Suberin is a wax like fatty substance, occurring in cork cell walls and in or between other cells. On alkaline hydrolysis it yields chiefly suberic acid. Suberin is highly hydrophobic and its main function is to prevent water from penetrating the tissue. In roots suberin is deposited in the radial and transverse cell walls of the endodermal cells. This structure is known as the Casparian strip or Casparian band. Suberin is found in the phellem layer of the periderm (or cork). This is outermost layer of the bark. The cells in this layer are dead and abundant in suberin, preventing water loss from the tissues below.
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