Use of infrared thermography for monitoring stomatal closure in the field: application to grapevine

• Published in: Journal of experimental botany 2002-11, Vol.53 (378), p.2249-2260
• Main Authors: Jones, Hamlyn G., Stoll, Manfred, Santos, Tiago, Sousa, Claudia de, Chaves, M. Manuela, Grant, Olga M.
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Algorithms; Atmosphere; Biological and medical sciences; Economic plant physiology; Forest canopy; Fundamental and applied biological sciences. Psychology; Infrared Rays; infrared thermography; infrared thermometry; Key words: Energy balance; leaf temperature; Models, Biological; Pixels; Plant Epidermis - cytology; Plant Epidermis - drug effects; Plant Epidermis - physiology; Plant Leaves - cytology; Plant Leaves - drug effects; Plant Leaves - physiology; Plant physiology and development; Plant Transpiration - drug effects; Plant Transpiration - physiology; Plants and the Environment; Porosity - radiation effects; Solar temperature; Stomatal conductance; Sunlight; Surface temperature; Temperature; Temperature distribution; Temperature measurement; thermal imaging; Thermography; Thermography - methods; Vegetation canopies; Vitis - drug effects; Vitis - physiology; Vitis vinifera; Water - pharmacology; Water and solutes. Absorption, translocation and permeability; Water relations, transpiration, stomata; Water temperature; Wind
• ISSN: 0022-0957; 1460-2431; 1460-2431
• DOI: 10.1093/jxb/erf083

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.