氮肥影响水稻农艺性状、秸秆细胞壁成分及生物质酶解效率分子机理研究

发布时间：2021-05-15 15:34

　　水稻是中国最主要的粮食作物之一,每年可生产大量秸秆材料,为生物能源和生物质产品的生产提供充足原料。植物细胞壁主要由纤维素,半纤维素和木质素组成,对植物形态发育、碳水化合成代谢和对外部环境应答等起着非常重要作用。植物生物质和组成受到环境因素如光照、水和土壤营养影响。在土壤营养中氮肥是最常见的肥料用来促进农作物生长、发育和提高种子产量。氮元素是植物正常生长的必需元素,是植物体内蛋白质和叶绿素的主要组分,因此会影响作物的生长和产量。尽管业已证明氮肥可以提高水稻种子和秸秆生物质产量,但对水稻秸秆细胞壁组分和生物质降解效率的影响尚未报导。本研究对两个水稻栽培品种施加了7种氮肥处理,观察了主要农艺性状,测定了秸秆细胞壁组成与结构,并分析了不同预处理条件下生物质酶解产糖效率和乙醇产量。对比实验发现,两个水稻品种在施加了7种氮肥处理后,其种子和秸秆生物质产量相对于空白对照都有大幅度提高。同时,氮肥处理后秸秆细胞壁中的纤维素含量大幅提高,硅元素含量显著降低,而在不同浓度氮肥处理材料间的半纤维素和木质素的相对含量存在差异。在不同酸碱预处理（Na OH,Ca O,H2SO4）和物理预处理（热水）条件下,施加... 

【文章来源】：华中农业大学湖北省 211工程院校 教育部直属院校

【文章页数】：117 页

【学位级别】：博士

【文章目录】：
摘要
Abstract
Abbreviations
1 Introduction
    1.1 Lignocellulosic biomass
    1.2 Major problems in biomass conversion to ethanol
        1.2.1 Harvesting and storage
        1.2.2 Biomass pretreatment
        1.2.3 Cellulase cost
        1.2.4 Ethanol fermentation
    1.3 Plant cell wall composition
        1.3.1 Cellulose
        1.3.2 Hemicelluloses
        1.3.3 Lignin
        1.3.4 Other compounds: pectins, silica and proteins
    1.4 Plant cell wall features
        1.4.1 Cellulose crystallinity
        1.4.2 Degree of polymerization (DP)
        1.4.3 Hemicellulose monosaccharide (Xyl/Ara)
        1.4.4 Lignin monomer (H,G,S)
    1.5 Pretreatment of lignocellulosic materials
        1.5.1 Physical pretreatments
        1.5.2 Chemical pretreatments
    1.6 Enzymatic hydrolysis of Lignocellulose
    1.7 Bioethanol fermentation
    1.8 Role of nitrogen in plant nutrition
    1.9 Effects of timing of nitrogen fertilizer application on crop production
    1.10 Nitrogen fertilizer effects on rice crop in china
    1.11 Effects of nitrogen fertilizer on cell wall composition
    1.12 Effects of nitrogen fertilizer on biomass digestibility
    1.13 Effects of nitrogen fertilizer on cellulosic ethanol production
    1.14 Objectives of this study
2 Materials and Methods
    2.1 Materials
    2.2 The main instruments and reagents
    2.3 Methods
        2.3.1 Agronomic data collection and measurements;
        2.3.2 Extraction and determination of cell wall polysaccharides
        2.3.3 Lignin determination process
        2.3.4 Colorimetric determination of hexose and pentose
        2.3.5 Measurement of silica content;
        2.3.6 Lignin monomer determination by HPLC
        2.3.7 Hemicelluloses monosaccharide determination by GC-MS
        2.3.8 Determination of cellulose crystallinity
        2.3.9 Determination of the cellulose degree of polymerization (DP)
        2.3.10 Biomass pretreatment and enzymatic hydrolysis
        2.3.11 Determination of ethanol production
        2.3.12 Statistical Analysis
3 Results
    3.1 Improved agronomic traits under nitrogen treatments
    3.2 Linear regression of total nitrogen with agronomic traits
    3.3 Biomass production and agronomic traits
    3.4 Effect of nitrogen fertilizer on cell wall composition and silica content in rice straw
    3.5 Linear regression of total nitrogen with cell wall composition and silica content
    3.6 Nitrogen fertilizer effects on cell wall features
    3.7 Effects of nitrogen fertilizer on cellulose crystallinity and polymerization degree
    3.8 Plant cell wall polymer and features affecting biomass production
    3.9 Biomass digestibility increased under nitrogen treatment
    3.10 Silica content and cellulose crystallinity affect biomass digestibility
    3.11 Ethanol production under nitrogen fertilizer
    3.12 Mechanism of nitrogen fertilizer enhancements on biomass saccharification
4 Discussions
5 Conclusion
6 Summary and future prospects
    6.1 Summary
    6.2 Future Prospects
References
Appendix 1. The reagent formulation
Appendix 2. Standard curve
Appendix 3. Profile
Acknowledgement



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