What is the mechanism underlying the phenomenon

What is the mechanism underlying the phenomenon by which the terminal/ apical bud suppresses the growth of lateral buds? Suggest measures to overcome this phenomenon.

This phenomenon is known as apical dominance. It is the phenomenon of suppresses of growth of lateral buds by the terminal bud. Removal of apical bud causes the sprouting of lateral buds. However, a paste of auxin can stimulate the effect of apical bud.