松嫩草地不同植物功能群土壤细菌碳源利用的研究

发布时间：2018-06-05 19:00

本文选题：松嫩草地 + 植物群落　；参考：《吉林农业大学》2017年硕士论文

【摘要】：在草地生态系统中,地上植物与地下土壤细菌群落之间紧密联系,植物群落的组成及其结构变化往往也可导致土壤细菌群落功能的改变。通过Biolog指纹解析不同植被类型土壤细菌群落功能差异,可以探讨草地植物群落和土壤细菌群落之间的关系,明确土壤细菌功能多样性对外界变化条件的敏感程度,在维持草地生态系统功能的稳定和发展上有重要意义。本试验以松嫩放牧草地为研究地点,利用Biolog-ECO技术,研究比较了放牧前后不同植物功能群土壤细菌碳源利用差异。研究结果表明:(1)通过植物群落组成对比分析表明,羊草、禾草、豆科植物和杂类草功能群中,各植物群落植物组成和群落结构具有明显差异。群落之间的高度、盖度、密度和地上生物量之间各不相同。羊草功能群中,4个群落特征指标之间均存在显著差异(P0.05);其中,羊草群落的高度、密度和地上生物量最大,盖度仅低于拂子茅群落;委陵菜群落的密度最低;蒙古蒿群落的高度、盖度和地上生物量最低。禾草功能群中,群落间高度、盖度和地上生物量之间存在显著差异(P0.05);牛鞭草群落的高度和地上生物量最大,狗尾草群落的盖度和密度最大。豆科植物功能群中,4个群落特征指标之间均存在显著差异(P0.05);其中,羊草群落的盖度、密度和地上生物量最大,胡枝子群落的高度最高。杂类草功能群中,群落间盖度、密度和地上生物量之间存在显著差异(P0.05);全叶马兰群落的密度和地上生物量最大,碱地肤群落的高度和盖度最大。与放牧前植物群落进行对比,植物群落特征变化明显,群落丰富程度略降低。(2)通过对不同植物群落土壤细菌碳源利用情况分析表明,各植物群落土壤细菌对碳源的利用情况均随培养时间的延长而升高,土壤细菌对碳源利用情况的AWCD值变化曲线各不相同。各植物功能群内的植物群落组成发生变化,土壤细菌对碳源的利用程度也不同,但无明显规律性变化。随着植物群落结构改变,其土壤细菌对碳源的利用程度发生明显差异,土壤细菌群落的丰富度与均匀度也发生一定变化。对不同碳源的利用上来看,各植物群落利用碳源的种类与数量各不相同,放牧后群落土壤细菌利用碳源的种类和数量更为广泛。所有植物群落土壤细菌均对糖类和氨基酸这两大类碳源的利用最好。在土壤理化性质方面,同一植物功能群中,不同植物群落间5种土壤理化指标各不相同;RDA分析表明,有机质含量对土壤细菌碳源利用的影响最大。(3)通过对5类植物功能群对土壤细菌功能多样性影响的分析表明:5类植物功能群土壤细菌碳源利用情况各有差异,羊杂草功能群土壤细菌碳源利用率最高,豆科植物功能群最低。通过RDA分析研究影响土壤细菌群落群落功能多样性的主要因素,表明土壤中全氮和有机质含量对土壤细菌的碳源利用率的影响最大。在对碳源的利用上,5类植物功能群均对糖类和氨基酸类碳源有较好的的利用,对胺类的利用较差;羊杂草和杂类草功能群土壤细菌对碳源的利用情况明显高于其他3类功能群,且利用碳源的种类和数量最多,土壤细菌群落的丰富度与均匀度最高。
[Abstract]:In the grassland ecosystem, the aboveground plants are closely related to the bacterial community in the underground soil. The composition and structural changes of the plant community can also lead to the change of the function of the soil bacterial community. The analysis of the functional differences of the bacterial community in different vegetation types by Biolog fingerprint can be used to discuss the grassland plant community and the soil bacterial community. The relationship between the bacterial functional diversity of soil and the sensitivity of the environment to the external changes is of great significance in maintaining the stability and development of the function of the grassland ecosystem. This experiment took the Songnen grazing grassland as the research site, and compared the use of Biolog-ECO technology to the utilization of soil bacteria carbon sources of different plant functional groups before and after grazing. The results showed that: (1) through the comparative analysis of plant community composition, the plant community composition and community structure of Leymus chinensis, grasses, legumes and miscellaneous grass had obvious differences. The height, coverage, density and aboveground biomass among the communities were different. Among the functional groups of Leymus chinensis, 4 characteristics of community characteristics were found. There were significant differences (P0.05). Among them, the height, density and aboveground biomass of Leymus chinensis community were the largest, the coverage was only lower than that of the grass community; the density of the community of Potentilla was the lowest; the height, the coverage and the aboveground biomass of the Mongolia Artemisia Artemisia community were the lowest. There were significant differences between the colony height, the coverage and the aboveground biomass in the grass functional group (P0 .05): the height and aboveground biomass of the community is the largest, and the coverage and density of the community are the largest. Among the functional groups of the leguminous plant, there are significant differences between the 4 community characteristics (P0.05). Among them, the coverage, density and aboveground biomass of Leymus chinensis community are the highest, and the height of the plant community is the highest. There was a significant difference between the coverage, the density and the aboveground biomass (P0.05); the density and aboveground biomass of the whole leaf Ma Lan community were the largest, the height and coverage of the base skin community were the largest. Compared with the plant community before grazing, the characteristics of the plant community were obviously changed and the community richness decreased slightly. (2) through the carbon source of soil bacteria in different plant communities. The utilization of soil bacteria to carbon sources increased with the prolongation of culture time, and the variation curves of AWCD value of soil bacteria to carbon source were different. The composition of plant community in various plant functional groups changed, and the utilization degree of soil bacteria to carbon sources was also different, but there was no obvious rule. With the change of plant community structure, the utilization degree of soil bacteria to carbon source was obviously different, the abundance and evenness of soil bacterial community also changed. All plant community soil bacteria are best used for the two major carbon sources of carbohydrates and amino acids. In the physical and chemical properties of the soil, 5 kinds of soil physical and chemical indexes are different among the same plant functional groups, and the RDA analysis shows that the organic content has the most influence on the utilization of soil bacterial carbon sources. (3) (3) through the analysis of the effects of 5 kinds of plant functional groups on the functional diversity of soil bacteria, the results showed that the utilization of soil bacteria carbon sources in 5 kinds of plant functional groups was different, the utilization rate of soil bacteria carbon source in the sheep weeds functional group was the highest, and the functional group of leguminous plants was the lowest. The functional diversity of soil bacteria community community was influenced by RDA analysis. The main factors were that the total nitrogen and organic matter content in the soil had the greatest impact on the carbon source utilization of soil bacteria. In the use of carbon sources, the 5 types of plant functional groups had better utilization of carbohydrates and amino acids, poor utilization of amines and the use of soil bacteria of sheep weeds and hetero grass functional groups to carbon sources. Compared with the other 3 functional groups, the richness and evenness of the soil bacterial community were the highest.
【学位授予单位】：吉林农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S812.2

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