DYNAMIC ASPECTS OF THE PLANT EXTRACELLULAR-MATRIX

This chapter discusses dynamic aspects of the plant extracellular matrix. It describes the current status of knowledge of biochemical regulation that leads to differential patterns of synthesis of wall components, their site of synthesis and deposition, and the changes that occur in response to developmental and environmental cues. The plant-cell wall, with its connotations of rigidity and maintenance of shape, is possibly considered as an extracellular matrix with dynamic properties. Various classes of polysaccharides of the extracellular matrix are well-conserved. Cellulose microfibrils are spun into a matrix consisting of both pectinaceous and hemicellulosic polysaccharides. In addition to cellulose microfibrils, plant walls also contain hemicelluloses and pectins. Phenolics are deposited mainly in the secondary wall but are also important constituents within the primary wall. Wall phenolics are based upon the phenylpropanoid unit and are found as both conjugated acids and, more familiarly, lignin alcohols. The cell wall is intimately involved as part of the sensing of the environment and in responding through the ensuing changes. © 1993 Academic Press Inc.