Plant Hormones and their Functions

Plant hormones are known as phytohormones in botanical terms. Plant hormones are chemicals just like animal hormones that help in the growth, development and functioning of plants. Like animals, plants too are living organisms that function as a unit. They carry out vital biochemical reactions that are required to survive. These biochemical reactions require hormones also known as 'plant growth substances'. These hormones help in formation of leaves, flowers, stems, fruit, etc. These hormones also help in determining the sex of the flowers, the color of the fruits and leaves. They help in formation of tissues, respiration, energy production and even plant longevity and death. Just as hormones are necessary for an animal body to function without any glitches, hormones too help the green living beings to survive normally. In this article, we shall cover some information related to plant hormones and their functions.

What are the Functions of Plant Hormones?
Plant hormones help in regulation of the plant body by responding to the various signals from the plant and environment. The hormones are regulated in different tissues during the different plant development stages. There are five major hormones, which are, auxin, cytokinin, gibberellin, abscisic acid and ethylene. Plant hormone differ in their effects. The auxins, gibberellins, cytokinins act as growth stimulators and abscisic acid and ethylene act as growth inhibitors. Plant hormones are simple in structure as compared to animal or human hormones. There are no specific or specialized glands that produce these hormones. These hormones are synthesized anywhere in the plant and act on any part as their target. There are many plant growth factors that affect the function and growth of plants.

Hormones and Their Functions in Plant Growth

Plant Hormone	Where They are Found	Plant Hormones Function
Auxin	This hormone is present in the seed embryo, young leaves and apical buds meristem	Stimulation of cell elongation; cell division in cambium, differentiation of phloem and xylem, root initiation on stem cuttings, lateral root development in tissue culture Delaying leaf senescence Suppression of lateral bud growth when supplied from apical buds Inhibition or promotion of fruit and leaf abscission through ethylene stimulation Fruit setting and growth is induced through auxin in some plants Auxin can delay fruit ripening In Bromeliads, the auxin hormone promotes flowering Stimulation of flower parts, femaleness of dioecious flowers and production of high concentration of ethylene in flowering plants
Cytokinin	Cytokinins are synthesized in roots and then transported to other plant parts	Stimulation of cell division, growth of lateral buds and apical dominance Stimulation of shoot initiation and bud formation in tissue culture Leaf cell enlargement that stimulation of leaf expansion In some plant species, enhancement of stomatal opening Etioplasts are converted into chloroplasts through stimulation of chlorophyll synthesis.
Ethylene	Ethylene is present in the tissues of ripening fruits, nodes of stems, senescent leaves and flowers	Ethylene leads to release of dormancy state It stimulates shoot and root growth along with differentiation Leaf and fruit abscission Flower induction in Bromiliad The femaleness of dioecious flowers is stimulated Flower opening is stimulated Flower and leaf senescence stimulation Fruit ripening is stimulated by ethylene
Abscisic Acid	Absicisic acid is found mostly near leaves, stems, unripe fruit	Stimulation of closing of stomata Inhibition of shoot growth Inducing seeds for synthesizing storage of proteins
Gibberellin	The gibberellins are present in the meristems of apical buds and roots, young leaves, embryo	Stimulates stem elongation Gibberellin can lead to development of seedless fruits It can delay senescence in leaves and citrus fruits It can end seed dormancy in plants that require light for induction of germination

This was some information related to what are plant hormones and their functions. I hope the table helped you learn a bit about phytohormones so that you can now differentiate each hormone according to their function and region of action in plants.