How do stomata help vascular plants exchange gases with the atmosphere?

Stomata are microscopic pores located primarily on the epidermis of leaves and young stems that facilitate the exchange of gases between the atmosphere and the plant's internal air canal system.1

These openings are essential for photosynthesis, as they allow carbon dioxide to enter the leaf interior while enabling oxygen to escape. The opening and closing of each stomate are regulated by two sausage-shaped guard cells. When these cells become turgid with water, the pore enlarges; conversely, they close in response to environmental stressors—such as high temperatures, wind, or internal water deficits—to prevent excessive water loss through transpiration.21

Some plants have evolved specialized adaptations to manage this gas exchange, such as the crassulacean acid metabolism (CAM) pathway, which allows them to open their stomata at night to intake carbon dioxide while remaining closed during the heat of the day to conserve moisture.12