酸碱和镉（Cd）胁迫条件下硅（Si）对小麦生理特性的作用机制
发布时间：2023-03-28 22:32
相较于其他重金属,镉(Cd)具有高流动性、高水溶性和植物致毒性,是一种高致死性元素。Cd以离子形态通过根系进入植物后,经主动运输和被动运输转移至植物木质部和韧皮部。植物体内大量累积的Cd会通过抑制根部Fe(III)还原酶的活性而降低光合作用,还可影响固定CO2的酶活性,影响矿物元素的吸收,进而引起植物营养失衡(如N和K+等)、气孔关闭等症状。Cd胁迫下植物细胞产生的大量活性氧(ROS)可导致植物体内抗氧化酶活性显著降低。此外,Cd通过食物链在人体累积,易对肾脏、骨骼和肺造成损害。在影响植物生长发育的非生物胁迫因子中,土壤pH是最关键的因子之一,这是因为土壤pH在土壤发生过程和物化性质中起核心作用,可影响植物生长、微生物多样性以及营养物质的溶解度和有效性,且酸性条件Cd的存在会使这些效应进一步复杂化。植物对Cd的生物利用度不仅与Cd化学形态和土壤中Cd含量相关,还受土壤pH值的影响。生态毒理学研究已表明土壤pH值对Cd生物利用度作用显著,因此研究酸性土壤条件下Cd对植物的影响具有重要的意义。硅(Si)作为一种有益元素,在不同类型植物的生长发育中起着至关重要的作用。施...
【文章页数】：127 页
【学位级别】：博士
【文章目录】：
摘要
Abstract
Chapter 1 Introduction
1.1 Background
1.2 Cadmium
1.2.1 Cadmium in the Soil
1.2.2 Cadmium Mobilization,Uptake,and Transport
1.2.3 Plant Response to Cd Toxicity
1.2.4 Factor Effecting Cd Uptake and Accumulation
1.3 Silicon
1.3.1 Silicon and Plants
1.3.2 Silicon Role in Wheat Plants
1.3.3 Silicon Role Against Abiotic Stress
1.4 Need for the Project
1.5 Significance of Research
1.6 Research Aims
Chapter 2 Materials and Methods
2.1 Plant Culture and Experimental Design
2.1.1 Recipe of Hoagland’s Solution
2.1.2 Recipe of Si Treatment
2.2 Experimental Layout
2.2.1 Experiment 01
2.2.2 Experiment 02
2.2.3 Experiment 03
2.2.4 Experiment 04
2.2.5 Experiment 05
2.3 Determination of Plant Growth and Biomass
2.4 Measurements of Photosynthetic Pigments
2.5 Biochemical Analysis
2.6 Electrolyte Leakage
2.7 Determination of Nutrient Elements in Plant Tissues
Chapter 3 The Effect of Silicon Foliar and Root Application on Growth,Physiology,and Antioxidant Enzymes Activity of Wheat Plants under Cadmium Toxicity
3.1 Introduction
3.2 Results
3.2.1 Growth Parameters
3.2.2 Photosynthetic Pigments
3.2.3 Reactive Oxygen Species(ROS)
3.2.4 Enzymatic and Non-enzymatic Antioxidants in Wheat Seedlings
3.2.5 Essential Nutrients in Wheat
3.3 Discussion
3.4 Conclusion
Chapter 4 Mechanisms of Silicon-Mediated Enhancement of Cadmium Tolerance in Wheat(Triticum Aestivum L.)Grown in Cadmium Contaminated Acidic Nutrient Solution
4.1 Introduction
4.2 Results
4.2.1 Biomass Production
4.2.2 Photosynthetic Pigments
4.2.3 Enzymatic Antioxidants
4.2.4 Non-enzymatic Antioxidants
4.2.5 Osmoprotectants
4.2.6 Protein Contents
4.2.7 Relative Water Contents and Membrane Stability Index
4.2.8 Reactive Oxygen Species(ROS)Production and Lipid Peroxidation
4.2.9 Nutrient Concentrations
4.2.10 Tissue-specific Cadmium Concentration
4.2.11 Tissue-specific Silicon Concentration
4.3 Discussions
4.4 Conclusions
Chapter 5 Silicon Attenuates Acidic and Alkaline Stress in the Wheat Plant by Improving Nutrient Availability,Membrane Stability Index and Antioxidative Defense System
5.1 Introduction
5.2 Results
5.2.1 Biomass Production
5.2.2 Photosynthetic Pigments
5.2.3 Antioxidative Enzymes
5.2.4 Reactive Oxygen Species(ROS)Production and Lipid Peroxidation
5.2.5 Nutrients Concentration
5.2.6 Tissue-specific Silicon Concentration
5.3 Discussion
5.4 Conclusion
Chapter 6 Interactions of pH and Cadmium Toxicity in Their Effect on Growth,Membrane Stability,and Antioxidant Defense Systems of Triticum Aestivum(L.)
6.1 Introduction
6.2 Results
6.2.1 Biomass Production
6.2.2 Photosynthetic Pigments
6.2.3 Enzymatic and Non-enzymatic Antioxidants
6.2.4 Reactive Oxygen Species(H2O2,EL,and MDA)Production and Lipid Peroxidation
6.2.5 Nutrient Concentration
6.2.6 Tissue-specific Cadmium Concentration
6.3 Discussion
6.4 Conclusion
Chapter 7 Alleviatory Effects of Silicon on the Physiology,Morphology and Antioxidative Mechanisms of Wheat(Triticum Aestivum L.)Roots under Cadmium Stress in Acidic Nutrient Solution
7.1 Introduction
7.2 Results
7.2.1 Effect of Silicon and Cadmium on Root Biomass
7.2.2 Effect of Silicon and Cadmium on Root Volume and Average Diameter
7.2.3 Effect of Silicon and Cadmium on Total Root Length and Root Tips
7.2.4 Effect of Silicon and Cadmium on Enzymatic Antioxidant and Protein Contents
7.2.5 Effect of Silicon and Cadmium on Non-enzymatic Antioxidants
7.2.6 Effect of Silicon and Cadmium on Osmoprotectants
7.2.7 Effect of Silicon and Cadmium on Reactive Oxygen Species
7.2.8 Effect of Silicon and Cadmium on Nutrient Concentrations in Roots of Wheat Plants
7.2.9 Tissue-specific Silicon Concentration in Roots
7.2.10 Tissue-specific Cadmium Concentration in Roots
7.3 Discussion
7.4 Conclusion
Chapter 8 Conclusion
8.1 Silicon Soil and Foliar Application Alleviates Cd Toxicity
8.2 Silicon Alleviates Alone as well as Combines Effects of Cd and Acidic pH Toxicities in Wheat Plants
8.3 Silicon Alleviates Acidic and Alkine pH Toxicities in Wheat Plants
8.4 Silicon Improves Morphology and Physiology of Roots of Wheat Plants Grown under Cd-contaminated Acidic Nutrient Solution
8.5 Cadmium Uptake and Accumulation in Different Levels of pHs
References
Acknowledgements
Curriculum Vitae Malik Shafeeq-ur-Rahman
本文编号：3773419
【文章页数】：127 页
【学位级别】：博士
【文章目录】：
摘要
Abstract
Chapter 1 Introduction
1.1 Background
1.2 Cadmium
1.2.1 Cadmium in the Soil
1.2.2 Cadmium Mobilization,Uptake,and Transport
1.2.3 Plant Response to Cd Toxicity
1.2.4 Factor Effecting Cd Uptake and Accumulation
1.3 Silicon
1.3.1 Silicon and Plants
1.3.2 Silicon Role in Wheat Plants
1.3.3 Silicon Role Against Abiotic Stress
1.4 Need for the Project
1.5 Significance of Research
1.6 Research Aims
Chapter 2 Materials and Methods
2.1 Plant Culture and Experimental Design
2.1.1 Recipe of Hoagland’s Solution
2.1.2 Recipe of Si Treatment
2.2 Experimental Layout
2.2.1 Experiment 01
2.2.2 Experiment 02
2.2.3 Experiment 03
2.2.4 Experiment 04
2.2.5 Experiment 05
2.3 Determination of Plant Growth and Biomass
2.4 Measurements of Photosynthetic Pigments
2.5 Biochemical Analysis
2.6 Electrolyte Leakage
2.7 Determination of Nutrient Elements in Plant Tissues
Chapter 3 The Effect of Silicon Foliar and Root Application on Growth,Physiology,and Antioxidant Enzymes Activity of Wheat Plants under Cadmium Toxicity
3.1 Introduction
3.2 Results
3.2.1 Growth Parameters
3.2.2 Photosynthetic Pigments
3.2.3 Reactive Oxygen Species(ROS)
3.2.4 Enzymatic and Non-enzymatic Antioxidants in Wheat Seedlings
3.2.5 Essential Nutrients in Wheat
3.3 Discussion
3.4 Conclusion
Chapter 4 Mechanisms of Silicon-Mediated Enhancement of Cadmium Tolerance in Wheat(Triticum Aestivum L.)Grown in Cadmium Contaminated Acidic Nutrient Solution
4.1 Introduction
4.2 Results
4.2.1 Biomass Production
4.2.2 Photosynthetic Pigments
4.2.3 Enzymatic Antioxidants
4.2.4 Non-enzymatic Antioxidants
4.2.5 Osmoprotectants
4.2.6 Protein Contents
4.2.7 Relative Water Contents and Membrane Stability Index
4.2.8 Reactive Oxygen Species(ROS)Production and Lipid Peroxidation
4.2.9 Nutrient Concentrations
4.2.10 Tissue-specific Cadmium Concentration
4.2.11 Tissue-specific Silicon Concentration
4.3 Discussions
4.4 Conclusions
Chapter 5 Silicon Attenuates Acidic and Alkaline Stress in the Wheat Plant by Improving Nutrient Availability,Membrane Stability Index and Antioxidative Defense System
5.1 Introduction
5.2 Results
5.2.1 Biomass Production
5.2.2 Photosynthetic Pigments
5.2.3 Antioxidative Enzymes
5.2.4 Reactive Oxygen Species(ROS)Production and Lipid Peroxidation
5.2.5 Nutrients Concentration
5.2.6 Tissue-specific Silicon Concentration
5.3 Discussion
5.4 Conclusion
Chapter 6 Interactions of pH and Cadmium Toxicity in Their Effect on Growth,Membrane Stability,and Antioxidant Defense Systems of Triticum Aestivum(L.)
6.1 Introduction
6.2 Results
6.2.1 Biomass Production
6.2.2 Photosynthetic Pigments
6.2.3 Enzymatic and Non-enzymatic Antioxidants
6.2.4 Reactive Oxygen Species(H2O2,EL,and MDA)Production and Lipid Peroxidation
6.2.5 Nutrient Concentration
6.2.6 Tissue-specific Cadmium Concentration
6.3 Discussion
6.4 Conclusion
Chapter 7 Alleviatory Effects of Silicon on the Physiology,Morphology and Antioxidative Mechanisms of Wheat(Triticum Aestivum L.)Roots under Cadmium Stress in Acidic Nutrient Solution
7.1 Introduction
7.2 Results
7.2.1 Effect of Silicon and Cadmium on Root Biomass
7.2.2 Effect of Silicon and Cadmium on Root Volume and Average Diameter
7.2.3 Effect of Silicon and Cadmium on Total Root Length and Root Tips
7.2.4 Effect of Silicon and Cadmium on Enzymatic Antioxidant and Protein Contents
7.2.5 Effect of Silicon and Cadmium on Non-enzymatic Antioxidants
7.2.6 Effect of Silicon and Cadmium on Osmoprotectants
7.2.7 Effect of Silicon and Cadmium on Reactive Oxygen Species
7.2.8 Effect of Silicon and Cadmium on Nutrient Concentrations in Roots of Wheat Plants
7.2.9 Tissue-specific Silicon Concentration in Roots
7.2.10 Tissue-specific Cadmium Concentration in Roots
7.3 Discussion
7.4 Conclusion
Chapter 8 Conclusion
8.1 Silicon Soil and Foliar Application Alleviates Cd Toxicity
8.2 Silicon Alleviates Alone as well as Combines Effects of Cd and Acidic pH Toxicities in Wheat Plants
8.3 Silicon Alleviates Acidic and Alkine pH Toxicities in Wheat Plants
8.4 Silicon Improves Morphology and Physiology of Roots of Wheat Plants Grown under Cd-contaminated Acidic Nutrient Solution
8.5 Cadmium Uptake and Accumulation in Different Levels of pHs
References
Acknowledgements
Curriculum Vitae Malik Shafeeq-ur-Rahman
本文编号：3773419
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