How do stomata help lower vascular plants exchange gases?

Stomata are microscopic pores located in the epidermis of the leaves and stems of lower vascular plants, such as ferns and horsetails. These structures facilitate the essential exchange of gases between the plant's internal air canals and the external environment.12

The opening and closing of these pores are regulated by two sausage-shaped guard cells. When these cells become turgid with water, the stomate enlarges, allowing for gas exchange. This mechanism is vital for balancing the plant's need for carbon dioxide for photosynthesis against the risk of excessive water loss through evaporation.1

Because lower vascular plants possess a cuticle—a waxy layer that prevents water loss—the stomata serve as the primary regulated gateways for gas movement, closing during hot or dry conditions to protect the plant's internal moisture.12