Infrared thermography for monitoring stomatal closure

Fig. 1. (a) Thermal image of side view of grapevine row from c. 1.5 m; (b) correction image obtained of a constant temperature object (lens cap) taken after running the camera for 30 min; (c) corrected version of original image obtained after subtraction of (b) from (a) and adding back the mean temperature of (b)


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

Jones H. G.Stoll M.Santos Sousa C.Chaves M. M.Grant O. M. (2002)

Hamlyn G. Jones, 1,4, Manfred Stoll, 1, Tiago Santos, 2, Claudia de Sousa, 3, M. Manuela Chaves, 2,3 and Olga M. Grant, 1

1 Division of Environmental and Applied Biology, School of Life Sciences, University of Dundee, SCRI, Invergowrie, Dundee DD2 5DN, UK

2 Instituto Superior de Agronomia, Tapada da Ajuda, 1349-017 Lisboa, Portugal

3 Instituto de Tecnologia QuõÂmica e BioloÂgica, Av. Republica, EAN. 2784-505 Oeiras, Portugal


in Journal of Experimental Botany 5322492260 – PMID: 12379792 – 

Abstract/FREE Full Text, Google Scholar CrossRef PubMed –


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.


Growth temperature and the response of stomata to drought and ABA.



Effect of growth temperature on the response of lupin stomata to drought and abscisic acid.

by Osório M. L., Rodrigues M. L., Chaves M. M., Correia M. J., (1999)

M. Leonor Osório, M. Lucília Rodrigues, M. Manuela Chaves, Maria João Correia,


in Austral. J. Plant Physiol. 26(6): 549-559 –


To assess how growth temperature affects stomatal responses to xylem-transported abscisic acid (ABA), leaf conductance (g), the concentrations of ABA and calcium ions, and the pH of the xylem sap were measured in well-watered and water-stressed Lupinus albusL. plants grown under two thermal regimes: 10/15°C and 20/25°C, night/day temperature. Moderate water deficit was imposed, at the same thermal time, and induced a significant reduction in g regardless of temperature. In the morning, g was higher in plants grown at 20/25°C than in cooler conditions, and these differences could not be explained by dissimilarities in shoot water status or xylem ABA concentration. At midday, the apparent stomatal sensitivity to xylem-carried ABA was increased and the effect of temperature on the relationship between g and xylem ABA was no longer observed. A positive effect of higher temperature on stomatal aperture was also evident when artificial sap containing ABA was fed to leaves of well-watered plants. In response to exogenous ABA, stomata closed to the same extent as observed in the morning in water-stressed plants. However, exogenous ABA feeding could not mimic the relationship between g and xylem ABA determined at midday in intact plants. The pH and the concentration of calcium in xylem were not affected by temperature. At midday, however, the calcium concentrations were higher in water-stressed than in well-watered plants. These changes in the concentrations of calcium or other xylem components, such as ABA conjugates, together with possible changes in the ability of the leaves to degrade and/or to compartmentalise ABA, may partly explain the midday increase in the apparent stomatal sensitivity to xylem ABA.

Hydraulic and chemical signalling in the regulation of stomatal conductance


Photo credit: Google

Vitis vinifera

Hydraulic and chemical signalling in the regulation of stomatal conductance and plant water use in field grapevines growing under deficit irrigation

by Rodrigues M.L., Santos T.P., Rodrigues A.P., de Souza C.R., Lopes C.M., Maroco J.P., Pereira J.S., Chaves M.M. (2008)

M. Lucília Rodrigues A D , Tiago P. Santos A , Ana P. Rodrigues A B , Claudia R. de Souza B , Carlos M. Lopes A , João P. Maroco B C , João S. Pereira A, M. Manuela Chaves A B

A Instituto Superior de Agronomia, Universidade Técnica de Lisboa, Tapada da Ajuda, 1349-017 Lisboa, Portugal.

B Laboratório de Ecofisiologia Molecular, Instituto de Tecnologia Química e Biológica, Apartado 127, 2780-901 Oeiras, Portugal.

C Instituto Superior de Psicologia Aplicada. Rua Jardim do Tabaco, 34, 1149-047 Lisboa, Portugal.


in Funct. Plant Biol. 35: 565–579 – –

Google Scholar CrossRef


Effects of irrigation strategies on stomata and plant water use were studied in field-grown grapevines (Vitis vinifera L.).

We assessed the importance of root-derived chemical signals vs. hydraulic signalling in stomatal regulation. The experiment included two treatments with the same water added to the soil (50% ETc) applied either to the whole root system (DI) or to half of the roots, alternating irrigation side every 15 days (PRD). Well-watered plants (FI) (100% ETc) and non-irrigated grapevines (NI) were also studied.

Partial stomata closure occurred in both PRD and DI plants. [ABA] of xylem sap remained constant during the day and was maintained throughout the season, with higher values in NI plants. Xylem sap pH was not affected by soil water availability.

A positive correlation between ψpd and maximum g s was found, indicating that grapevine stomata strongly respond to plant water status.

In contrast, ABA did not explain stomatal control at veraison. At mid-ripening g s was significantly correlated with ABA, apparently interacting with the rise in xylem sap pH.

Therefore, our data suggest that hydraulic feedback and feed-forward root-to-shoot chemical signalling mechanisms might be involved in the control of stomata in response to decreased soil water availability, hydraulic signals playing the dominant role.