Apical dominance is a phenomenon where the growth of lateral buds is suppressed in favor of the growth of the apical bud, which is located at the tip of the stem. This leads to a dominant central stem with limited branching.
The control of apical dominance is regulated by the balance between two plant hormones called cytokinin and auxin. Cytokinins promote lateral bud growth, while auxins inhibit it.
In plants with strong apical dominance, such as tall trees, the concentration of auxin is high in the apical bud. This high auxin concentration inhibits lateral bud growth by suppressing the production of cytokinins. As a result, the apical bud grows more vigorously, leading to vertical growth and minimal branching.
When the apical bud is removed or damaged, the concentration of auxin decreases. This reduction in auxin concentration leads to an increase in cytokinin production in the lateral buds. The enhanced cytokinin levels promote lateral bud growth, resulting in the development of branches.
Overall, the ratio of cytokinin to auxin is crucial in determining whether apical dominance is maintained or lateral bud growth is stimulated. High auxin to cytokinin ratio favors apical dominance, while a decrease in this ratio promotes lateral bud growth and branching.
cytokinin and auxin ratio in apical dominance
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