Lignin, Pectin & Mucilage
Lignins are a highly branched polymer formed from aromatic phenolic alcohols (monolignols). They are present in cell walls ( especially in secondary walls of xylem tracheary elements). Pectin's are Complex heterogeneous mixture of water soluble noncellulosic polysaccharides found in cell walls & intercellular spaces of plants, Rich in galacturonic acid (acid form of galactose), Present in the primary walls (35%) & middle lamella of cell wall. Mucilage is a thick, gluey or slimy substance widely distributed in different parts (leaves, roots, flower & fruits) in plants. Chemically it is complex carbohydrate (Proteins & polysaccharides). Sugars present are arabinose, galactose, xylose, rhamnose, uronic acid etc