| |
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 |