Auxins are plant hormones produced in the stem tip that promotes cell elongation.. The most important auxin produced by plants is indole-3-acetic acid (IAA).It plays important roles in a number of plant activities, including:
* development of the embryo
* leaf formation
* phototropism
* gravitropism
* apical dominance
* fruit development
* abscission
* root initiation and development
* the shade-avoidance effect