- Auxins produced at the tops of roots and shoots cause cell elongation, prevent leaf abscission, maintain apical dominance, control tropisms and stimulate the release of ethene for fruit ripening.
- Gibberellins cause stem elongation, the breaking of dormancy and the use of food stores during germination and pollen tube growth during fertilisation.
- Ethene causes fruit ripening and leaf fall.
- ABA (abscisic acid) maintains dormancy, stimulates antifreeze production and stomatal closing in response to abiotic stress.
