声明
论文说明
Acknowledgements
Contents
Abstract
摘要
Abbreviations
Chapter 1：Literature Review
1．1 Historical background of tobacco and heavy metal stress
1．2 Lead (Pb) availability and uptake
1．3 Effect of Pb stress on plants
1．3．1 Effect on growth and photosynthetic activity
1．3．2 Genotoxic effects of Pb stress
1．3．3 Effect on plant water status
1．3．4 Effect on germination
1．3．4 Pb induced oxidative stress and lipid peroxidation
1．4 Defense mechanisms against Pb stress
1．5 The role of thiolic compounds in heavy metal stress alleviation
1．6 Genotypic variations in heavy metal stress resistance
1．7 Research objectives
Chapter 2：Genotypic differences in tolerance to Pb stress in different tobacco varieties (Nicodana tabacum) and the associated physiological mechanisms
2．0 Materials and Methods
2．1 Plant materials and growth conditions
2．1．1 Measurement of growth parameters
2．1．2 Measurement of photosynthetic parameters
2．1．3 Quantification of photosynthetic pigments
2．1．4 Assay for antioxidant enzymes and lipid peroxidation
2．1．5 Measurement of Pb content
2．1．6 Calculation of Tolerance indices(TI)
2．1．7 Statistical analysis
2．2 Results
2．2．1 Growth response to Pb toxicity
2．2．2 Photosynthetic response to Pb toxicity
2．2．3 Photosynthetic pigments response to Pb toxicity
2．2．4 Tissue Pb concentration
2．2．5 Enzyme activity
2．2．6 Lipid peroxidation
2．3 Discussion
2．4 Conclusion
Chapter 3：Alleviation of Pb toxicity in tobacco through application of N-acetyl cysteine (NAC)
3．2 Materials and Methods
3．2．1 Measurement of growth parameters
3．1．2 Measurement of photosynthetic parameters
3．1．3 Quantification of photosynthetic pigments
3．1．4 Assay for antioxidant enzymes and lipid peroxidation
3．1．5 Measurement of Pb content
3．1．6 Statistical analysis
3．1．7 Leaf ultra-structure analysis
3．2 Results
3．2．1 Growth response to Pb toxicity and NAC application
3．2．2 Photosynthetic response to Pb toxicity and NAC application
3．2．3 Photosynthetic pigments response to Pb toxicity and NAC application
3．2．4 Antioxidant enzymes response to Pb toxicity and NAC application
3．2．5 Lipid peroxidation response to Pb toxicity and NAC application
3．2．6 The effect of NAC application on Pb content
3．2．7 Effects of Pb toxicity and NAC application on leaf ultrastructure
3．3 Discussion
3．4 Conclusion
References
Publications
