Write a note on agricultural / horticultural applications of auxins.

Explanation

Auxins, Gibberellins, Cytokinins, Abscisic acid, Ethylene.
Auxins:
Discovery : Observation of Charles Darwin and his son Francis Darwin, that the coleoptiles of canary grass responded to unilateral illumination by growing towards the light. It was concluded that.the tip of the coleoptile was the site of transmittable influence that caused the bending of the entire coleoptile. Auxin was isolated by F.W. Went from the tips of coleoptiles of oat seedlings.
Physiological functions :
1) Auxins help of initiate rooting in stem cuttings.
2) Auxins promote flowering in pineapples.
3) They help to prevent fruit and leaf drop at early stages but promote the abscission of older mature leaves and fruits.
4) Auxins promote apical dominance.
5) Auxins also induce parthenocarpy in tomatoes.
6) They are widely used as herbicides 2,4-D widely used to kill- dicotyledonous weeds.
7) Auxins also controls zylem differentiation and help in cell division.
Agricultural / Horticultural applications :
1) Auxins help to initiate rooting in stem cuttings, widely used for plant propagation in Horticulture.
2) Auxins, 2,4-D widely used as herbicide ie, Mis dicotyledonous weeds to prepares weed free-lawns.