The Biosynthesis and Biogenesis of Lignin in Plant Cell Walls

THE BIOSYNTHESIS AND BIOGENESIS OF LIGNIN IN PLANT CELL WALLS 

A clear understanding of lignin deposition in the cell wall is not yet possible, but a number of facts are known. Lignin precursors of the phenylglucoside type are formed either in the region of the cambium (the zone of new cell synthesis) or within the lignifying cell itself. Lignification is thus initiated in the differentiated wood cells from the primary walls adjacent to the cell corners and then extends into the inter-cellular area, the lamella, and thereafter to the primary and secondary cell walls. 

It is possible to prepare a lignin-like polymer, known as dehydrogenated polymerisate (DHP) in the laboratory by treating con-iferyl alcohol in vitro under aerobic conditions with a phenoloxidase 

Wood Morphological region Tissue volume (%) Lignin (% of total) Lignin concentration (%) 

Lignin and carbohydrates exist in close association in the wood structure and there is now strong evidence to suggest that formal covalent links exist between the lignin macromolecule and carbo- 

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