TERMIUM Plus^®

Record 1,  Textual support,  English

Record number: 1, Textual support number: 1 DEF

... a measure of the tendency of water to move from high free energy to lower free energy.  3, record 1, English, - water%20potential

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Water potential is the sum of osmotic potential, pressure potential, [gravitational potential, ] and matric potential.  4, record 1, English, - water%20potential

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For historical and practical reasons, however, plant physiologists have developed another parameter called the water potential (psi_w). Water potential is expressed in pressure units such as megapascals (MPa). ... Like chemical potential, water potential is a relative quantity, and is always determined as a difference between the sample in question and a standard reference. For plant physiologists, the standard reference for water potential measurements is the water potential of pure water at one atmosphere of pressure. This reference value is defined as 0 MegaPascals.  2, record 1, English, - water%20potential

Record number: 1, Textual support number: 1 OBS

[Water potential] is replacing the concept of osmotic pressure and differs from osmotic pressure in taking capillary and imbibitional forces into account.  4, record 1, English, - water%20potential

Record number: 1, Textual support number: 2 OBS

The symbol for water potential is the Greek letter Psi. ... Water potential is measured in units of atmospheric pressure; bars or dynes per square centimeter. (1 bar = 106 dynes/cm²).  3, record 1, English, - water%20potential

Record number: 1, Textual support number: 3 OBS

The symbol used is the Greek letter psi_w.  5, record 1, English, - water%20potential

Record 1,  Textual support,  French

Record number: 1, Textual support number: 1 CONT

Les composantes du potentiel hydrique. Dans un sol, l'énergie potentielle de l'eau peut provenir de plusieurs sources. [...] Potentiel gravitationnel [...] Potentiel matriciel [...] Potentiel osmotique [...]  2, record 1, French, - potentiel%20hydrique

Record number: 1, Textual support number: 1 OBS

Paramètre de l'eau du sol ou de la plante.  3, record 1, French, - potentiel%20hydrique

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Bien qu'aujourd'hui le terme potentiel hydrique soit le terme recommandé, on trouve encore, héritage du passé, d'autres appellations de cette même grandeur : potentiel de succion, tension de succion, déficit de pression, hauteur capillaire, etc. Le fait à retenir est que ces différentes dénominations, qu'il faut désormais éviter d'utiliser en physiologie végétale et en agronomie, sont le plus souvent équivalentes (au signe près et compte tenu des unités dans lesquelles elles sont exprimées); elles définissent toutes «l'état énergétique» de l'eau dans un substrat.  4, record 1, French, - potentiel%20hydrique

Record 1,  Textual support,  Spanish

Record number: 1, Textual support number: 1 DEF

Gradiente de presión que provoca el flujo de agua, especialmente en relación a su absorción del suelo por las plantas.  1, record 1, Spanish, - potencial%20h%C3%ADdrico

Record number: 1, Textual support number: 1 OBS

Depende de los componentes gravitatorios, matricial, osmótico y de presión.  1, record 1, Spanish, - potencial%20h%C3%ADdrico

Record 2,  Textual support,  English

Record number: 2, Textual support number: 1 DEF

The amount of work that must be done per unit quantity of pure water in order to transport reversibly and isothermally an infinitesimal quantity of water from a pool of pure water, at a specified elevation and at atmospheric pressure, to a pool of water identical in composition with the soil water at the point under consideration, but in all other respects being identical with the reference pool.  5, record 2, English, - osmotic%20potential

Record number: 2, Textual support number: 1 CONT

... solute potential. The tendency for water to undergo phase changes or to pass through membranes is controlled by the presence of solutes in the water. This is important in soil for two reasons :(1) evaporation of soil water is an important phase change,(2) water flow from soil into cells of organisms, including plant roots, requires transport through membranes.... As with matric potential, solute potential is never positive; it can be negative for impure water, or approximately zero for very pure water. Solute potential is also called osmotic potential, because the process of passing selectively through a semi-permeable membrane is called osmosis.  4, record 2, English, - osmotic%20potential

Record number: 2, Textual support number: 1 OBS

The symbols used is the Greek letter Psi sub Pi for osmotic potential ...  2, record 2, English, - osmotic%20potential

Record number: 2, Textual support number: 2 OBS

The symbol for solute potential is psi_s.  6, record 2, English, - osmotic%20potential

Record 2,  Textual support,  French

Record number: 2, Textual support number: 1 DEF

Quantité de travail qu'il faut fournir par quantité unitaire d'eau pure pour transporter de façon réversible et isothermique une quantité infinitésimale d'eau d'un bassin d'eau pure, d'une élévation donnée et à la pression atmosphérique, à un bassin d'eau de composition identique à l'eau du sol située au point à l'étude, mais en tout autre qualité identique à l'eau du bassin de référence.  3, record 2, French, - potentiel%20osmotique

Record number: 2, Textual support number: 1 CONT

Potentiel osmotique (psi_os). Ce potentiel résulte de la présence de molécule dissoute dans l'eau. L'état de référence étant l'eau pure, ce potentiel sera toujours [plus petit que ou égal à] 0.  2, record 2, French, - potentiel%20osmotique

Record number: 2, Textual support number: 2 CONT

Pour les organes végétaux (vivants ou récoltés), le potentiel hydrique [...] se réduit pratiquement à deux composantes qui peuvent être mesurés séparément : le potentiel hydrostatique P et le potentiel osmotique [...]  4, record 2, French, - potentiel%20osmotique

Record number: 2, Textual support number: 1 OBS

Symbole : psi_os.  5, record 2, French, - potentiel%20osmotique

Record 2,  Textual support,  Spanish

Record 3,  Textual support,  English

Record number: 3, Textual support number: 1 DEF

The amount of work that must be done per unit quantity of pure water in order to transport reversibly and isothermally an infinitesimal quantity of water, identical in composition with the soil water, from a pool at the elevation and the external gas pressure of the point under consideration, to the soil water.  4, record 3, English, - capillary%20potential

Record number: 3, Textual support number: 1 CONT

Matric potential is the most important component in soil, but is more difficult to visualize. Water will not freely leave soil unless soil is very wet. This is because of adhesion and cohesion. Imagine placing a clump of dry soil on a table, then dropping a drop of water onto the clump of dry soil. If you elevate the soil off of the table, will the water leap out of it, dropping to the table? Of course not. It will stay in the soil, held by adhesion, or what we often call matric forces. The symbol for matric potential is [psi subscript m]. These values are negative or zero, but never positive, because this water is not free to move to the zero state.... The matric potential of a soil refers to the potential of the most easily removed molecule...  5, record 3, English, - capillary%20potential

Record number: 3, Textual support number: 2 CONT

This work is less than zero, or negative work, thus reported in negative values. Matric potential nearly equals water potential in nonsalty soils.  6, record 3, English, - capillary%20potential

Record 3,  Textual support,  French

Record number: 3, Textual support number: 1 DEF

Quantité de travail qu'il faut fournir par quantité unitaire d'eau pure pour transporter de façon réversible et isothermique une quantité infinitésimale d'eau, de composition identique à l'eau du sol, d'un bassin d'une élévation et à une pression extérieure des gaz égales à celles du point à l'étude, jusqu'à l'eau du sol.  4, record 3, French, - potentiel%20capillaire

Record number: 3, Textual support number: 1 CONT

Les composantes du potentiel hydrique. Dans un sol, l'énergie potentielle de l'eau peut provenir de plusieurs sources. [...] Potentiel matriciel [(psi indice m]) : Ce potentiel résulte des forces d'hydratation (affinité des surfaces solides pour l'eau) et des forces de capillarité (différence de pression à l'interface eau /air dans un système triphasique eau-gaz-solide; [...]). L'état de référence étant l'eau libre, ce potentiel sera toujours [plus petit ou égal à] 0.  5, record 3, French, - potentiel%20capillaire

Record number: 3, Textual support number: 1 OBS

Mis à part certains cas très particuliers, il n'est pas possible de mesurer séparément, dans un tissu végétal vivant, une composante matricielle. Celle-ci est en fait incluse, soit dans le potentiel hydrostatique, soit dans le potentiel osmotique.  6, record 3, French, - potentiel%20capillaire

Record 3,  Textual support,  Spanish

Record number: 3, Textual support number: 1 DEF

Trabajo necesario para mover una unidad de peso de agua desde una superficie libre hasta un punto determinado del suelo en el nivel de la superficie de agua.  3, record 3, Spanish, - potencial%20capilar

Record 4,  Textual support,  English

Record number: 4, Textual support number: 1 DEF

... ability of water to do work. i.e. Move from one location to another.  2, record 4, English, - total%20water%20potential

Record number: 4, Textual support number: 1 CONT

Water Potential is defined as the potential energy of water per unit mass of water in the system. The total water potential of a sample is the sum of four component potentials : gravitational, matric, osmotic, and pressure. Gravitational potential depends on the position of the water in a gravitational field. Matric potential depends on the adsorptive forces binding water to a matrix. Osmotic potential depends on the concentration of dissolved substance in the water. Pressure potential depends on the hydrostatic or pneumatic pressure on the water.  3, record 4, English, - total%20water%20potential

Record number: 4, Textual support number: 2 CONT

Total water potential=matric potential + osmotic potential + gravitational potential...  4, record 4, English, - total%20water%20potential

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Pure water has a potential of 0 by definition.  2, record 4, English, - total%20water%20potential

Record 4,  Textual support,  French

Record number: 4, Textual support number: 1 CONT

Le potentiel total, somme en chaque point de tous les potentiels énumérés ci-dessous. [...] - le potentiel pascalien ou hydrostatique [...]; - le potentiel capillaire [...]; - le potentiel d'adhésion [...]; - le potentiel gravitationnel [...]; - le potentiel matriciel [...]  1, record 4, French, - potentiel%20hydrique%20total

Record number: 4, Textual support number: 2 CONT

Le plus souvent l'eau se déplace : infiltration dans le sol après une pluie ou une irrigation, percolation en profondeur jusqu'à la nappe, déplacement de l'eau de la nappe, vers une source ou des drains, remontées capillaires jusqu'à la surface évaporante ou la zone de succion racinaire, flux liquide du sol jusqu'au feuilles. Ces transferts sont dus à des différences de potentiel hydrique total.  1, record 4, French, - potentiel%20hydrique%20total

Record 4,  Textual support,  Spanish

Record 5,  Textual support,  English

Record number: 5, Textual support number: 1 CONT

The matric potential h_c is negative in unsaturated soil(pores partly filled with water and partly with air), because work is needed to withdraw water against the soil matric forces. It is not essential to know these forces in detail : it suffices that h_c can be measured by tensiometry or other techniques.  2, record 5, English, - tensiometry

Record number: 5, Textual support number: 2 CONT

Tensiometry... : Two kinds of devices are widely distributed on the French market :'standard’ tensiometers(porous cup linked to a depression manometer by a tube filled with water) ;and watermark sensors(electrical measure block buried in the ground and removable meter). Tensiometers measure the soil matric potential(but only below 100 kPa). A little delicate to implement, exacting to pick out(automation is desirable), nevertheless they are a good tool for controlling the irrigations(particularly drip). Nowadays they are more used by agricultural advisers than by farmers, unless the latter are well trained.  3, record 5, English, - tensiometry

Record 5,  Textual support,  French

Record number: 5, Textual support number: 1 CONT

Le potentiel matriciel de l'eau du sol. [...] Trois types de mesure sont couramment utilisés : - par extraction de l'eau sous pression [...] - par équilibre hygroscopique [...] - par tensiométrie. Les tensiomètres laissés à demeure dans le sol donnent le potentiel matriciel par simple lecture de la hauteur d'une colonne manométrique. Cette méthode est applicable dans la gamme allant de 0 à -0,1 MPa environ.  1, record 5, French, - tensiom%C3%A9trie

Record 5,  Textual support,  Spanish

Record 6,  Textual support,  English

Record number: 6, Textual support number: 1 DEF

The total potential for water in a leaf, consisting of the balance between osmotic potential(arising from the presence of solutes), turgor pressure(the hydrostatic pressure developed in the cell in response to the osmotic potential and the tensile strength of the cell wall) and the matric potential(arising from the imbibitional forces of colloids and of capillaries in the cell wall).  2, record 6, English, - leaf%20water%20potential

Record number: 6, Textual support number: 1 OBS

This determination of water deficit in leaves can be measured with a "pressure bomb" or by psychrometric methods.  2, record 6, English, - leaf%20water%20potential

Record 6,  Textual support,  French

Record number: 6, Textual support number: 1 CONT

La transpiration végétale. [...] Lorsque le sol se dessèche, la transpiration diminue. Cette réponse a longtemps été expliquée en considérant que la diminution du flux hydrique entraînerait automatiquement une modification du potentiel hydrique foliaire et la fermeture des stomates à partir d'un certain seuil.  3, record 6, French, - potentiel%20hydrique%20foliaire

Record number: 6, Textual support number: 2 CONT

La mesure du potentiel hydrique foliaire s'opère grâce à une chambre de pression.  4, record 6, French, - potentiel%20hydrique%20foliaire

Record 6,  Textual support,  Spanish

Record 7,  Textual support,  English

Record number: 7, Textual support number: 1 DEF

The pressure(positive or negative), in relation to the external gas pressure on the soil water, to which a solution identical in composition with the soil water must be subjected in order to be in equilibrium through a porous permeable wall with the soil water. It may be identified with the matric potential....  1, record 7, English, - soil%20water%20pressure

Record 7,  Textual support,  French

Record number: 7, Textual support number: 1 DEF

Pression positive ou négative (tension), par rapport à la pression extérieure des gaz sur l'eau du sol, qu'il faut exercer sur une solution de même composition que l'eau du sol pour que la solution soit en équilibre avec l'eau du sol, à travers une membrane poreuse perméable. Elle peut correspondre au potentiel capillaire (de matrice) (...)  1, record 7, French, - pression%20de%20l%27eau%20du%20sol

Record 7,  Textual support,  Spanish