Evaluation of loss of viability and morphological alterations in pollen of Fraxinus uhdei exposed to particulate matter (PM10) in the Valley of Mexico

In this study, the viability and morphological changes of Fraxinus uhdei pollen grains exposed to particulate matter (PM₁₀) in the Metropolitan Area of the Valley of Mexico (ZMVM) were experimentally assessed. Samples of both anthers and air were collected and examined using viability tests (TTC), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). The results demonstrated a notable reduction in pollen viability in areas with elevated PM₁₀ levels, particularly in the north (Ecatepec) and east (Iztapalapa), compared to the west (Cuajimalpa) and south (Coyoacán). Significant structural disruptions in the exine and dense accumulation of particles on the surface of airborne pollen were also observed. Elemental analysis indicated the presence of silicon, calcium, aluminum, and iron, linked to both geogenic and anthropogenic sources. These findings confirm the potential of F. uhdei as a sensitive bioindicator of air quality and emphasize the ecological and health implications of urban air pollution.