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Cytokinins are a type of plant growth regulator that is largely engaged in cell division in plant roots and shoot systems. This hormone promotes cell proliferation, development, and diversification while also influencing apical dominance and delaying leaf senescence. These hormones are mostly found in complex plants, bacteria, mosses, and fungus. There are around 200 distinct kinds of naturally derived cytokinins, and the majority of them are produced in the root meristem. It is the term of plant cells that actively encourages cell division. A meristem is a region in plants that develops like the main stem. Cytokinins are often produced in quickly dividing tissues including root apices, developing shoots, and so on.
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Key Terms: Cytokinins, Kinetin, Cell, Zeatin, Cellular Division, Mitosis, Plant Growth Regulator, Tissues, Synthetic Substances, Roots
What are Cytokinins?
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Cytokinins, which have distinct effects on cytokinesis, were identified in autoclaved herring sperm DNA as kinetin (a modified version of adenine, a purine). Kinetin is not found in plants organically.
- The extraction of zeatin from maize kernels and coconut milk resulted from a search for natural compounds having cytokinin-like activity. Several naturally existing cytokinins and synthetic substances with cell division stimulating activities have been found since the identification of zeatin.
- Natural cytokinins are produced in areas of fast cell division, such as root apices, growing shoot buds, early fruits, and so on. It promotes the growth of new leaves, chloroplasts in leaves, lateral branch growth, and the creation of adventitious shoots.
- Cytokinins aid in the overthrow of apical predominance. They encourage nutrient mobilisation, which helps to prolong leaf senescence.
Cytokinins (Plant Growth Regulators)
Structure of Cytokinins
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The structure of Cytokinins is as follows:
Structure of Cytokinins
Read More: Difference Between Auxin and Gibberellins
Functions of Cytokinins
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The functions of cytokinins are as follows:
- Cytokinins promote cellular division by sustaining protein synthesis, which is required for mitosis. Mitosis is a non-sexual division of cells that happens in all living organisms at periods by creating new cells for body expansion.
- Mitosis happens once a day and involves the replacement of damaged cells by enabling them to proliferate. When you are harmed and lose your tissue from the kneecap, it's the same mitotic that aids in the regeneration of all the cellular you lost and gives you the epidermis.
- Mitosis in plants creates new cells that allow the plant to grow. You must have played with construction blocks as a youngster, which you will associate with plant cells. Mitosis occurs when a replacement cell is formed and delivered to the upper end of the plant by expanding its length. This is analogous to glueing a construction block to the core building.
Read More: Animal Cell Diagram with Label and Explanation
Uses of Cytokinins
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Some major uses of Cytokinins are given below:
- Aids in the promotion of cell division and plant development.
- Farmers use it to boost agricultural productivity.
- When sprayed to cotton seedlings, it resulted in a 5-10% rise even under drought circumstances.
- By generating resistance to specific disease-causing bacteria, plays an important role in plant pathophysiology.
Read More: Plant Physiology
Types of Cytokinins
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Trans-zeatin and kinetin are two types of the cytokinin group that have an anti-ageing impact on human fibroblast cells. These cytokinins can be detected in coconut water and also most plant xylem fluids.
- Trans-zeatin
It has a purine ring system with hydroxyl, amino, and olefin groups on the side chain. It was found and named after the maize genus Zea. Plant root systems generate zeatin and other cytokinins.
- Kinetin
Kinetin is a kind of cytokinin. Cytokinins are substances that encourage plant growth. Kinetin is used in the production of pharmaceuticals. Kinetin is applied directly to the skin to minimise the signs of ageing such as roughness, fine wrinkles, dilated blood vessels, and uneven pigmentation.
Read More: Pigments: Definition, Types & Uses
Things to Remember
- Cytokinins are plant growth regulators.
- Cytokinins encourage the development of new leaves, chloroplasts in leaves, lateral branch growth, and the formation of adventitious shoots.
- The cytokinin category includes trans-zeatin and kinetin.
- C10H9N5O is the molecular formula of cytokinin.
- Natural cytokinins are generated in sites of rapid cell division, such as root apices, developing shoot buds, and early fruits.
Sample Questions
Ques. What are Cytokinins? (3 Marks)
Ans. Cytokinins are plant growth regulators that are primarily involved in cell division in plant roots and shoot systems. This hormone stimulates cell proliferation, growth, and diversity, as well as alters apical dominance and delays leaf senescence.
Ques. What are the Cytokinin’s functions? (3 Marks)
Ans. The functions of Cytokinins are:
- Cytokinins stimulate cell division via maintaining protein synthesis, which is essential for mitosis. Mitosis is a non-sexual cell division that occurs in all living creatures at certain times to create new cells for body expansion.
- Mitosis occurs once every day and involves the replacement of damaged cells by allowing them to multiply. Mitosis is the process through which plants generate new cells that allow them to grow.
- Mitosis happens when a replacement cell is generated and supplied to the plant's higher-end via lengthening. This is akin to glueing a building piece to the main structure.
Ques. What are the two types of Cytokinins? (3 Marks)
Ans. Trans-zeatin and kinetin are two types of cytokinin.
- Trans-zeatin: It features a purine ring structure with hydroxyl, amino, and olefin groups on the side chain. It was discovered and named after the maize genus Zea. Plant root systems produce zeatin and other cytokinins.
- Kinetin: Kinetin is a kind of cytokinin. Kinetin is used in the manufacture of medicines. Kinetin is applied directly to the skin to reduce indications of ageing such as roughness, fine wrinkles, dilated blood vessels, and uneven pigmentation.
Ques. What is the use of Cytokinins? (3 Marks)
Ans. The uses of Cytokinins are listed as follows:
- Helps to promote cell division and plant development.
- It is used by farmers to increase agricultural output.
- It results in a 5-10% rise when sprayed to cotton seedlings, even under drought circumstances.
- It plays a key function in plant pathophysiology by building resistance to certain disease-causing microorganisms.
Ques. List the structure and molecular formula of Cytokinins. (3 Marks)
Ans. The structure of Cutokinins is as follows:
The molecular formula is C10H9N5O.
Ques. What is Mitosis? (3 Marks)
Ans. Mitosis can be defined as the non-sexual division of cells that usually happens in all living things and develops additional cells for the growth of the body. Mitosis is a process that occurs every day by replacing the damaged cells by allowing them to grow. We lose cells every day in our lives by hurting or some other reasons and it is due to mitosis that the cells we lost are grown and get us the skin.
Ques. How are Cytokinins formed? (3 Marks)
Ans. Usually, cytokinins are formed in the rapidly dividing tissues such as growing shoot, root apices, etc. They are mostly found in all the complex plants, bacteria, mosses, and fungi. Some 200 different types of synthetic and natural cytokinins are present there and most of them are usually developed in the meristem of the roots.
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