RCEES OpenIR  > 土壤环境科学实验室
基于高分辨质谱的土壤溶解性有机质化学多样性研究
Alternative TitleCharacterization of soil dissolved organic matter chemodiversity by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry
李晓明
Subtype博士
Thesis Advisor朱永官
2018-12
Degree Grantor中国科学院生态环境研究中心
Place of Conferral北京
Degree Name理学博士
Degree Discipline环境科学
Keyword土壤溶解性有机质, 化学多样性,微生物多样性, 傅立叶变换离子回旋 共振质谱 decreased WIth IncreasIng Iron ComplexIng Index. PAtterns In Molecular PrOfiles IndicAted Dom In Paddy Soils To Become More RecalcItrAnt At Higher Soil C/n rAtio And Higher Soil Ph. furTherMore, PlAnt-derived polyPh.nols And Pyrogenic Dom Were retaIned Favorably By Iron And The ChemodiversIty Of Dom In Paddy Soil Increased WIth IncreasIng Soil C/n rAtios. These Results Provide Novel InFormAtion regardIng Dom Characteristics At a Molecular Level And Will InForm Better Global MAnagement Of Soil Carbon In Paddy Soil EcosysteMs Global. 2) Through The applicAtion Of Ft-icr-Ms, The ChemodiversIty Of Dom In Soil Subjected To Long-term OrgAnic Carbon And InOrgAnic Fertilizer Amendments Was Established. In Parallel, Bcc Was Assessed. Through This Coupled Approach It Was Established.thAt sustaIned OrgAnic Carbon Amendment Resulted In: SignificAntly (p < 0.05) Increased Total Carbon And Total nItrogen Reservoirs In Soil, Dom PrOfiles Of greAter ChemodiversIty, And Emergence Of RecalcItrAnt Dom Moieties (H/c < 1.5). In Contrast, Carbon And nItrogen Reservoirs In Soil Subjected To sustaIned InOrgAnic Fertilizer applicAtion Were Unaltered, While Soil OrgAnic Carbon ChemodiversIty Was Observed To Shift To Less RecalcItrAnt Dom Moieties (H/c rAtio > 1.5 And O/c rAtios < 0.5). furTherMore, sustaIned OrgAnic Carbon Amendment Shaped Bcc To a eutroPh.c stAte While Long-term Chemical fertilizAtion Directed The Bcc Towards An oligotroPh.c stAte. Higher connectivIty And Network complexIty Were Observed In OrgAnic Carbon Amended Soils. Dom-Bcc Network Analysis, IndicAtIng thAt Soil Microbes Had More Interaction WIth Dom Molecules followIng sustaIned OrgAnic mAtter Input. These Results Highlight The Potential For OrgAnic Carbon Amendments To Not Only Build Soil Carbon sTocks And Increase Their Resilience, But To Also Improve The Functional stAte Of Soil Microbial communIties. Key Words: Dom, ChemodiversIty, Microbial diversIty, Ft-icr Ms
Abstract

      土壤有机碳库是陆地生态系统中最大的有机碳库,其碳含量约是大气碳库的2倍。土壤溶解性有机质( Dissolved Organic Matter DOM)是土壤碳库中最活跃的有机组分,是土壤微生物重要的物质和能量来源。 DOM的分子组成及其反应活性影响 多种 生物地球化学循环过程,对土壤肥力提升及全球碳贮存等具有 显著 影响。 因此, 近年来 DOM已成为土壤,环境和生态科学领域所关注的焦点和研究热点之一。但由于土壤 DOM组成的高度复杂性和极端异质性,以往的研究手段一直不能从分子水平上对 DOM的组成及化学多样性进行全面深入的研究。
      迄今为止,国内外关于土壤 DOM化学多样性的研究也鲜有报道,对土壤 DOM与土壤微生物间的相互作用的认识仍局限于有限的微生物类群和 预先选择的、 特定 种类 的化合物上。而目前, 超 高分辨率傅立叶变换离子回旋共振质谱( Fourier Transform Ion Cyclotron Resonance Mass Spectrometry FT-ICR MS),作为能够获得像天然 DOM一样 复杂 的 混合物中 单独化合物的详细信息的唯一方法,近年来在 DOM研究中的新兴应用,极大地促进了我们在分子水平上对土壤 DOM分子组成的了解。 本研究采用 FT-ICR MS与 16S rRNA高通量测序 技术 的结合应用,对 多种 类型 农田土壤 中 的 DOM进行 了 比较 分析, 为 我们 探索土壤 DOM和土壤微生物群落组成间的关系提供了先决条件。因此本论文的具体研究内容包括
      1) 针对我国不同土壤类型典型水稻土的溶解性有机物 DOM,利用高分辨傅里叶变换离子回旋共振质谱( FT-ICR MS)分析技术,建立了基于 FT-ICR MS的土 壤 溶 解性有机物 DOM 的分析方法 ,并 针对我国不同土壤类型水稻土 在分子水平上表征了 水稻土 DOM的分子组成特征、化学多样性及其 分子 分布规律 。进一步结合 多元统计分析方法,从分子水平上分析 了 水稻土 DOM化学多样性 的驱动机制 。
      2)在前期研究基础上,采集田间长期定位施肥处理的小麦 -玉米轮作 的旱地土壤样品,利用 FT-ICR MS与 16S rRNA高通量测序相结合的手段,表征了长期施用有机肥(污泥和鸡粪)对土壤 DOM分子组成和微生物群落组成的影响,结合网络分析,深入解析了土壤 DOM分子组成与土壤微生物群落组成间协同变化的相关关系。
论文的主要研究结果 概括 如下:
      1) 在 16个采样点的水稻土壤 DOM中共检测到 1,1361种分子并明确分配了分子式。其中, CHO类、 CHON类及 CHOS类化合物为水稻土 DOM的主要组成成分,且多氮多氧类化合物( NxOy)所占比例远高于 湖水、海洋及沉积物等其他体系 DOM。结合多元统计分析方法,评价了不同水稻土 DOM分子组成驱动因子及分子分布模式。结果显示,大尺度环境梯度下土壤 pH为水稻土 DOM分子组成的主要驱动因子,同时土壤碳氮比 C/N 和有机质结合态铁的络合度Fep/FeR 对水稻土 DOM的分子组成也具有重要影响。在土壤 pH、 C/N及 Fep/FeR的驱动下,水稻土 DOM呈现出了明显不同的分子分布模式。 即 随土壤 pH及 C/N的升高, DOM中燃烧源的稠环芳烃类化合物及维管植物源的多酚类化合物等难降解的分子组 分 显著增加 ,而在铁的络合度影响下 DOM分子组成则呈现出了相反的分布模式。借助 LEfSe分析方法,在不同 pH水稻土 DOM中共确定了 564种化学标志物分子 (chemo-marker),在低 pH pH < 5.63)水稻土 DOM中,以氨基糖类等微生物源的不稳定化合物为主,而在 pH > 5.63 的水稻土 DOM中燃烧源的稠环芳香烃类化合物等难降解的化合物为主要组 分 。随铁络合度的升高,DOM中燃烧源的稠环芳烃类化合物及维管植物源的多酚类化合物等难降解的分子组 分 显著下降,这一结果也从分子水平上证明了,在 DOM与 Fe耦合的水稻土壤中,铁主要选择性的 保留 燃烧源的多环芳香烃类化合物及维管植物源的多酚类化合物。参考微生物多样性的概念,我们发现土壤 C/N对 DOM的化学多样性指数 Chao 1的贡献率最大,随土壤 C/N升高水稻土 DOM的化学多样性增高。观察到的分子水平的分布模式表明,提高土壤 pH及 C/N,有利于增加 DOM的化学多样性,有助于土壤有机碳的贮存和稳定。高分辨率傅立叶变换离子回旋共振质谱与多元统计分析的结合应用,使得我们可以在大样本下,根据环境梯度分析 DOM的化学多样 性, 可以 更好的预测和控制 DOM在环境过程中的转换及变化规律。
      2) 利用 傅里叶变换离子旋流共振质谱 FT-ICR MS 对土壤溶解有机质 DOM的化学多样性进行了表征,研究结果表明长期施用有机肥 和无机肥料 施用 对 旱地土壤碳储量及其 DOM分子 稳定性有显著 影响。 同时, 结合应用 16S rRNA高通量测序技术对土壤微生物 群落组成 进行 评估 。通过 FT-ICR MS 和 16S rRNA高通量测序技术的结合应用,结果证明长期施用有机肥显著增加了土壤中有机碳含量,提高了土壤 DOM的化学多样性和稳定性。相反,无机肥的长期施用则导 致土壤有机碳库中稳定的惰性组分向活性组分转变,并减少了土壤中有机碳含量。长期施用有机肥提高了土壤富营养细菌类群相对丰度,而无机肥长期施用则增加了贫营养型细菌的相对丰度。无机肥与有机肥处理下土壤 DOM与微生物群落间生态学网络差异显著,有机肥处理使土壤微生物群落组成向富营养型演替,有利于土壤养分循环,提升土壤质量。

Other Abstract

      Soil organic matter (SOM) represents the largest pool of terrestrially organic carbon in the biosphere, this being more than two times the amount of carbon held in the atmosphere. DOM is the most active fraction of SOM, and as a substrate for microbial utilization, it facilitates interactions between soil microorganisms. DOM is comprised of a vast number of compounds, that they play important roles in element cycles, contribute to the storage of carbon in soil, facilitate interactions between soil organisms and support soil ecosystems. At the heart of the DOM cycle are molecular-level relationships between the individual DOM molecules and specific members of the soil microbiome that produce and consume them. Characterizing molecular chemodiversity of DOM is essential to providing a better understand of the soil environment and its ecology. However, due to the high complexity and extreme heterogeneity of DOM, previous research has not been able to provide comprehensive characterization DOM and its chemical diversity. To date, few studies have reported on soil DOM chemodiversity, and understanding of microbe-DOM interactions has been biased toward oversimplified experiments that make use of only a limited number of DOM compounds.
      Electrospray ionization (ESI) coupled with Fourier-Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR-MS) currently stands apart as the only method through which to obtain detailed information regarding individual compounds in complex mixtures, such as DOM. Though the application of (FT-ICR MS) this present study provides novel insights into the molecular composition and chemodiversity of DOM in soils. Also assessed the bacterial community composition (BCC) in soils via 16S rRNA gene-tag sequencing. Network analysis has been used to decipher the associations between DOM molecules, bacterial species and environmental variables.
      This thesis reports:
      1) The application of FT-ICR MS to unambiguously resolve 11,361 molecular formulae in 16 paddy soils; thereby elucidating the molecular characteristics of paddy soil DOM. Soil pH, iron complexing index (Fep/FeR) and C/N ratio were established to be key factors controlling DOM profiles. Polycyclic aromatics (derived from combustion) and polyphenols (derived from plants) increased with increasing soil pH, while polyphenols molecules, pyrogenic aromatics and carboxylic compounds decreased with increasing iron complexing index. Patterns in molecular profiles indicated DOM in paddy soils to become more recalcitrant at higher soil C/N ratio and higher soil pH. Furthermore, plant-derived polyphenols and pyrogenic DOM were retained favorably by iron and the chemodiversity of DOM in paddy soil increased with increasing soil C/N ratios. These results provide novel information regarding DOM characteristics at a molecular level and will inform better global management of soil carbon in paddy soil ecosystems global.
      2) Through the application of FT-ICR-MS, the chemodiversity of DOM in soil subjected to long-term organic carbon and inorganic fertilizer amendments was established. In parallel, BCC was assessed. Through this coupled approach it was established that sustained organic carbon amendment resulted in: significantly (P < 0.05) increased total carbon and total nitrogen reservoirs in soil, DOM profiles of greater chemodiversity, and emergence of recalcitrant DOM moieties (H/C < 1.5). In contrast, carbon and nitrogen reservoirs in soil subjected to sustained inorganic fertilizer application were unaltered, while soil organic carbon chemodiversity was observed to shift to less recalcitrant DOM moieties (H/C ratio > 1.5 and O/C ratios < 0.5). Furthermore, sustained organic carbon amendment shaped BCC to a eutrophic state while long-term chemical fertilization directed the BCC towards an oligotrophic state. Higher connectivity and network complexity were observed in organic carbon amended soils. DOM-BCC network analysis, indicating that soil microbes had more interaction with DOM molecules following sustained organic matter input. These results highlight the potential for organic carbon amendments to not only build soil carbon stocks and increase their resilience, but to also improve the functional state of soil microbial communities.

Pages121
Language中文
Document Type学位论文
Identifierhttp://ir.rcees.ac.cn/handle/311016/42240
Collection土壤环境科学实验室
Recommended Citation
GB/T 7714
李晓明. 基于高分辨质谱的土壤溶解性有机质化学多样性研究[D]. 北京. 中国科学院生态环境研究中心,2018.
Files in This Item:
File Name/Size DocType Version Access License
李晓明-基于高分辨质谱的土壤溶解性有机质(3887KB)学位论文 开放获取CC BY-NC-SAApplication Full Text
Related Services
Recommend this item
Bookmark
Usage statistics
Export to Endnote
Google Scholar
Similar articles in Google Scholar
[李晓明]'s Articles
Baidu academic
Similar articles in Baidu academic
[李晓明]'s Articles
Bing Scholar
Similar articles in Bing Scholar
[李晓明]'s Articles
Terms of Use
No data!
Social Bookmark/Share
All comments (0)
No comment.
 

Items in the repository are protected by copyright, with all rights reserved, unless otherwise indicated.