Plants are autotrophs, that is they obtain organic food molecules without eating other organisms or substances derived from other organisms. Plants use the energy provided by the sun to convert inorganic carbon and water into sugar and oxygen (photosynthesis) CO2 + H2O + Sunlight + Sugar + O2

Water is an integral component of photosynthesis and also performs a number of structural functions for land plants. Water loss in the terrestrial environment is one challenge that plants had to overcome as they adapted to drier conditions. Plants have evolved to deal with water loss in a number of ways; manipulating when or where the dark reactions of photosynthesis occur, structural differences (e.g., leaf size, shape) along with many others. The process of transpiration is the major mechanism of water movement in plants. It is essential to a plant to move water up from the roots system to the stem and leaves to allow for continued photosynthesis.

This movement is due to the physical properties of water- the ability of water to be "pulled" to an area where it is lacking. Unforunately, this movement of water through the plant body also leads to a loss of water through the stomata in leaves due to evaporation. There are a number of environmental factors that can influence the amountof water lost through the stomata.