Texas FFA Nursery Landscape Practice Exam

In most plants, a hormone called auxin inhibits the growth of lateral buds. This phenomenon is known as?

1. A. Lateral dominance

2. B. The apex auxin complex

3. C. Apical dominance

4. D. Terminal bud inhibition

The correct answer is: C. Apical dominance

Apical dominance refers to the phenomenon where the growth of lateral buds is inhibited by the presence of the apical bud, primarily due to the influence of the plant hormone auxin. In an ideal scenario, the apical bud, located at the top of the plant, produces auxin, which travels down and suppresses the growth of the lateral buds located further down the stem. This ensures that the plant grows taller rather than bushier, allowing it to compete effectively for sunlight. This process is vital for plants as it helps maintain a single, dominant stem that can grow more efficiently in the direction of light. The concept of lateral dominance is related but focuses more on the priority of the main stem over lateral growth, while the apex auxin complex is not a standard term used in plant biology. Terminal bud inhibition, while related to the effects of apical dominance, does not fully encapsulate the hormonal control aspect of auxin's effect on lateral buds. Thus, understanding apical dominance is key to grasping how plants regulate their growth patterns in response to hormonal signals.