Effect of particulates generated from asphalt production on the morphological and leaf epidermal traits of some common plants

Abstract

A comparative study was carried out to ascertain the effects of particulate matter on the gross morphological and leaf epidermal features of some tropical plants. Two populations of Xanthosoma mafaffa Schott, Chromolaena odorata (L.) King and Robinson, and Ageratum conyzoides (L.) were collected; one from an unpolluted area and the other from a polluted environment (generated from an asphalt production industry). Plants from the polluted area show marked reduction in leaf size and area, and reduced chlorophyll content in leaves. There were chlorotic and necrotic leaf spots on the species from polluted area and an average leaf area of 94.81 cm², 15.81 cm², and 17.29 cm² for X. mafaffa, C. odorata and A. conyzoides respectively while the non-polluted species had no leaf spots and an average leaf area of 181.95cm², 36.75 cm², and 32.11cm² for X. mafaffa, C. odorata and A. conyzoides respectively. Length and width of stomatal pore of leaves from polluted area had increased number of stomata, but the length and width of stomata were reduced by -12.89% and -08.42%, -19.54% and -28.60% and -27.50% and -37.86% in the length and width of X. mafaffa, C. odorata and A. conyzoides respectively, as compared to the leaf samples from unpolluted area. Also, epidermal cells decreased compared to the leaves from unpolluted area, while the density of epidermal cells per unit area increased. These suggest that these plants are under air pollution stress and the results are adaptive and compensated mechanism to the adverse effects of the particulate matter.