1. The presence of apical bud inhibits the growth of lateral buds. This phenomenon in which the apical (terminal) bud is active and lateral buds remain inactive is called apical dominance.
2. It is believed that apical dominance is controlled by an auxin which is synthesized in the apical bud.
3. From the apical bud, the auxin migrates to the lateral buds and inhibits their growth.
4. When apical bud is removed, the lateral buds grow and form branches.
5. For producing more branches therefore, the apical buds are removed.
6. Cytokinins reverse apical dominance effect by promoting growth of lateral buds by cell division.