| Acknowledgements | 第11-13页 |
| Contents | 第13-17页 |
| List of Figures | 第17-20页 |
| List of Tables | 第20-21页 |
| List of Abbreviations | 第21-22页 |
| ABSTRACT | 第22-24页 |
| 摘要 | 第25-27页 |
| Chapter 1 Literature review | 第27-49页 |
| 1.1 Phosphorus in agriculture | 第27-30页 |
| 1.2 Mechanisms for low P tolerance or high P utilization efficiency in plants | 第30-36页 |
| 1.2.1 Root architecture/morphology changes | 第30-34页 |
| 1.2.1.1 Lateral root development | 第30-32页 |
| 1.2.1.2 Root hair development | 第32页 |
| 1.2.1.3 Increase in root/shoot ratio | 第32-34页 |
| 1.2.2 Modification in the microenvironments of the rhizosphere | 第34-35页 |
| 1.2.2.1 Organic acid secretion | 第34页 |
| 1.2.2.2 Induction of acid phosphatase | 第34-35页 |
| 1.2.3 Biochemical modification | 第35-36页 |
| 1.2.3.1 Membrane transporter | 第35-36页 |
| 1.2.3.2 Activation of enzyme | 第36页 |
| 1.3 P uptake and translocation/mobilization within a plant | 第36-37页 |
| 1.4 Genetic controlling of low P tolerance in plants | 第37-42页 |
| 1.4.1 Phosphate transporters | 第37-39页 |
| 1.4.2 Genetic regulation of organic acid and acid phosphatase secretion | 第39-40页 |
| 1.4.3 Genetic regulation of P uptake and transportation | 第40-41页 |
| 1.4.4 Genetic regulation of root architecture | 第41-42页 |
| 1.5 Signal transduction during Pi starvation | 第42-47页 |
| 1.5.1 Pi stress sensing and signaling | 第43-44页 |
| 1.5.2 Signals involved in root morphological adaptations/local Pi sensing and signaling | 第44页 |
| 1.5.3 Hormonal regulation in Pi signaling | 第44-47页 |
| 1.6 The main contents and objectives of the current research | 第47-49页 |
| Chapter 2 Identification of Tibetan wild barley genotypes with high tolerance to low phosphorus stress | 第49-68页 |
| 2.1 Materials and methods | 第50-53页 |
| 2.1.1 Plant materials and experimental design | 第50-51页 |
| 2.1.2 Plant sampling and biomass measurement | 第51-52页 |
| 2.1.3 Phosphorus and other mineral element analysis | 第52页 |
| 2.1.4 Calculation of plant growth and phosphorus accumulation parameters | 第52页 |
| 2.1.5 Statistical analysis | 第52-53页 |
| 2.2 Results | 第53-64页 |
| 2.2.1 Preliminary screening experiment | 第53-59页 |
| 2.2.2 Secondary selection experiment | 第59-64页 |
| 2.3 Discussion | 第64-66页 |
| 2.4 Conclusion | 第66-68页 |
| Chapter 3 The changes in physiological and biochemical traits of Tibetan wild and cultivated barley in response to low phosphorus stress | 第68-89页 |
| 3.1 Materials and methods | 第69-73页 |
| 3.1.1 Plant materials and experimental design | 第69-70页 |
| 3.1.2 Plant sampling | 第70页 |
| 3.1.3 Phosphorus determination | 第70页 |
| 3.1.4 Calculation of various growth parameters and phosphorus uptake | 第70页 |
| 3.1.5 Root morphology | 第70页 |
| 3.1.6 Measurement of photosynthetic parameter | 第70-71页 |
| 3.1.7 Determination of hydrogen peroxide (H_2O_2), superoxide radical (O_2·~-), and their histochemical detection | 第71页 |
| 3.1.8 Determination of the enzyme activities relevant to carbohydrate metabolism | 第71-72页 |
| 3.1.9 Determination intracellular acid phosphatases (APase) and ATPase activity | 第72页 |
| 3.1.10 Collection of exudates and measurement of organic acids | 第72-73页 |
| 3.1.11 Examination of root ultrastructure | 第73页 |
| 3.1.12 Statistical analysis | 第73页 |
| 3.2 Results | 第73-83页 |
| 3.2.1 Root and shoot length and dry weight | 第73-74页 |
| 3.2.2 Phosphorus concentration and accumulation | 第74-75页 |
| 3.2.3 Root morphology | 第75-76页 |
| 3.2.4 Photosynthetic parameters | 第76-77页 |
| 3.2.5 Hydrogen peroxide (H_2O_2) and superoxide radical (O_2·~-) concentrations | 第77-79页 |
| 3.2.6 Activities of acid invertase (AI), sucrose synthase (SuSy) and sucrose phosphate synthase (SPS) | 第79-80页 |
| 3.2.7 Activity of intracellular acid phosphatases (APase), plasma membrane H+, Ca~(2+)Mg~(2+)- and Na~+K~+-ATPase | 第80-81页 |
| 3.2.8 Organic acids (OAs) | 第81-82页 |
| 3.2.9 Ultrastructure of root cells | 第82-83页 |
| 3.3 Discussion | 第83-87页 |
| 3.4 Conclusion | 第87-89页 |
| Chapter 4 Identification of the differentially accumulated proteins associated with low phosphorous tolerance in a Tibetan wild barley accession | 第89-115页 |
| 4.1 Materials and methods | 第90-94页 |
| 4.1.1 Plant materials and experimental design | 第90页 |
| 4.1.2 Protein extraction and two-dimensional gel electrophoresis analysis | 第90-91页 |
| 4.1.3 Protein visualization, image analysis, and quantification and MALDI-TOF/TOF MS | 第91-92页 |
| 4.1.4 Tryptic in-gel digestion | 第92页 |
| 4.1.5 MALDI-TOF/TOF MS analysis and protein identification | 第92-93页 |
| 4.1.6 Total RNA extraction, cDNA synthesis, and quantitative real-time PCR (qRT-PCR) analyses | 第93页 |
| 4.1.7 Statistic analysis | 第93-94页 |
| 4.2 Results | 第94-108页 |
| 4.2.1 Phenotypic differences under LP condition | 第94-95页 |
| 4.2.2 Differentially accumulated proteins in leaves and roots of the three genotypes under LP | 第95-98页 |
| 4.2.3 Identification of low Pi responsive proteins in leaves and roots | 第98-106页 |
| 4.2.4 Analysis of selected transcripts of differentially accumulated proteins | 第106-108页 |
| 4.3 Discussion | 第108-114页 |
| 4.3.1 The differentially accumulated proteins under LP in leaves | 第108-110页 |
| 4.3.2 The differentially accumulated proteins under LP in roots | 第110-114页 |
| 4.4 Conclusions | 第114-115页 |
| Chapter 5 The regulation of root growth in response to phosphorus deficiency mediatedby phytohormones and sugar signaling in a Tibetan wild barley accession | 第115-133页 |
| 5.1 Materials and methods | 第116-118页 |
| 5.1.1 Plant materials and experimental design | 第116页 |
| 5.1.2 Plant sampling | 第116页 |
| 5.1.3 Phosphorus determination and measurement of root hair morphology | 第116页 |
| 5.1.4 Extraction of endogenous plant hormones and Liquid chromatography mass spectroscopy (LC-MS/MS) | 第116-117页 |
| 5.1.5 Sugar extraction and analysis | 第117-118页 |
| 5.1.6 Collection and analysis of phloem exudates | 第118页 |
| 5.1.7 Total RNA extraction, cDNA synthesis, and quantitative real-time PCR (qRT-PCR) analyses | 第118页 |
| 5.1.8 Statistic analysis | 第118页 |
| 5.2 Results | 第118-127页 |
| 5.2.1 Phenotypic changes of the barley seedlings under LP stress | 第118-119页 |
| 5.2.2 Phosphorus content | 第119-120页 |
| 5.2.3 Changes in the levels of endogenous plant hormones | 第120-122页 |
| 5.2.4 Expression of genes involved in hormone synthesis | 第122-123页 |
| 5.2.5 Carbohydrate content | 第123-125页 |
| 5.2.6 Sucrose content in phloem loading and expression of sucrose transporter 2 (SUC2) | 第125页 |
| 5.2.7 The expression of some genes related to phosphate transporter | 第125-127页 |
| 5.3 Discussion | 第127-132页 |
| 5.4 Conclusion | 第132-133页 |
| Chapter 6 Major findings and future perspectives | 第133-136页 |
| 6.1 Major findings | 第133-134页 |
| 6.2 Future perspectives | 第134-136页 |
| References | 第136-162页 |
| List of publications | 第162页 |
