2019 ASHS Annual Conference

Infrared thermography is a non-contact measurement which allows us to visualize the temperature of an object by measuring the objects emittance of long wave radiation. Previous research has found a relationship between thermal imaging parameters and stomatal conductance. Stomatal conductance is a parameter frequently measured in plant science research; primarily to determine the effects of stressors on stomata and plant water relations. This measurement gives us insight into plant photosynthesis and the impact of stress on plants. Stomatal conductance can be influenced by various abiotic stressors, including drought. Porometry is a common method of stomatal conductance measurement, which requires contact with the leaf surface. This can cause disturbance of the boundary layer and effect light interception and temperature at the point of measurement. These disturbances can induce stomatal response and in doing so, influence the measurement being taken. Thermal imaging offers multiple advantages over porometry for measurement of stomatal conductance. Thermal imaging is well suited for automation, scalable, non-contact and can generate large amounts of data in a short timeframe. The objective of this study is to explore applications of thermal imaging during plant development and post-harvest. Aspects of this study include defining the relationship between thermal image parameters and stomatal conductance in Capsicum annum L. under ambient and drought stressed conditions, using thermal imaging to quantify and visualize dynamic stomatal response to drought stress, as well as post-harvest quality analysis. Three image analysis methods were used to explore the relationship between thermal imaging parameters and stomatal conductance. Thermal images captured under summer greenhouse conditions found no significant correlation between the two parameters. To determine if extreme temperatures were a factor in these findings, the experiment was repeated under winter greenhouse conditions. Drought stress treatments were also applied to plants to evaluate if induced stress could impact results. Thermal images were captured and, stomatal conductance, chlorophyll fluorescence, relative turgidity and membrane permeability were measured.