【作者】 卢萍；

【导师】 杨忠岐；

【作者基本信息】 中国林业科学研究院 ， 森林保护学， 2014， 博士

【摘要】 弹尾虫（节肢动物门六足总纲Hexapoda：弹尾纲Collembola）是土壤生态系统中分布最广，类群和数量最丰富的节肢动物，是中小型土壤动物的主要组成部分。它们在加速土壤中有机物质的分解速率，提高土壤潜在碳截获能力和土壤肥力等方面具有重要作用。外界的干扰，如外源性C、N等物质输入土壤，直接或间接影响土壤弹尾虫群落丰富性和多样性，并削弱了它们在土壤生态系统中的功能性作用，进而影响与其相关联的生态系统的功能。因此，研究土壤弹尾虫群落丰富性和多样性动态变化以及对外源性C、N的响应，对进一步揭示弹尾虫在土壤有机质分解和矿化过程中的功能性作用具有重要意义。本文在研究自然条件下黑土区土壤弹尾虫群落丰富性和多样性动态变化规律以及对不同浓度外源性C、N干扰响应的基础上，通过人工模拟实验，进一步研究在外源性C、N干扰下，土壤弹尾虫多样性变化与土壤微生物群落结构以及土壤主要性质之间的相互关系。本研究得出如下结论：1、在自然条件下，采用改良干漏斗法和贝尔曼漏斗法对2011年和2012年不同外源C、N干扰下的土壤弹尾虫群落结构进行调查，共采集270个土壤样本，获得42634头土壤弹尾虫，隶属12科。土壤弹尾虫群落多样性受外源性质和采样时段的影响显著。不同外源C、N干扰对土壤弹尾虫群落多样性的影响不同，外源C干扰下的土壤弹尾虫个体数高于外源N干扰下的土壤弹尾虫个体数，并且在外源C分解和矿化初期阶段（2011年），土壤弹尾虫类群数是随着时间的变化呈上升趋势，9月开始下降，在后期阶段（2012年），土壤弹尾虫类群数随时间的变化呈下降趋势。主成分分析表明，土壤弹尾虫群落组成与采样时间和干扰源性质相关。外源C、N的干扰对土壤理化性质，如土壤温度、湿度、pH、土壤有机质含量、全氮含量和碳氮比，存在不同程度的影响。与未受干扰的处理（CK）相比，外源C的输入会增加土壤温度（6.59%~9.16%）和土壤湿度（1.16%~6.26%），并增加土壤有机质含量（9.43%~26.37%）和全氮含量（7.93%~21.01%），从而提高土壤肥力；外源N的输入会降低土壤碳氮比，加速有机物的分解速率，不利有机物质的积累。发生变化后的土壤理化性质会对土壤弹尾虫群落多样性产生影响。土壤弹尾虫与土壤理化性质的相关分析表明，土壤弹尾虫群落的变化与土壤温度、湿度、土壤有机质和全氮含量显著相关（p<0.05），其中，土壤湿度对土壤弹尾虫群落的变化影响最大。2、在人工模拟条件下，首次采用变性梯度凝胶电泳方法对土壤弹尾虫群落多样性进行分析，结果发现，土壤弹尾虫群落的丰富度受外源性质和采样时间共同作用的影响极显著（p<0.01），并且随月份变化明显（p<0.05）。在采样时间段内，土壤弹尾虫群落的丰富度主要是在5月与6月、7月、8月之间存在显著差异（p<0.05）；在不同外源C、N干扰下，土壤弹尾虫群落的丰富度主要是在N1.5与对照（CK）存在显著差异（p<0.05）。利用磷脂脂肪酸（PLFA）生物标记法分析不同外源C、N干扰对土壤微生物群落结构的影响，结果发现，土壤微生物磷脂脂肪酸（PLFA）总量受采样时间和外源性质共同作用的影响极显著（p<0.01），外源C的施入增加了PLFA总量，而外源N的施入则减少了PLFA总量，并且相关分析结果显示，PLFA总量与土壤全氮含量有着密切的相关性（p<0.05）。另外，外源C的施入同时也增加了细菌PLFAs、真菌PLFAs、菌根真菌PLFAs、革兰氏阳性菌PLFAs和革兰氏阴性菌PLFAs含量，外源N的施入则减少了它们的含量。土壤温度、湿度、pH对土壤微生物群落变异的影响显著（p<0.05），其中pH对土壤微生物群落变异的影响最显著。外源物质、土壤理化性质和土壤微生物对土壤弹尾虫群落遗传多样性的影响各不相同。冗余分析（RDA）结果表明，土壤微生物对土壤弹尾虫群落遗传多样性变异的影响很大（p<0.01），为24%，并且土壤微生物与土壤理化性质交互作用下对土壤弹尾虫遗传多样性变异的影响最大（p<0.01），达到了38%。根据上述研究的结论表明，外源C干扰对土壤弹尾虫群落的影响高于外源N的干扰；外源C、N分解过程会改变土壤理化性质，外源C干扰以增加土壤有机质、土壤氮含量和土壤微生物量的方式来增加土壤肥力；土壤理化性质发生改变后，土壤弹尾虫的群落结构和土壤微生物群落结构也会随之发生变化，而土壤微生物也影响土壤弹尾虫群落多样性。这些结论为加强土壤管理、提高土壤生物多样性、改善土壤营养状况，创造有利于林木和作物生长的良好土壤生态环境提供了基础资料，具有重要的科学意义。更多还原

【Abstract】 Collembolan (Hexapoda: Collembola) are among the most widespread and abundantterrestrial arthropods. They play an important role in accelerating the rate of decomposition ofsoil organic matter, improving the potential soil carbon sequestration and soil fertility, and soon. The abundance and diversity of soil collembolan could be affected, directly or indirectly, byexternal disturbance, such as inputting exogenous carbon and nitrogen to soil. This couldundermine their functional role in the soil ecosystem, and further affect the ecosystemfunctions associated with soil collembolan. Therefore, a study of the dynamic changes in soilcollembolan community richness and diversity and their response to exogenous carbon andnitrogen has great significance in revealing the functional role of soil collembolan in theprocess of decomposition and mineralization of soil organic matter.In this paper, dynamic changes in the richness and diversity of soil collembolancommunities and their response to disturbance with exogenous carbon and nitrogen werestudied in a field experiment in the black soil area; thereafter greenhouse pot experiments wereconducted to investigate the relationship among soil collembolan community diversity, soilmicrobial community structure and soil properties in response to disturbance by exogenouscarbon and nitrogen. The main results were as follows:1. In the field experiment, the methods of modified Tullgren and Baermann were used tosurvey the composition and structure of soil collembolan as affected by exogenous carbon andnitrogen in2011and2012. A total of270soil samples and42634soil collembolan individualswere collected and sorted into12families.The effects of exogenous carbon and nitrogen and sampling time on soil collembolancommunity diversity were significant. The number of soil collembolan individuals subjected todisturbance by exogenous carbon was higher than the number subjected to disturbance ofexogenous nitrogen. In2011, the number of soil collembolan individuals rose from May to August and declined in September; in2012, the number of soil collembolan individualsdeclined from May to September. A principal component analysis (PCA) showed that thecomposition of soil collembolan was related to sampling time and type of exogenousdisturbance.Soil properties, such as temperature, moisture, pH, organic carbon, total nitrogen and thecarbon to nitrogen ratio, were influenced by exogenous carbon and nitrogen. Compared to acontrol treatment (CK), soil temperature, moisture, carbon and soil total nitrogen increased by6.59%~9.16%,1.16%~6.26%,9.43%~26.37%and7.93%~21.01%, respectively. Soil fertilitywas improved with disturbance by exogenous carbon. The soil carbon-nitrogen ratio wasreduced and the rate of decomposition of organic matter was accelerated with disturbance byexogenous nitrogen, which was not conducive to the accumulation of organic material.Soil collembolan community diversity was influenced by the changed soil properties. Aredundancy analysis (RDA) showed that soil collembolan communities were affectedsignificantly by soil temperature, soil moisture, soil organic carbon and total nitrogen (p<0.05),the influence of soil moisture was greatest.2. In the greenhouse pot experiments, the method of denaturing gradient gelelectrophoresis was used for the first time to survey the diversity of soil collembolancommunity. The results showed that the richness of soil collembolan communities wasinfluenced significantly by exogenous carbon and nitrogen and sampling time (p<0.01). Further,the richness of soil collembolan communities varied over season. The richness in May wasdifferent significantly with that in June, July and August (p<0.05); and the richness in N1.5wassignificantly different from that in the control treatment (CK)(p<0.05).Using the method of phospholipid fatty acids to survey the composition and structure ofsoil microbial community as affected by exogenous carbon and nitrogen, the results showedthat the total PLFAs was increased in the treatments of exogenous carbon, decreased in thetreatments of exogenous nitrogen, and influenced significantly by exogenous substances andsampling time (p<0.01). And the results of Pearson correlation analysis showed that the total PLFAs was correlated significantly with soil total nitrogen (p<0.05). The bacterial PLFAs,fungal PLFAs, arbuscular mycorrhizal fungi PLFAs, gram-positive bacterial PLFAs andgram-negative bacterial PLFAs were also increased in the treatments of exogenous carbon anddecreased in the treatments of exogenous nitrogen. The soil microbial communities weresignificantly influenced by soil moisture, temperature and pH (p<0.05), and the influence ofpH was greatest (p<0.01).The influences of exogenous substances, soil properties, and soil microbial on soilcollembolan community were different. A redundancy analysis (RDA) showed that theinfluence of soil microbial on the soil collembolan community was the largest (p<0.01), whichwas24%, and the genetic diversity of soil collembolan was most influenced significantly bythe interaction between the soil properties and the soil microbial (p<0.01), which was38%.In summary, the impact of exogenous carbon on soil collembolan community was higherthan that of the exogenous nitrogen. Soil properties could be changed in the decompositionprocess of exogenous carbon and nitrogen, such as soil organic carbon and total nitrogen, andsoil microbial biomass could be increased under disturbances by the exogenous carbon. Soilcollembolan community structure and soil microbial community structure could be changedwith a change of soil properties, and then soil collembolan community could be furtherinfluenced by soil microbial. These conclusions have important scientific significance andprovide basic information for reinforcing soil management, increasing soil biodiversity,improving soil nutrition and creating a better soil ecological environment for plant and crop.更多还原