korkokambium

Korkokambium, also known as the cork cambium or phellogen, is a secondary meristematic tissue found in the stems and roots of many vascular plants. It is one of the two main types of lateral meristems, the other being the vascular cambium. The cork cambium originates from the cortex or epidermis and is responsible for producing the periderm, a protective outer layer of tissue that replaces the epidermis as the plant grows in girth.

The cork cambium is a layer of actively dividing cells that produce new cells on its outer and inner surfaces. The cells produced on the outer surface differentiate into cork cells, also known as phellem, which are dead at maturity and filled with suberin, a waxy substance that provides waterproofing and protection against mechanical injury and pathogens. The cells produced on the inner surface differentiate into phelloderm, which are living parenchyma cells that can function in storage or photosynthesis.

Together, the cork cambium, cork, and phelloderm constitute the periderm. The periderm replaces the epidermis as the primary protective layer of the plant, particularly in woody plants where extensive secondary growth occurs. Lenticels, which are pores in the periderm, allow for gas exchange between the internal tissues of the plant and the atmosphere. The activity of the cork cambium is a crucial component of secondary growth, contributing to the increased diameter and structural integrity of stems and roots.