The loss of water from a plant by
evaporation. Most water is lost from the
leaves through pores known as stomata, whose
primary function is to allow gas exchange
between the internal plant tissues and the
atmosphere. Transpiration from the leaf
surfaces causes a continuous upward flow of
water from the roots via the xylem, which is
known as the transpiration stream. A single
maize plant has been estimated to transpire
245 litres/54 gallons of water in one growing
season.