During the growth and development of vascular plants, specific phenylpropanoid metabolites differentially accumulate in particular tissues and/or cells of specialized function(s). Examples include the deposition of lignins in xylem tissue and vascular bundles and suberins in suberized cells, the accumulation of flavonoids in vacuolar and sometimes in wall compartments, and the ester attachment of hydroxycinnamic acids to arabinoxylans in the cell wall. Many of these metabolites confer unique properties to particular tissues or cells without which the competitive survival of vascular plants would be severely, if not fatally, compromised.