Question

Describe various plant hormones with their functions.

Answer 1

A hormone is any chemical produced in one part of the body that has a target in another part of the body. Plants have five kinds of hormones. Hormones and enzymes are used as regulation chemicals in multicellular organisms. A significant part of this is the processing of food and/or nutrients.

Complete answer:
Plant hormones are chemical compounds found in plants at very low concentrations. They are derivatives of indole (auxins), terpenes (Gibberellins), adenine (Cytokinins), carotenoids (Abscisic acid), and ethylene.
These hormones are produced in almost all parts of the plant and are transferred to different parts of the plant.
Plant hormones regulate all growth and development events such as cell division, enlargement, flowering, seed formation, dormancy, and abscission.
Based on their activity, plant hormones are classified into two categories:
-Promoters of Plant Growth
-Inhibitors of Plant Growth

Auxin: Auxin means to "grow." They are commonly used in agricultural and horticultural practice. They are found in rising roots and stem apices and then move to other sections to function.
Functions:
-Elongation of stems and roots by cells
-Apical predominance, IAA in the apical bud suppresses the development of lateral buds.
-Induces parthenocarpy, i.e. the growth of fruit without fertilization, e.g. in tomatoes
-Prevents premature fall of leaves, bulbs, vegetables, etc.
-Useful in stem cuttings and grafting where rooting is started.
-Promotes pineapple flowering
-2,4-D is commonly used as an herbicide to destroy unwanted weeds of dicot plants without harming monocot plants.
-Helps with cell division and xylem differentiation

Gibberellins Hormone:
Functions:
- Promotes bolting, i.e. sudden internode elongation shortly before flowering in rosette plants such as cabbage, beet.
-Senescence Delays
-Parthenocarpy induces
-Stem elongation and reversing dwarfism
-Induces maleness of such plants such as marijuana
-Induces the formation of lipase, amylase hydrolytic enzymes in the endosperm of germinating cereal grains, and barley seeds
-Breaks the Dormancy of Seed

Cytokinins Hormone: Cytokinins play a major role in the mechanism of cytokinesis. In plants where rapid cell division occurs, cytokinins are naturally synthesized, such as root apices, shoot buds, young fruits, etc. Basipetal and polar movement of cytokinins.
Functions:
- It encourages lateral and adventitious shoot growth and is used in culture to initiate shoot growth
-Helps to resolve auxins in-induced apical dominance
-Stimulate chloroplast formation in the leaves
-Promotes mobilization of nutrients and slows senescence of leaves

Abscisic Acid:
Functions:
-Induces abscission of fruits and leaves
-Inhibits germination of seeds
-Induces leaf senescence
-Accelerates seed dormancy, which is useful for storage purposes,
-Stimulates stomatal closure to stop transpiration under water stress

Ethylene Plant Hormone: It functions both as a promoter of growth and as an inhibitor. It exists in the form of gases. In the maturing fruit and tissues undergoing senescence, it is synthesized. Many physiological procedures and one of the most commonly used hormones in agriculture are regulated.
Function:
- The ripening of fruits hastens
-Epinasty of leaves Monitors
-Breaks the dormancy of seed and bud
-Stimulates rapid petiole and internode elongation
-Encourages senescence and abscission of flowers and leaves
-Inducing root growth and the development of root hair, thus growing the surface of absorption
-Stimulates femininity in single-seeded plants

Note: - Plants need sunshine, water, oxygen, minerals to grow and develop. Those are external influences. Apart from these, some inherent factors control the growth and development of plants. They are referred to as plant hormones or "phytohormones."
- Plant hormones can behave synergistically or independently. The functions of various hormones can be complementary or antagonistic.
- Hormones play an important role in processes such as vernalization, phototropism, seed germination, dormancy, etc., along with extrinsic influences.
-Synthetic plant hormones are used exogenously for regulated crop production.