Edisto Field Day Assignment: Stomata and Gas Exchange in Plants Like we as humans need oxygen to breathe plants need carbon dioxide to photosynthesize and therefore survive. Plants take in CO2 through openings located on all of their above ground parts in the top layer of the plant called the epidermis. Most importantly we find these stomata on the underside of the plants leaves so that they are shaded in an attempt to help conserve water. A stoma (plural stomata) is sort of like a pore that facilitates gas exchange allowing for photosynthesis, so that the plant can make its food as well as transpiration which is water loss that occurs as a result of photosynthesis. Stomata are surrounded by two kidney bean shaped guard cells that change shape to provide both the opening and closing mechanism for the stomata. These guard cells allow the stomata to open when they gain turgor and osmotic pressure making them more rigid due to an uptake in potassium ions following a proton pump pushing H+ ions from the guard cells increasing the solutes that fill the guard cells. You can imagine it as a magicians balloon. When the balloon is empty or deflating it can be completely straight and flaccid. When you blow the balloons up they often bend outward. So, two balloons half full may lay directly next to each other creating a closed stomata, when we add air to the balloons as they both bend outward they form a circle and represent an open stomata.
This opening of