Anatomy of Cork Tissue in Plants

The cork plant or the cork layer is made up of the phellem layer of the bark tissue. The cork plant is present in the outermost covering of the trees. Suberin is present in the cork cells. As the cork has deposits of suberin, they are impermeable to water and insects and thus they can be used in a variety of products. The cork is mainly obtained from the bark of trees or we can call it from the cork cells of the cork plant. The cork meaning in science is that it is a buoyant material that is obtained from the barks of trees and cork plants and it is impermeable in nature. The suberin that is present in cork cells is a hydrophobic substance. This helps us to define the meaning of what is cork. Now we will learn about what are cork cells and how is cork formed. 

Cork Cell

The cork cells are non-living in nature. As we read above the cork cells are composed of suberin. This suberin is waxy in nature and this helps to block the gases and water. Sometimes these cork cells are filled with air and sometimes with lignin. This is dependent on the species of the wooden plants from which they are obtained. In some species, tannins and fatty acids are also present. These cells are arranged in radial rows. Lenticels are small pores in the barks of the tree and this helps in gaseous exchange to the tree and they also bring about the separation among the cork cells. As these cork cells are non-living in nature, it helps in providing insulation and protection to the internal cells of the plant. 

This is what is cork in biology. 

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Cork Formation

Here we will learn about what is cork formation. The cork cells are formed in the cork plant. This cork plant or the bark of the tree is formed in the secondary growth of the plant. The secondary growth is done with the help of vascular bundles. The vascular bundles get arranged in a ring-like manner. They are arranged around the central pith and are conjoint and open. As they possess cambium therefore they are called open tissues. It is known as intrafascicular cambium. The cells start the process of dedifferentiation and in this way, the cambium rings are formed. These cambium rings that are formed by the cambium start dividing. From the observations, it is seen that the cambium is more active on the inner side as compared to the outer side. The cork cambium is responsible for the growth of cork cells.

Cork Origin

Here we will know about what is cork cell origin. It is a meristematic tissue that arises from the cells of the pericycle. The cells of the pericycle get divided and it results in the formation of cork cambium. This cork cambium further gives rise to the periderm. The activity of the cork cambium is similar in both the dicot root and dicot stem. Cork cells are produced on the outer side and secondary cortex on the inner side. The cork cells have the presence of suberin in their cell wall. These cells become dead due to more and more deposition of suberin. The activity of cork cambium builds pressure in the layers that are peripheral to the phellogen. 

Cork Cambium

The cork cambium is the main tissue that is responsible for the formation of wood. The girth of the stem increases due to increased activity of the vascular cambium. As the girth keeps increasing the outer cortical layers starts rupturing. So, cork cambium produces new layers that replace the damaged or ruptured layers. 

Cork cambium is also called phellogen. The cork cambium has another name that is stellar cambium. Phellogen is thick and has two layers. The outer one forms the cork and the inner one forms the secondary cortex. The cells of cork are compactly arranged and in the beginning, they have thin cellulose cell walls. When they mature the living part is replaced by the non-living part which is the formation of wood material. The cell walls of the cork become thick by the deposition of suberin. This chemical makes the cork or wood material impervious to water by getting deposited in the cell walls. 

The phelloderm is the secondary cortex. It is called so because it develops at the time of secondary growth. It is made up of thin-walled parenchymatous cells. They have cellulose cell walls and are living in nature. The periderm is the collective name given to phellogen, phellem and phelloderm. They are the protective layers of the cell. They grow when the epidermis layer is ruptured and also when the outer cortical layers are ruptured. When secondary growth in the vascular cambium takes place, then only the secondary growth of the cork cambium happens. As the growth of cork cambium is continuous, the layers peripheral to phellogen are damaged and they need continuous replacement. 

Lenticels

They are the small openings that are formed in the bark. They are formed by a small portion of the periderm. They are produced by the activity of the phellogen. As we read above, the phellogen is the meristematic tissue that is formed during the secondary growth of plants. They are lens-shaped openings. As they are openings, they help in the exchange of gases. The exchange of gases takes place between the internal tissue of the stem and the outer atmosphere. They help in exchanging gases from the woody areas of the plant. Water is also lost from them in the form of vapours. As they help in the exchange of gases, they are also known as breathing pores.