| List of Signs and Abbreviations | 第9-10页 |
| 摘要 | 第10-13页 |
| Abstract | 第13-15页 |
| 1 INTRODUCTION | 第16-24页 |
| 1.1 General introduction | 第16-17页 |
| 1.2 Literature review | 第17-22页 |
| 1.2.1 Distribution and world importance of rice | 第17-18页 |
| 1.2.2 Importance and sources of salt stress | 第18页 |
| 1.2.3 Effect of salt stress on physiological and biochemical traits in rice | 第18-20页 |
| 1.2.4 Plant responses and mechanisms of tolerating salt stress | 第20-21页 |
| 1.2.5 Breeding process for salt-tolerance in rice plants | 第21-22页 |
| 1.3 Outline | 第22页 |
| 1.4 Need of project and justification | 第22-23页 |
| 1.5 Objectives of this study | 第23-24页 |
| 2 MATERIALS AND METHODS | 第24-34页 |
| 2.1 The editing of HST1 gene | 第24-26页 |
| 2.1.1 Construction of Cas9/gRNA-HST1 knockout vector | 第24-25页 |
| 2.1.2 Genetic transformation of rice | 第25页 |
| 2.1.3 Detection of hygromycin in transgenic plants | 第25页 |
| 2.1.4 Gene target site modification analysis | 第25-26页 |
| 2.2 Seeds sterilization and preparation | 第26页 |
| 2.3 Planting and growth conditions | 第26-27页 |
| 2.4 Salt stress treatment | 第27页 |
| 2.5 Plant growth rate and biomass determination | 第27页 |
| 2.6 Relative leaf water maintenance analysis | 第27页 |
| 2.7 Photosynthetic pigments (chlorophyll)determination | 第27-28页 |
| 2.8 Electrolyte leakage conductivity measurements | 第28页 |
| 2.9 Osmolytes (proline) determination | 第28-29页 |
| 2.10 Lipid peroxidation (MDA) level determination | 第29页 |
| 2.11 RNA extraction, cDNA synthesis and qRT-PCR for antioxidant defence genes | 第29-31页 |
| 2.11.1 RNA extraction | 第29-30页 |
| 2.11.2 cDNA synthesis | 第30页 |
| 2.11.3 Polymerase Chain Reaction of cDNA | 第30-31页 |
| 2.12 Inorganic ions (K+ and Na+) spectrophotometry analysis | 第31-32页 |
| 2.13 Data analysis | 第32-34页 |
| 3 RESULTS AND ANALYSIS | 第34-54页 |
| 3.1 HST1 gene editing and modification analysis | 第34-35页 |
| 3.1.1 Construction of HST1 gene knockout vector and genetic transformation | 第34页 |
| 3.1.2 Analysis of HST1 gene editing and modification types of transgenic plants | 第34-35页 |
| 3.2 Analysis of growth rate and biomass of mutants and WT plants | 第35-39页 |
| 3.2.1 Growth rate of mutants and WT plants | 第35-37页 |
| 3.2.2 Plant biomass of mutants and WT | 第37-39页 |
| 3.3 Water maintenance level of mutants and WT | 第39-40页 |
| 3.4 Photosynthesis level of mutants and WT | 第40-42页 |
| 3.5 Electrolyte leakage in cells of mutants and WT | 第42-43页 |
| 3.6 Organic solutes level in cells of mutants and WT | 第43-44页 |
| 3.7 Lipid peroxidation level in cells of mutants and WT | 第44-45页 |
| 3.8 Antioxidant defence in mutants and WT at transcription level | 第45-49页 |
| 3.8.1 Transcription patterns of 6 major antioxidant genes in sst and hstl seedlings | 第45-48页 |
| 3.8.2 Relative expression of OsSODB and OsAPXl genes in mature plants | 第48-49页 |
| 3.9 Balance of inorganic ions (K+/Na+) in mutants and WT | 第49-54页 |
| 3.9.1 Levels of potassium (K+) and sodium (Na+) ions in rice seedlings | 第50-51页 |
| 3.9.2 Level of potassium (K+) ions in mature plants | 第51页 |
| 3.9.3 The K+/ Na+ ratios and salt tolerance indexes in rice seedlings | 第51-54页 |
| 4 DISCUSSION, CONCLUSION AND RECOMMENDATIONS | 第54-59页 |
| 4.1 General discussion | 第54-57页 |
| 4.1.1 Vegetative growth rate and biomass of mutants and WT | 第54页 |
| 4.1.2 RWC, photosynthesis and cell electrolyte leakage in mutants and WT | 第54-55页 |
| 4.1.3 Organic solutes (proline) and lipids peroxidation (MDA) levels | 第55页 |
| 4.1.4 Antioxidant defence activity in mutants and WT at transcription level | 第55-56页 |
| 4.1.5 Level of K+ and Na+ ions in mutants and WT | 第56-57页 |
| 4.2 Conclusion | 第57-58页 |
| 4.3 Recommendations | 第58-59页 |
| References | 第59-63页 |
| Acknowledgements | 第63-64页 |
| 致谢 | 第64-65页 |
| List of Appendix | 第65-67页 |
