Thermal imaging as a viable tool for monitoring plant stress

Abstract

Aims: The objective of this paper was to describe an approach to the use of thermal data for shaded leaves rather than areas fully exposed to the sun. Secondly to make use of infrared thermography as a powerful tool to measure effects of solar radiation on berry temperature. Methods and results: Thermal images were obtained with a long-wave thermal imager. There is often less variability within an image for a shaded portion of the canopy than for a sunlit canopy. The temperature frequency distributions of sunlit leaves displayed a far wider range of temperature variation compared to shaded leaves. Conclusion: With thermal imagers it is feasible to select precisely the leaves for investigation. The remote sensing approach using infrared thermography combined with techniques available for image analysis open up a number of opportunities for comparative studies such as screening activities. Significance and impact of study: Infrared thermography can be implemented as a first line of detection to determine the onset of plant stress due to changes in stomatal aperture. This approach can give reliable and sensitive indications of leaf temperature and hence to calculate stomatal conductance. ©Vigne et Vin Publications Internationales (Bordeaux, France).