鹃灌丛中最高,而20-30厘米土壤真菌多样性也在杜鹃灌丛中最高。杜鹃灌丛中草本多样性最高,乔木和灌木多样性最低。同时土壤微生物特有种占比最高的植被类型也是杜鹃灌丛。土壤真菌多样性与植被的关系较细菌与植被的关系更紧密,并且0-30厘米较30-50厘米土壤真菌更易受到地上植被的影响。

Other Abstract

      Soil microbial distribution pattern is currently a hot research topic in ecology. The water and heat conditions along the elevation, to a certain extent, can reflect the water and heat conditions along the latitude. Furthermore, the environmental factors vary sharply in the short distance on mountain ecosystems. The distribution patterns of plants and animals in mountain ecosystems have been well studied, while only a few studies focus on microbial distribution in mountain ecosystems and the vertical distributions of soil microorganisms are not clearly. Microorganisms on the vertical distribution is not only elevation gradients but also soil depths. The vertical distribution of soil microorganisms, which is beneficial to the development of the theory of ecology. And the high variability of soil microbial makes it can be used to predict the environmental changes.

      This research used the sequencing method to study the bacterial and fungal distributions in Western Sichuan Plateau. Community composition, diversity and impact factors of microbes were tested. At the same time, the relationship between vegetation and soil microbial were also examined. The results of the study are as follows:

      1. Soil bacterial diversity showed significant "U" pattern along the elevational gradients. Diversities of Acidobacteria, Proteobacteria, Actinomycetes, Chloroflexi, Planctomycetes showed similar "U" pattern with increasing elevation. When all the factors analyzed individually, soil pH and TN contributed 7.4% and 6.01% to bacterial variation, respectively. When all the factors analyzed synthetically, soil pH and TN explained 19.12% of the total bacterial variation.

      2. The diversity of soil fungi at 3000 m was the highest and the diversity of soil fungi at 3700 m was the lowest, and fungal diversity increased insignificantly with altitude. Soil fungal species richness and phylodiversity were significantly related with soil pH (23.72% and 24.25%) and total nitrogen (22.33% and 13.01%). Soil fungal species richness and phylodiversity increased linearly with increasing soil pH. The diversities of Ascomycetes, Basidiomycetes, Chytridiomycota and Glomeromycota increased linearly with increasing soil pH.

      3. Bacterial diversity exhibited the highest value in the illuvium and the lowest value in the litter. At the same time, the number of endemic bacteria was higher in the illuvium than in the litter, humus and eluvium. The endemic bacteria in the illuvium mainly derived from the Chloroflexi, Planctomycetes, Actinomycetes and Acidobacteria. Bacterial community of brown coniferous forest soil was mainly determined by soil TN (11.87%) and soil pH (10.43%).

       4. Fungal diversity showed no significant difference among the soil profiles, but the proportion of the endemic fungi in the litter was higher than in the humus, eluvium and illuvium. The endemic fungi in the litter mainly derived from the Ascomycetes, Basidiomycota and Chytridiomycota. And the soil fungi community was mainly driven by shrubs (8.04%) and herbs (6.74%).

      5. Among the different vegetation types, 10-20 cm and 20-30 cm soil bacterial diversity were higher in the Rhododendron thickets than other vegetal types. Fungal diversity in the rhododendron thickets was higher than Fargesia-Abies forest and Rhododendron-Abies forest. And the number of soil endemic microbe was also higher in the Rhododendron thickets, 14.2% for bacteria and 22.4% for fungi. Regression analysis showed that the relationship between soil fungal diversity and vegetation was closer than the relationship between bacterial diversity and vegetation, and soil fungal diversity in the 0-10 cm responded to shrub diversity more rapidly than that in the 30-50 cm soil.

Pages120
Language中文
Document Type学位论文
Identifierhttp://ir.rcees.ac.cn/handle/311016/41487
Collection城市与区域生态国家重点实验室
Recommended Citation
GB/T 7714
刘丹. 川西亚高山土壤微生物垂直分布格局及影响因子[D]. 北京. 中国科学院生态环境研究中心,2018.
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