The origin and theoretical correction of thermal gradients in thermocouple psychrometers |
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Authors: | E. VANDERCHMITT F.-A. DAUDET |
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Affiliation: | Station de Bioclimatologie, INRA, Centre de recherches d'Avignon, domaine Saint Paul, F-84143 Montfavet Cedex;Unitéassociée de Physiologie Intégrée de l'Arbre Fruitier (INRA-UniversitéBlaise Pascal), domaine de Crouelle, F-63039 Clermont-Ferrand Cedex 02, France |
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Abstract: | Temperature-compensated psychrometers are explained and a theoretical correction for temperature gradients, with its boundaries, is given. The correction was elaborated for in situ determination of water potential on soybean and tomato stems where it was indispensable. The origin of the thermal gradients in the psychrometric chamber is then discussed. Cooling of the conducting tissue by the circulation of xylem sap seemed to be the major cause for these gradients, while the heating of the psychrometer (thermally insulated) by the surroundings through radiative or conductive transfer was negligible. |
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Keywords: | plant water potential compensated thermocouple psychrometers in situ measurements thermal gradients theoretical correction stem hygrometer Glycine max Lycopersicon aesculentum |
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