More than 50 years, ago researchers discovered that plants can sense carbon dioxide (CO2) concentrations. As CO2 levels change, "breathing" pores in leaves called stomata open and close, thus controlling evaporation of water, photosynthesis and plant growth. Plants lose more than 90% of their water by evaporation through stomata. The regulation of stomatal pore openings by CO2 is crucial for determining how much water plants lose, and is critical due to increased carbon dioxide effects on climate and water resources in a warming world.
