Apical dominance

Apical dominance is a growth phenomenon in plants where the main, central stem of the plant is dominant over (i.e., grows more strongly than) other side stems; on a branch the main stem of the branch is further dominant over its own side twigs. This dominance is maintained by the production of auxins by the apical meristem that suppresses the growth of the lateral buds.

Mechanism of Apical Dominance

The mechanism of apical dominance is complex and involves a balance between auxins, cytokinins, and abscisic acid. Auxins produced in the apical meristem move down the stem and inhibit the growth of lateral buds. This inhibition is overcome by cytokinins produced in the roots that move up the stem and promote the growth of lateral buds. Abscisic acid, also produced in the roots, moves up the stem and inhibits the growth of lateral buds. The balance between these three hormones controls the degree of apical dominance.

Role in Plant Growth and Development

Apical dominance plays a crucial role in the growth and development of plants. It allows plants to grow in a manner that maximizes their exposure to sunlight, which is essential for photosynthesis. It also helps in the efficient use of resources as the growth of unnecessary branches is prevented. Moreover, apical dominance gives plants their characteristic shape and form.

Manipulation of Apical Dominance

Manipulation of apical dominance is a common practice in horticulture and agriculture. It is done to control the shape and size of plants, to increase yield, and to produce plants with certain desirable characteristics. Methods of manipulating apical dominance include pruning, pinching, and the application of growth regulators.

See Also

• Plant physiology
• Plant hormone
• Horticulture
• Agriculture