What does apical dominance mean in crown architecture?

What is apical dominance in tree crown architecture?

 

Apical dominance is a fundamental phenomenon in plant biology that determines the overall architecture of the aerial parts of plants. Including trees.

Apical dominance describes the control that the top of the shoot or apex exerts on the growth of side branches.

This phenomenon causes the main shoot to grow predominantly and suppresses the growth of side branches or axillary buds. Resulting in a linear, directional growth pattern with little branching.

This has important implications for the shape and structure of the tree crown.

Apical dominance is regulated by a complex network of phytohormones, involving auxin, which is produced in the apical meristems, plays a key role.

Auxin is made from the apex transported downwards and suppresses the growth of lateral buds.

This hormonal signaling pathway is modulated by other hormones, such as cytokinins, which can promote bud outgrowth. And strigolactones, which can strengthen apical dominance.

Recent research has shown that apical dominance is not only limited to the suppression of bud outgrowth, but is also involved in more complex regulatory mechanisms that influence plant architecture.

This includes the modulation of source-supply balance, nutrient distribution and plant response to environmental stress and damage.

The study of apical dominance in trees provides insight into how trees allocate their energy and resources to grow. And respond to their environment, and has practical applications in forestry and horticulture for shaping the growth and development of trees.

For more detailed information on apical dominance and the control of lateral branch growth, read the following studies:

• Cline, M. (1997). Concepts and terminology of apical dominance. American Journal of Botany, 84 (8), 1064.
• Dun, E. A., Ferguson, B. J., & Beveridge, C. A. (2006). Apical Dominance and Shoot Branching. Divergent Opinions or Divergent Mechanisms? Plant Physiology, 142(3), 812 – 819.

These studies provide insight into the complex regulation of apical dominance and its influence on the growth and development of plants and trees.