Apical dominance is a phenomenon in plants in which the growth of the main stem or leader is suppressed in favor of the growth of lateral buds. This allows the plant to maintain a single, dominant stem or trunk, rather than branching out into multiple stems.
Apical dominance is regulated by plant hormones called auxins, which are produced in the apical meristem (the actively growing tip of the plant).
High concentrations of auxins in the apical meristem inhibit the growth of lateral buds, while lower concentrations of auxins allow the lateral buds to grow.
One way that apical dominance can be disrupted is through the removal of the apical meristem, either through pruning or other means.
When the apical meristem is removed, the lateral buds are able to grow and develop into new stems or branches. This is why pruning plants is often used to encourage branching and promote a fuller, more symmetrical growth habit.
Apical dominance can also be affected by other factors, such as light exposure, nutrient availability, and plant genetics. Understanding the role of apical dominance in plant growth can help horticulturists and gardeners better care for and cultivate their plants.
What Causes Apical Dominance
Apical dominance is caused by the production and distribution of plant hormones called auxins.
Auxins are produced in the apical meristem, which is the actively growing tip of the plant. High concentrations of auxins in the apical meristem inhibit the growth of lateral buds, while lower concentrations of auxins allow the lateral buds to grow.
The concentration of auxins in the apical meristem is determined by the balance between auxin production and degradation.
Auxins are produced in the apical meristem and transported down the stem towards the base of the plant, where they are degraded. This transport of auxins helps to maintain a high concentration of auxins in the apical meristem and suppress the growth of lateral buds.
However, the balance between auxin production and degradation can be disrupted by various factors, such as light exposure, nutrient availability, and plant genetics. For example, plants that are grown in low light conditions may produce less auxin, which can allow the lateral buds to grow more freely.
Similarly, plants that are grown in nutrient-poor soils may produce more auxin in order to compensate for the lack of nutrients, leading to stronger apical dominance. Understanding these factors can help horticulturists and gardeners better care for and cultivate their plants.
Apical Dominance Examples
Apical dominance is the phenomenon where the terminal bud (located at the top or apex of the plant) inhibits the growth of lateral buds (buds located on the sides of the plant).
This results in the plant’s energy being directed toward the growth of the terminal bud, rather than being distributed among multiple buds. Here are two examples of apical dominance:
Example 1: In a young apple tree, the terminal bud is dominant and suppresses the growth of lateral buds. As a result, the tree grows a single main trunk with a few branches.
Example 2: In a young tomato plant, the terminal bud is also dominant and suppresses the growth of lateral buds. This results in the plant growing a single main stem with a few branches.