Bioindicator Potential of Calatropis procera and Azadirachta indica Leaf Epidermal Traits for Monitoring Cement Dust Pollution

Airborne particulate pollution from cement industries represents a significant environmental stressor, adversely affecting plant physiology and altering leaf epidermal traits that serve as reliable biomarkers of pollution impact. This study investigated the effects of cement dust pollution on the leaf epidermal indices of Calotropis procera and Azadirachta indica collected from the vicinity of the Dangote Cement Company in Obajana, Kogi State. Epidermal peels were obtained using both chemical and mechanical methods, prepared on slides, and examined under a light microscope. The epidermal cells were analyzed for stomatal index, length, and breadth. Results revealed that the abaxial leaf surface of A. indica at the polluted site exhibited reductions in epidermal cell number (95.50), stomatal number (27.20), stomatal length (1.52), and stomatal breadth (1.42), compared with 103.30, 54.00, 1.80, and 1.58, respectively, at the control site, with differences being statistically significant (p < 0.05). Similarly, C. procera leaves showed marked modifications, including reduced epidermal cells (78.70), stomatal number (12.30), and stomatal breadth (1.26) on the abaxial surface, compared with 112.10, 40.60, and 1.44, respectively, at the control site, which were significantly different (p < 0.05). These alterations in epidermal indices of A. indica and C. procera highlight their potential as sensitive biomarkers for monitoring the impacts of cement dust and other airborne pollutants on living organisms