cytokinin and auxin ratio in apical dominance
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.
Apical dominance is a phenomenon in plants where the growth of lateral buds is inhibited by the dominant apical bud. The ratio of cytokinin to auxin plays a crucial role in regulating this process.
Cytokinins promote cell division, shoot branching, and the growth of lateral buds. They are synthesized in the root tips and transported to the shoot apex, where they promote shoot growth and decrease apical dominance.
Auxins, on the other hand, inhibit lateral bud growth and promote apical dominance. They are mainly synthesized in the shoot apex and transported downwards, inhibiting the growth of lateral buds.
Thus, the ratio of cytokinin to auxin determines the balance between shoot growth and lateral bud growth. A higher cytokinin to auxin ratio promotes lateral bud development, resulting in decreased apical dominance. Conversely, a lower cytokinin to auxin ratio promotes apical dominance by inhibiting lateral bud growth.
It is important to note that the exact ratio required for apical dominance regulation can vary between different plant species and environmental conditions. Additionally, other factors such as light, soil nutrients, and developmental stage can also influence the cytokinin to auxin ratio and subsequently affect apical dominance.