Novel structures and properties of lignins in relation to their natural and induced variability in ecotypes, mutants and transgenic plants

Lignins definition, potential applications, (macro)molecular structures and properties, analytical characterisations and natural versus induced variability are reviewed with reference to both the biological diversity of lignification patterns in ecotypes, mutants and transgenic plants and the levels of organisation of the lignins polymeric networks. A discrimination between a common primary, guaiacyl type metabolism and a more specific secondary, syringyl type is suggested as a base of this variability and properties.