Making Plant Physiology Visible: Ten Inquiry-Based Infrared Thermography Activities for Undergraduate Teaching

Many of the processes studied in plant physiology, including stomatal regulation, responses to drought, formation of graft unions, interactions with pathogens, floral thermogenesis and freezing, are dynamic but difficult for students to observe directly. Consequently, teaching these topics often relies on indirect measurements or theoretical explanations, which makes it difficult for students to understand the link between physiological concepts and observable plant behaviour. Infrared thermography offers a rapid, non-invasive way to visualise temperature patterns that reflect underlying physiological processes. This article presents ten inquiry-based laboratory and field activities that integrate infrared thermography into undergraduate plant physiology teaching. Rather than focusing on the technology itself, the activities are organised around fundamental physiological concepts, challenging students to formulate hypotheses, interpret thermal images and relate temperature patterns to plant function. The activities cover topics such as water relations and transpiration, graft union formation, plant–pathogen interactions, drought detection, host–parasitic plant relationships, floral thermogenesis, floral cooling, ice nucleation, seed vigour assessment and responses to abiotic and biotic stresses. Beyond illustrating individual physiological phenomena, the activities emphasise the unifying principle that infrared thermography does not simply measure temperature but provides an integrated window into plant physiology by revealing processes that would otherwise be invisible. At the same time, students become familiar with a research tool that is increasingly used in plant science, precision agriculture and crop phenotyping. As infrared cameras become more affordable and accessible, thermography represents a powerful and realistic approach to enriching inquiry-based learning and strengthening the connection between undergraduate teaching and contemporary plant research.