棉花是世界上最重要的纖維作物。中國在世界棉花生產中居領先地位,而湖北是中國產棉大省之一。然而盡管推廣了高產品種,采用了育苗移栽這種高投入生產模式,但近年來該地區(qū)棉花單產仍然停滯不前。因此,棉花生產面積因利潤低下而逐漸減小。為了提高農民的植棉收入,已經探索出一種新型高效種植模式,其特點是生長期短、晚播、直播、高密和減少氮肥、且一次施肥,而不影響棉花產量。但是,這種新的棉花種植模式,是否也需要較高的鉀氮比例?為此,我們于2016-2017年,在中國武漢華中農業(yè)大學試驗農場(北緯30°37′,東經114°21′,海拔23米)進行了大田試驗。完全隨機區(qū)組設計,品種為華棉3109(Gossypium hirsutumn L.)。試驗設置3個鉀氮比例(施鉀量)[K08{K(K₂O):N=0.8:1(168:210 kg ha^-1)},K10{K(K₂O):N=1:1(210:210 kg ha^-1)}和K12{K(K₂O):N=1.2:1(252:210 kg ha^-1

【文章頁數(shù)】：141 頁

【學位級別】：博士

【文章目錄】：
ABSTRACT
摘要
LIST OF ABBREVIATIONS
CHAPTER 1 LITERATURE REVIEW
    1.1 Cotton production in China
        1.1.1 Challenges in cotton production in China
        1.1.2 Possible solutions
    1.2 Potassium
        1.2.1 Potassium scenario in the world
        1.2.2 Potassium significance for plants and cotton production
        1.2.3 Potassium-nitrogen ratio in relation to plant photosynthesis
            1.2.3.1 Plants photosynthesis
            1.2.3.2 Stomatal regulation
            1.2.3.3 Rubisco activity
            1.2.3.4 Assimilate transport
        1.2.4 Potassium-nitrogen ratio in relation to carbohydrate metabolism
            1.2.4.1 Enzyme synthesis and activation
            1.2.4.2 Carbohydrate metabolic enzymes
            1.2.4.3 Sucrose phosphate synthase
            1.2.4.4 Sucrose synthase
            1.2.4.5 SAI and G6PDH
            1.2.4.6 Carbohydrate contents
        1.2.5 Potassium-nitrogen ratio in relation to plant stress mitigation
            1.2.5.1 Osmotic adjustments
            1.2.5.2 Drought stress alleviation
            1.2.5.3 Salt stress mitigation
    1.3 Significance and perspectives of the study
        1.3.1 Significance
        1.3.2 Objectives
        1.3.3 The road map
CHAPTER 2 EFFECTS OF POTASSIUM-NITROGEN RATIO ON PHOTOSYNTHESIS IN COTTON MAIN STEM LEAVES
    2.1 Introduction
    2.2 Materials and Methods
        2.2.1 Climatic conditions
        2.2.2 Experimental area,soil characteristics and cultivar
        2.2.3 Experimental design,treatments and crop management
        2.2.4 Photosynthesis measurements
            2.2.4.1 Photosynthetic attributes at varied light intensities
            2.2.4.2 Photosynthetic attributes of the leaves at different nodes
            2.2.4.3 Diurnal dynamics of photosynthetic attributes of functional leaves
        2.2.5 Chlorophyll parameters
            2.2.5.1 Chlorophyll fluorescence
            2.2.5.2 Chlorophyll contents(SPAD values)
        2.2.6 Cotton yield attributes
        2.2.7 Statistical analysis
    2.3 Results
        2.3.1 Cotton yield attributes
        2.3.2 Photosynthetic parameters
            2.3.2.1 Photosynthetic attributes at varied light intensities
            2.3.2.2 Diurnal dynamics of photosynthetic attributes of functional leaves
            2.3.2.3 Photosynthetic attributes of all main stem leaves
        2.3.3 Chlorophyll parameters
            2.3.3.1 Chlorophyll fluorescence of 4^th leaf
            2.3.3.2 SPAD values of 4^th leaf
        2.3.4 Relationship of photosynthetic attributes,chlorophyll parameters cotton yield
    2.4 Discussion
    2.5 Conclusion
CHAPTER 3 EFFECTS OF POTASSIUM TO NITROGEN RATIO ON PHOTOSYNTHETIC ATTRIBUTES AND SUCROSE METABOLISM IN COTTON SUBTENDING LEAVES
    3.1 Introduction
    3.2 Materials and Methods
        3.2.1 Climatic conditions
        3.2.2 Experimental area,soil characteristics and cultivar
        3.2.3 Experimental design,treatments,and crop management
        3.2.4 Leaf growth attributes
        3.2.5 Photosynthetic attributes
            3.2.5.1 Photosynthesis measurements
        3.2.6 Chlorophyll fluorescence
            3.2.6.1 Sampling
            3.2.6.2 Measurement of chlorophyll fluorescence attributes
        3.2.7 Determination of chlorophyll and ATP contents,and enzymatic activity
            3.2.7.1 Chlorophyll(a,b)contents
            3.2.7.2 Total Rubisco activity and ATP contents
        3.2.8 Leaf carbohydrate analysis
            3.2.8.1 Extraction
            3.2.8.2 Measurement
            3.2.8.3 Extraction and analysis of carbohydrate metabolic enzymes
        3.2.9 Statistical analysis
    3.3 Results
        3.3.1 Leaf growth attributes
        3.3.2 Photosynthetic attributes
        3.3.3 Chlorophyll fluorescence
        3.3.4 Chlorophyll contents
        3.3.5 Total Rubisco activity and ATP contents
        3.3.6 Changes in carbohydrate contents
        3.3.7 Changes in sucrose metabolizing enzymes activity and their relationship with sucrose contents in subtending leaves
        3.3.8 Relationship among Pn,sucrose metabolizing enzymes,sucrose content in subtending leaf and cotton yield
        3.3.9 Correlation coefficients between the source and sink indices
    3.4 Discussion
    3.5 Conclusion
CHAPTER 4 DISCUSSION AND CONCLUSION
    4.1 Discussion
        4.1.1 Potassium-nitrogen ratio in relation to photosynthesis
        4.1.2 Potassium-nitrogen ratio in relation to carbohydrate metabolism
        4.1.3 Photosynthesis in relation to cotton yield formation
        4.1.4 Carbohydrate metabolism in relation to cotton yield formation
        4.1.5 Comparison between photosynthetic attributes of main stem leaf at the 6^th node from the top and its corresponding first fruiting branch leaf at the same node
        4.1.6 A possible mutual action of photosynthesis and carbohydrate metabolism on cotton yield formation
            4.1.6.1 Relationship of photosynthetic attributes of 4^th main stem leaf and cotton yield
            4.1.6.2 The relationship amongst Pn,sucrose metabolism in subtending leaves and yield
            4.1.6.3 Correlation coefficients between the source(subtending leaf)and sink indices
    4.2 Conclusion
    4.3 Innovations
    4.4 Perspective for further work
REFERENCES
SUPPLEMENTARY
    List of Publications
ACKNOWLEDGMENTS



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