Physiological effects of plant growth regulator

 *AUXIN *

.  AUXIN (from Greek 'AUXIN':to grow) was frist isolated  from human  urine 

The term 'is applied to the indole -3-acetic

Acid (IAA) ,and to other natural and synthetic compound having certain growth regulating properties they are generally product by the growing apices of the stems and roots from where they migrate to the region of their action. AUXIN like IAA. and indole butyric acid (IBA) have been isolated from plants. NAA(naphthalene acetic acid) and 2,4-D(2,-4dicholorophenoxyacetic)are synthetic AUXIN all these AUXINS have been used extensive in agriculture and horticulture practice 

They help to initiate rooting in stem  cuttings, an application widely used  for plants  provocation. Auxins promoted flowering e.g.in pineapples they help to prevent fruit and leaf drop at early stage but promoted the abscission of older mature leave and fruits. 

In most higher plant ,the growing apical bud inhibits the growth of the leteral (axillary) buds, a phenomenon called apical dominance  .removal of shoot tips (decapitation) usually result in the growth of lateral buds it is widely applied in tea plantation, hedge -making can you explain way ?

Auxins  also included parthenocarpy ,.e.g.,in tomato they are widely use as herbicides 2,4-D, widely used to kill dicotyledonous weeds ,dose not  affect. Mature  monocotyledonous plants .it in used to prepare weed-free lawns by gardeners .Auxin also control xylem by gardener  .AUXIN also control xylem differentiation and helps in cell division