ABSTRACT
This chapter provides a general view of the formation of lignins in plant cell walls, chemical structure of lignins, distribution of lignins in wood tissues, and the location of chemically different types of lignins in woods in relation to the elucidation of the biodegradation of lignin by microorganisms. The fine distribution of lignin in respective layers of xylem cell walls can be observed by the ultraviolet microscope — a technique which can be applicable for morphological approach of microbial degradation of lignin in woods. It has been shown that lignin, which comprises 17 to 33% of wood, is a complex aromatic polymer and has a role in cementing the polysaccharide components in cell walls both chemically and physically, thus increasing the mechanical strength of wood as a composite material and its decay resistance toward micoorganisms. T. Fukuda confirmed that the lignins of callus tissue and cultured cells of poplar are related to conifer lignin.
