Plant Hormones

This chart shows the five plant hormones and their functions.
Where Found in Plant Major Functions
Auxin Embryo of seed, young leaves, meristems of apical buds Stimulates cell elongation; involved in phototropism, gravitropism, apical domincance, and vascular differentiation; inhibits abscission prior to formation of abscission layer; stimulates ethylene synthesis; stimualtes fruit development; induces adventitious roots on cuttings
Cytokinin Synthesized in roots and transported to other organs Stimulates cell division, reverse apical dominance, involved in shoot growth, delay leaf sequence
Ethylene Tissues of ripening fruits, nodes of stems, senescent leaves and flowers Stimulates fruit ripening, leaf and flower senescence, and abscission
Abscisic Acid Leaves, stems, green fruit Stimulates stomatal closure
Gibberellin Meristems of apical buds and roots, young leaves, embryo Stimulates shoot elongation, stimulates bolting and flowering in biennials, regulates production of hydrolytic enzymes in grains