Today we will discuss about transpiration. Transpiration, in botany, a plants loss of water, mainly through the stomata of leaves. Stomato openings are necessary to admit carbon dioxide to the leaf interior and to allow oxygen to escape during photosynthesis. Stomata are cell structures in the epidermis of tree leaves and needles that are involved in the exchange of carbon dioxide and water between plants and the atmosphere. Stomata must open to allow the gas exchange of carbon dioxide and oxygen for efficient photosynthesis. See photo respiration, and light thus typically triggers stomatal opening. When stomata are open, however, water vapor is lost to the external environment, increasing the rate of transpiration. A closed stomata results in reduced rate of transpiration or loss of water as well as a reduction in the amount of carbon dioxide entering the leaf.