The most interesting particularity of the cork oak lies in the fact that it produces an outer bark, formed of an elastic, waterproof and thermally insulating fabric: cork. This bark is made up of dead cells with walls waterproofed by a chemical compound called suberin.
All trees produce layers of corked cells as a form of protection, but only the cork oak is able to "build" its outer bark by adding cork rings annually resulting from the activity of a set of mother cells: the phellogen. The homogeneity of cork results from the fact that the phellogen of the cork oak is maintained for
throughout the life of the tree. This contrasts with other trees where each phellogen has a reduced lifespan.
Formation The growth in diameter of the cork oak stem results from
two cell-generating bases, one of which is called “phellogen”, “mother of cork” or more scientifically “subero-phellodermic base”, located
e between cork and bast. The subero-phellodermic layer produces cork on the outside and phelloderm on the inside; the libero-ligneous base (also called cambium) produces the bast (responsible for transporting the elaborated sap) outwards and the xylem or wood (responsible for transporting the raw sap) inwards.
After debarking, the mother thus discovered dries out in part to form a crust and is reformed more deeply by dedifferentiation of the cells.
In the old days, the mother was harvested from old individuals that had reached the end of their exploitation cycle to remove the tan.
used in the tanning of hides.
Composition
Cork cells have the shape of a hexagonal or pentagonal prism. The size of a cell rarely exceeds 0.045 millimeters; the smallest cells only 0.02 or 0.01 millimeters. In the 17th century, the British physicist Robert Hooke succeeded in obtaining the first image of cork using a microscope of his invention. He is thus the first to observe a cork cell. He discovers that the walls of these cells are made of suberin, the main component of cork, supported by lignin and cellulose. Suberin is a mixture of fatty acids and heavy organic alcohols that make cork impermeable to liquids and very slightly permeable to gases. The suberi
ne has remarkable properties: it practically does not melt, is insoluble in water, in alcohol, in ether, in chloroform, in sulfuric acid….
Cork fan
Buy
#le #liège #structure #et #composition #france #paris #architecture #art #lille #instagood #lyon #la #love #picoftheday #french #de #beautiful #francais #nantes #photography #photooftheday #antwerpen #design #exposure #French #Bordeaux #travel #capture #civilization