Plants have pores, Stomata, on their leaf surfaces that allow CO2 (Carbon Dioxide) in for photosynthesis and through which water evaporates. The specific cells that border and define these pores are Guard Cells. Guard Cells literally guard the size of the pore by alternately swelling, which opens the pore, or shrinking, which closes the pore. Plants must respond to a variety of environmental cues and regulate their Stomata accordingly so that enough CO2 gets in, but not so much water escapes that the plant dries out. This balance between opening and closure of Stomata is essential in determining a plant’s survival and how much it will grow and yield. The swelling and shrinking of Guard Cells occurs through the coordinated [...]