FFA Horticulture CDE General Practice Exam

What is the small opening on the underside of most leaves called?

1. Cuticle

2. Stomata

3. Chloroplast

4. Phloem

The correct answer is: Stomata

The small opening on the underside of most leaves is known as stomata. These are tiny pores that play a crucial role in the process of photosynthesis and gas exchange. Stomata allow carbon dioxide to enter the leaf, which is necessary for photosynthesis, and they also facilitate the release of oxygen as a byproduct. Additionally, they help regulate transpiration, which is the loss of water vapor from the plant to the atmosphere. This process is essential for maintaining water balance within the plant and for the overall health of the plant. Although cuticle, chloroplast, and phloem are all important components of a leaf's structure and function, they serve different purposes. The cuticle is a waxy layer that protects the leaf from water loss and damage. Chloroplasts are the organelles where photosynthesis occurs, containing the chlorophyll that captures sunlight. Phloem is the vascular tissue responsible for the transport of nutrients and sugars throughout the plant. Each of these components contributes to the leaf's overall function but does not refer to the small openings that facilitate gas exchange.