LIGNIN-CARBOHYDRATE COMPLEXES IN GRAMINEOUS CELL-WALLS IN RELATION TO DIGESTIBILITY

Lignin is directly or indirectly covalently bound to polysaccharides in the intact plant cell wall. Relatively little is known about the structures of these lignin-carbohydrate complexes in graminaceous cell walls, despite their evident importance in limiting cell wall degradability. The present state of knowledge on this subject is briefly reviewed with emphasis on results recently obtained by the authors in which two different lignin structures were isolated from a single plant species. It is concluded that much remains to be learnt about lignin-carbohydrate structures especially in terms of their heterogeneity and distribution throughout the cell wall.