Jane

JANE M. OGARIO II-PILOT

CORK CELLS

Mature cork cells are plant cells that form the protective water-resistant tissue in the outer covering of stems or trunks. Cork cells are genetically programmed not to divide, but instead to remain as they are, and are considered dead cells. Each cell wall is comprised of a waxy substance known as suberi n, which is highly impermeable to gases and water. Depending upon the species of woody plant, the cork cell may be filled with air or may contain traces of lignin, tannins, or fatty acids. Thickness of cork tissue varies from one plant to the next. Packed closely together, the cells are generally arranged in radial rows and separation is achieved by structures called lenticels. These pore-like structures allow gases to be exchanged between the plant stem and the outside environment. The layer of dead cells formed by the cork cambium provides internal plant tissue, including the vascular system, with extra insulation and protection. The Quer cus su ber , also known as the cork oak, is cultivated for cork and is stripped of its outer cork layer about every nine years. Qualities most prized in cork material include insulating, shock absorbing, and gas and water impermeable properties. Probably the most familiar use of cork is as the bottle stopper used to preserve fine wines and champagnes. Cork from oak trees native to southern Europe and northern Africa is generally harvested every several years after the thick layers have accumulated.