Sustainable agriculture with LEAFS: a low-cost electrochemical analyzer of foliage stress

Sustainable agricultural practices are vital to meet the needs of a rapidly growing global demand for food. Monitoring plant health is crucial for enhancing crop yields. Salicylic acid (SA) is a plant hormone that plays a key role in the defense mechanisms plants employ against various stress factors. Changes in SA levels serve as an indicator that a plant is experiencing stress. Here, we present a low-cost electrochemical sensor fabricated using porous laser-induced graphene material for the measurement of plant stress. It employs square wave voltammetry to monitor SA levels using a wireless potentiostat. The sensor shows a high sensitivity of 144.28 mu A mM-1 to SA, with a linear detection range of 6.6 mu M to 200 mu M and a limit of detection of 1.44 mu M. The surface of the working electrode was modified with Nafion to enable continuous in situ stress monitoring. The sensor's practicality has been demonstrated through real-time stress monitoring in aloe vera and philodendron hederaceum plant species. LEAFS (a low-cost electrochemical analyzer of foliage stress) measures SA, a biomarker for plant stress, in a blended leaf mixture or can be inserted directly in the plant leaf or stem for continuous monitoring.