Antitranspirants are compounds that are designed to reduce the loss of water vapor from plants, a process known as transpiration. Most water loss occurs through the leaves of plants. Leaf surfaces are covered with tiny openings called stoma. These openings are where plants take in carbon dioxide and release oxygen during photosynthesis. Water is also released during this process. On most plants a majority of the stomata (plural) are located on the bottom side of the leaves. The stems and branches of the plants have stomata as well, though most of the water loss in these areas happens through the cuticles.
There are three common types of antitranspirants, the most common being a foliar spray. Not surprisingly the most common as this is where most water loss occurs, and they are very effective in reducing water loss. This form of antitranspirant is sprayed on all surfaces of the plants forming a permeable protective plant coating that helps plants retain water while still allowing plant to take in carbon dioxide and release oxygen, thus not affecting plant growth. The protective plant coating created by this type of antitranspirant acts as a barrier from stresses caused by nature. It shields plants from an increase of water loss during temperature extremes and drying winds. It provides added protection from stresses related to the processing and handling of plant material, for example summer digging, transplanting material during a growth flush. When shipping material to hotter or colder regions it helps acclimatize plants as well as protecting them from water loss when shipping plants under refrigeration.