title: Use of infrared thermography for monitoring stomatal closure in the field: application to grapevine.
abstract: This paper reviews and discusses strategies for the use of thermal imaging for studies of stomatal conductance in the field and compares techniques for image collection and analysis. Measurements were taken under a range of environmental conditions and on sunlit and shaded canopies to illustrate the variability of temperatures and derived stress indices. A simple procedure is presented for correcting for calibration drift within the images from the low-cost thermal imager used (SnapShot 225, Infrared Solutions, Inc.). The use of wet and dry reference surfaces as thresholds to eliminate the inclusion of non-leaf material in the analysis of canopy temperature is discussed. An index that is proportional to stomatal conductance was compared with stomatal measurements with a porometer. The advantages and disadvantages of a possible new approach to the use of thermal imagery for the detection of stomatal closure in grapevine canopies, based on an analysis of the temperature of shaded leaves, rather than sunlit leaves, are discussed. Evidence is presented that the temperature of reference surfaces exposed within the canopy can be affected by the canopy water status.
authors.affiliation: Division of Environmental and Applied Biology, School of Life Sciences, University of Dundee, SCRI, Invergowrie, Dundee DD2 5DN, UK. h.g.jones@dundee.ac.uk
authors.forename: Hamlyn G
authors.initials: HG
authors.lastname: Jones
authors.forename: Manfred
authors.initials: M
authors.lastname: Stoll
authors.forename: Tiago
authors.initials: T
authors.lastname: Santos
authors.forename: Claudia
authors.initials: C
authors.lastname: de Sousa
authors.forename: M Manuela
authors.initials: MM
authors.lastname: Chaves
authors.forename: Olga M
authors.initials: OM
authors.lastname: Grant
mesh_terms: D000465:Algorithms; D001272:Atmosphere; D007259:Infrared Rays; D008954:Models, Biological; D019441:Plant Epidermis / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D018515:Plant Leaves / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D018526:Plant Transpiration / Q000187:drug effects / Q000502:physiology*; D016062:Porosity / Q000528:radiation effects; D013472:Sunlight; D013696:Temperature; D013817:Thermography / Q000379:methods; D027843:Vitis / Q000187:drug effects / Q000502:physiology*; D014867:Water / Q000494:pharmacology; D014919:Wind
chemical_list: D014867:Water