Edit page | Page history | Printable version

Lignin

(Science: plant biology) organic substance which act as a binder for the cellulose fibres in wood and certain plants and adds strength and stiffness to the cell walls.

The chemical structure of lignin is composed of a complex polymer of phenylpropanoid subunits, laid down in the walls of plant cells such as xylem vessels and sclerenchyma. It imparts considerable strength to the wall and also protects it against degradation by microorganisms. It is also laid down as a defence reaction against pathogenic attack, as part of the hypersensitive response of plants. A complex polymer; the chief non-carbohydrate constituent of wood; binds to cellulose fibers to harden and strengthen cell walls of plants.A compound found in cell walls, and this non living component provides a structural function in xylem and bark in plants.