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By Whitney M. Holden, Ph.D.

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Transpiration is the process of water movement through a plant, starting from absorption by the roots and culminating in its evaporation from leaves through structures known as stomata. Stomata are important for two reasons: 1) they open to allow the exchange of oxygen and carbon dioxide gases during photosynthesis and 2) they close to prevent dehydration due to loss of water vapor. The opening and closing of stomata are dictated by the plant’s immediate needs; that is, which is more importantatthistime–photosynthesisorpreventingwaterloss? Thismoduleincludesthreevideos:1)an introduction to transpiration, 2) a virtual lab where transpiration is observed in pepper plants, and 3) a short bonus video of an inchworm discovered on a pepper plant during filming of the virtual lab.