Non-invasive "Electroplantogram" (EPG) of greenhouse crops for real-time detection of water deficit

C. Camps, C. Plummer, N. Wallbridge
By analogy with the electrocardiogram (ECG), the proposed term “Electroplantogram” (EPG) is a graphical representation of the digitized electrical activity of the plant. In the present study, non-invasive EPG of tomato and eggplant have been recorded and analyzed to detect water deficit of plants in real-time. Such perspectives open the possibility to improve crop management efficiencies (water, nutrient supply). The key innovations of the study are 1) monitoring directly at plant level to manage the crop and 2) performing monitoring of electrical signals of plant outside a Faraday cage. Two case studies have been carried out. Firstly the long-term monitoring was done using electrical signals in eggplant at nursery stage and analysis of the electrical signals in the case of water deficit. In this experiment, we simulated a breakdown of the irrigation system. The results showed that it was possible to record a non-noisy EPG over several days. The electrical signal presented strong positive peaks each morning (10 mV) at sunrise and at each irrigation (3 to 10 mV). When an irrigation was lacking, a strong negative peak has been observed (-30 mV). The experiment was repeated two times with similar results. In the second case study, electrical signals of tomato plants in a greenhouse were monitored again for water deficit. Similarly to eggplant, an irrigation breakdown resulted in a strong negative peak of the electrical signal (-40 mV). After re-watering, the EPG recovered its normal level the following day. A second irrigation breakdown resulted in a second strong negative EPG peak of (-60 mV). Such a novel approach needs to be developed and adapted to professional greenhouse conditions. If future developments are successful the management of greenhouse inputs could be made more efficient because interventions would respond directly to plant behavior and could be made in real-time.
Camps, C., Plummer, C. and Wallbridge, N. (2020). Non-invasive "Electroplantogram" (EPG) of greenhouse crops for real-time detection of water deficit. Acta Hortic. 1279, 303-310
DOI: 10.17660/ActaHortic.2020.1279.43
electrophysiology, electrical signal, water stress, irrigation system breakdown, tomato, eggplant

Acta Horticulturae