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题名: 全球变化对土壤微生物与植物交互作用的影响
作者: 张翠景1
学位类别: 博士
答辩日期: 2017-05
授予单位: 中国科学院大学
授予地点: 北京
导师: 贺纪正 ; 沈菊培
关键词: 全球变化,氨氧化,反硝化,植物,交互作用,生态系统功能 ; Global change, ammonia oxidation, denitrification, plant, interaction,ecosystem function
其他题名: Effects of global change on the interactions of soil microorganisms and plant
学位专业: 生态学
中文摘要: 随着人类活动对生态系统干扰的加剧,全球变化受到越来越多的关注,主要 表现在 CO2浓度的增加、气温的升高、降水格局的改变、氮沉降的增多等方面。 微生物作为元素生物地球化学循环过程的主要参与者与驱动者,是陆地生态系统 中最活跃的组分之一,在维护生态系统功能中起到了重要作用。土壤微生物组成 及其功能对环境变化敏感,响应迅速。目前对多种同时发生的全球变化因子对土 壤微生物的交互作用的研究还很不够,且对于全球变化背景下地上植被和地下微 生物相互作用及其内在机理的认识还没有普遍接受的结论。全球变化会改变植物 凋落物和根系分泌物的数量和质量,从而影响微生物的群落结构。植物物种可以 调节微生物群落对全球变化的响应。然而,人们对不同生长时期、不同产地的同一 种植物对微生物群落的影响以及对微生物响应全球变化的介导作用尚知之甚少。 因此研究微生物对全球变化的响应,对于预测生态系统功能的变化,制定合理的 应对策略,保护和管理未来的生态系统十分必要。 本研究使用定量聚合酶链式反应( PCR)、末端限制性片段长度多样性 (T-RFLP)分析和克隆文库测序、高通量测序等分子生物学手段,对草地、农田 和森林生态系统的土壤微生物进行了分析,探讨全球变化对微生物丰度、群落结 构和多样性的直接和间接影响,找到驱动微生物变化的关键环境因子。主要研究 内容与成果如下: (1 )在内蒙古多伦温带草原野外控制实验站共采集了三个样地的土壤样 品,主要研究多种全球变化因子对氨氧化和反硝化微生物的交互作用。三个样地 分别为开始于 2011年的四因子全球变化(CO2浓度升高、夜间增温、增雨、氮 沉降)实验样地;开始于 2005年的三因子(割草、氮添加和增雨)全球变化实 验样地;开始于 2005年的两因子(增温和增雨)全球变化实验样地。综合整理 三个样地的结果发现,在微生物活性方面,长期增温显著降低了土壤呼吸,增雨 减缓了增温对土壤呼吸的抑制作用。基因丰度方面,长期割草显著刺激了细菌 16S rRNA的基因丰度,氨氧化细菌的丰度随着氮添加显著增加,随着增雨显著降低。 群落结构方面,长期增雨显著影响土壤氨氧化细菌的群落结构,氮添加对土壤氨 氧化细菌 amoA和反硝化微生物 nosZ的群落结构有显著的影响;气候变暖和增雨 对细菌 amoA的群落结构、增温和氮添加对 nosZ群落结构有交互作用。冗余分析 表明,古菌 amoA的群落结构受到总氮、总碳的显著影响,而细菌 amoA和 nosZ 的群落结构主要受土壤 pH的影响。根据结构方程模型结果,全球变化通过改变 微生物丰度和活性间接影响植物净初级生产力,植物多样性与氨氧化细菌 amoA 群落结构显著相关,暗示着全球变化背景下植物和微生物之间存在着交互作用。 总的来说,我们的研究(暗)预示着短期和单因素实验可能高估了全球变化对土 壤微生物的影响。 (2)利用两种土壤(灰土和黑土)种植棉花,在全球变化(升高的 CO2 和温度)处理下,采集第一年开花期和收获期,第二年播种前和开花期共四个时 期的土壤样品进行了土壤微生物变化的研究。利用高通量测序技术,研究了在植 物不同发育阶段二氧化碳和温度升高对土壤细菌群落的影响。结果发现,不同土 壤中,细菌群落对二氧化碳和温度升高的响应大小、方向有很大程度的不同,灰 土比黑土的细菌群落对升高的 CO2、温度和植物生长期更为敏感。灰土中,升高 的 CO2增加了土壤细菌的多样性;在黑土中,升高的 CO2降低了细菌多样性。两 种土壤中,暖化持续地促进了细菌的多样性。棉花不同生长期对土壤细菌多样性 和群落组成有强烈的影响。四个时期相比,第二年播种前的土壤微生物对全球变 化的响应最为显著,其次是开花期,对全球变化最不敏感的时期是收获期。这暗 示着植物对于细菌群落对全球变化的响应有着很强的调节作用,植物生长活跃的 时期,土壤细菌对全球变化响应较敏感。 (3)采用控制温度的温室,在一系列温度梯度(18,21.5,25,28.5,32 和 35.5℃)下,利用同一土壤培养不同产地(温带、亚热带和热带)的同一树种 小叶桉。使用高通量测序和定量 PCR方法研究细菌和真菌多样性、群落结构和 丰度的变化。测定了关键的土壤功能包括微生物呼吸作用、酶活性和营养的可用 性。总体而言,我们的研究结果表明,三种产地下的微生物和土壤功能对温度变 化的响应相似,但产地的温度不同导致暖化的效应不同:相比于热带和亚热带产 地,温带产地下的微生物的丰度和土壤功能受到了暖化的促进,暗示着温带产地 的营养循环和植物生长在未来气候变暖的条件下是有利的。网络和线性识别分析 显示在三种产地下,细菌和真菌群落沿温度梯度有显著的变化。不同产地的植物 会调节土壤细菌组成及无机氮对温度变化的响应。土壤微生物群落与土壤功能显 著相关,表明植物产地的变化导致的微生物群落的改变可能会影响土壤的功能。 可见,即使是生态系统小的变化如植物产地的改变,都会影响土壤微生物和功能 对全球变化的响应。
英文摘要: With intensified interference of human activities on ecosystem, global change such as increase of CO2 concentration, the rise of temperature, changes in rainfall patterns and increasing nitrogen deposition, has become a world concern. Microorganisms play important role in driving biogeochemical cycle and is one of the most active components in terrestrial ecosystem. It was reported that microbial community was correlated with ecosystem function. Microorganism could shift its abundance and community in response to global change. The interactive effects of multiple co-occurring global change factors on microbially-mediated processes are not extensively explored. There was no consist conclusion about the interaction between aboveground plant and belowground microbes as well as the underlying mechanisms in the context of global change. Plant species could regulate microbial responseto global change, while the quality and quantity of litter and root exudates could also be altered by global change, lead to alteration of microbial community. However, there was a knowledge gap about whether different growing seasons or provenances of a particular species modulate microbial response to climate change. It is necessary to investigate microbial response to global change for predicting future ecosystem function and protecting ecosystem. Quantitative polymerase chain reaction (QPCR), terminal restriction fragment length diversity (T - RFLP), clone library and high throughput sequencing were used to investigate the direct and indirect effects of climate change on soil microbial abundance, community structure and diversity in grassland, farmland and forest ecosystem. Our aim was to find out the key factors driving microbial alteration. The main research contents and results were as follows: 1) Soil samples were collected from three long-term field experiment sites in a temperate steppe of northern China to investigate interactive effects of multiple climate change factors. Three sites included a four-factorial field experiment with elevated CO2, watering, nitrogen addition and night warming commenced from 2011; a three-factorial field experiment with mowing, nitrogen addition, watering commenced from 2005; and a two-factorial field experiment with warming and increased precipitation conducted from 2005. Our results showed that soil respiration was inhibited with warming. Mowing significantly stimulated bacterial 16S rRNA gene abundance. The abundance of ammonia-oxidizing bacteria (AOB) significantly increased by nitrogen addition and decreased by watering. Long term watering significantly affected community of ammonia oxidizing bacteria. Nitrogen addition showed a strong effect on soil AOB amoA and denitrifier nosZ community structure. The interactions of watering × warming on the bacterial amoA community and warming × nitrogen addition on the nosZ community were found. Redundancy analysis indicated that the ammonia-oxidizing archaeal community was affected by total nitrogen and total carbon, while the community of bacterial amoA and nosZ were significantly affected by soil pH. According to the structural equation modeling analysis, climate change influences plant net primary production indirectly by altering microbial abundance and activities. Plant diversity was significantly correlated with the AOB amoA community. These results indicated that microbial responses to the combination of chronic global change tend to be smaller than expected from single-factor global change manipulations. 2) We examined the impacts of elevated CO2 and temperature on soil bacterial community of two vertosols (grey and black vertosol) planted with cotton over two seasons including 2013 flowering, 2013 harvest, 2014 pre-planting and 2014 flowering. High through-put sequencing technique was used to assess elevated CO2 and temperature impacts on soil bacterial diversity and community composition during plant developmental stages. We found that soil bacterial communities differed between the two soils, and their responses to CO2 and temperature treatments also differed in their direction, magnitude and timing with grey soil showing up less resistance to climate change. Elevated CO2 increased bacterial diversity in grey soil and decreased that in black soil. In contrast, warming stimulated bacterial diversity in both soils. There were strong temporal variations in their diversity and community composition, with particularly strong responses at pre-planting of the second season in both soils. It reflected strong regulation of plant to microbial response to climate change. Microbes respond stronger when plants were active growth stage. 3) We conducted a controlled glasshouse incubation experiment to determine whether different provenance (tropical, subtropical and temperate) from a tree species (i.e. Eucalyptus tereticornis) regulated the response of soil functioning and microbial communities across a gradient of growth temperatures (18, 21.5, 25, 28.5, 32 and 35.5 ℃). Amplicon sequencing and QPCR approaches were employed to investigate the changes in bacterial and fungal diversity, community composition and abundance. Key soil functions included microbial respiration, enzyme activities and nutrient availability. Our results showed that there was a similarity of microbial and soil functional response to temperatures across three provenances, but different position of provenances on the hump-shaped curve resulted in different effects: in contrast to soils of tropical and sub-tropical provenances, microbial abundance and soil functions were promoted by warming in the cool-origin trees (temperate), suggesting that nutrient cycling and plant production in these cooler provenances might benefit in warmer climate. For both bacteria and fungi, network and linear discriminant analyses revealed clear shifts of community structure along temperature gradient among the three provenances. Intra-species variation regulated the responses of soil bacterial composition and inorganic nitrogen to changing temperatures. Soil microbial community structure were significantly correlated with soil function, suggesting that the shifts in microbial communities linked to different tree provenances may result in altered soil functions. Our study provided novel evidence that even small variation in biotic components (i.e. tree provenances) has a critical influence in regulating the responses of soil microbes and functions to predicted global warming.
内容类型: 学位论文
URI标识: http://ir.rcees.ac.cn/handle/311016/38740
Appears in Collections:中澳联合土壤环境研究室_学位论文

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作者单位: 1.中国科学院生态环境研究中心

Recommended Citation:
张翠景. 全球变化对土壤微生物与植物交互作用的影响[D]. 北京. 中国科学院大学. 2017.
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