Cork Cambium

Cork cambium, also called phellogen, is a type of lateral meristem found in the stems and roots of many plants.

• It plays an important role in secondary growth, which increases the thickness or girth of plant organs.
• Forms part of the periderm, a protective tissue that replaces the epidermis in older stems and roots.
• The cork cells are dead and contain suberin, a waxy substance that prevents water loss and protects the plant from mechanical injury and pathogen attack.

Structure of Cork Cambium

The periderm's cork cambium is made up of a single layer of relatively undifferentiated cells. A ring of cells known as the cambium tissue forms on the outside of the plant's woody tissue and extends the entire length of the mature stem or branch.

• These undifferentiated cells divide to produce the periderm's growing cells, particularly the cork cells that make up the branch's or trunk's outermost surface.
• Early or soft bark is the term used to describe bark that forms early in the season.
• Late or hard bark forms when the season comes to a close. Give the cell layers of diverse types that make up the bark. 
• In some areas, the phellogen, instead of cork cells, removes closely packed parenchymatous cells.
• Immediately after breaking through the epidermis, parenchymatous cells create lenticels, or apertures resembling lenses.
• Lenticels allow the transfer of gases that exist between the exterior environment and the stem's interior tissue. Most woody trees have these.

Formation of Cork Cambium

• The outer cortical and epidermal layers break down and need to be replaced to produce new protective cell layers, while the stem continues to grow as a result of the activity of the vascular cambium.
• As a result, cork cambium or phellogen, another meristematic tissue, eventually forms, mainly in the cortical area. There are a few levels of phellogen.
• It is constructed of compact, almost rectangular compartments with thin walls. Cells are separated on both sides by phellogen. Differentiating into cork or phellem are the outer cells.
• The inner cells develop into a secondary cortex or phelloderm, whereas water cannot penetrate the cork because of suberin deposition in the cell wall. Secondary cortical cells are parenchymatous.
• The periderm is the aggregate name for phellogen, phellem, and phelloderm.

Periderm = Phellogen (Cork cambium) + Phellem (Cork) + Phelloderm

• Pressure accumulates on the remaining peripheral layers as a result of the cork cambium's activity. These layers eventually phellogen, perish and peel off.
• All tissues outside of the circulatory system are referred to as "bark" in a non-technical sense. Cork cambium, which comprises secondary phloem.
• Periderm and secondary phloem are two of the tissue types that are referred to as bark.

Functions of Cork Cambium

• The cork, a robust protective substance, and the secondary cortex are produced by the cork cambium.
• In roots and stems, it is in charge of secondary growth that takes the place of the epidermis.
• One of the plant's meristems, a group of tissues made up of embryonic cells from which the plant develops, is the cork cambium.
  It guards the tree against fungal or bacterial illness.
• It stops water from escaping through the bark.
• Phellogen (cork cambium) is a meristem that produces periderm tissue. 

Cork Cambium vs. Vascular Cambium