apical bud dominance
Apical bud dominance refers to the tendency of the terminal bud at the top of a plant to inhibit the growth of lateral (or axillary) buds lower down on the stem. The apical bud produces hormones called auxins that suppress the growth of nearby lateral buds, resulting in a pyramid-like shape with the main stem growing taller and the side branches suppressed or delayed. This phenomenon allows the plant to allocate more resources to the growth of the main stem, increasing its height and competitive advantage for accessing light. However, if the apical bud is removed (e.g., through pruning or damage), the lateral buds are released from inhibition and can start growing, resulting in the branching and bushier appearance of the plant.
Apical bud dominance refers to the phenomenon in which the growth of a plant is primarily regulated by the apical (terminal) bud at the tip of the stem. This bud inhibits the growth of lateral (axillary) buds located along the sides of the stem. It exerts hormonal control over lateral bud development through the production and distribution of a plant hormone called auxin.
When the apical bud is intact and actively growing, it produces auxin, which inhibits the growth of lateral buds below it. This results in the elongation of the main stem and the suppression of side branching. The apical bud releases auxin downwards, preventing the lateral buds from growing and forming branches. This process ensures that resources are allocated to the upward growth of the main stem, optimizing vertical growth and increasing the plant's ability to compete for light.
However, if the apical bud is damaged or removed, the inhibitory effect of auxin is no longer present, allowing the lateral buds to grow. This leads to the development of side branches and the lateral growth of the plant.
Apical bud dominance plays a crucial role in shaping the overall growth form of a plant. It is particularly important in determining the architecture of trees and other tall plants, allowing them to reach heights that maximize access to sunlight.