Plants may appear to do nothing, but in fact they are actively sensing and responding to a wide range of environmental stimuli such as light levels, temperature, gas concentrations, soil chemistry and humidity, the presence of insects or mammals and other conditions. Many plants use transient electrical signals to control the speed of photosynthesis or respiration, the rate or direction of growth, the emission of chemicals as a defence against herbivores, and other physiological responses. Scientists have known about these signals for many years but they have not been practically applied because of difficulties in measuring them, as they are tiny relative to background electromagnetic interference. The Horizon 2020 PhytlSigns project has achieved a breakthrough by creating a low-cost, real-time plant monitoring device based on bioelectrical signals. “PhytlSigns is the first ‘wearable’ for plants, harnessing electrical signals and translating them into digital form before visualising them for further analysis. By amplifying plant signals and reducing background noise researchers and growers can measure activity in response to changing conditions,” says project coordinator Carrol Plummer. Customer feedback for next-generation sensors The project is forging ahead with plans to commercialise real-time plant electrophysiology sensors, augmenting scientific studies with research into commercial markets. “Our main challenge is determining effective ways of creating a market for PhytlSigns bio-sensors given that plant electrophysiology is relatively unknown. We interviewed users of PhytlSigns prototypes, using their feedback to refine the next generation of plant electrophysiology sensors,” Plummer explains. Researchers also examined how tomato breeders develop new tomato varieties and herbicide developers test new formulations. According to Plummer: “These insights helped us develop strategies for bringing our product to market effectively and ensured that we were able to identify our market appropriately.” For herbicide developers, it is clear PhytlSigns’ devices provide faster feedback on the effectiveness of a formulation than using visual cues. “It enables the manufacturer to shorten their product development cycle, using the device in much the same way as an academic researcher. However, tomato breeders need to monitor plants for much longer periods and want early detection of plant stressors. This is akin to how a professional grower will use the sensors,” Plummer points out. Major benefits identified “Multi-disciplinary research shows great promise in plant electrophysiology and is at the project’s heart. We are delighted to encourage links between information scientists and biologists,” states Plummer. PhytlSigns recognises that the use of machine-learning algorithms provides important insights when processing plant electrophysiology signals. Scientists investigating electrical signaling or the interplay of chemical, electrical and hydraulic signaling will be the first to benefit from the innovative electronics and sophisticated signal processing that comprise PhytlSigns sensors. However, the most important impact comes from applying real-time plant electrophysiology sensors to reduce the number and intensity of interventions for indoor crops like tomatoes, peppers or eggplants. Plants can very quickly sense changes in irrigation, the application of nutrients and other environmental conditions and these signals can be interpreted by growers to optimise conditions for their crops. “This will lead to improved yields and lower environmental impact from growing crops important for the human food chain,” Plummer concludes.
PhytlSigns, signal, plants, bioelectrical, biosensor