The walls of cork cells in the bark of trees are impregnated with suberin, and suberin also forms the permeability barrier in primary roots known as the Casparian strip.
The older parts of roots are sheathed in layers of dead cork cells impregnated with a waxy, waterproof (and airproof) substance called suberin. This sheath reduces water loss but is as impervious to oxygen and carbon dioxide as it is to water.
Additional layers may be formed containing lignin inside xylem cells, or containing suberin in cork cells. These compounds are rigid and waterproof, making the secondary wall stiff. Both wood and bark cells of trees have secondary walls.
cork cambium Meristematic tissue that produces cork cells on its outer surface and phelloderm on its inner surface.
corm Underground, enlarged, food-storing stem covered by papery leaves.
cornea The outer transparent coat of the eye.
Secondary growth is produced by a cambium. It occurs in rows or ranks of cork, secondary xylem or secondary phloem cells. Cork cells (produced by a cork cambium) are technically part of the epidermis, and contribute to the bark of woody stems.
[L. cortex, bark + cambium, exchange]
A cylinder of meristematic tissue in plants that produces cork cells to replace the epidermis during secondary growth.
Robert Hooke person who‚ in 1665‚ was the first to see and name cells - actually‚ what he first saw was the cell walls that were the remains of formerly-living cork cells ...
See also: Cells, Cork, Plant, Tissue, Trans