Any of a group of plant hormones chemically related to terpenes and occurring naturally in plants and fungi. They promote elongation of stems, e.g. bolting in cabbage plants, by enhancing both cell division and elongation. In germinating seeds following imbibition of water, the embryo releases gibberellins, which mobilize food reserves by activating enzymes in the aleurone layer. They are also influential in inducing flowering and fruit development. For example, gibberellins are sprayed to promote the growth of seedless grapes, to replace the gibberellin normally produced by the seeds. Commercially available gibberellins, such as gibberellic acid, are used to manipulate the onset of sexual maturity in various species, e.g. to induce cone-bearing in young conifer trees.