發(fā)布時(shí)間：2023-02-09 13:17

　　增加玉米的種植密度是提高其籽粒產(chǎn)量的最有效農(nóng)藝方法之一。然而,增加種植密度會(huì)引起作物植株高度的增加和莖稈直徑減小,從而增加了植株的倒伏風(fēng)險(xiǎn),這對作物產(chǎn)量有著不利的影響。倒伏是制約玉米籽粒產(chǎn)量的重要因素,它不僅降低了玉米產(chǎn)量,而且降低了籽粒的質(zhì)量。在半干旱地區(qū),除倒伏因素外,水分供應(yīng)不足也是導(dǎo)致玉米產(chǎn)量低下的另一個(gè)原因。應(yīng)用植物生長調(diào)節(jié)劑的是一種有效的作物生長調(diào)控措施,它可以調(diào)節(jié)作物冠層結(jié)構(gòu)、優(yōu)化種植密度、提高作物對非生物脅迫的耐受性、改善作物的抗倒伏能力和提高作物籽粒產(chǎn)量。因此,本研究通過大田試驗(yàn),擬闡明兩種植物生長調(diào)節(jié)劑“多效唑”和“縮節(jié)胺”處理種子對株高、莖稈機(jī)械強(qiáng)度、木質(zhì)素含量及高密度下玉米抗倒伏性能的影響機(jī)制;研究多效唑浸種和拌種兩種方法對半干旱地區(qū)玉米根系的形態(tài)和生理特性、葉綠素含量、光合能力,葉綠素?zé)晒夥磻?yīng)和抗氧化酶的活性的影響,并分析它們與玉米籽粒產(chǎn)量的相互關(guān)系。最終通過生長調(diào)節(jié)劑處理降低高密度種植玉米的倒伏率,同時(shí)提高作物對水分虧缺的耐受性,達(dá)到增加玉米產(chǎn)量的目標(biāo)。研究設(shè)置多效唑0、200、300、400 mg L^-1四個(gè)浸種濃度,和0、1.5、2...

【文章頁數(shù)】：154 頁

【學(xué)位級別】：博士

【文章目錄】：
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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