A thermal imaging approach for dynamic stomatal response and phenotyping of three tomato genotypes

MSc-minor thesis abstract (submitted 23 January 2017): Imaging offers various advantages over porometry for measurement of stomatal conductance. Thermal index can be calculated using thermal images, the relationship between thermal index and stomatal conductance has previously been defined as linear and proportional. The aim of this study was to define the relationship between thermal index and stomatal conductance over a series of light intensities, then to observe genotypic differences in stomatal response to change in light intensity using thermal imaging in three tomato cultivars.

It was hypothesized that the relationship between thermal index and stomatal conductance was linear and proportional over the range of light intensities explored for all cultivars. Phenotypic differences in stomatal response to change in light intensity was also expected.

Findings supported the hypothesis that the relationship between thermal index and stomatal conductance was linear, however proportionality was not confirmed, phenotypic differences in this relationship were observed. Because of the lack of proportionality, and high variation, it was not possible to infer stomatal conductance given thermal index.
However, it was possible to observe phenotypic variation in thermal index in response to change in light intensity from ambient light to darkness, and returning to ambient light.

Keywords: Stomatal conductance, dynamic stomatal response, thermal imaging, thermal index, phenotyping, light intensity