Phytohormones are organic compounds that control the growth, development, and movement of plants, and are either synthesised in laboratories or produced naturally within the plants.
Plant growth regulators are of two types:-
(I) Plant growth promoters
(II) Plant growth inhibitors
Auxins, Gibberellins, and Cytokinins are Plant growth promoters while Abscisic acid and Ethylene are Plant growth inhibitors. Ethylene is synthesised by the ripening fruits and ageing tissues, and it can be grouped either into the promoters or into the plant inhibitors.
Ethylene helps in regulating many physiological processes, like;
Induce flowering in the mango tree and sprouting of potato tubers.
Breaking the dormancy of seeds and buds.
During the ripening of fruits, it enhances respiration rate.
Stimulates the flow of latex, when applied to rubber trees.
Facilitates abscission and senescence of both flowers and leaves.