In situ NIR-IIb imaging of endogenous H2S signaling for high-resolution abiotic stress visualization in plants

In vivo analysis of plant stress responses remains a major challenge in precision agriculture, limiting dynamic optimization of crop growth under variable environmental conditions. Fluorescence imaging enables nondestructive tracking of stress biomarkers, but its accuracy is compromised by the low abundance of endogenous signaling molecules, tissue autofluorescence interference, and limited signal penetration depth. Here, we develop a ratiometric near-infrared IIb fluorescent probe for sensitive monitoring of endogenous hydrogen sulfide (H2S). This nanoprobe integrates lanthanide nanoparticles with H2S-responsive molecular units, enabling enhanced tissue penetration and high-resolution imaging through an absorption competition-induced emission mechanism. Under abiotic stress conditions, the probe visualizes stress-induced fluctuations of H2S in living plants. This work establishes an H2S-centered strategy for plant stress visualization and provides a foundation for developing early diagnosis platforms. Real-time monitoring of plant stress responses is essential for precision agriculture. Here, the authors report a ratiometric near-infrared IIb (NIR-IIb) fluorescent probe that enables sensitive detection of endogenous hydrogen sulfide (H₂S) in living plants, providing a powerful tool for monitoring plant stress responses.