Biochemistry and Molecular Biology of Wood

Progress in wood chemistry has been related mainly to chemical wood pulping and bleaching and chemical utilization of wood and wood extractives. Meth­ ods of wood analysis were developed by Schorger (proximate analysis in 1917) and Dore (summative analysis in 1919), and standard methods based on Schorger's method, e.g., TAPPI standards (Technical Association of the Pulp and Paper Industry), have been widely used for chemical analysis of woods in many countries. Thus it is generally known that wood is composed of about 50% cellulose, 20-35% of lignin, 15-25% of hemicelluloses, and variable amounts of extractives. Chemical characterization and efficient utilization of these wood components have been studied in laboratories of wood chemistry and technology in universities and government institutions. In the last decade, biochemistry and molecular biology of microorganisms, animals, and plants have greatly progressed. At the same time wood has been recognized as a unique renewable ecomaterial produced by trees using solar energy. In addition, many desirable properties of wood and wood components as biomaterial that affects physiology and psychology in humans have recently attracted attention.

Contenu

1 Structure and Functions of Wood.- 1.1 Microscopic Structure.- 1.1.1 Softwoods (Conifers).- 1.1.2 Hardwoods (Dicot Angiosperms).- 1.1.3 Bamboos.- 1.2 Ultrastructure of Wood Cell Walls.- 1.2.1 Cellulose Microfibrils.- 1.2.2 Orientation of Microfibrils.- 1.2.3 Cell Walls of Reaction Woods.- 1.3 Ultrastructure and Functions of Wood Cells.- 1.3.1 Nucleus.- 1.3.2 Ribosomes.- 1.3.3 Endoplasmic Reticulum.- 1.3.4 Golgi Apparatus.- 1.3.5 Mitochondria.- 1.3.6 Plastids.- 1.3.6.1 Amyloplasts.- 1.3.6.2 Chloroplasts.- 1.3.7 Vacuoles.- 1.3.8 Cytoskeletons.- 1.3.8.1 Microtubules.- 1.3.8.2 Microfilaments.- 1.3.9 Cell Membrane.- 1.3.10 Cell Wall.- 2 Primary Metabolism in Woody Plants.- 2.1 Primary and Secondary Metabolism.- 2.2 Photosynthesis.- 2.3 Photorespiration.- 2.4 Glycolysis.- 2.5 Tricarboxylic Acid Cycle.- 2.6 Pentose Phosphate Cycle.- 2.7 Glyoxylate Cycle.- 2.8 Nitrogen Metabolism.- 2.8.1 Nitrogen Fixation.- 2.8.2 Amino Acid Formation.- 2.8.3 Transamination.- 3 Genome Organization, Protein Synthesis, and Gene Expression.- 3.1 Genome Organization.- 3.1.1 DNA and Genes.- 3.1.2 Genes and Chromosomes.- 3.1.3 Structure and Duplication of DNA.- 3.1.4 RNA Synthesis.- 3.1.4.1 Structure and Function of mRNA.- 3.1.4.2 Structure and Function of tRNA.- 3.1.4.3 rRNA.- 3.1.4.4 Splicing of RNA.- 3.1.4.5 RNA Editing.- 3.1.5 mRNA and the Genetic Code.- 3.2 Protein Synthesis.- 3.3 Gene Expression.- 3.3.1 Fundamental Structure of the Gene.- 3.3.2 RNA Polymerase and Transcription Apparatus.- 3.3.3 Base Sequence of Transcription Promoter.- 3.3.4 The Factor of Transcriptional Control.- 3.3.5 Regulation of Gene Expression.- 3.4 Gene Expression in Plants.- 3.4.1 Regulation of Gene Expression by Light.- 3.4.2 Gene Expression in Chloroplasts.- 3.4.3 Gene Expression in Mitochondria.- 4 Biosynthesis of Wood Components.- 4.1 Chemical Composition of Wood.- 4.1.1 Cellulose.- 4.1.2 Hemicelluloses.- 4.1.3 Lignin.- 4.1.4 Aliphatic Compounds.- 4.1.5 Sugars.- 4.1.6 Aromatic Compounds.- 4.1.7 Terpenes.- 4.1.8 Biosynthetic Pathways.- 4.2 Biosynthesis of Cell Wall Polysaccharides.- 4.2.1 Localization of Polysaccharides in Wood Cell Walls.- 4.2.2 Metabolism of Sugar Nucleotides.- 4.2.2.1 UDP-Glucose Pyrophosphorylase.- 4.2.2.2 Sucrose Synthase.- 4.2.2.3 UDP-Glucose Dehydrogenase.- 4.2.2.4 UDP-Glucuronate Carboxylase.- 4.2.2.5 UDP-Glucose 4-Epimerase.- 4.2.2.6 UDP-Glucuronate 4-Epimerase.- 4.2.2.7 UDP-Arabinose 4-Epimerase.- 4.2.2.8 The myo-Inositol Oxidation Pathway.- 4.2.3 Biosynthesis of Cellulose.- 4.2.3.1 Microorganisms.- 4.2.3.2 Plants.- 4.2.4 Cellulose Microfibrils.- 4.2.4.1 Structure of Microfibrils.- 4.2.4.2 Formation of Microfibrils.- 4.2.4.3 Cell Growth and Microfibril Orientation.- 4.2.5 Biosynthesis of ?-1,3-Glucan.- 4.2.6 Biosynthesis of Xyloglucan.- 4.2.7 Biosynthesis of Xylan (Arabinoxylan).- 4.2.8 Biosynthesis of Glucomannan.- 4.2.9 Biosynthesis of Galactan.- 4.2.10 Biosynthesis of Arabinan.- 4.2.11 Biosynthesis of Pectin (Polygalacturonic Acid).- 4.2.12 Biosynthesis of Sugar Chains of Glycoproteins.- 4.2.13 Cell Organelles Involved in Polysaccharide Synthesis.- 4.3 Phenylpropane Derivatives.- 4.3.1 The Shikimate Pathway Commonly Involved in the Biosynthesis of Aromatic Compounds.- 4.3.1.1 The Enzyme System in Aromatric Biosynthesis.- 4.3.2 Biosynthesis of Phenylalanine and Tyrosine.- 4.3.2.1 Phenylalanine and Tyrosine.- 4.3.2.2 Diversity of the Shikimate Pathway.- 4.3.3 The General Phenylpropanoid Pathway.- 4.3.3.1 Phenyalanine Ammonia-Lyase.- 4.3.3.2 Cinnamate 4-Hydroxylase (C4H).- 4.3.3.3 4-Coumarate: Coenzyme A Ligase (4CL).- 4.3.4 Lignin.- 4.3.4.1 Formation of Monolignols.- 4.3.4.2 Dehydrogenative Polymerization of Monolignols to Lignins.- 4.3.4.3 Structural Differences in Dehydrogenation Polymers.- 4.3.4.4 Differences in Biosynthesis of Lignins Between Tissues and Plants.- 4.3.5 Lignans.- 4.3.5.1 Introduction.- 4.3.5.2 Structural Features of Lignans.- 4.3.5.3 Biosynthetic Pathways of Lignans - In Vivo Experiments.- 4.3.5.4 Enzymatic Lignan Formation.- 4.3.6 Flavonoids.- 4.3.6.1 Biosynthetic Pathways.- 4.3.6.2 Isoflavonoids.- 4.3.7 Stilbenes.- 4.3.7.1 Biosynthesis.- 4.3.7.2 Induction of Stilbene Formation.- 4.3.8 Quinones.- 4.3.9 Tannins.- 4.3.9.1 Hydrolyzable Tannins.- 4.3.9.2 Condensed Tannins.- 4.3.10 Suberin.- 4.4 Lipids.- 4.4.1 Membrane Lipids.- 4.4.2 Acyltriglycerides (Fats).- 4.4.2.1 Saturated Fatty Acids.- 4.4.2.2 Unsaturated Fatty Acids.- 4.4.2.3 Acyltriglycerides.- 4.4.3 Waxes.- 4.5 Isoprenoids.- 4.5.1 Structure of Isoprenoids.- 4.5.2 Polymerization of Active Isoprene.- 4.5.3 Formation of Cyclic Mono- and Sesquiterpenes.- 4.5.4 Biosynthesis of Carotenoids.- 4.5.5 Di- and Triterpenes.- 4.5.6 Biosynthesis of Polyterpenes.- 4.5.7 Prenylation of Proteins.- 4.5.8 Tropolones.- 5 Formation and Development of Wood Tissues.- 5.1 Development of Phloem and Xylem.- 5.1.1 Formation of Phloem and Xylem.- 5.1.1.1 Primary Xylem.- 5.1.1.2 Primary Phloem.- 5.1.1.3 Vascular Cambium.- 5.1.2 Regulation of Xylem and Phloem Differentiation.- 5.1.2.1 Plant Hormones.- 5.1.2.2 Other Factors.- 5.1.3 Physiological and Biochemical Processes of Xylem and Phloem Differentiation.- 5.1.3.1 Acquisition of Differentiation Ability.- 5.1.3.2 Cell Elongation.- 5.1.3.3 Formation of Secondary Walls.- 5.1.3.4 Disappearance of Cell Content.- 5.1.4 Genes Involved in Tracheary Element Differentiation.- 5.1.4.1 Genes Expressed Before Vascular Bundle Differentiation.- 5.1.4.2 Genes Expressed in Vascular Bundle Formation.- 5.1.4.3 Regulation of Gene Expression in Vascular Bundle Differentiation.- 5.1.5 Deposition of Polysaccharides and Lignin in Xylem Cell Walls.- 5.1.5.1 Deposition of Lignin in Xylem Cell Wall.- 5.1.5.2 Formation and Structure of Conifer Lignin.- 5.1.5.3 Formation and Structure of Hardwood Lignin.- 5.1.5.4 Formation and Structure of Grass Lignin.- 5.1.5.5 Deposition of Lignin at the Molecular Level.- 5.1.5.6 Transportation and Polymerization of Monolignols in Cell Walls.- 6 Formation of Earlywood, Latewood, and Heartwood.- 6.1 Regulation of Formation of Earlywood and Latewood.- 6.1.1 Auxins.- 6.1.1.1 Formation and Distribution of Auxins in Conifers.- 6.1.1.2 Effect of Indole Acetic Acid on Formation of Tree Stems.- 6.1.2 Abscisic Acid.- 6.1.3 Cytokinins.- 6.1.4 Gibberellins.- 6.1.5 Ethylene.- 6.1.6 Brassinosteroids.- 6.2 Regulation of Heartwood Formation.- 6.2.1 Histological Characteristics of Heartwood.- 6.2.2 Heartwood and Extractives.- 6.2.3 Metabolism of Ray Parenchyma Cells.- 6.2.4 Gene Expression in Heartwood Formation.- References.