FFA Floriculture Practice Test

What is the effect of apical dominance in a plant's growth?

1. Enhances side branching

2. Prevents flowering

3. Inhibits growth of side buds

4. Reduces leaf size

The correct answer is: Inhibits growth of side buds

Apical dominance is a phenomenon in which the main central stem of a plant grows more strongly than its side branches. This is primarily regulated by the presence of the apical bud, which produces auxins, a class of plant hormones, that inhibit the growth of lateral (side) buds. As a result, the inhibitory effect of auxins on the growth of these side buds leads to the characteristic elongated growth of the main stem and a reduction in the development of branches, giving the plant a more upright growth habit. Thus, the concept of apical dominance effectively explains why the correct answer focuses on the inhibition of side bud growth. This process is crucial for determining the overall shape and structure of many plants and plays a significant role in their developmental patterns. While other factors can influence flowering, leaf size, and side branching, the central role of auxins in maintaining apical dominance is primarily to ensure that the plant's energy is directed towards vertical growth rather than lateral expansion, reinforcing the importance of this concept in understanding plant physiology.