Plant growth regulators (PGRs) are synthetic or natural compounds other than nutrients that affect the development of plant tissues or metabolic processes in in vitro cultures. PGRs can be used to modify a plant's growth in a variety of ways, such as enhancing branching, reducing shoot growth, promoting regrowth, removing extra fruit, or changing the ripeness of the fruit.
PGRs, commonly referred to as biostimulants or bioinhibitors, work to control plant metabolism by stimulating or inhibiting particular enzymes or enzyme systems within plant cells. They are usually present in the plant at very low concentrations.
Plant growth regulators can be categorized into five groups: auxin-related substances, gibberellin and gibberellin biosynthesis inhibitors, cytokines, abscisic acid, and substances that change the state of the ethylene hormone. There are additional items on the market that prevent the manufacture of plant hormones.
Plant growth regulators are crucial in both biotechnology and nature. All facets of plant growth and morphology are managed by plant growth regulators in nature. Regulators of plant growth can also aid plants in surviving environmental shocks and changes. Plant growth regulators can be introduced in biotechnology to boost plant longevity, improve the quality of plant fruits, and propagate plants for breeding. Plant growth regulators can also be used by researchers to explore molecular regulation of plants.
Among these PGRs, growth hormone and cytokinin and the ratio between them are associated with organogenesis and somatic embryogenesis (SE) processes. Natural plant PGRs are produced endogenously in plants. They interact with added plant growth regulators (natural or synthetic) to stimulate development in vitro.