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元谋干热河谷土壤微生物群落对水热变化的响应
Alternative TitleResponses of soil microbial communities to water and temperature changes in Yuanmou Dry-hot Valley
Language中文
彭思利
Thesis Advisor刘刚才
2014
Degree Grantor中国科学院研究生院
Place of Conferral北京
Degree Name博士
Degree Discipline土壤学
Keyword干热河谷 454高通量测序 土壤微生物群落多样性 时空分布 水热变化
Abstract干热河谷区由于其特殊的地理位置和生态环境,水热矛盾突出,在全球气候变暖的背景下有转凉变湿的趋势。本研究以元谋干热河谷为研究对象,分别在南亚热带、中亚热带、北亚热带及温暖-中温带四个垂直气候带设置样地,结合传统的土壤微生物生理研究方法和现代分子生物技术(高通量测序),从土壤微生物生物量碳(MBC)、微生物生物量氮(MBN)、土壤酶活性、土壤微生物基础呼吸(SBR)、土壤细菌群落和真核生物群落结构多样性方面,研究了元谋干热河谷不同气候带土壤微生物群落时空分布特征及其与环境因子的关系。同时,采用不同气候带间土壤置换和纯培养的方法,研究了土壤微生物群落对水热变化的响应。本研究为干热河谷区生态环境保护和可持续发展提供了基础科学支撑,同时为干热河谷区气候变化下土壤微生物多样性演变和土壤生态过程研究提供了理论依据。主要研究结论如下: (1)由于不同气候带间气候、土壤和植被状况的差异,MBC、MBN、SBR和土壤酶活性均呈现差异性,并随着取样季节的变化而变化。中亚热带各个季节土壤MBC含量最低(447.06-222.86 mg?kg-1),显著低于南亚热带和北亚热带;夏季MBN含量各气候带间变化方式与MBC一致,而冬季和春季,中亚热带和北亚热带土壤MBN含量显著低于南亚热带和温暖-中温带;SBR与MBC各个季节下气候带间的变化大致相同,而各气候带间土壤呼吸熵(qCO2)的变化方式与SBR正好相反;各取样季节土壤蛋白酶、脱氢酶和芳基硫酸酯酶活性随海拔梯度的变化方式各不相同。 相关分析表明,土壤有机碳含量(SOC)、总氮(TN)、总磷(TP)含量和植被干重与不同气候带土壤MBC、MBN和SBR有显著的正相关关系(P <0.05),与土壤呼吸熵有着显著的负相关关系。土壤pH与MBC、MBN和脱氢酶活性有着显著的正相关关系。土壤颗粒组成显著影响着MBC、SBR和酶活性在气候带间的变化。不同样带气候差异导致的土壤温湿度变化,也是影响元谋干热河谷微生物群落特征的重要因素:土壤湿度与SBR、MBC、蛋白酶、脱氢酶、芳基硫酸酯酶活性和qCO2间均呈显著的幂函数关系,随着土壤湿度的增加,SBR、MBC、蛋白酶活性增加;而脱氢酶、芳基硫酸酯酶活性和qCO2随着土壤湿度的增加而减小。土壤温度与蛋白酶和脱氢酶活性也有较好的幂函数关系,不过随着土壤温度的增加,蛋白酶活性显著降低,而脱氢酶活性显著增加。 (2)高通量测序结果表明元谋干热河谷四个气候带上土壤细菌群落分布在32个门,53个纲,土壤真核生物分布在51个门,91个纲。总的来说,细菌和真核生物群落分布均存在少部分的群落数量较多,而其余的大多数则含量较少的“长尾效应”。pH、SOC、土壤温度和湿度是影响不同气候带土壤细菌群落结构的主要因子,而影响真核生物群落组成的主要是土壤温度、pH、TN和TP含量。在微生物群落的时空变化中,土壤温度与多个纲水平的细菌群落多样性有显著的正相关关系,其中,与Acidobacteria纲(酸杆菌门)和Gammaproteobacteria纲(变形菌门)细菌的相关系数最大,分别为0.536、0.504(P<0.01)。土壤湿度则与Actinobacteria纲(放线菌门)、Thermoleophilia纲(放线菌门)和Chloroflexia纲(绿弯菌门)细菌相对多样性有显著的负相关关系。土壤真核生物群落主要与湿度有显著的负相关关系,包括相对多样性较大的Eurotiomycetes纲(子囊菌门)、Glomeromycetes纲(球囊菌门)、Orbiliomycetes纲(子囊菌门)、Pezizomycetes纲(子囊菌门)真核生物群落。 (3)不同土壤微生物群落对水热变化的响应不同,真核生物群落多样性的变化大于细菌群落,真核生物群落在水热条件改变后可能会都朝着更加离散的方向演变。在温度范围9-22℃,湿度4-13%的冬季和春季,降低南亚热带土壤温度和湿度后(南亚热带土壤置换到温暖-中温带),变形菌门和拟杆菌门细菌相对多样性降低,浮霉菌门增加;顶复亚门和毛霉亚门真核生物相对多样性分别降低了87.0%和89.0%。在土壤温度范围为19℃-25℃,湿度10%-15%的夏季,降低土壤温度并增加土壤湿度后,除厚壁菌门细菌相对多样性增加外,放线菌门、变形菌门、拟杆菌门和硝化螺旋菌门分别降低了49.6%、34.8%、59.9% 和50.8%;子囊菌门真菌相对多样性增加了1.43倍,膜生植物门和绿藻门真核生物相对多样性降低88.8%和43.2%。在此温度和湿度范围内改变土壤温湿度条件后,与土壤湿度相比,土壤温度变化对细菌群落多样性的影响更大。 (4)元谋干热河谷南亚热带土壤温度在15℃-35℃,湿度22%-45%的大范围条件下变化时,对土壤微生物群落活动和多样性产生显著影响。不同土壤细菌群落占据着不同的温度和水分生态位。绿弯菌门、变细菌门、放线菌门和芽单胞杆菌门细菌在低水分条件下相对多样性最大;厚壁菌门细菌在中水分水平时有最大相对多样性68.6%;酸杆菌门细菌在高水分水平下相对多样性最大。绿弯菌门、变形菌门、放线菌门和酸杆菌门在15℃下相对多样性最大,比最低值分别增加了19.7%,28.7%,26.2%和30.7%,厚壁菌门细菌在25℃下相对多样性最大,而芽单胞杆菌门在35℃下相对多样性最大。 (5)不同的温湿度变化范围试验均表明,水热变化对微生物群落丰度和多样性均有显著影响。因此,在元谋干热河谷,若气候条件继续保持转凉变湿的变化趋势,由此导致的土壤水热变化会使得微生物群落多样性发生改变,占据较低温度和较高水分生态位的土壤微生物群落多样性将增加,进而可能导致整个微生物群落功能改变。
Other AbstractDry-hot valley is a typical ecologically vulnerable area, which has an arid climate and the vegetation is termed valley-type savanna vegetation. The contradiction between water and heat is serious and the climate change in this area is special under the background of global warming. In this study, we focused on Yuanmou dry-hot valley, using microbial physiological methods and 454 pyrosequencing, soil microbial characteristics, including soil microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), soil enzymes activities, soil basic respiration (SBR), soil bacterial and eukaryotic community diversity, were measured along four vertical climate zones, which are South subtropical zone (SS), Mid-subtropical zone (MS), North subtropical zone (NS) and Warm-mid temperature zone (WM). The spatial and temporal distributions of these soil microbial characteristics and their relationships with environmental factors were researched. At the same time, the responses of soil microorganism to water and heat changes were studied by soil transplanting between SS and WM and manipulating soil temperature and moisture in the laboratory. The major findings are as following: (1) Soil MBC, MBN, SBR and soil enzyme activities showed totally different spatial and temporal distributions along climatic zones in Yuanmou dry-hot valley. At four sampling season, MBC contents in MS had smallest values, which were significantly lower than that in SS and NS. The variation of soil MBN contents along the elevation in summer was similar with MBC. However, in winter and spring, MBN contents in MS and NS were significantly lower than that in SS and WM. SBR rates changed in the same way as MBC, while the variation of soil respiration quotient (qCO2) were on the opposite. Correlation and regression analysis showed MBC, MBN and SBR had significant positive correlations with soil organic carbon, pH, nitrogen, phosphorus, plant height and dry weight, whereas these environmental factors were negatively correlated with qCO2. Soil pH was also positively correlated with MBC, MBN and dehydrogenase activity, and the soil particle composition significantly influenced MBC, SBR and enzyme activities. There were exponential relationships between soil moisture and SBR, MBC, enzyme activities and qCO2. SBR, MBC and protease activity all increased with the increase of soil moisture. Besides, the soil temperature also had exponential relationships with the activities of protease and dehydrogenase, which showed protease activity reduced with the increase of soil temperature, but the dehydrogenase activity was on the opposite. (2) Based on 454 pyrosequencing, 32 phylum levels and 53 class levels bacterial information and 51 phylum levels and 91 class levels eukaryotic communities were found in Yuanmou dry-hot valley in four climatic zones. However, only a few classes were abundant, whereas most of the others were relatively rare, which showed the classic “long tail” phenomenon. Soil bacterial and eukaryotic diversity exhibited no apparent altitudinal patterns along the altitude. Soil pH, soil organic content, soil temperature and moisture were the primary factors affecting bacterial community structure and diversity, while eukaryotic community mainly influenced by soil temperature, pH, total N and P contents. The seasonal variation of climate conditions had great effects on soil bacterial and eukaryotic community. In general, soil temperature had significant positive correlations with the relative diversities of many classed level bacterial community (high correlation coefficients of 0.536 and 0.504 with Acidobacteria and Gammaproteobacteria, respectively). Soil moisture showed negative relationships with the diversities of Actinobacteria, Thermoleophilia and Chloroflexia. On the contrary, the diversities of soil eukaryotic community, including Eurotiomycetes, Glomeromycetes, Orbiliomycetes and Pezizomycetes, mainly negatively related to the changes of soil water content. (3)
Document Type学位论文
Identifierhttp://ir.imde.ac.cn/handle/131551/7932
Collection山地表生过程与生态调控重点实验室
Recommended Citation
GB/T 7714
彭思利. 元谋干热河谷土壤微生物群落对水热变化的响应[D]. 北京. 中国科学院研究生院,2014.
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