| Acknowledgements | 第8-18页 |
| List of Abbreviations | 第18-20页 |
| Abstract | 第20-24页 |
| 摘要 | 第25-28页 |
| Chapter 1 General Introduction | 第28-32页 |
| 1.1 Background information | 第28-30页 |
| 1.2 Project Goals | 第30-31页 |
| 1.3 Specific objectives | 第31-32页 |
| Chapter 2 Literature review | 第32-50页 |
| 2.1 Plant stress | 第32-33页 |
| 2.2 Persistent organic pollutants (POPs) and polycyclic aromatic hydrocarbons (PAHs) | 第33-34页 |
| 2.3 Uptake and translocation of PAHs | 第34-35页 |
| 2.4 Metabolism and detoxification of PAHs | 第35-37页 |
| 2.5 Phytotoxicity and stress responses of plants to PAHs | 第37-44页 |
| 2.5.1 Germination and early seedling growth | 第37-38页 |
| 2.5.2 Effects of PAHs on photosynthesis | 第38-39页 |
| 2.5.3 Effects of PAHs on chlorophyll fluorescence | 第39页 |
| 2.5.4 Effects of PAHs on chlorophyll contents | 第39-40页 |
| 2.5.5 Other morphological symptoms in plants under PAHs exposure | 第40-41页 |
| 2.5.6 Oxidative stress and enzymatic regulation | 第41-43页 |
| 2.5.7 Effects of PAHs on cell ultrastructure | 第43-44页 |
| 2.6 Stress and plant secondary metabolism | 第44-45页 |
| 2.7 Brassinosteroids | 第45-50页 |
| 2.7.1 BRs and biotic stress | 第46页 |
| 2.7.2 BRs and abiotic stress | 第46-48页 |
| 2.7.2.1 BRs improve photosynthesis under various abiotic stresses | 第46-47页 |
| 2.7.2.2 BRs enhance ROS scavenging under various abiotic stresses | 第47页 |
| 2.7.2.3 BRs promote detoxification of xenobiotics | 第47-48页 |
| 2.7.3 BRs and secondary metabolism | 第48页 |
| 2.7.4 BRs cross talk with other plant hormones | 第48-50页 |
| Chapter 3 Brassinosteroid improves seed germination and early development of tomato seedlingunder phenanthrene stress | 第50-64页 |
| Abstract | 第50页 |
| 3.1 Introduction | 第50-52页 |
| 3.2 Materials and methods | 第52-54页 |
| 3.2.1 Seed treatment, sowing, growth condition and treatment application | 第52页 |
| 3.2.2 Determination of germination, seedling growth and sample harvesting | 第52-53页 |
| 3.2.3 Determination of chlorophyll fluorescence parameters | 第53页 |
| 3.2.4 Determination of antioxidant enzyme activity and lipid peroxidation | 第53-54页 |
| 3.2.5 Statistical analyses | 第54页 |
| 3.3 Results | 第54-61页 |
| 3.3.1 Effect of PHE and EBR on germination and growth of tomato seedlings | 第54-56页 |
| 3.3.2 Effects of PHE and EBR on chlorophyll a fluorescence parameters | 第56-57页 |
| 3.3.3 Effects of PHE and EBR on antioxidant enzyme activity | 第57-60页 |
| 3.3.4 Effects of PHE and EBR on lipid peroxidation | 第60-61页 |
| 3.4 Discussion | 第61-64页 |
| Chapter 4 Brassinosteroid alleviates phenanthrene and pyrene phytotoxicity by increasingdetoxification activity and photosynthesis in tomato | 第64-83页 |
| Abstract | 第64-65页 |
| 4.1 Introduction | 第65-66页 |
| 4.2 Materials and methods | 第66-70页 |
| 4.2.1 Plant materials and growth conditions | 第66-67页 |
| 4.2.2 Epibrassinolide preparation and treatment application | 第67-68页 |
| 4.2.3 Analyses of length and fresh weight of shoot and root | 第68页 |
| 4.2.4 Photosynthetic pigments,gas exchange and chlorophyll fluorescence | 第68页 |
| 4.2.5 Assay of antioxidant enzymes | 第68-69页 |
| 4.2.6 Malondialdehyde content determination | 第69-70页 |
| 4.2.7 Estimation of glutathione contents | 第70页 |
| 4.2.8 Statistical analyses | 第70页 |
| 4.3 Results | 第70-79页 |
| 4.3.1 BR improves morphological parameters of tomato seedlings | 第70-72页 |
| 4.3.2 BR increased the photosynthetic pigments under PHE or PYR exposure | 第72-73页 |
| 4.3.3 BR protected photosynthetic machinery and improved photosynthesis under PHE or PYR stress | 第73页 |
| 4.3.4 BR stimulated chlorophyll fluorescence parameters towards enhanced stress tolerance | 第73-74页 |
| 4.3.5 BR improved the antioxidant enzyme system under PHE or PYR stress | 第74-77页 |
| 4.3.6 BR decreased MDA content under PHE or PYR stress | 第77页 |
| 4.3.7 BR altered glutathione metabolism towards enhanced tolerance to PHE or PYR | 第77-79页 |
| 4.4 Discussion | 第79-83页 |
| Chapter 5 Brassinosteroids induce plant tolerance against phenanthrene by enhancingdegradation and detoxification in Solanum lycopersicum L | 第83-101页 |
| Abstract | 第83-84页 |
| 5.1 Introduction | 第84-85页 |
| 5.2 Materials and methods | 第85-90页 |
| 5.2.1 Plant materials and growth conditions | 第85-86页 |
| 5.2.2 Chemical preparation,treatment application and dry weight analysis | 第86-87页 |
| 5.2.3 Leaf gas exchange and chlorophyll a fluorescence measurements | 第87页 |
| 5.2.4 Determination of enzyme activity | 第87-88页 |
| 5.2.5 Determination of contents of glutathione,H_2O_2 and DAB staining | 第88-89页 |
| 5.2.6 Determination of lipid peroxidation | 第89页 |
| 5.2.7 RNA isolation and RT-PCR reaction | 第89-90页 |
| 5.2.8 Determination of phenanthrene | 第90页 |
| 5.2.9 Statistical analyses | 第90页 |
| 5.3 Results | 第90-97页 |
| 5.3.1 Effects of PHE and EBR on biomass,leaf gas exchange and chlorophyll fluorescence parameters | 第90-91页 |
| 5.3.2 Effects of PHE and EBR application on lipid peroxidation and H_2O_2 accumulation | 第91-92页 |
| 5.3.4 Effects of PHE and EBR application on activities of antionxidant enzymes | 第92-93页 |
| 5.3.5 Effects of EBR on PHE detoxification related gene expression | 第93-95页 |
| 5.3.6 Effects of PHE and EBR application on glutathione contents and GST activity | 第95页 |
| 5.3.7 Effects of EBR application on PHE uptake | 第95-97页 |
| 5.4 Discussion | 第97-100页 |
| 5.4.1 Growth reduction and inhibition of photosynthesis were alleviated by EBR | 第97-98页 |
| 5.4.2 ROS generation and enzyme activity under PHE stress and role of EBR | 第98页 |
| 5.4.4 EBR promotes metabolism of PHE | 第98-100页 |
| 5.5 Conclusions | 第100-101页 |
| Chapter 6 Brassinosteroids regulate secondary metabolism toward enhanced tolerance and savetomato roots from phenantherne induced damage | 第101-117页 |
| Abstract | 第101页 |
| 6.1 Introduction | 第101-103页 |
| 6.2 Materials and methods | 第103-106页 |
| 6.2.1 Plant materials and growth conditions | 第103页 |
| 6.2.2 Chemical preparation and treatment application | 第103页 |
| 6.2.3 Determination of length and fresh weight of shoots and roots | 第103页 |
| 6.2.4 Determination of glutathione S-transferase (GST) activity | 第103页 |
| 6.2.5 Determination of secondary metabolism related enzymes | 第103-105页 |
| 6.2.6 Analyses of total phenol, DPPH activity and flavonoids | 第105页 |
| 6.2.7 Analyses of secondary metabolism related gene expression | 第105-106页 |
| 6.2.8 Root ultrastructure observation by transmission electron microscopy (TEM) | 第106页 |
| 6.2.9 Statistical analyses | 第106页 |
| 6.3 Results and discussion | 第106-116页 |
| 6.3.1 EBR improves growth and biomass production under PHE stress | 第106-107页 |
| 6.3.2 EBR increased secondary metabolism related enzyme activities and gene expressions under PHE stress | 第107-111页 |
| 6.3.3 Root ultrastructural changes under PHE stress and effect of EBR | 第111-116页 |
| 6.4 Conclusions | 第116-117页 |
| Chapter 7 Role of brassinosteroid in alleviation of phenanthrene-cadmium co-contamination-induced photosynthetic inhibition and oxidative stress in tomato | 第117-137页 |
| Abstract | 第117-118页 |
| 7.1 Introduction | 第118-120页 |
| 7.2 Materials and methods | 第120-122页 |
| 7.2.1 Plant material and growth condition | 第120页 |
| 7.2.2 Experimental treatment application | 第120-121页 |
| 7.2.3 Photosynthesis and chlorphyll a fluorescence quenching measurements | 第121页 |
| 7.2.4 Analyses of dry weight analysis and chlorophyll contents | 第121页 |
| 7.2.5 Determination of H_2O_2 its histochemical staining and MDA contents | 第121页 |
| 7.2.6 Determination of antioxidant and detoxification related enzymes activity | 第121页 |
| 7.2.7 Determination of secondary metabolism related enzymes | 第121页 |
| 7.2.8 Determination of H_2O_2, DAB staining and MDA contents | 第121页 |
| 7.2.9 Determination of PHE and Cd contents | 第121-122页 |
| 7.2.10 RNA isolation and RT-PCR reaction | 第122页 |
| 7.2.11 Statistical analyses | 第122页 |
| 7.3 Results | 第122-131页 |
| 7.3.1 Effects of PHE-Cd cocontamination on dry weight of tomato and role of EBR | 第122-123页 |
| 7.3.2 Effects of PHE-Cd cocontamination on leaf gas exchange and role of EBR | 第123-124页 |
| 7.3.3 Effects of PHE-Cd cocontamination on chlorophyll fluorescence and chlorophyll contents in tomato leaves and role of EBR | 第124-125页 |
| 7.3.4 Effects of PHE-Cd cocontamination on H_2O_2 accumulation and lipid peroxiddation in tomato leaves and role of EBR | 第125-126页 |
| 7.3.5 Effects of PHE-Cd cocontamination on antioxidant enzymes and related gene expressions in tomato leaves | 第126-127页 |
| 7.3.6 Effects of PHE-Cd cocontamination and role of EBR on pollutant detoxification | 第127-130页 |
| 7.3.7 Effects of PHE-Cd cocontamination on secondary metabolism related enzymes and genes in tomato leaves and role of EBR | 第130页 |
| 7.3.8 Effects of EBR on accumulation of PHE and Cd in tomato | 第130-131页 |
| 7.4 Discussion | 第131-137页 |
| Chapter 8 The growth, photosynthesis and antioxidant defense responses of five vegetable cropsto phenanthrene stress | 第137-156页 |
| Abstract | 第137页 |
| 8.1 Introduction | 第137-139页 |
| 8.2 Materials and methods | 第139-143页 |
| 8.2.1 Plant materials and growth conditions | 第139-140页 |
| 8.2.2 Phenanthrene preparation and treatment application | 第140-141页 |
| 8.2.3 Biomass determination | 第141页 |
| 8.2.4 Photosynthesis measurement | 第141页 |
| 8.2.5 Chlorophyll fluorescence and chlorophyll content measurements | 第141-142页 |
| 8.2.6 Determination of enzyme activity | 第142页 |
| 8.2.7 Malondialdehyde content determination | 第142-143页 |
| 8.2.8 Histochemical detection of H_2O_2 accumulation | 第143页 |
| 8.2.9 Statistical analyses | 第143页 |
| 8.3 Results | 第143-151页 |
| 8.3.1 Phenanthrene caused growth retardation | 第143-144页 |
| 8.3.2 Phenanthrene inhibited photosynthesis | 第144-145页 |
| 8.3.3 Changes in the chlorophyll fluorescence parameters in response to PHE | 第145-147页 |
| 8.3.4 Changes in the chlorophyll contents in response to PHE | 第147页 |
| 8.3.5 Effects of PHE on antioxidant enzymes of vegetable crops | 第147-150页 |
| 8.3.6 Effects of PHE foliar application on lipid peroxidation and H_2O_2 accumulation in leaves of vegetable crops | 第150-151页 |
| 8.4 Discussion | 第151-155页 |
| 8.5 Conclusions | 第155-156页 |
| Chapter 9 Brassinosteroid alleviates polychlorinated biphenyls-induced oxidative stress byenhancing antioxidant enzymes activity in tomato | 第156-175页 |
| Abstract | 第156-157页 |
| 9.1 Introduction | 第157-159页 |
| 9.2 Materials and methods | 第159-163页 |
| 9.2.1 Plant material and growing conditions | 第159-160页 |
| 9.2.2 Treatment application, sample harvesting and dry weight analysis | 第160页 |
| 9.2.3 Photosynthesis measurement | 第160-161页 |
| 9.2.4 Chlorophyll fluorescence and chlorophyll content measurements | 第161页 |
| 9.2.5 Determination of activity of antioxidant enzymes | 第161-162页 |
| 9.2.6 Visual detection of H_2O_2 accumulation and determination of H_2O_2 content | 第162-163页 |
| 9.2.7 Determination of lipid peroxidation | 第163页 |
| 9.2.8 Statistical analysis | 第163页 |
| 9.3 Results | 第163-170页 |
| 9.3.1 Effects of PCBs on dry weight and role of EBR | 第163-164页 |
| 9.3.2 Effects of PCBs on leaf gas exchange and role of EBR | 第164页 |
| 9.3.3 Effects of PCBs and EBR on chlorophyll fluorescence quenching and chlorophyll contents | 第164-166页 |
| 9.3.4 Effects of PCBs and EBR on H_2O_2 accumulation and membrane lipid peroxidation | 第166-169页 |
| 9.3.5 Responses of antioxidant enzymes to PCBs and EBR application | 第169-170页 |
| 9.4 Discussion | 第170-174页 |
| 9.5 Conclusions | 第174-175页 |
| References | 第175-197页 |
| List of Publications | 第197页 |
