Effect of automobile exhaust on some leaf micromorphological characteristics of some members of Verbanaceae, Annonaceae and Euphorbiaceae families

Abstract

The study was carried using the Botanic Garden of the Kano State Zoological Garden as the control site in comparison with roadside in order to determine the effect of exhaust from vehicles on the number of stomata, epidermal cells, stomatal length, stomatal breadth, pore length and pore breadth. Results obtained showed an increase in the number of stomata and epidermal cells per unit area in leaf samples collected from polluted sites than those from unpolluted site. However, the length and breadth of stomata, pore length and pore breadth in the polluted sites was lower than that of the control site. Furthermore, there was no significant difference based on the type of stomata in the species studied at the two different sites. An increase in number of stomata, number of epidermal cells and stomatal density was found in plants growing on the road side both on the abaxial and adaxial surfaces, a decrease was found on the stomatal length, stomatal breadth, pore length, pore breadth and stomatal index of the plants growing on the road side when compared with those in the control site. These changes in stomata and epidermal cells per unit area could be used as an indicator of environmental stress which could be recommended in high traffic density areas for the early detection of urban air pollution.

Keywords: Automobile exhaust, Micromorphology, Leaf, Verbanaceae, Annonaceae, Euphorbiaceae