Gibberellins are normal constituents of green plants and are also produced by several microorganisms. Gibberellins are extracted from rice seedling suffering from 'bakanae disease' which is caused by Gibberella fujikuroi fungus. The gibberellins are named GA1 through GAn in order of discovery. Gibberellic acid, which was the first gibberellin to be structurally characterized, is GA3.