Changes

[[File:lighterstill.jpg]][[File:Transpiration.jpg|right|frame]]

[[File:lighterstill.jpg]][[File:Transpiration.jpg|right|frame]]

*[http://en.wikipedia.org/wiki/15th_century 15th Century]

*[https://en.wikipedia.org/wiki/15th_century 15th Century]

==Definitions==

==Definitions==

*1: the [[act]] or [[process]] or an instance of ''transpiring''; especially : the passage of watery [[vapor]] from a living [[body]] (as of a [[plant]]) through a membrane or pores  

*1: the [[act]] or [[process]] or an instance of ''transpiring''; especially : the passage of watery [[vapor]] from a living [[body]] (as of a [[plant]]) through a membrane or pores  

==Description==

==Description==

'''Transpiration''' is a [[process]] similar to [[evaporation]]. It is a part of the [[water]] [[cycle]], and it is the loss of water [[vapor]] from parts of [[plants]] (similar to [[sweating]]), especially in leaves but also in stems, flowers and [[roots]]. Leaf surfaces are dotted with openings which are collectively called [http://en.wikipedia.org/wiki/Stomata stomata], and in most plants they are more numerous on the undersides of the foliage. The stomata are bordered by guard cells that open and close the pore. Leaf transpiration occurs through stomata, and can be [[thought]] of as a necessary "cost" associated with the opening of the stomata to allow the [[diffusion]] of carbon dioxide [[gas]] from the [[air]] for [[photosynthesis]]. Transpiration also cools plants and enables [http://en.wikipedia.org/wiki/Mass_flow mass flow] of mineral nutrients and water from roots to shoots.

'''Transpiration''' is a [[process]] similar to [[evaporation]]. It is a part of the [[water]] [[cycle]], and it is the loss of water [[vapor]] from parts of [[plants]] (similar to [[sweating]]), especially in leaves but also in stems, flowers and [[roots]]. Leaf surfaces are dotted with openings which are collectively called [https://en.wikipedia.org/wiki/Stomata stomata], and in most plants they are more numerous on the undersides of the foliage. The stomata are bordered by guard cells that open and close the pore. Leaf transpiration occurs through stomata, and can be [[thought]] of as a necessary "cost" associated with the opening of the stomata to allow the [[diffusion]] of carbon dioxide [[gas]] from the [[air]] for [[photosynthesis]]. Transpiration also cools plants and enables [https://en.wikipedia.org/wiki/Mass_flow mass flow] of mineral nutrients and water from roots to shoots.

Mass flow of liquid water from the [[roots]] to the leaves is driven in part by [http://en.wikipedia.org/wiki/Capillary_action capillary action]. In taller plants and trees however, the force of [[gravity]] can only be overcome by the decrease in hydrostatic (water) [[pressure]] in the upper parts of the plants due to the [[diffusion]] of water out of stomata into the [[atmosphere]]. Water is absorbed at the [[roots]] by [http://en.wikipedia.org/wiki/Osmosis osmosis], and any dissolved mineral nutrients travel with it through the [http://en.wikipedia.org/wiki/Xylem xylem].

Mass flow of liquid water from the [[roots]] to the leaves is driven in part by [https://en.wikipedia.org/wiki/Capillary_action capillary action]. In taller plants and trees however, the force of [[gravity]] can only be overcome by the decrease in hydrostatic (water) [[pressure]] in the upper parts of the plants due to the [[diffusion]] of water out of stomata into the [[atmosphere]]. Water is absorbed at the [[roots]] by [https://en.wikipedia.org/wiki/Osmosis osmosis], and any dissolved mineral nutrients travel with it through the [https://en.wikipedia.org/wiki/Xylem xylem].

Plants regulate the rate of transpiration by the [[degree]] of [http://en.wikipedia.org/wiki/Stomata stomatal] opening. The [[rate]] of transpiration is also influenced by the [[evaporative]] demand of the [[atmosphere]] [[surrounding]] the leaf such as [[humidity]], [[temperature]], [[wind]] and incident sunlight. [[Soil]] water supply and soil temperature can influence stomatal opening, and thus transpiration [[rate]]. The amount of water lost by a [[plant]] also depends on its size and the amount of water absorbed at the [[roots]]. Stomatic transpiration accounts for most of the water loss by a plant, but some direct [[evaporation]] also takes place through the cuticle of the leaves and young stems. Transpiration serves to evaporatively cool plants as the escaping water [[vapor]] carries away [[heat]] energy. A plant should not be transplanted in full sunshine because it may lose too much water and wilt before the damaged roots can supply enough [[water]].  

Plants regulate the rate of transpiration by the [[degree]] of [https://en.wikipedia.org/wiki/Stomata stomatal] opening. The [[rate]] of transpiration is also influenced by the [[evaporative]] demand of the [[atmosphere]] [[surrounding]] the leaf such as [[humidity]], [[temperature]], [[wind]] and incident sunlight. [[Soil]] water supply and soil temperature can influence stomatal opening, and thus transpiration [[rate]]. The amount of water lost by a [[plant]] also depends on its size and the amount of water absorbed at the [[roots]]. Stomatic transpiration accounts for most of the water loss by a plant, but some direct [[evaporation]] also takes place through the cuticle of the leaves and young stems. Transpiration serves to evaporatively cool plants as the escaping water [[vapor]] carries away [[heat]] energy. A plant should not be transplanted in full sunshine because it may lose too much water and wilt before the damaged roots can supply enough [[water]].  

[[Category: Botany]]

[[Category: Botany]]