Apical dominance
/ˈeɪpɪkəl ˈdɑmənəns/
Definition
Apical dominance describes a plant growth pattern in which the terminal bud at the shoot tip suppresses the growth of side buds below it. This happens largely through hormones, especially auxin produced near the apex, which helps direct growth upward rather than outward. When the apical bud is removed or damaged, lateral buds often begin to grow more strongly, changing branching and overall plant shape.
Biological Role
- Crown shape and branching: It strongly influences overall plant form by limiting side-shoot growth near the stem tip, which helps many species maintain a taller, more upright habit.
- Hormone control from the shoot tip: Its strength is tied to plant hormones, especially auxin produced in the growing tip, working with signals such as cytokinins and strigolactones that affect bud outgrowth.
- Response to pruning and damage: When the terminal bud is removed or injured, suppressed lateral buds often begin growing. This is why pinching and heading cuts can make plants fuller or more branched.
- Variation among plant types: It is not equally strong in all plants. Trees with a clear central leader often show it strongly, while many naturally bushy species show weaker control of side buds.
Related Terms
Auxin
Auxin is a class of plant hormones that regulate growth and development. Produced mainly in shoot tips and young…
Terminal bud
Terminal bud refers to the bud at the very tip of a stem or shoot. It contains the shoot apical meristem, a region of…
Bud
Bud refers to a compact, undeveloped plant structure that contains embryonic tissue capable of growing into a leaf…
Node
Node refers to the point on a plant stem where leaves, buds, branches, or flowers attach or can develop. It is a…
Internode
Internode refers to the section of a plant stem between two nodes, the points where leaves, buds, or branches attach…
Pinching
Pinching is a pruning technique that removes the soft growing tip of a stem, usually with fingers or small snips…
Topping
Topping is a pruning technique that removes the main growing tip, or apical shoot, of a plant. Cutting off this…
Pruning
Pruning is the horticultural practice of selectively cutting off plant parts, usually stems, branches, shoots, flowers…