Morphological responses of plants to air pollutants: A comparative study on leaf changes in five species

This study investigates the impact of long-term exposure to sulfur dioxide (SO2), nitrogen dioxide (NO2), and suspended particulate matter (SPM) on leaf morphology and physiology in five plant species. The pollutants were measured at concentrations of 1.20ppm for SO2, 1.40 ppm for NO2, and 230μg/m³ (12 hours daily) for SPM, representing annual average exposures. Leaf measurements were conducted on Myrtus communis, Ziziphus spina-christi, Nerium oleander, Sesbania sesban, and Eucalyptus camaldulensis. The results revealed variations in leaf length and width across exposure conditions. Notably, exposure to pollutants led to significant changes in leaf morphology, with SPM showing the most pronounced effects. Leaf area rates were calculated for each plant species, indicating the impact of pollutants on overall leaf development. Control groups exhibited higher leaf area rates compared to pollutant-exposed groups, with E. camaldulensis particularly sensitive to SO2 and NO2 exposures. Additionally, stomatal density was assessed, revealing pollutant-induced alterations in stomatal patterns. Epidermal cell numbers were quantified, showcasing the sensitivity of N. oleander and S. sesban to pollutant exposures. These findings contribute to our understanding of the complex interactions between air pollutants and plant physiology, emphasizing the importance of considering multiple morphological parameters. The results have implications for environmental management and plant health in polluted regions.