Cytokinin in Plants Structure Functions and Role

Hormones are biochemical substances synthesized inside the cells, tissues, and organs for certain biological functions. Plant hormones such as cytokinin are produced for regulating growth and cell division in the roots and shoots. In this article, we will study the features of this hormone cytokinin and its biological functions in detail.

What is Cytokinin?

Cytokinin hormone is a growth regulator in plants with the primary functions of controlling cell division and growth in the meristematic regions of a plant. It is produced in the shoots and roots where active growth takes place in leaves, buds, branches, flowers, and fruits. The prime cytokinin function is to regulate cell division, cell growth, differentiation, development, etc. This hormone is responsible for leaf senescence, axillary growth, and apical dominance.

It can be found in different forms in plants, mosses, fungi, and bacteria performing the same functions. More than 200 types of cytokinin hormone exist. Some are produced by the cells naturally and the rest are synthetically produced. The prime synthesis site of this hormone is the meristematic tissues present in the growing sections of the roots. 

A meristem is a tissue where active cell division and growth in plants is taking place. It can be found majorly in the apical portion of the branches of stem and roots. This is why this hormone can be found in these areas for controlling cell division and growth and causing differentiation of tissues. After its synthesis in the roots, it is carried to the different growing sections of the plant via xylem. It is then delivered to the meristematic tissues of apical branches, leaves, buds, seeds, fruits, and flowers.

The Function of Cytokinin in Plants

As mentioned earlier, the prime cytokinin hormone function is to supervise cell division and growth. Let us discuss this elaborately.

Cytokinin promotes cellular division by managing protein production in the cells. It is important to generate protein to prepare a cell for mitosis. The cells will enlarge in size by creating more cytoplasm and by duplicating the nuclear content. For this, a large amount of protein is required.

Mitosis is an asexual method of cell division where the meristematic cells increase in size are divided into two daughter cells. It is done for exceptional growth rates or to replace damaged cells in growing tissues. This cell division process takes place in a day. In other words, mitosis is the prime cell division process that enables a plant to grow. It is a rapid process that needs the role of cytokinin to produce protein and for proper differentiation of cells according to their functions. This simple process enacts the way we used to add toy blocks in a building to create a structure.

Mitosis does the same thing. In this case, the newly generated cell elongates and reaches to replace the old and damaged ones and to take their places. Eventually, the cell then achieves its actual form and matures.

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Uses of Cytokinin

Let us jot down the application of cytokinin considering its functions and find its significance.

• Promoting Cell Division

As mentioned earlier, the prime cytokinin function is to promote cell division. It is generally produced in the meristem of roots and then transported to the growth-prone areas of a plant via xylem tissues. These areas include apical meristem, buds, young leaves, flowers, fruits, small branches, etc. It promotes cell division to help these growing areas achieve their mature form and to strengthen.

• Promotes Plant Growth

It can be easily concluded that this hormone aims to develop cells in the growing areas. The permanent tissues in the complex plants remain the same. Hence, it is synthesized and transported to those areas where active cell division is going on. It manages and maintains protein synthesis inside the dividing cells for mitosis and aids in plant growth.

• Crop Production

The synthetic versions of this hormone are used for promoting plant growth. They are used to stop the yellowing of leaves. In fact, it is also used to prevent the senescence of leaves, flowers, fruits, and buds. This is one of the prime synthetic cytokinin uses you will use in the agricultural field.

• Increasing Yield

Let us consider an example. When cytokinin is applied to the cotton seedlings, the growth of the plants and cotton yield increases at least 5 to 10% of the normal yield even in a drought. It is specifically used to meet the growing demands of the world in various agricultural domains.

• Resisting Pathogens

Many bacteria damage leaves, fruits, flowers, and even hinder the normal growth of plants. When this hormone is applied, it can stop the propagation of bacterial infection in the plants resulting in reducing the yellowing of leaves and premature falling of fruits and flowers. It is also applied to increase the resistance of crop species against various bacterial pathogens.

From this discussion, we found that cytokinins are organic biochemical substances of phytohormones that promote cell division and growth in the respective areas. It is also synthetically produced for agricultural purposes.