the growth of harmones, responsible for bolting are

1. coumarins
2. auxins
3. gibberellins
4. kinetins

Boltingis when agricultural and horticulturalcropsprematurely produce a flowering stem (or stems) before the crop is harvested, in a natural attempt to produce seedsand hencereproduce. These flowering stems are usually vigorous extensions of existing leaf-bearing stems, and in order to produce them, a plant diverts resources away from producing the edible parts such as leaves or roots, resulting in a poor quality harvest from the grower's point of view. Plants that have produced flowering stems in this way are said to havebolted. Crops inclined to bolt includelettuce,beetroot,brassicas,spinach,celeryandonion. Bolting is induced by plant hormones of thegibberellinfamily.