| 摘要 | 第6-8页 |
| Abstract | 第8-9页 |
| Chapter 1 Introduction | 第20-47页 |
| 1.1 Brassica rapa L | 第20-22页 |
| 1.1.1 General information | 第20-21页 |
| 1.1.2 Nutritional and economic importance | 第21-22页 |
| 1.2 Nitrogen(N) | 第22-26页 |
| 1.2.1 Origin | 第22页 |
| 1.2.2 The global use of(N)fertilizers | 第22-23页 |
| 1.2.3 Functions of N in the plants | 第23页 |
| 1.2.4 Deficiency symptoms of N in the plants | 第23页 |
| 1.2.5 Excessive use of N in the plants | 第23-24页 |
| 1.2.6 Nitrogen interaction with other nutrients | 第24-25页 |
| 1.2.7 Sources of N Fertilizers in Agriculture | 第25页 |
| 1.2.8 Forms of nitrogen | 第25-26页 |
| 1.3 Environmental concerns associated with nitrogen fertilizer use in China | 第26-27页 |
| 1.4 Estimation of Nitrogen Use Efficiency(NUE)in plants | 第27-29页 |
| 1.4.1 Nitrogen use efficiency(NUE) | 第27-28页 |
| 1.4.2 Nitrogen uptake effciency(NUpE) | 第28页 |
| 1.4.3 Nitrogen utilization efficiency(NUtE) | 第28页 |
| 1.4.4 Agronomic efficiency(AE) | 第28页 |
| 1.4.5 Apparent N Recovery(AR) | 第28-29页 |
| 1.4.6 Physiological Efficiency(PE) | 第29页 |
| 1.4.7 Nitrogen harvestindex(NHI) | 第29页 |
| 1.5 Mechanism of nitrogen assimilation | 第29-34页 |
| 1.5.1 Nitrate assimilation | 第30页 |
| 1.5.2 Function of nitrate transporters | 第30-31页 |
| 1.5.3 Ammonium assimilation | 第31-34页 |
| 1.6 Significance of root system | 第34-36页 |
| 1.7 Mechanism of plant growth adaptation to N limitation | 第36页 |
| 1.8 Using model plants to assess biomass and NUE related traits | 第36-37页 |
| 1.9 Nitrogen use in Brassica rapa L | 第37-39页 |
| 1.9.1 Root architecture system of Brassica rapa L | 第38-39页 |
| 1.10 Quantitative trait loci (QTL) | 第39-40页 |
| 1.11 Doubled haploid populations:description and suitability for analysis | 第40-41页 |
| 1.12 QTL mapping studies for various traits in Brassica rapa L | 第41-43页 |
| 1.13 QTL studies for Nitrogen Use Efficiency (NUE) in different crops and modelplants | 第43-45页 |
| 1.14 The need and significance of research | 第45-46页 |
| 1.15 Objectives of proposed study | 第46-47页 |
| Chapter 2 Natural variation of shoot and root growth in response to nitrogenavailability in Brassica rapa L | 第47-69页 |
| 2.1 Summary | 第47页 |
| 2.2 Introduction | 第47-49页 |
| 2.3 Materials and methods | 第49-50页 |
| 2.3.1 Plant material and growth conditions | 第49页 |
| 2.3.2 Trait measurements | 第49-50页 |
| 2.3.3 Statistical analysis | 第50页 |
| 2.4 Results | 第50-53页 |
| 2.4.1 Genetic variability for shoot and root traits in relation to nitrogen availability in Brassica rapa L accessions | 第50-52页 |
| 2.4.2 Nitrogen (N) status modifies the plant strategy for growth and development | 第52页 |
| 2.4.3 Correlation between traits | 第52-53页 |
| 2.5 Discussion | 第53-56页 |
| 2.5.1 Identification of key traits and attractive features to enhance NUE in Brassica rapa L | 第54-56页 |
| 附图表 | 第56-69页 |
| Chapter-3 Phenotypic analysis of shoot and root morphological traits under differentnitrogen levels in Brassica rapa L | 第69-89页 |
| 3.1 Summary | 第69页 |
| 3.2 Introducction | 第69-70页 |
| 3.3 Materials and methods | 第70-72页 |
| 3.3.1 Plant material | 第70-71页 |
| 3.3.2 Phenotypic analysis and growth conditions | 第71页 |
| 3.3.3 Statistical analysis | 第71-72页 |
| 3.4 Results | 第72-88页 |
| 3.4.1 Evaluation of phenotypes | 第72-73页 |
| 3.4.2 Correlations among phenotypic traits | 第73-88页 |
| 3.5 Discussion | 第88-89页 |
| 3.5.1 Effect of N on shoot and root growth | 第88-89页 |
| Chapter-4 Mapping QTLs for shoot and root morphological traits under different nitrogenlevels in Brassica rapa L | 第89-99页 |
| 4.1 Summary | 第89页 |
| 4.2 Introduction | 第89-90页 |
| 4.3. Materials and methods | 第90-91页 |
| 4.3.1 Plant Population for QTL mapping | 第90页 |
| 4.3.2 Statistical analysis and QTL mapping | 第90-91页 |
| 4.4 Results | 第91-97页 |
| 4.4.1 QTL analysis | 第91-97页 |
| 4.5 Discussion | 第97-99页 |
| 4.5.1 QTLs related to plant growth under different N levels | 第97-99页 |
| Chapter-5 General discussion,conclusion and suggestions | 第99-102页 |
| 5.1 Characterization of natural variation of shoot and root growth response in relation to N supply | 第99页 |
| 5.2 Quantitative trait analysis(QTL)analysis of NUE in Brassica rapa L | 第99-100页 |
| 5.3 Suggestions | 第100-102页 |
| References | 第102-125页 |
| Acknowledgment | 第125-127页 |
| Authors’ Biography | 第127-128页 |
