%gibberellin%

n. (Chem.), Any of a number plant growth hormones, the first of which was isolated in 1938 from the fungus Gibberella fujikuroi; more than 60 related gibberelins are known. The most important is gibberellin A₃, also called gibberellic acid. They are used in agriculture for promoting plant growth. [ WordNet 1.5 +PJC ]