No abstract
The tissue distributions of sinapic acid esters (1-sinapoylglucose, sinapolyl-L-malate, 6,3'-disinapoylsucrose), kaempferol glycosides, free malic acid and of the enzyme involved in the synthesis of sinapoyl-L-malate, 1-sinapoylglucose: L-malate sinapoyltransferase (SMT), have been investigated in cotyledons of Raphanus sativus L. seedlings. The kaempferol glycosides were mainly localized in the upper epidermis. The sinapoyl esters were found in all tissues, but differed markedly in their concentrations. While disinapoylsucrose was localized predominantly in the mesophyll, most sinapoylmalate was found in the epidermal layers, as was most SMT activity. Ultraviolet microscopy and microfluorospectrophotometry of isolated epidermal peels indicated that the epidermal sinapoyl esters were restricted to guard cells, guard mother cells and adjacent epidermal cells. Upon excitation by UV light (365 nm) these exhibited strong blue fluorescence with an emission maximum at about 480 nm. Our results indicate a highly tissue-and cell-specific secondary metabolism in Raphanus cotyledons and indicate that the biosynthesis of sinapoylmalate is intimately related to the malic-acid metabolism of the guard cells.
The article contains sections titled: 1. Introduction 2. Vulcanization Chemicals 2.1. Basics of Vulcanization 2.2. Sulfur‐Containing Cross‐Linking Agents 2.3. Vulcanization Accelerators 2.3.1. Classes of Accelerators 2.3.2. Toxicology and Ecology of Organic Vulcanization Accelerators 2.3.3. Delivery Forms of Vulcanization Accelerators 2.4. Accelerator Activators 2.5. Sulfur‐Free Cross‐Linking Agents 2.5.1. Peroxides (Organic Peroxides and Peroxycarboxylic Acids) 2.5.2. Quinone Dioxime 2.5.3. Polymethylolphenol Resins 2.5.4. Other Cross‐Linking Agents 2.5.5. Radiation Cross‐Linking 2.6. Vulcanization Retarders 3. Antidegradants 3.1. Appearance of Aging and Fatigue 3.2. Classification and Types of Antidegradants 3.2.1. Staining Antidegradants that Act as Anti‐Flex‐Cracking Agents and Antiozonants 3.2.2. Staining Antidegradants with Protection against Fatigue, but Not against Ozone 3.2.3. Staining Antidegradants with Little or No Protection against Fatigue and None against Ozone 3.2.4. Nonstaining Antidegradants with Protection against Fatigue or Ozone 3.2.5. Nonstaining Antidegradants without Protection against Fatigue or Ozone 3.2.6. Nonstaining Antiozonants without Protection against Aging 3.2.7. Other Antidegradants 3.3. Choice of Antidegradants 4. Fillers and Pigments 4.1. Typical Properties and Types of Fillers 4.1.1. Action of Fillers 4.1.2. Properties of Fillers and Their Significance 4.2. Carbon Blacks 4.3. White Fillers 4.3.1. Precipitated Silicas 4.3.1.1. Production 4.3.1.2. Physicochemical Properties 4.3.1.3. Commercial Products 4.3.1.4. Essentials of Rubber Silicas 4.3.2. Inactive White Fillers 4.3.3. Coating of Fillers 4.4. Pigments 4.4.1. White Pigments 4.4.2. Inorganic Colored Pigments 4.4.3. Organic Colored Pigments 4.5. Organic Fillers 5. Plasticizers 5.1. General 5.2. Mineral Oils 5.3. Synthetic Plasticizers 5.4. Natural Products 6. Processing Additives 6.1. Behavior and Classification of Processing Additives 6.2. Peptizers 6.3. Dispersing Agents and Lubricants 6.4. Homogenizers 6.5. Tackifiers 6.6. Release Agents 6.6.1. Batch‐Off Release Agents 6.6.2. Mold Release Agents 6.6.3. Release Agents for Special Applications 6.6.3.1. Mandrel Release Agents 6.6.3.2. Bladder Release Agents 6.6.3.3. Inside Tire Paint 6.6.3.4. Outside Tire Paints 6.7. Other Processing Additives 7. Rubber Adhesion 7.1. Adhesion of Rubber to Reinforcing Materials 7.2. Rubber – Metal Bond 8. Chemical Blowing Agents 8.1. Cellular Rubber Articles 8.2. Product Types and Properties 9. Latex Chemicals 10. Flameresistant Rubber Articles 10.1. Combustion Process in Polymeric Materials 10.2. Testing of Flammability 10.3. Inhibition of Combustion
In the oxidation of polycyclophosphanes, oxygen is bound exocyclically and is not inserted into the PP bonds. The P skeleton of the educts remains intact during the oxidation. l a and its isomer, with oxygen on P3 of the five‐mem‐bered ring, and 2a and 2b are obtained from P6,tBu4, and P,tBu, respectively. Proof of the constitution of the compounds followed from the 31P{1H}‐NMR spectra, which could be taken from an NMR handbook.
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