多效唑和缩节胺对玉米根系生长、光合特性、抗倒伏性和产量的影响

发布时间：2023-02-09 13:17

　　增加玉米的种植密度是提高其籽粒产量的最有效农艺方法之一。然而,增加种植密度会引起作物植株高度的增加和茎秆直径减小,从而增加了植株的倒伏风险,这对作物产量有着不利的影响。倒伏是制约玉米籽粒产量的重要因素,它不仅降低了玉米产量,而且降低了籽粒的质量。在半干旱地区,除倒伏因素外,水分供应不足也是导致玉米产量低下的另一个原因。应用植物生长调节剂的是一种有效的作物生长调控措施,它可以调节作物冠层结构、优化种植密度、提高作物对非生物胁迫的耐受性、改善作物的抗倒伏能力和提高作物籽粒产量。因此,本研究通过大田试验,拟阐明两种植物生长调节剂“多效唑”和“缩节胺”处理种子对株高、茎秆机械强度、木质素含量及高密度下玉米抗倒伏性能的影响机制;研究多效唑浸种和拌种两种方法对半干旱地区玉米根系的形态和生理特性、叶绿素含量、光合能力,叶绿素荧光反应和抗氧化酶的活性的影响,并分析它们与玉米籽粒产量的相互关系。最终通过生长调节剂处理降低高密度种植玉米的倒伏率,同时提高作物对水分亏缺的耐受性,达到增加玉米产量的目标。研究设置多效唑0、200、300、400 mg L^-1四个浸种浓度,和0、1.5、2...

【文章页数】：154 页

【学位级别】：博士

【文章目录】：
ABSTRACT
摘要
CHAPTER 1 REVIEW OF LITERATURE
    1.1 An introduction to global maize production and its importance
    1.2 Plant growth regulators (PGRs)
        1.2.1 Plant growth retardants and their mode of action
        1.2.2 Gibberellins
        1.2.3 Paclobutrazol (PBZ)
        1.2.4 Mepiquat chloride (MC)
    1.3 The application methods for growth regulators
        1.3.1 Soil Drenching
        1.3.2 Foliar Spray
        1.3.3 Seed Treatment
    1.4 Agricultural importance of PGRs
        1.4.1 Effect of PGRs on root growth characteristics
        1.4.2 Effect of PGRs on plant above ground morphological characteristics
        1.4.3 Effect of PGRs on chlorophyll pigments and photosynthesis
        1.4.4 Efficacy of PGRs in lodging resistance of crops
        1.4.5 Efficacy of PGRs on antioxidants and their role as stress protectants
        1.4.6 Effect of growth retardants on yield attributes
    1.5 Objectives of the Research
Chapter 2 Materials and Methods
    2.1 Site Description
    2.2 Experimental design and crop management
    2.3 Sampling and Measurement
        2.3.1 Root length, volume, area, and diameter
        2.3.2 Root length density (RLD)
        2.3.3 Root surface area density (RSD)
        2.3.4 Root dry biomass
        2.3.5 Root weight density (RWD)
        2.3.6 Determination of root activity
        2.3.7 Collection of root-bleeding sap
        2.3.8 Above ground dry biomass
        2.3.9 Plant height, ear height, and center of gravity height
        2.3.10 Internode length, diameter and wall thickness
        2.3.11 Stalk breaking strength (BS) and rind penetration strength (RPS)
        2.3.12 Dry weight per unit length (DWUL)
        2.3.13 Determination lignin content
        2.3.14 Lignin-related enzymatic activities
        2.3.15 Measurement of lodging rate
        2.3.16 Measurement of leaf area
        2.3.17 Determination of chlorophyll contents
        2.3.18 Leaf gas exchange parameters
        2.3.19 Chlorophyll fluorescence parameters
        2.3.20 Determination of antioxidants activities and soluble protein content
        2.3.21 Determination of malondialdehyde (MDA)
        2.3.22 Measurement of proline contents
        2.3.23 Ear characteristics and grain yield
    2.4 Statistical analysis
CHAPTER 3 EFFECT OF PACLOBUTRAZOL ON ROOT GROWTH CHARACTERISTICS AND GRAIN YIELD OF MAIZE UNDER A SEMI-ARID REGION
    3.1 Root activity and root-bleeding sap flow
    3.2 Root diameter
    3.3 Root dry weight
    3.4 Root/shoot ratio
    3.5 Root weight density (RWD)
    3.6 Root length density (RLD)
    3.7 Root surface area density (RSD)
    3.8 Ear characteristics and grain yield
    3.9 Correlation analysis of root characteristics and grain yield
    3.10 Discussion
        3.10.1 Effect of paclobutrazol on root growth and distribution
        3.10.2 Effect of paclobutrazol on ear characteristics and grain yield of maize
    3.11 Conclusion
CHAPTER 4 EFFECT OF PACLOBUTRAZOL ON LODGING RESISTANCE OF MAIZE BY REGULATING STEM MECHANICAL STRENGTH, AND LIGNIN ACCUMULATION
    4.1 Morphological characteristics of the basal third internode
    4.2 Plant height, ear height, and center of gravity height
    4.3 Rind penetration strength, stalk breaking strength and dry weight per unit length
    4.4 Enzymes activities
    4.5 Lignin accumulation
    4.6 Lodging percentage and grain yield
    4.7 Correlation analysis of lignin, related enzymes, lodging rate, plant height, stalk breaking strength and various morphological characteristics of stem
    4.8 Discussion
    4.9 Conclusion
CHAPTER 5 PACLOBUTRAZOL IMPROVES MAIZE GRAIN YIELD BY REGULATING PHOTOSYNTHETIC CAPACITY AND ANTIOXIDANTS UNDER A SEMI-ARID REGION
    5.1 Photosynthetic pigments
    5.2 Gas exchange parameters
    5.3 Leaf chlorophyll fluorescence
    5.4 Leaf area
    5.5 Antioxidant enzyme activity
    5.6 Malondialdehyde (MDA) content
    5.7 Soluble protein and proline content
    5.8 Ear length and diameter
    5.9 Yield and yield components
    5.10 Discussion
    5.11 Conclusion
CHAPTER 6 MEPIQUAT CHLORIDE INCREASES LODGING RESISTANCE OF MAIZE BY ENHANCING STEM PHYSICAL STRENGTH AND LIGNIN BIOSYNTHESIS
    6.1 Grain yield and lodging rate
    6.2 Plant, ear and gravity center height
    6.3 Stalk morphological traits
    6.4 Stalk bending strength (BS) and rind puncture strength (RPS)
    6.5 Lignin-related enzymes activities
    6.6 Lignin accumulation
    6.7 Correlation analysis among physical strength of stem, lodging percentage, and lignin content
    6.8 Discussion
    6.9 Conclusion
CHAPTER 7 SUMMARY AND MAIN CONCLUSIONS
REFERENCES
ACKNOWLEDGEMENT
RESEARCH PUBLICATIONS



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