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Proceedings Paper

Thermographic measurements on plant leaves
Author(s): Christoph Garbe; Ulrich Schurr; Bernd Jaehne
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Paper Abstract

An important process of plant physiology is the transpiration of plant leaves. It is actively controlled by pores (stomata) in the leaf and the governing feature for vital factors such as gas exchange and water transport affixed to which is the nutrient transport from the root to the shoot. Because of its importance, the transpiration and water transport in leaves have been extensively studied. However, current measurement techniques provide poor spatial and temporal resolution. With the use of one single low-NETD infrared camera important parameter of plant physiology such as transpiration rates, heat capacity per unit area of the leaf and the water flow velocity can be measured to high temporal and special resolution by techniques presented in this paper. The latent heat flux of a plant, which is directly proportional to the transpiration rate, can be measured with passive thermography. Here use is made of the linear relationship between the temperature difference between a non transpiring reference body and the transpiring leaf and the latent heat flux. From active thermography the heat capacity per unit area of the leaf can be measured. This method is termed active, because the response of the leaf temperature to an imposed energy flux is measured. Through the use of digital image processing techniques simultaneous measurements of the velocity field and temporal change of heated water parcels traveling through the leaf can be estimated from thermal image sequences.

Paper Details

Date Published: 15 March 2002
PDF: 10 pages
Proc. SPIE 4710, Thermosense XXIV, (15 March 2002); doi: 10.1117/12.459590
Show Author Affiliations
Christoph Garbe, Ruprecht-Karls Univ. Heidelberg (Germany)
Ulrich Schurr, Forschungszentrum Juelich GmbH (Germany)
Bernd Jaehne, Ruprecht-Karls Univ. Heidelberg (Germany)

Published in SPIE Proceedings Vol. 4710:
Thermosense XXIV
Xavier P. Maldague; Andres E. Rozlosnik, Editor(s)

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