Abstract

Atmospheric ozone is a major phytotoxic pollutant that induces oxidative stress and cellular damage in plants, often manifesting as changes in cell membrane integrity and function. This study investigates the potential of **azulene**, a bicyclic aromatic hydrocarbon, as a novel, non-invasive biomarker for assessing ozone sensitivity in plant cells. The objective was to determine if the presence or accumulation of azulene on the plant cell surface correlates with the plant's susceptibility to ozone exposure. Using a combination of high-resolution fluorescence microscopy and spectroscopic analysis, researchers exposed various plant species to controlled levels of ozone and monitored the subsequent localization and concentration of exogenously applied azulene. Key findings reveal a significant, dose-dependent increase in azulene retention or altered distribution on the cell surface of ozone-sensitive plants compared to tolerant varieties. This phenomenon is hypothesized to be linked to ozone-induced modifications in the physicochemical properties of the plasma membrane and cell wall components. The results establish a rapid, visual test for ozone sensitivity, offering a valuable tool for ecological monitoring and agricultural screening programs to identify vulnerable plant populations and improve crop resilience against environmental stress.