Micro-morphological adaptations and tolerance assessment of selected vascular plant species exposed to vehicular exhausts

Abstract

The vehicular exhausts on roadsides negatively affect living organisms and disturb their environment. These negative impacts of vehicular exhausts on plants demand a scientific investigation of roadside plants in Abbottabad, Pakistan. So, this observational and experimental study was conducted to evaluate the effect of vehicular exhausts on morphology, epidermal structure and biochemical characteristics of leaves of plants near roadsides and compared with the non-polluted site. The quantitative morphological parameters: leaf area, length of petiole and vein-to-vein difference along with anatomical attributes such as stomata and epidermal cells were recorded. Compared to non-polluted areas, the chlorophyll content of plant leaves from polluted areas was higher. The results indicate that vehicular exhaust negatively affects leaf morphology and increases the Stomatal number at adaxial (front surface) of leaves. The air pollution tolerance index evaluated Melia azedarach and Salix angustifolia as tolerant tree species and Rumex dentatus, Amaranthus viridis and Sonchus hydrophilus as tolerant herbaceous species. In order to survive in polluted environments, this study demonstrated that plants go through adaptive processes.