Plant growth regulators (PGRs) are chemical substances produced naturally within plants that regulate various physiological processes. Applied plant physiology has made significant contributions to the development of PGRs and their applications in agriculture, horticulture, and other fields.
The following are some examples of PGRs and their applications:
- Auxins: Auxins promote cell elongation, root initiation, and apical dominance. They are used to control fruit drop, stimulate rooting of cuttings, and promote uniform fruit set in crops.
- Gibberellins: Gibberellins promote stem elongation, seed germination, and flower induction. They are used to increase fruit size and yield, and to induce parthenocarpy (fruit development without fertilization) in some crops.
- Cytokinins: Cytokinins promote cell division, delay senescence, and stimulate shoot growth. They are used to promote lateral bud development, increase yield, and improve fruit quality.
- Abscisic acid: Abscisic acid plays a role in stress tolerance and dormancy. It is used to promote leaf abscission in ornamental plants, induce dormancy in seeds and buds, and regulate stomatal closure in crops.
- Ethylene: Ethylene promotes fruit ripening and senescence. It is used to control fruit ripening and prevent premature fruit drop.
Applied plant physiology has also contributed to the development of biotechnology, including genetic engineering and tissue culture. For example, tissue culture techniques are used to propagate plants with desirable traits, and genetic engineering is used to introduce new traits into crops, such as resistance to pests and diseases or tolerance to environmental stresses.
Overall, the applications of plant physiology have led to significant improvements in crop productivity, quality, and sustainability, and will continue to play a critical role in the development of agriculture and biotechnology.