| Where Found in Plant | Major Functions | |
|---|---|---|
| Auxin ¥Íªø¯À | 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 ¶}¹ç¯À | Synthesized in roots and transported to other organs | Stimulates cell division, reverse apical dominance, involved in shoot growth, delay leaf sequence |
| Ethylene ¤A²m | Tissues of ripening fruits, nodes of stems, senescent leaves and flowers | Stimulates fruit ripening, leaf and flower senescence, and abscission |
| Abscisic Acid Â÷¼h»Ä | Leaves, stems, green fruit | Stimulates stomatal closure |
| Gibberellin ¿E«k¯À | 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 |