| 附表 | 第5-6页 |
| 摘要 | 第6-8页 |
| abstract | 第8-9页 |
| LIST OF ABBRIVATION | 第15-16页 |
| Chapter Ⅰ- Introduction | 第16-23页 |
| 1.1 Regulatory mechanisms of EBRs in plants | 第17-18页 |
| 1.2 The role of EBR in major abiotic stresses | 第18-22页 |
| 1.2.1 Response to low temperature/chilling stress | 第18-19页 |
| 1.2.2 High temperature or heat stress | 第19-20页 |
| 1.2.3 Water deficit or drought stress | 第20页 |
| 1.2.4 Saline or NaCl stress | 第20-21页 |
| 1.2.5 Heavy metal stress | 第21-22页 |
| 1.2.6 Cucumber | 第22页 |
| 1.3 Objective of study | 第22-23页 |
| Chapter Ⅱ-24-Epibrassinolide Ameliorates Endogenous Hormone Levels to Enhance Low-Temperature Stress Tolerance in Cucumber Seedlings | 第23-42页 |
| 2.1 Introduction | 第23-25页 |
| 2.2 Materials and Methods | 第25-29页 |
| 2.2.1 Plant material and growth conditions | 第25页 |
| 2.2.2 Treatments and sampling | 第25-26页 |
| 2.2.3 Measurement of growth parameters | 第26页 |
| 2.2.4 Measurement of chlorophyll content | 第26页 |
| 2.2.5 Measurement of Gas-Exchange parameters | 第26页 |
| 2.2.6 Antioxidant enzyme activities and malondialdehyde(MDA)contents | 第26-27页 |
| 2.2.7 Determination of H_2O_2 and O_2~(??) contents | 第27页 |
| 2.2.8 Cell membrane stability(CMS) | 第27页 |
| 2.2.9 Leaf hormone extractions and quantifications | 第27-28页 |
| 2.2.10 Quantitative Real-Time PCR(qRT-PCR) | 第28页 |
| 2.2.11 Statistical analyses | 第28-29页 |
| 2.3 Results | 第29-37页 |
| 2.3.1 Effects of EBR treatments on cucumber seedling growth | 第29-30页 |
| 2.3.2 Effects of EBR treatments on chlorophyll contents | 第30-31页 |
| 2.3.3 Effects of EBR treatments on photosynthesis | 第31-32页 |
| 2.3.4 Effects of EBR on antioxidant enzyme activities | 第32-33页 |
| 2.3.5 Effects of EBR treatments on ROS,MDA,and CMS | 第33-34页 |
| 2.3.6 Effects of EBR on endogenous hormone regulation | 第34-37页 |
| 2.3.7 EBR biosynthesis genes expression levels under low-temperature stress | 第37页 |
| 2.4 Discussion | 第37-41页 |
| 2.5 Conclusions | 第41-42页 |
| Chapter Ⅲ- Exogenous24-Epibrassinolide positively regulate antioxidant enzyme activities,hormone and nutrient contents in cucumber under suboptimal root zone temperature | 第42-59页 |
| 3.1 Introduction | 第42-44页 |
| 3.2 Material and Methods | 第44-47页 |
| 3.2.1 Plant material and growth conditions | 第44页 |
| 3.2.2 Measurement of growth parameters | 第44-45页 |
| 3.2.3 Measurement of chlorophyll contents | 第45页 |
| 3.2.4 Measurement of Gas-exchange parameters | 第45页 |
| 3.2.5 Antioxidant enzyme activity and malondialdehyde contents measurements | 第45页 |
| 3.2.6 Measurement of H_2O_2 and O_2~(??) contents | 第45-46页 |
| 3.2.7 Total nutrients contents determination | 第46页 |
| 3.2.8 Leaf hormones extraction and quantification | 第46页 |
| 3.2.9 Quantitative real-time polymerase chain reaction(qRT-PCR) | 第46页 |
| 3.2.10 Statistical analysis | 第46-47页 |
| 3.3 Results | 第47-55页 |
| 3.3.1 Effect of EBR on cucumber seedling growth under suboptimal RZT | 第47-48页 |
| 3.3.2 Effect of EBR on chlorophyll contents under suboptimal RZT | 第48-49页 |
| 3.3.3 Effect of EBR on Photosynthesis under suboptimal RZT | 第49-50页 |
| 3.3.4 Effect of EBR on antioxidant enzymes activities,MDA,H_2O_2 and O_2~(??) contents | 第50-51页 |
| 3.3.5 Effect of EBR on total nutrients contents under suboptimal RZT | 第51-53页 |
| 3.3.6 Effect of EBR on endogenous hormone accumulation under suboptimal RZT | 第53-54页 |
| 3.3.7 EBR biosynthesis gene expression | 第54-55页 |
| 3.4 Discussion | 第55-57页 |
| 3.5 Conclusion | 第57-59页 |
| Chapter Ⅳ-24-Epibrassinolide mitigates the negative effects of suboptimal root zone temperature by modulating nitrogen metabolism in cucumber | 第59-76页 |
| 4.1 Introduction | 第59-62页 |
| 4.2 Materials and methods | 第62-65页 |
| 4.2.1 Plant material and growth conditions | 第62页 |
| 4.2.2 Measurement of growth | 第62页 |
| 4.2.3 Determination of root activity and bleeding rate | 第62-63页 |
| 4.2.4 Enzyme assays | 第63页 |
| 4.2.5 Determination of nitrate and ammonium contents | 第63页 |
| 4.2.6 Flux rate measurement of NO_3~- and NH_4~+ in cucumber roots | 第63页 |
| 4.2.7 Total nutrients contents determination | 第63页 |
| 4.2.8 Quantitative real-time polymerase chain reaction(qRT-PCR) | 第63-65页 |
| 4.3 Results | 第65-71页 |
| 4.3.1 Root activity and bleeding rate | 第65页 |
| 4.3.2 Enzyme activities | 第65-66页 |
| 4.3.3 NO_3~- and NH_4~+ contents | 第66-67页 |
| 4.3.4 NH_4~+ and NO_3~- flux rate in cucumber root | 第67-68页 |
| 4.3.5 The effect of EBR on N accumulation under suboptimal RZT | 第68-69页 |
| 4.3.6 Nitrate transporter(NRT1)gene expression | 第69-71页 |
| 4.4 Discussion | 第71-74页 |
| 4.5 Conclusion | 第74-76页 |
| References | 第76-89页 |
| ACKNOWLEDGEMENT | 第89-90页 |
| Curriculum Vitae | 第90-91页 |
