在世界范圍內(nèi)磷(P)是限制作物生長的主要因素之一,因為土壤中大部分磷生物有效性低。鉬是存在于土壤中的一種微量元素,同時也是是微生物和植物生長所必需的微量元素。磷與鉬在植物體內(nèi)存在協(xié)同效應(yīng)。然而,鉬介導(dǎo)的不同作物根際磷素動態(tài)變化及轉(zhuǎn)化特征尚沒有系統(tǒng)研究,本文利用長期定位試驗研究了在豆科作物和非豆科作物系統(tǒng)中,鉬對作物根際土壤微生物群落結(jié)構(gòu)、根際代謝物及土壤磷轉(zhuǎn)化特征的影響。(1)16S r RNA測序結(jié)果表明鉬在不同分類水平上影響土壤微生物的多樣性及其組成。與不施鉬處理相比,無論是在大豆還是玉米根際土壤中,施鉬均增加了變形菌門(Proteobacteria)和酸桿菌門(Acidobacteria)所占的比例。在大豆根際土壤中,2個細(xì)菌門(變形菌門和酸桿菌門)在缺鉬和施鉬處理所占比例之和分別為39.43%和57.74%,而在玉米根際土壤中,2個細(xì)菌門所占比例之和在缺鉬和施鉬處理分別為44.51%和46.64%。在綱(class)水平上,大豆根際土壤缺鉬與施鉬處理在酸桿菌、放線桿菌、變形桿菌、氯氟萊西菌、酸桿菌DA052、假絲酵母菌科瑞氏桿菌、羅氏桿菌、開氏桿菌等綱的豐度上存在顯著差異,而在玉...

【文章頁數(shù)】：163 頁

【學(xué)位級別】：博士

【文章目錄】：
摘要
ABSTRACT
LIST OF ABBREVIATIONS
CHAPTER1:RESEARCH BACKGROUND AND OBJECTIVES
    1.1 RESEARCH BACKGROUND:
    1.2 WHAT MAKES P SO SPECIAL
        1.2.1 The forms,mobility and transformations of soil P
        1.2.2 Applied chemical P fertilizer in Soil
    1.3 MECHANISMS OF NUTRIENT ACQUISITION BY PLANT ROOTS
        1.3.1 Phosphorus availability and uptake
    1.4 MECHANISMS OF P MOBILIZATION BY SOIL MICROORGANISMS
        1.4.1 Phosphatase activity and the potential for accessing soil organic phosphorus
        1.4.2 Solubilization of inorganic P
        1.4.3 Accumulation and turnover of microbial biomass P
    1.5 RHIZOSPHERE INTERACTIONS
        1.5.1 P dynamics in the rhizosphere
        1.5.2 Root Architecture
        1.5.3 Can the release of organic anions from roots mobilise soil phosphorus?
    1.6 MOLYBDENUM AS AN ESSENTIAL MICROELEMENT
        1.6.1 Identification of molybdenum as an essential plant element
        1.6.2 The role of molybdenum in agricultural plant production
        1.6.3 Importance of molybdenum in agricultural crop plants
        1.6.4 Importance of molybdenum in leaf ultra-structure
        1.6.5 Availability of molybdenum in agricultural soils
    1.7 MOLYBDENUM AND PHOSPHORUS INTERACTION
    1.8 RESEARCH OBJECTIVES
CHAPTER2:16S RRNA GENE-BASED PYROSEQUENCING REVEALED THE EFFECT OF MOLYBDENUM ON MICROBIAL COMMUNITY STRUCTURAL COMPOSITION IN MAIZE AND SOYBEAN
    2.1 INTRODUCTION
    2.2 MATERIALS AND METHODS
        2.2.1 Experimental materials and treatment
        2.2.2 Sample collection
        2.2.3 Plant analysis
        2.2.4 Determination of soil chemical properties
        2.2.5 Bacterial community analysis
        2.2.6 Statistical analysis
    2.3 RESULTS
        2.3.1 Response of soil characteristics,crop nutrients acquisition and accumulation
        2.3.2 Species richness and bacterial community diversity
        2.3.3 Bacterial community structure
    2.4 DISCUSSION
    2.5 CONCLUSION
CHAPTER3:MOLYBDENUM-INDUCED EFFECTS ON METABOLITES VARIATIONS IN SOIL OF MAIZE AND SOYBEAN INCLUDING THE COMPREHENSIVE ALTERATIONS COMPARISON WITHIN THE CROPS
    3.1 INTRODUCTION
    3.2 MATERIALS AND METHOD
        3.2.1 Experimental materials and treatment
        3.2.2 Sample collection
        3.2.3 Metabolomics Analysis
    3.3 RESULTS
        3.3.1 Visual analysis of original chromatogram
        3.3.2 Analysis of PLS-DA and supervised OPLS-DA
        3.3.3 Metabolic changes in response NPK and NPKMO
    3.4 DISCUSSION
    3.5 CONCLUSION
CHAPTER4:MOLYBDENUM INDUCED CHANGES ON RHIZOSPHERE AND NON-RHIZOSPHERE SOIL PHOSPHORUS TRANSFORMATION CHARACTERISTICS AND BIOAVAILABILITY IN LEGUMINOUS AND NON-LEGUMINOUS CROPPING SYSTEMS
    4.1 INTRODUCTION
    4.2 MATERIALS AND METHOD
        4.2.1 Experimental materials and treatment
        4.2.2 Sample collection
        4.2.3 Soil chemical analysis
        4.2.4 Soil P-enzymes activity
        4.2.5 Total RNA extraction and quantitative RT-PCR
    4.3 RESULTS
        4.3.1 Changes in p H,soil organic matter(SOM)and available molybdenum in response of molybdenum application
        4.3.2 Molybdenum application enhanced the soil microbial phosphorus(SMP)
        4.3.3 Phosphorus fractionation as effected by molybdenum application
        4.3.4 Soil P enzymes activities
        4.3.5 Mo supply regulated the expression of pho N,pho C,pho D and BPP genes transcripts
    4.4.DISCUSSION
    4.5 CONCLUSION
CHAPTER5:MO SUPPLY INCREASED BIOMASS AND GRAIN YIELD THROUGH ENHANCING P,MO UPTAKE,ASSIMILATION AND BY INDUCED EFFECT IN LEAF ULTRA-STRUCTURES
    5.1 INTRODUCTION
    5.2 MATERIALS AND METHOD
        5.2.1 Experimental materials and treatment
        5.2.2 Sample collection
        5.2.3 Plant analysis
        5.2.4 Scanning electron microscopy(SEM)analysis
        5.2.5 Transmission electron microscopy(TEM)analysis
    5.3 RESULTS
        5.3.1 Effect of molybdenum on biomass yield and yield components of non-leguminous and leguminous crops
        5.3.2 Impact of Molybdenum(Mo)application on Phosphorus(P)and Mo acquisition
        5.3.3 Mo supply altered the leaf anatomy and chloroplast morphology configuration
    5.4 DISCUSSION
    5.5 Conclusion
CHAPTER6:CONCLUSIONS AND FUTURE DIRECTIONS
    6.1 MAIN CONCLUSIONS
        6.1.1 Molybdenum application complementary effect toward the biomass yield and yield components
        6.1.2 Extent of Mo fertilizer effect on crop nutrients acquisition and accumulation in different parts
        6.1.3 Molybdenum fertilizer improved the soil chemical properties
        6.1.4 Microbial community structural composition is affected by Mo supply revealed by pyrosequencing analysis
        6.1.5 Molybdenum-induced effects on metabolites variations in comparison within the treatment and between the maize and soybean
        6.1.6 Molybdenum induced changes on rhizosphere and non-rhizosphere soil P fractionation
        6.1.7 Mo application increased the soil P enzymes activities and expressions of these enzymes
        6.1.8 Mo supply increased the microbial biomass P
        6.1.9 Mo application also has positive effect on leaf ultrastructure
    6.2 FUTURE DIRECTIONS
REFERENCES
SCIENTIFIC CONTRIBUTION
ACKNOWLEDGEMENT



本文編號：4012541