鎘(Cd)作為可致癌金屬,是環(huán)境中廣泛存在的有毒重金屬之一。由于土壤中的Cd污染而引起的環(huán)境問題日益嚴重,因此鼓勵采取公共衛(wèi)生防治措施極為重要。甘藍型油菜(Brassica napus L.)因與Cd超富集物種在某些特征上具有相似性,被認為是修復Cd污染土壤的最佳選擇之一。然而Cd在營養(yǎng)和生殖階段的解毒機理尚未完全闡明,盡管這是使該作物易于應用于植物修復技術的前提。本研究采用短期(水培)和長期(土培)的方法,旨在探究耐鎘甘藍型油菜中質(zhì)外體和共質(zhì)體對Cd積累耐性的反應機理,并著重于代謝組的分析,同時分析了鎘對植物生殖適應性的影響。實驗結(jié)果如下:(1)為了篩選Cd耐受性的油菜材料,本研究利用102個不同遺傳背景的甘藍型油菜材料,經(jīng)過兩次篩選,測試了代表不同Cd耐性范圍的11個基因型的根和芽中Cd積累和轉(zhuǎn)運。發(fā)現(xiàn)Cd抗性和積累的顯著變化,并鑒定出兩個耐高Cd積累的基因型(CB671和HL672)。巧合的是,這兩個基因型是白花油菜的基因型,命名為“高鎘基因型”。在102個被篩選的基因型中,只有兩個具有Cd-超積累的表現(xiàn),這表明該表型在甘藍型油菜中很少發(fā)生。因此,這些材料(高鎘基因型)成為后續(xù)研...

【文章頁數(shù)】：159 頁

【學位級別】：博士

【文章目錄】：
Acknowledgements
List of abbreviations
Abstract
摘要
CHAPTER1.General Introduction and Literature Review
    1.1.Cadmium occurrence in the environment
        1.1.1.Worldwide occurrence of cadmium
        1.1.2.Cadmium-soil contamination in China
    1.2.Environmental issues of cadmium exposure
        1.2.1.Cadmium phytotoxicity effects
        1.2.2 Cadmium and human health risks
    1.3.Brassica napus,a tool for sustainable management of Cd-contaminated soils
    1.4.Current state of knowledge on Cd adaptive responses in Brassica napus
    1.5.Research objectives
    1.6.Outline of the study
CHAPTER2.Intraspecific variability of cadmium accumulation,subcellular distribution and chemical forms in Brassica napus
    2.1.Introduction
    2.2.Materials and methods
        2.2.1.Plant material and experimental conditions
        2.2.2.Determination of cadmium content
        2.2.3.Plant tissues fractionation and metal analysis
        2.2.4.Analysis of metal chemical forms
        2.2.5.Statistical analysis
    2.3.Results
        2.3.1.Variation in cadmium-induced changes in plant biomass,and trend of metal accumulation
        2.3.2.Metal subcellular distribution
        2.3.3.Metal chemical forms
    2.4.Discussion
    2.5.Conclusion
CHAPTER3.Cadmium detoxification in high Cd-accumulating Brassica napus genotypes involves changes in cell wall compositional profiles
    3.1.Introduction
    3.2.Materials and methods
        3.2.1.Plant material and experimental conditions
        3.2.2.Cell wall extraction and polysaccharides fractionation
        3.2.3.Measurement of uronic acid and total sugar in fractionated cell wall polysaccharides
        3.2.4.Quantification of different fractions of pectin and estimation of its methyl-esterification degree
        3.2.5.Determination of Cd contents in fractionated cell wall polysaccharides
        3.2.6.Measurement of ascorbic acid content
        3.2.7.Processing of cell wall-related RNA-seq data
            3.2.7.1.Total RNA extraction,reliability assessment and RNA-sequence analyses
            3.2.7.2.Verification of RNA-Seq data by qRT-PCR assay
        3.2.8.Statistical analysis
    3.3.Results
        3.3.1.Cd-induced remodelling of cell wall polysaccharides among B.napus genotypes
        3.3.2.Relative contribution of different cell wall sub-fractions to Cd immobilization
        3.3.3.Cadmium influence on transcriptional regulation of pectin and hemicellulose biosynthesis
        3.3.4.Pectin as possible substrat for ascorbic acid production in leaves
    3.4.Discussion
    3.5.Conclusion
CHAPTER4.Comparative metabolomic responses of low-and high-cadmium accumulating genotypes reveal the Cd adaptive mechanism in Brassica napus
    4.1.Introduction
    4.2.Materials and methods
        4.2.1.Plant material and experimental conditions
        4.2.2.Metabolomic analysis
            4.2.2.1.Metabolites extraction and liquid chromatography-mass spectrometry
            4.2.2.2.Data processing
        4.2.3.Analysis of other physio-biochemical endpoints
            4.2.3.1.Assessment of Cd accumulation in plant tissues
            4.2.3.2.Transmission electron microscopy,scanning electron microscopy and chlorophyll fluorescence imaging
            4.2.3.3.Determination of phenolic contents and total antioxidant capacity
            4.2.3.4.Total RNA extraction,cDNA synthesis,and qRT-PCR assay
        4.2.4.Statistical analyses
    4.3.Results
        4.3.1.Genotypic variation of responses to cadmium stress
        4.3.2.General metabolomic changes in the two genotypes following Cd stress
        4.3.3.Profiling of metabolites specifically regulated in either genotype under Cd stress
            4.3.3.1.Metabolomic signature in plant primary metabolism
            4.3.3.2.Metabolomic signature in plant secondary metabolism
    4.4.Discussion
    4.5.Conclusion
CHAPTER5.Cadmium-induced reproductive repercussions in two Brassica napus genotypes supplemented with serotonin,and glimpses into potential adaptive mechanisms
    5.1.Introduction
    5.2.Materials and methods
        5.2.1.Plant material and experimental conditions
        5.2.2.Data collection and samples preparation for analysis
        5.2.3.Elements analysis in different plant parts
        5.2.4.Seed oil content determination
        5.2.5.Seed transmission electron microscopy
        5.2.6.Evaluation of pollen grain viability and cross-pollination experiments
        5.2.7.Measurement of other physio-biochemical end points
            5.2.7.1.Determination of indices of oxidative stress
            5.2.7.2.Photosynthetic parameters
            5.2.7.3.Determination of antioxidant enzymes
            5.2.7.4.Thiol compounds assays
            5.2.7.5.Assays of activities of sulfur assimilation enzymes
            5.2.7.6.Measurement of phenolic contents
        5.2.8.Data analysis
    5.3.Results
        5.3.1.Gross effets of long term cadmium exposure
        5.3.2.Trend of cadmium accumulation in plant and related seed ultrasctructural changes
        5.3.3.Analysis of plant reproductive fitness
        5.3.4.Physio-biochemical changes in silique wall
    5.4.Discussion
    5.5.Conclusion
CHAPTER6.Major findings and future perspectives
    6.1.Major findings
    6.2.Future perspectives
References
List of publications during PhD study period
Supplemental materials



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