Lenticel

Lenticels or Korkporen are areas of the bark of woody plants, in which a formed by tearing the top layer of cells opening with underlying dead, not firmly connected cork cells allows gas exchange between ambient air and the living tissue below the Lentizelle. Lenticels are on the trunks and branches of shrubs or trees as small, round or elongated protuberances ( " Korkwarzen " ) recognizable; they are also formed on stilt roots and pneumatophores.

Lenticels occur during the formation of crusts. Below the epidermis forms a cork cambium ( cork cambium ) cork cells; the bark of cork finally replaces the epidermis. Cork cells are impermeable to gases and water Suberineinlagerung. At sites with high mitotic activity of Phellogens (often below a gap opening ) is caused by the production of cork cells, a swelling, which pushes the cork cambium inward and the epidermis can be tear. The produced here and after Suberineinlagerung dying, rounded filler cells detached from each other and are loosely below the opening. About the spaces between the cells ( intercellular spaces ) can occur, as can be demonstrated in experiments with radioactively labeled carbon dioxide or with infrared gas analyzers gas exchange.

The stomata formed by living guard cells ( stomata ) in the epidermis of photosynthetically active tissues also serve the gas exchange; in contrast to lenticels stomata are, however, actively opened or closed by the plant.