A gibberellin is a major type of plant [hormone] ([auxin]s are the other major type). Gibberellins are produced in comparatively large quantities by plant [seed]s, [algae], [moss]es, [fern]s and [fungi] (especially fungi in the [genus] Gibberella). Gibberelic acid is commonly used in [seed] [germination] [experiment]s to induce growth.

Gibberellins can produce dramatic [growth], especially in plant [stem]s. If a plant under-produces gibberellins, it becomes a [dwarf]. Gibberellins are relatively expensive, but have been used in the production of [seedless grape]s and [navel orange]s and have been found to reverse the effects of some [herbicide]s.

This writeup is based partly on work I did for the [science] [dictionary] at http://biotech.icmb.utexas.edu/

gibberellin (thing)