Visualizing hydrogen sulfide dynamics in crop roots under heavy metal and salt stress using a selective fluorescent probe.

Hydrogen sulfide (H₂S) is a gaseous signaling molecule that plays critical roles in numerous physiological and pathological processes, including plant stress responses. Effective fluorescent probes for visualizing H₂S in complex biological and plant systems are still highly demanded. In this work, a novel fluorescent probe ZT was constructed using 4-nitrobenzofurazan as the recognition moiety. Upon reaction with H₂S via nucleophilic substitution, the probe displays a typical off-on fluorescence response. ZT possesses superior sensing performance including high anti-interference ability, ultrahigh sensitivity (LOD = 34 nM) and good biocompatibility, which enables reliable detection of trace H₂S in complex biological environments. The probe achieves real-time in-situ imaging of endogenous H₂S in onion epidermal cells, zebrafish larvae and mammalian living cells. Furthermore, it was applied to monitor H₂S dynamics in wheat seedlings exposed to heavy metal and salt stresses. This work presents a high-performance H₂S fluorescent probe with broad application prospects, and provides new clues for studying the regulatory mechanism of H₂S in plant abiotic stress resistance.