S12 - Session O2 - Electrophysiological estimation of drought stress in apple trees

Authors: Andrzej Kurenda *, Philippe Monney, Thomas Caloz, Alja van der Shuren, Moritz Graef, Nigel Wallbridge, Carrol Plumer

The increase in the frequency of extreme weather events resulting from climate change, creates a need for more precise and faster determination of plant stresses to avoid yield losses. Extracellular electrophysiology has proven potential to detect water and nutrient deficit and biotic stresses in tomato plants. However, information about application of plant electrophysiology in tree status monitoring is scarce. To verify if plant electrophysiology is suitable for drought detection in horticulturally important trees, we performed season-long electrical potential recordings and leaf water potential measurements from groups of optimally watered and drought stressed apple trees. Electrophysiological recordings were subjected to a previously developed General Stress algorithm (a Machine Learning model), created to detect wound-related stress, drought and nutrient deficits. Analysis indicated that the group of plants subjected to drought, expressed higher stress levels than optimally watered plants and that the high stress periods correspond with low stem water potential measurements. This indicates that electrophysiology-based drought stress detection systems can be successfully used in commercial orchards for real-rime, remote monitoring of tree water status. Coupling of automatic watering systems and electrophysiology-based drought stress detection may result in the creation of an autonomous system that efficiently supports growers in their challenges related to climate change and increasing market quality demands.