| 摘要 | 第9-11页 |
| Abstract | 第11-13页 |
| Abbreviations | 第14-15页 |
| 1 Introduction | 第15-30页 |
| 1.1 Grafting Modify Ion Accumulation in Horticultural Crops | 第16-23页 |
| 1.1.1 Vegetable Crops | 第16-18页 |
| 1.1.2 Fruit Crops | 第18-23页 |
| 1.2 Mechanism of Rootstocks to Modify Ion Accumulation | 第23-27页 |
| 1.2.1 Root System Architecture and Ion Uptake | 第24页 |
| 1.2.2 Transporters and Ion Uptake | 第24-26页 |
| 1.2.3 Hormones, mi RNAs and Ion Uptake | 第26-27页 |
| 1.3 Rootstock Limits the Uptake and Transport of Heavy Metals | 第27-28页 |
| 1.4 Melatonin Improves Abiotic Stress Tolerance of Plants | 第28-29页 |
| 1.5 Objectives of This Research | 第29-30页 |
| 2 Effect of Grafting on Nitrogen Use Efficiency of Watermelon under Different Levels of Nitrogen Supply | 第30-47页 |
| 2.1 Materials and Methods | 第30-34页 |
| 2.1.1 Plant Material and Treatments | 第30-31页 |
| 2.1.2 Plant Growth | 第31-32页 |
| 2.1.3 SPAD Index (Relative Chlorophyll Content) | 第32页 |
| 2.1.4 Nitrogen Use Efficiency | 第32页 |
| 2.1.5 Leaf Microscopy Analysis | 第32页 |
| 2.1.6 Ion Analysis | 第32-33页 |
| 2.1.7 Cytokinin Analysis | 第33页 |
| 2.1.8 RNA Extraction and Gene expression Analysis | 第33-34页 |
| 2.1.9 Statistical Analysis | 第34页 |
| 2.2 Results | 第34-43页 |
| 2.2.1 Plant growth | 第34页 |
| 2.2.2 SPAD Index and Leaf Structure | 第34-37页 |
| 2.2.3 Mineral Nutrition | 第37-41页 |
| 2.2.4 N Uptake and N Use Efficiency | 第41-42页 |
| 2.2.5 Cytokinin Content | 第42页 |
| 2.2.6 Nitrate Reductase Gene Expression | 第42-43页 |
| 2.3 Discussion | 第43-46页 |
| 2.4 Conclusion | 第46-47页 |
| 3 Genome-wide Expression Profiling of Leaves and Roots of Watermelon in Response to Low Nitrogen | 第47-73页 |
| 3.1 Materials and Methods | 第48-51页 |
| 3.1.1 Plant Material and Treatments | 第48页 |
| 3.1.2 Plant Growth, Nitrogen and Photosynthetic Parameters | 第48页 |
| 3.1.3 Transcriptome Analysis | 第48-50页 |
| 3.1.3.1 RNA extraction | 第48-49页 |
| 3.1.3.2 Library preparation for transcriptome sequencing | 第49页 |
| 3.1.3.3 Clustering and sequencing | 第49页 |
| 3.1.3.4 Quality control | 第49页 |
| 3.1.3.5 Reads mapping to the reference genome | 第49-50页 |
| 3.1.3.6 Quantification of gene expression | 第50页 |
| 3.1.3.7 Differential gene expression analysis | 第50页 |
| 3.1.3.8 GO and KEGG enrichment analysis of differentially expressed genes | 第50页 |
| 3.1.4 Validation of RNA-seq by qRT-PCR | 第50-51页 |
| 3.2 Results | 第51-66页 |
| 3.2.1 Response to Growth and Physiological Traits | 第51-55页 |
| 3.2.1.1 Plant growth | 第51-53页 |
| 3.2.1.2 Photosynthetic assimilation | 第53-55页 |
| 3.2.2 Nitrogen Concentration in Different Plant Parts | 第55页 |
| 3.2.3 Transcriptome Responses to Low N | 第55-65页 |
| 3.2.3.1 Overview of the RNA sequencing data | 第55-56页 |
| 3.2.3.2 Analysis of differentially expressed genes (DEGs) | 第56-62页 |
| 3.2.3.3 Nitrate transporters gene expression | 第62页 |
| 3.2.3.4 Cytokinin, chlorophyll and photosynthesis gene expression | 第62-65页 |
| 3.2.3.5 Identification of low N-responsive transcription factors (TFs) | 第65页 |
| 3.2.4 Quantitative Real?time PCR for RNA-seq Data Validation | 第65-66页 |
| 3.3 Discussion | 第66-72页 |
| 3.3.1 DEGs in the Leaf | 第67-68页 |
| 3.3.2 DEGs in the Root | 第68-69页 |
| 3.3.3 Cytokinin and Nitrate Reductase Gene Expression | 第69-70页 |
| 3.3.4 The Five Main Families of Transcription Factors (TFs) Responding to Low N | 第70-72页 |
| 3.4 Conclusion | 第72-73页 |
| 4 Assessment of Melatonin Application on Root Growth and Nitrogen Uptake of Watermelon | 第73-80页 |
| 4.1 Materials and Methods | 第73-74页 |
| 4.1.1 Plant Material and Treatments | 第73-74页 |
| 4.1.2 Root Morphology and Nitrogen Analysis | 第74页 |
| 4.1.3 Statistical analysis | 第74页 |
| 4.2 Results | 第74-76页 |
| 4.2.1 Root Morphology | 第74-76页 |
| 4.2.2 Nitrogen Concentration | 第76页 |
| 4.3 Discussion | 第76-79页 |
| 4.4 Conclusion | 第79-80页 |
| 5 Effect of Melatonin Pretreatment on Vanadium Stress Tolerance of Watermelon | 第80-98页 |
| 5.1 Materials and Methods | 第80-83页 |
| 5.1.1 Plant Material and Treatments | 第80-81页 |
| 5.1.2 Plant Growth | 第81-82页 |
| 5.1.3 SPAD Index and Leaf Photosynthetic Parameters | 第82页 |
| 5.1.4 Root Morphology | 第82页 |
| 5.1.5 Ion Analysis | 第82页 |
| 5.1.6 Antioxidant System Analysis | 第82-83页 |
| 5.1.7 RNA Extraction and Gene Expression Analysis | 第83页 |
| 5.1.8 Statistical Analysis | 第83页 |
| 5.2 Results | 第83-93页 |
| 5.2.1 Plant Growth | 第83-85页 |
| 5.2.2 Root Morphology | 第85页 |
| 5.2.3 SPAD Index and Leaf Photosynthetic Parameters | 第85-86页 |
| 5.2.4 Vanadium and Phosphorus Concentration of Leaf, Stem, and Root | 第86-87页 |
| 5.2.5 Hydrogen Peroxide (H2O2) and Malondialdehyde (MDA) Contents | 第87-88页 |
| 5.2.6 Superoxide Dismutase (SOD) and Catalase (CAT) Activities… | 第88-89页 |
| 5.2.7 Relative Gene Expression | 第89-93页 |
| 5.3 Discussion | 第93-97页 |
| 5.3.1 Melatonin Improves SPAD Index and Photosynthetic Assimilation | 第93-94页 |
| 5.3.2 Melatonin Improves Root Morphology | 第94页 |
| 5.3.3 Melatonin Reduces the Shoot V Concentration | 第94-95页 |
| 5.3.4 Melatonin Activates the Antioxidant System and Improves V Stress Tolerance. | 第95-97页 |
| 5.4 Conclusion | 第97-98页 |
| 6 Impacts of Bottle Gourd and Pumpkin Rootstock on Vanadium Stress Tolerance of Watermelon | 第98-116页 |
| 6.1 Materials and Methods | 第98-99页 |
| 6.1.1 Plant Materials and Treatments | 第98页 |
| 6.1.2 Root Morphology and Scanning Electron Microscopy (SEM) of Root Tips | 第98-99页 |
| 6.2 Results | 第99-110页 |
| 6.2.1 Grafting Improves Plant Growth of Watermelon | 第99-101页 |
| 6.2.2 Grafting Improves Photosynthetic Assimilation | 第101-102页 |
| 6.2.3 Root Morphology and Scanning Electron Microscopy (SEM) of Root Tips | 第102-105页 |
| 6.2.4 Grafting Reduces Vanadium and Improves Phosphorus Concentration of Leaves | 第105-107页 |
| 6.2.5 Grafting Regulates the Antioxidant System | 第107-108页 |
| 6.2.6 Grafting Regulates Gene Expression | 第108-110页 |
| 6.3 Discussion | 第110-115页 |
| 6.3.1 Grafting Improves V Stress Tolerance by Enhancing Plant Growth, Chlorophyll Content and Photosynthetic Assimilation | 第110-112页 |
| 6.3.2 Grafting Improves V Stress Tolerance by Decreasing V and Increasing P Concentration in Leaf | 第112-113页 |
| 6.3.3 Grafting Improves V Stress Tolerance by Enhancing the SOD and CAT Activities and Regulating the Expression of Antioxidant Enzymes-Related Genes | 第113-115页 |
| 6.4 Conclusion | 第115-116页 |
| 7 Summary and Future Perspectives | 第116-118页 |
| References | 第118-134页 |
| Appendices | 第134-141页 |
| List of Publications | 第141-142页 |
| Acknowledgements | 第142-144页 |
