硒(Se)是動(dòng)物必需的微量營(yíng)養(yǎng)元素,但其營(yíng)養(yǎng)必需量和致毒劑量之間的差距很小。硒的毒性主要與土壤中無(wú)機(jī)態(tài)的硒有關(guān),即通過(guò)植物吸收進(jìn)入食物鏈的亞硒酸鹽和硒酸鹽,對(duì)營(yíng)養(yǎng)水平較高的生物構(gòu)成了威脅。本實(shí)驗(yàn)使用蚯蚓(赤子愛(ài)勝蚓)和豆科植物(菜豆)研究了蚯蚓活性對(duì)土壤中Se的生物可利用性和隨后的植物吸收的影響,二者都在1或4 mg Se kg^-1的亞硒酸鹽或硒酸鹽中暴露16周。在所有的硒處理中,植物吸收硒酸鹽的速度要比吸收亞硒酸鹽的速度快(最多可達(dá)221倍),并且高達(dá)84%的硒會(huì)快速轉(zhuǎn)移到芽上。在有蚯蚓存在的條件下,添加了硒酸鹽的裝置中,植物中硒的含量明顯增加,除亞硒酸鹽為1 mg kg^-1以外的其他硒處理裝置中,硒的轉(zhuǎn)運(yùn)因子增加了0.85-4.08%。其中,有蚯蚓和硒酸鹽存在的裝置中,觀察到植物組織中硒的積累更快(高達(dá)274.38 mg.kg^-1 DW)。為了評(píng)估硒對(duì)人和其他動(dòng)物的潛在毒性,我們使用X射線吸收光譜法對(duì)暴露于硒的植物和蚯蚓進(jìn)行了硒形態(tài)分析。與無(wú)蚯蚓處理的硒酸鹽裝置相比,在有蚯蚓存在的情況下,豆子中有機(jī)硒(即Se Met...

【文章頁(yè)數(shù)】：91 頁(yè)

【學(xué)位級(jí)別】：碩士

【文章目錄】：
摘要
Abstract
Nomenclature
Chapter 1:Introduction
    1.1 Selenium Overview
        1.1.1 Background
        1.1.2 Selenium deficiency
        1.1.3 Selenium toxicity
        1.1.4 Selenium in Soils
        1.1.5 Selenium uptake in plants
        1.1.6 Selenium metabolism in plants
    1.2 Conventional techniques to remediate contaminated soils
        1.2.1 Physical methods
        1.2.2 Chemical methods
    1.3 Bioremediation technologies
        1.3.1 In-situ bioremediation
        1.3.2 Ex-Situ Bioremediation
    1.4 Phytoremediation
        1.4.1 Phytoextraction
        1.4.2 Phytostabilization
        1.4.3 Phytovolatilization
        1.4.4 Phytodegradation
        1.4.5 Phytofilteration
        1.4.6 Rhizodegradation
    1.5 Role of earthworms in phytoremediation
        1.5.1 Interactions between earthworms and plants
        1.5.2 Interactions between earthworms and heavy metals
        1.5.3 Earthworms and soil enzymes activities
        1.5.4 Interactions between earthworms and soil microorganisms
    1.6 Eco-toxicity of Se
        1.6.1 Eco-toxicity of Se to humans
        1.6.2 Eco-toxicity of Se to animals
    1.7 Research Significance,Content,and Technical Route
        1.7.1 Research significance,purpose,and novelty
        1.7.2 Research content
        1.7.3 Technical route
Chapter 2:Materials and methods
    2.1 Materials
    2.2 Experimental setup
    2.3 Sample Collection
    2.4 Total Se analysis
    2.5 Statistical analysis
    2.6 Se speciation by X-ray absorption spectroscopy(XAS)
Chapter 3:Effect of selenite and selenate on Se accumulation and toxicity in earthworm Eisenia fetida
    3.1 Introduction
    3.2 Experimental
        3.2.1 Materials
        3.2.2 Experimental Setup
        3.2.3 Sample Collection
        3.2.4 Total Se analysis
        3.2.5 Statistical analysis
    3.3 Results
        3.3.1 Se toxicity to earthworms
        3.3.2 Se uptake and excretion by earthworms
    3.4 Discussions
        3.4.1 Earthworm survival and growth and Se uptake
    3.5 Conclusions
Chapter:4 Effect of earthworm Eisenia fetida on Se uptake and growth of bean plant Phaseolus vulgaris L
    4.1 Introduction
    4.2 Experimental
        4.2.1 Materials
        4.2.2 Experimental setup
        4.2.3 Sample collection
        4.2.4 Total Se analysis
        4.2.5 Statistical analysis
    4.3 Results
        4.3.1 Se uptake, accumulation, and translocation in plants
        4.3.2 Effect of earthworm activity and Se on plant growth
        4.3.3 Fate of soil Se
    4.4 Discussions
        4.4.1 Interactions between plants and earthworms
        4.4.2 Effect of earthworm activity on plant growth
        4.4.3 Mass balance of Se
    4.5 Conclusions
Chapter 5:Effect of earthworm Eisenia fetida on Se metabolism in plant Phaseolus vulgaris L.
    5.1 Introduction
    5.2 Experimental
        5.2.1 Materials
        5.2.2 Experimental setup
        5.2.3 Sample collection
        5.2.4 Se speciation by X-ray absorption spectroscopy(XAS)
    5.3 Results
        5.3.1 Biotransformation of Se in plants
        5.3.2 Biotransformation of Se in earthworms
    5.4 Discussions
        5.4.1 Biotransformation of Se in plants
        5.4.2 Biotransformation of Se in earthworms
        5.4.3 Potential eco-risk of Se
    5.5 Conclusions
Chapter 6:Conclusions and recommendations
    6.1 Conclusions
    6.2 Recommendations
References
Acknowledgement
List of Publications



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