Highly Sensitive and Selective Turn-On Fluorescent Carbon Dots for Real-Time Ethylene Sensing and Imaging in Plant Tissues

Ethylene is a volatile and low-reactivity plant hormone that is indispensable for regulating plant growth and fruit ripening. However, real-time and highly sensitive detection of ethylene in plants remains a significant challenge. Herein, we developed orange-emitting carbon dots (e-CDs) through solvothermal synthesis, integrating Grubbs catalyst-mediated olefin metathesis with the inherent adsorption properties of carbon dots to specifically recognize and turn-on response to a nonpolar ethylene molecule. By employing this innovative design, our fluorescent probe achieves a detection limit of 0.12 ppm and delivers a rapid (within 3 min), highly selective response in complex biological matrices. Utilizing these capabilities, we monitored endogenous ethylene release during fruit ripening and achieved spatially resolved fluorescence imaging of ethylene in both fruits and Arabidopsis leaves. This versatile sensor platform not only surpasses the sensitivity of previously reported small-molecule sensors but also broadens the applicability of carbon dots to nonpolar gas detection, providing a powerful new tool for advancing agricultural practices, food preservation, and fundamental plant physiology research.