Which term describes the dominance of the main stem over any branches?

Apical dominance refers to the phenomenon where the main stem of a plant exerts control over the growth of its lateral branches. This dominance occurs primarily due to the presence of the apical bud at the tip of the main stem, which produces hormones such as auxins. These hormones inhibit the growth of lateral buds, ensuring that the plant allocates more resources to vertical growth rather than allowing side branches to proliferate. This is an advantageous adaptation for plants since it helps them compete for sunlight and grow taller in dense habitats.

While other terms may be relevant to plant growth, they describe different aspects. Deliquescent branching refers to a growth form where branches spread out in a more horizontal fashion, typically seen in certain tree species but does not specifically address stem dominance. A columnar structure describes a growth form that is tall and narrow but is not directly related to the dominance of the main stem. Secondary growth pertains to the thickening of the plant stem and roots due to the activity of the vascular cambium and does not focus on the relationship between main stems and branches.