Abstract: The quantification of ethylene can be achieved through the change of fluorescence signal, but there are few reports about the real-time monitoring of ethylene level in plant tissues. The development of environmentally friendly and biocompatible chemical-based fluorescent probes is one of the ways to achieve plant tissue imaging. This article uses casein as a carrier to create a water-soluble fluorescent probe (C-E-P) by encapsulating a fluorescent probe (P3) that combines the first-generation Grubbs catalyst with 6-methoxy-2-naphthylene in a hydrophobic pocket. The successful synthesis of probe P3 was confirmed through various structural characterization methods. Performance tests demonstrated that P3 exhibited a strong linear relationship with ethylene, rapid reaction time, and high selectivity. The C-E-P, created by encapsulating P3 with casein, facilitated fluorescence imaging of ethylene release from apple, bitter water rose, and aloe tissues. This approach allowed for the observation of changes in ethylene release between different plant tissues over time. Additionally, it was successfully employed to monitor ethylene variations in the tissues of white ripe tomatoes during ripening, revealing that the peak ethylene release from the seeds occurs prior to that from the pericarp. The C-E-P developed in this study can effectively capture ethylene release information in plant tissues, providing an effective tool for fruit ripening and plant health monitoring in agricultural production.

Key words: Plant tissue fluorescence imaging, Ethylene, Fluorescent probe, Casein