Integrated plant temperature measurement using heat-sensitive paint and colour image analysis

1. Despite the fundamental importance of temperature to a variety of physiological processes, such as photosynthesis and transpiration in plants, accurately quantifying and integrating differences in surface temperatures is often difficult, if not impossible. 2. An inexpensive, user-friendly technique is now available whereby plants and animals can be air-brushed with a non-toxic, heat-sensitive paint that will generate six or more distinguishable colours across a temperature range of approximate to5 degreesC and a resolution of <1 degreesC. These temperature-indicating colours can then be photographed and evaluated quantitatively using image analysis software. 3. Compared to a more traditional temperature measurement technique (thermocouples), this method resulted in a mean surface temperature of up 5.1 degreesC warmer than the mean thermocouple temperature, as well as a computed 45% difference in transpirational water loss for a single leaf, multiple leaves on a shoot, and leaves within a crown.