Gibberellin
/ˌdʒɪbəˈrɛlɪn/
Definition
Gibberellin is a class of plant hormones, also called growth regulators, that control key stages of development. They are produced in young tissues, seeds, and developing fruits, and they promote stem elongation, seed germination, flowering in some species, and fruit growth. Unlike auxins, which mainly direct growth responses, gibberellin is best known for stimulating cell elongation and helping break seed dormancy, the resting state that prevents sprouting.
Biological Role
- Stem elongation signals: gibberellin promotes cell elongation and internode extension, so shoots grow taller and less compact. Low activity can contribute to dwarf growth, while higher activity can produce longer, weaker-looking stems.
- Seed and bud release: In many species, gibberellin helps break dormancy and supports germination by activating growth in the embryo. It can also encourage some buds to resume growth after a resting period.
- Flowering and fruit effects: Some plants use gibberellin as part of the shift from vegetative growth to flowering, especially under the right day length or cold exposure. It can also influence fruit set and fruit enlargement in certain crops.
- Horticultural use: Growers sometimes apply gibberellin to improve germination, alter plant height, or manage fruit development. Results depend strongly on species, timing, and dose, so it is used more often in production than in routine home plant care.