北方主要草地类型土壤线虫群落结构及多样性的比较研究

发布时间：2018-05-12 15:07

本文选题：草地 + 土壤线虫　；参考：《东北师范大学》2015年硕士论文

【摘要】：土壤线虫(soil nematode)作为小型土壤动物,有捕食、竞争、共生等角色,占据了土壤腐食食物网的多个营养级,直接参与生态系统的物质营养循环及能量流动,因此,土壤线虫的群落结构及多样性在一定程度上直接影响整个生态系统的功能及稳定性。以往有关土壤线虫多样性的研究多集中在小尺度范围,而在区域大尺度上的研究较少。本研究以大尺度空间为背景,将研究样带设在欧亚草原带东部,分析不同草地类型的土壤线虫多样性和群落结构的变化规律,这样不仅可以增进人们对大尺度背景下土壤线虫多样性及群落结构变化规律以及驱动因子的认识,而且也为草原的合理利用和可持续发展提供了一定的理论依据。本研究选取欧亚草原带东部的四种草地类型:草甸草原、典型草原、荒漠草原以及高寒草甸为研究对象,利用贝尔曼漏斗法提取土壤线虫,在体视镜下计数,显微镜下鉴定,最后计算其相关生态指数并与土壤理化性质进行相关性分析,获得的主要研究结果及结论如下:(1)本实验共鉴定出土壤线虫79属,四种草地类型的土壤线虫优势属不同,草甸草原的优势属为丽突属(Acrobeles)和拟丽突属(Acrobeloides);典型草原的优势属为真鹿角唇属(Cervidellus);荒漠草原的优势属为真鹿角唇属(Cervidellus)和板唇属(Chiloplacus);高寒草甸的优势属为垫刃属(Filenchus)、拟丽突属(Acrobeloides)和板唇属(Chiloplacus)。草甸草原、典型草原、荒漠草原的优势属均是食细菌线虫,高寒草甸的优势属除食细菌线虫外还有一属是植食性线虫。(2)四种草地类型土壤线虫多度各不相同,草甸草原的土壤线虫多度最高(518条/100 g干土),荒漠草原最低(113条/100 g干土)。土壤线虫多度主要受土壤含水量、土壤电导率以及土壤碳氮比的影响,其中,土壤线虫多度随土壤含水量的增加先增加后降低,随土壤碳氮比的增加而增加,随土壤电导率的升高而下降。(3)四种草地类型土壤线虫群落组成各不相同,除了典型草原和荒漠草原有部分相似外,其余各个草原之间差异很显著。从营养类群来看,四种草地类型均表现为食细菌线虫比例最高,捕食/杂食性线虫最少,而食真菌线虫和植食性线虫在不同区域比例高低有所差异;从c-p类群来看,四种草地类型c-p2类群均占最高比例,而c-p1类群最少,c-p5次之,c-p3和c-p4类群不同区域比列高低有所差异。(4)土壤线虫多样性在草甸草原最高(H’=4.14),综合冗余(Redundancy analysis,RDA)分析结果可知,土壤线虫多样性变化的主要驱动因子是土壤电导率,二者呈负相关关系。土壤电导率主要通过改变土壤线虫群落结构的稳定性来影响其多样性的。(5)从土壤线虫的通道指数来看,四种草地类型土壤有机质分解以细菌途径为主的是草甸草原和典型草原(NCR㧐0.75),以真菌途径为主的是荒漠草原和高寒草甸(NCR㩳0.75)。从土壤线虫的瓦斯乐斯卡指数来看,四种草地类型土壤健康状况相比最好的是典型草原(WI=9.40),最差的是草甸草原(WI=4.09)。综上所述,在大尺度区域的研究背景下,四种不同草地类型间土壤线虫多样性及群落结构组成各不相同,其中土壤线虫多样性主要受土壤电导率的驱动,土壤线虫多度主要受土壤碳氮比的驱动。本研究不仅可以加深人们对土壤线虫群落在大尺度背景下变化规律的认识,同时也为草原合理利用及可持续发展提供了一定的理论基础。
[Abstract]:Soil nematode (soil nematode), as a small soil animal, has the role of predator-prey, competition and symbiosis, which occupies a number of nutrient levels in the soil rotten food network, and directly participates in the nutrient cycling and energy flow of the ecosystem. Therefore, the community structure and diversity of soil nematodes directly affect the function of the whole ecosystem to a certain extent. The study of soil nematode diversity in the past is mostly focused on small scale, but there are few studies on regional large scale. In this study, the research sample is located in the eastern part of the Eurasian steppe with the background of large scale, and the variation of soil nematode diversity and community structure of different grassland types is analyzed, so that not only can the variation of soil nematode diversity and community structure be analyzed in different grassland types. In order to enhance people's understanding of soil nematode diversity, community structure changes and driving factors in large scale background, it also provides a certain theoretical basis for rational utilization and sustainable development of grassland. This study selected four types of grassland in the east of Eurasia Steppe: meadow steppe, typical steppe, desert steppe and high In cold meadow, the soil nematode was extracted by the Behrman funnel method. Under the stereoscope, the soil nematode was counted, under the microscope, the relevant ecological index was calculated and the correlation between the soil physical and chemical properties was calculated. The main results and conclusions obtained were as follows: (1) the soil nematode 79 genera and four kinds of grassland types were identified. The dominant genera of the soil nematode are different. The dominant genera of the meadow steppe are Acrobeles and Acrobeloides; the dominant genus of the typical steppe is Cervidellus, and the dominant genus of the desert steppe is Cervidellus and Chiloplacus; the dominant genus of alpine meadow is Filenchus, and the genus pantoninus. (Acrobeloides) and the genus Chiloplacus. Meadow meadow grassland, typical steppe and desert steppe are both bacterial eating nematodes, the advantage of alpine meadow and one genus are herbivorous nematodes. (2) the four species of soil nematodes are not the same, and the soil nematode in meadow grassland has the highest degree of soil nematode (518 /100 g dry soil) The desert steppe is the lowest (113 /100 g dry soil). Soil nematode abundance is mainly influenced by soil water content, soil conductivity and soil carbon and nitrogen ratio. The soil nematode abundance increases first and then decreases with the increase of soil water content, with the increase of soil carbon and nitrogen ratio and the increase of soil conductivity. (3) four kinds of grassland type soil The composition of the soil nematode community is different. Except for the typical steppe and the desert steppe, the difference between the other prairies is very significant. From the point of view of the nutrition group, the four kinds of grassland types show the highest proportion of bacteria eating nematodes, the predatory / omnivorous nematodes are the least, and the proportion of the edible fungus nematode and the phytophagous nematode in different regions is high and low. From the C-P group, the four types of grassland type c-p2 groups accounted for the highest proportion, while the c-p1 group was the least, c-p5 was the least, the c-p3 and c-p4 groups were different in different regions. (4) the soil nematode diversity in meadow steppe (H '=4.14), the comprehensive redundancy (Redundancy analysis, RDA) analysis results, the soil nematode diversity The main driving factor of the change is soil conductivity, and the two has a negative correlation. Soil conductivity mainly affects its diversity by changing the stability of soil nematode community structure. (5) from the channel index of soil nematode, the soil organic matter of four types of grassland types mainly is meadow steppe and typical steppe. NCR? 0.75), the main fungal pathways are the desert steppe and the alpine meadow (NCR? 0.75). From the data of the soil nematode, the best soil health status of four grassland types is the typical steppe (WI=9.40), and the worst is the meadow grassland (WI=4.09). In the context of the large scale region, four different meadows are in the background of the large scale region. The diversity of soil nematode and the structure of soil nematode are different. The diversity of soil nematode is mainly driven by soil conductivity, and the degree of soil nematode is mainly driven by soil carbon and nitrogen ratio. This study not only deepens people's understanding of soil nematode community in the large scale background, but also is reasonable for the grassland. It provides a theoretical basis for utilization and sustainable development.

【学位授予单位】：东北师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S812

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