transpiration


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transpiration

 [trans″pĭ-ra´shun]
discharge of air, vapor, or sweat through the skin.

tran·spi·ra·tion

(tran'spī-rā'shŭn),
Passage of watery vapor through the skin or any membrane.
See also: insensible perspiration.
[trans- + L. spiro, pp. -atus, to breathe]

transpiration

/tran·spi·ra·tion/ (tran″spĭ-ra´shun) discharge of air, vapor, or sweat through the skin.

transpiration

(trăn′spə-rā′shən)
n.
The act or process of transpiring, especially through the stomata of plant tissue or the pores of the skin.

tran′spi·ra′tion·al adj.

tran·spi·ra·tion

(trans'pir-ā'shŭn)
Passage of water vapor through the skin or any membrane.
See also: insensible perspiration
[trans- + L. spiro, pp. -atus, to breathe]

transpiration

the loss of water vapour from the inside of a leaf to the outside atmosphere, via STOMATA and LENTICELS. Transpiration exerts a considerable upward pressure in the stem and is thought to be part of the explanation of how water ascends from roots to leaves.

The rate at which transpiration proceeds depends upon several physical factors:

  1. (a) the Water Vapour Pressure at the MESOPHYLL cell surface inside the leaf. The evaporating surface is saturated and will have a VAPOUR PRESSURE (WVPsatn) that is highly affected by ambient temperature. For example, at 20 °C the WVPsatn = 2.34 kPa, at 10 °C the WVPsatn = 1.23 kPa.
  2. (b) the Water Vapour Pressure in the outside air (WVPa ir ), the maximum value being equal to WVPsatn at that temperature. If there is the same temperature inside and outside the leaf, the rate of flow of water vapour between the surface of the mesophyll cell and the outside is the difference between WVPsatn and WVPair; i.e:WVPdiff= WVPsatn - WVPair Thus the greater the WVPdi ff value, the greater the diffusion gradient and the higher the transpiration rate.
  3. (c) the size and number of stomatal pores per unit area of a leaf. The smaller the pore diameter, the greater the resistance to water vapour diffusion. The presence of'vapour shells’ over each stoma creates a boundary layer of high Water Vapour Pressure in still air, which will slow down the transpiration rate since it increases the WVPa ir value. This effect is most important when the pore diameter is large. In moving air, the vapour shells cannot form and thus transpiration rates increase.
  4. (d) the stomatal and leaf structure, which are modified in some XEROPHYTES to reduce transpiration rates.
  5. (e) a constant supply of water from the roots.

transpiration

passage of water vapour through any membrane

transpiration

discharge of air, vapor or sweat through the skin.
References in periodicals archive ?
After years of careful research, Inorganic Ventures developed its Transpiration Control Technology, heat-sealed aluminized bags that effectively stop transpiration when equilibrium is reached inside.
The portion of the absorbed solar energy remaining in the plant leaf will be used for transpiration and convective heat exchange with the environment.
Separate one way ANOVAs were used to determine if net photosynthesis, stomatal conductance, and transpiration were significantly different over the PFD's tested (Sail et al.
max]) and transpiration rates (E) were measured with an LI-6400 infrared gas exchange system (LI-Cor, Lincoln, Nebraska, USA) on the most recently expanded, intact and de-trichomed leaflets.
function of the rate of leaf transpiration (Turner et al.
It is a very fine line and you are playing with nature - you have got to take into account all the factors, like temperature and transpiration rates.
By reducing transpiration or water loss from a plant, you can cut back on water application.
Stich, "Water Words: Rhymed And Defined" combines water-related poems with colorful artwork to provide young readers with definitions, information, and interesting facts about water and water related terms such as water cycle, rain, wetlands, condensation, watershed, aquifer, acid rain, precipitation, evaporation, erosion, point source pollution, transpiration, conversation, overdraft, and bodies of water.
However, the carbon dioxide effect on transpiration, well-known in the laboratory, has been overlooked in models that parcel fresh water among the atmosphere, rivers, and oceans.