【作者】 王国荣；

【导师】 陈秀蓉；

【作者基本信息】 甘肃农业大学 ， 草业科学， 2006， 硕士

【摘要】 作为高寒草地生态系统的重要分解者，土壤微生物在物质循环和能量转化中占有重要地位，其作用不容小视。它们往往从系统微观层面驾驭草地的发育和演替。因此，对高寒草地生念系统中土壤微生物的研究，可以为改善高寒草地生生态系统中天然草地的土壤状况以及提高灌丛草地的生产力提供微生物学方面的理论依据。 根据甘肃省天祝县东祁连山高寒灌丛草地的不同植被类型，本文选取三种具有代表性的高寒灌丛草地植被类型，样地1杜鹃高寒灌丛(Rhododendron fruticosa shrubs)草地，样地2高山柳高寒灌丛(Salix cupularis fruticosa shrubs)草地，样地3金露梅高寒灌丛(Dasiphoru fruticosa shrubs)草地，各样地均为公共牧场。应用土壤微生物学原理，对各样地的土壤微生物数量、种群多样性、季节动态、生态区系、土壤微生物生理类群，及其与土壤环境关系进行分析，结果如下： 1、土壤微生物季节动态 土壤微生物种群数量变化表现为11月和5月份数量较多，9月和7月份数量较少。不同样地间，各类微生物数量变化为：(1)细菌：各样地均以细菌占绝对优势，全年细菌总数量以高山柳样地较多，杜鹃样地次之，金露梅样地较少，全年平均总数量分别占各自样地微生物总数的88.38％、82.01％，80.67％。三个样地中高山柳样地的种群的季节波动较小(10.06％)，以金露梅样地的变幅较大(41.14％)。(2)真菌：全年真菌总数量以杜鹃样地较多，高山柳样地次之，金露梅样地较少，分别占各自样地微生物总数的0.34％、0.17％、0.21％。三个样地中杜鹃样地的季节波动性较大(0.52％)，高山柳样地的季节波动性较小(0.08％)。(3)放线菌：全年放线菌总数量以金露梅样地较多，杜鹃样地次之，高山柳样地较少，分别占各自样地微生物总数的19.12％、17.66％、11.45％。三个样地中，金露梅样地的季节波动性较大(41.24％)，高山柳样地的季节波动性较小(7.07％)。这说明，三个样地中，高山柳样地的种群季节稳定性较好，金露梅样地群落的季节稳定性较差。各样地微生物种群数量的差异又受到土壤理化性状、小生境、植物群落等因素的影响。 2、不同土层深度微生物数量 高寒灌丛草地土壤微生物数量的垂直分布规律表现为：随着土层的加深，数量逐渐减少。3个样地中细菌总数量大于放线菌，真菌数量最少。每种微生物在各样地的表现为：(1)细菌：三个样地的细菌数量在0～10cm与10～20cm土层之间均差异极显著。(2)放线菌：杜鹃灌丛和高山柳灌丛在0～10cm与10～20cm土层间数量达到极显著差更多还原

【Abstract】 As an important decomposer in the alpine shrubs grassland ecosystem, which affected the development and succession of the grassland through microcosmic view of the system, the soil microorganisms play vital roles in substance cycling and energy conversion. Thus, studies on soil microorganisms in the alpine shrubs grassland ecosystem can supply the microbiological theory evidences for improving soil conditions and increasing productivity of shrubs grassland in the alpine shrub(?) grassland ecosystem.According to the different vegetation types in Tian Zhu county of Gan Su province, three representative alpine shrubs grassland samples were selected for research.,that was sample 1.Rhododendron fruticosa shrubs,sample 2.Salix cupularis fruticosa shrubs and sample 3. Dasiphoru fruticosa shrubs,all of which were common pasturage. The quantity, community diversity, seasonal dynamics, zoological distribution and physiological floraof of soil microorganism as well as the relationship between soil microorganisms and soil environment were studied and analized. The results were as follows: 1. Seasonal dynamics of soil microorganism quantitiesA significant change in soil community microorganism quantities could be seen. The number of microorganism in November and May were the highest,while it was less in September and July. The change of all kinds of microorganisms in different shrubs were showed as follows. (1)Bacteria: Bacteria were absolutely dominant regardless of the months and sites during all the year. A regulation of total bacterial quantities that Salix cupularis fruticosa shrubs had the most, and then Rhododendron fruticosa shrubs, Dasiphoru fruticosa shrubs had the least could be found. Its annual average proportion in each total soil microorganism quantities were 88.38%、 82.01%, 80.67%, respectively. Among the three sites, the seasonal fluctuation was the lightest in Salix cupularis fruticosa shrubs (10.06% ) while the strongest happened in Dasiphoru fruticosa shrubs (41.14%) .(2)Fungi: The total number of fungi during the year was most in Rhododendron fruticosa shrubs, followed by Salix cupularis fruticosa shrubs, and Dasiphoru fruticosa shrubs was the least in different shrubs with the annual average proportion in total soil microorganisms 0.34%、 0.17%、 0.21%. Among the three sites, the seasonal fluctuation was the most significant (0.52 % ) in Rhododendron fruticosa shrubs, and Salix cupularis fruticosa shrubs (0.08 % ) was the lightest.(3) Actionmyces: Its annual average proportion against total soil related更多还原