Bioelectronic Delivery of Biomolecules Combined with Thermography Enables Spatially Resolved Stomatal Signaling in Succulent Plants

Abstract Achieving localized delivery of signaling molecules in plants while obtaining spatially resolved, non-invasive readout of physiological responses remains a key challenge due to limitations in conventional methods for exogenous biomolecule application. These approaches typically rely on solution-based delivery or systemic treatments, which limit spatial precision and can disrupt the native physiological environment, making it difficult to study signal propagation. Here, we use the capillary organic electronic ion pump (c-OEIP) for localized, electronically controlled dry delivery of the phytohormone abscisic acid (ABA) in intact succulent plants. By combining the c-OEIP technology with infrared thermography, we obtain real-time, spatially resolved monitoring of physiological responses. We demonstrate this approach in Kalanchoë blossfeldiana, a drought-tolerant succulent species whose stomatal responses to exogenous signaling molecules remain poorly understood. Our results show that ABA delivery triggers stomatal closure during the day, consistent with observations in non-succulent plants. This work establishes a minimally invasive platform that combines bioelectronic delivery with spatially resolved readout, enabling spatiotemporal mapping of plant responses.