The molecular basis of plant cell wall extension

In all terrestrial and aquatic plant species the primary cell wall is a dyn amic structure, adjusted to fulfil a diversity of functions. However a univ ersal property is its considerable mechanical and tensile strength, whilst being flexible enough to accommodate turgor and allow for cell elongation. The wall is a composite material consisting of a framework of cellulose mic rofibrils embedded in a matrix of non-cellulosic polysaccharides, interlace d with structural proteins and pectic polymers. The assembly and modificati on of these polymers within the growing cell wall has, until recently, been poorly understood. Advances in cytological and genetic techniques have thr own light on these processes and have led to the discovery of a number of w all-modifying enzymes which, either directly or indirectly, play a role in the molecular basis of cell wall expansion.