Leaf-FIT: A Wearable Leaf Sensor for In-Situ and Real-Time Monitoring of Plant Phytohormones

This work presents the development of leaf-FIT: a multiplexed electrochemical sensor on a flexible substrate for real-time and in situ monitoring of phytohormones in the leaves of a living plant. Salicylic acid is a key signaling phytohormone, the elevated levels of which denote crop stresses. The sensor was demonstrated to effectively measure the salicylic acid concentrations in the leaves of a bell pepper plant under water and light stresses. The salicylic acid levels measured with our sensor demonstrated good agreement with the values from Fourier Transform Infrared Spectroscopy. As phytohormone signaling is a plant's first response to environmental stresses, their real-time monitoring with the presented in-situ sensor can help producers in making informed decision about timely intervention.