Transpiration

Information about Transpiration

Transpiration may also refer to sweating and hyperhydrosis.

Transpiration is the evaporation of water from the aerial parts of plants, especially leaves but also stems, flowers and roots. Leaf transpiration occurs through stomata, and can be thought of as a necessary "cost" associated with the opening of stomata to allow the diffusion of carbon dioxide gas from the air for photosynthesis. Transpiration also cools plants and enables mass flow of mineral nutrients from roots to shoots. Mass flow is caused 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 osmosis, and any dissolved mineral nutrients travel with it through the xylem.

The rate of transpiration is directly related to the degree of stomatal opening, and to the evaporative demand of the atmosphere surrounding the leaf. The amount of water lost by a plant depends on its size, along with the surrounding light intensity, temperature, humidity, and wind speed (all of which influence evaporative demand). Soil water supply and soil temperature can influence stomatal opening, and thus transpiration rate.

A fully grown tree may lose several hundred gallons (a few cubic meters) of water through its leaves on a hot, dry day. About 90% of the water that enters a plant's roots is used for this process. The transpiration ratio is the ratio of the mass of water transpired to the mass of dry matter produced; the transpiration ratio of crops tends to fall between 200 and 1000 (i.e., crop plants transpire 200 to 1000 kg of water for every kg of dry matter produced) .

Transpiration rate of plants can be measured by a number of techniques, including potometers, lysimeters, porometers, and heat balance sap flow gauges.

Desert plants and conifers have specially adapted structures, such as thick cuticles, reduced leaf areas, sunken stomata and hairs to reduce transpiration and conserve water. Many cacti conduct photosynthesis in succulent stems, rather than leaves, so the surface area of the shoot is very low. Many desert plants have a special type of photosynthesis, termed Crassulacean acid metabolism or CAM photosynthesis in which the stomata are closed during the day and open at night when transpiration will be lower.

References

A description of transpiration, including a short animation illustrating the process
Martin, J.; W. Leonard & D. Stamp (1976), Principles of Field Crop Production (Third Edition), New York: Macmillan Publishing Co., Inc., ISBN 0-02-376720-0

External Links

Transpiration by Trees

• • [ e] Botany
Subdisciplines of botany	Ethnobotany Paleobotany Plant anatomy Plant ecology Plant morphology Plant physiology
Plants	Evolutionary history of plants Algae Bryophyte Pteridophyte Gymnosperm Angiosperm
Plant parts	Flower Fruit Leaf Meristem Root Stem Stoma Vascular tissue Wood
Plant cells	Cell wall Chlorophyll Chloroplast Photosynthesis Plant hormone Plastid Transpiration
Plant life cycles	Gametophyte Plant sexuality Pollen Pollination Seed Spore Sporophyte
Botanical nomenclature	Botanical name Herbarium IAPT ICBN Species Plantarum
Project

Perspiration (also called sweating or sometimes transpiration) is the production and evaporation of a fluid, consisting primarily of water as well as a smaller amount of sodium chloride (the main constituent of "table salt"), that is excreted by the sweat glands in the skin of
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Hyperhidrosis
Classifications and external resources

ICD-10 R 61.
ICD-9 780.8

Primary hyperhidrosis is the condition characterized by abnormally increased perspiration, in excess of that required for regulation of body temperature.
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Evaporation is the process by which molecules in a liquid state (e.g. water) spontaneously become gaseous (e.g. water vapor), without being heated to boiling point. It is the opposite of condensation.
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Plantae
Haeckel, 1866^[1]

Divisions

Green algae

Chlorophyta
Charophyta

Land plants (embryophytes)

Non-vascular land plants (bryophytes)

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leaf is an above-ground plant organ specialized for photosynthesis. For this purpose, a leaf is typically flat (laminar) and thin, to expose the cells containing chloroplast (chlorenchyma tissue, a type of parenchyma) to light over a broad area, and to allow light to penetrate
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stem is one of two main structural axes of a vascular plant. The stem is normally divided into nodes and internodes, the nodes hold buds which grow into one or more leaves, inflorescence (flowers), cones or other stems etc.
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ROOT is an object-oriented software package developed by CERN. It was originally designed for particle physics data analysis and contains several features specific to this field, but it is also commonly used in other applications such as astronomy and data mining.
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stomata) is a tiny opening or pore, found mostly on the underside of a plant leaf, and used for gas exchange. The pore is formed by a pair of specialized sclerenchyma cells known as guard cells which are responsible for regulating the size of the opening.
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Carbon dioxide is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. It is a gas at standard temperature and pressure and exists in Earth's atmosphere in this state.
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Mass flow is the movement of substances at equal rates or as a single body. For example, blood circulation, transport of water and assimilates in xylem vessels and phloem tubes of plants.
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Plant nutrition is the study of the chemical elements that are necessary for plant growth. There are several principles that apply to plant nutrition.

Some elements are essential, meaning that the absence of a given mineral element will cause the plant to fail to complete
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Shoots are fresh new plant growth, they can include stems, flowering stems with flower buds, leaves. The new growth from seed germination that grows upward is a shoot where leaves will develop.
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This article is about the physical mechanism of diffusion. For alternative meanings, see diffusion (disambiguation).

Diffusion is the net movement of particles from an area of high concentration to an area of low concentration.
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Earth's atmosphere is a layer of gases surrounding the planet Earth and retained by the Earth's gravity. It contains roughly (by molar content/volume) 78% nitrogen, 20.95% oxygen, 0.93% argon, 0.
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Osmosis is the net movement of water across a partially permeable membrane from a region of high solvent potential to an area of low solvent potential, up a solute concentration gradient.
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In vascular plants, xylem is one of the two types of transport tissue, phloem being the other one. The word "xylem" is derived from classical Greek ξυλον (xylon
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Light is electromagnetic radiation of a wavelength that is visible to the eye (visible light). In a scientific context, the word "light" is sometimes used to refer to the entire electromagnetic spectrum.
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trillion fold).]]

Temperature is a physical property of a system that underlies the common notions of hot and cold; something that is hotter generally has the greater temperature. Temperature is one of the principal parameters of thermodynamics.
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Humidity is the amount of water vapor in a sample of air compared to the maximum amount of water vapor the air can hold at any specific temperature. Absolute humidity, relative humidity and specific humidity are different ways to express the water content in a parcel of air.
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WIND (SOLARWIND) was a NASA spacecraft launched on November 1, 1994. It was deployed to study radio and plasma that occur in solar wind, in the Earth's magnetosphere. The spacecraft's original mission was to orbit the Sun at the L₁
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SOiL is a five-piece Hard Rock band from Chicago, Illinois, United States. They formed in 1997 and are still active. They are signed to DRT Entertainment and have released four albums, their most recent being True Self which was released in March 27 2006.
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Water is a common chemical substance that is essential to all known forms of life.^[1] In typical usage, water refers only to its liquid form or state, but the substance also has a solid state, ice, and a gaseous state, water vapor.
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There are three definitions in current use:

U.S. liquid gallon is legally defined as 231 cubic inches, and is equal to 3.785411784 litres (exactly) or about 0.13368 cubic foot. This is the most common definition of a gallon in the USA. The U.S.

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A crop is any plant that is grown in significant quantities to be harvested as food, livestock fodder, or for another economic purpose. This category includes crop species as well as agricultural techniques related to cropping.
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A potometer is a device used for measuring the rate of water uptake of a leafy shoot. The reasons for water uptake are for photosynthesis and transpiration.
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A lysimeter is a measuring device which can be used to measure the amount of actual evapotranspiration which is released from an area of woodland. By recording the amount of precipitation that an area receives and the amount lost through the soil, the amount of water lost to
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Transpiration

Information about Transpiration

See also

References

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