Auxin

Auxin is present in the seed embryo, young leaves, and apical bud meristem of a plant. It stimulates stem elongation and occasionally cell division. It can also suppress lateral bud growth from apical buds. It can delay leaf senescence in the autumn and also can inhibit fruit. It also differentiates between phloem and xylem during development.

 Auxin stimulated cell elongation in the bulb and at the meristem in the stem shoot.