Most all plants breathe in CO₂ during the day to photosynthesize through tiny pores called stomata. At night these pores are closed. Some plants like agave, cactus, and certain orchids do the opposite as a drought-fighting strategy. These plants open their pores only at night, taking in CO₂ when the air is cooler and less dry. It stores the CO₂ in its tissues and later uses it to photosynthesize during daytime. With their pores closed during the day these plants conserve water. This allows many desert plants to survive on much less water.
Growing Home - Stomata
