Gibberellins (GAs) are tetracyclic diterpene carboxylic acids that are present in nature and act as plant hormones to control several developmental processes in plants. The majority of them have carbon skeletons made of ent-gibberellane (C20) or ent-20-norgibberellane (C19). They participate in a number of biological processes in plants, including stem lengthening, germination, dormancy, flowering, the growth of flowers, and the withering of leaves and fruits. GAs mutants played a key role during the Green Revolution thanks to their sturdier semi-dwarf stature that can increase yields.
136 different GAs have been identified from higher plants, fungi or bacteria. some GAs are biologically active in higher plants, where limited amounts of GA act as endogenous regulators of plant growth and development, regulating developmental and environmental signals. Their functions include promoting organ growth by stimulating cell elongation and/or division, and activating developmental switches, such as seed dormancy and germination, juvenile and adult growth stages, and transitions between nutritional and reproductive development.
GAs play a role in germination processes that occur naturally, such as breaking dormancy. Because gibberellins stimulate the production of -amylase in gibberellic cells, it is believed that gibberellins in seed embryos signal starch hydrolysis. GAs boost the transcript levels of genes that produce -amylase, which promotes the production of -amylase.
Gibberellins are widely produced by plants when they are subjected to low temperatures. They encourage the germination of seeds, seedless fruit, and cell elongation, rupture, and germination. By releasing seeds from their dormancy and acting as a chemical messenger, gAs promote seed germination. An enzyme that promotes embryo growth is created when the hormone connects to a receptor, calcium activates the protein calmodulin, and the complex binds to DNA.