Observations on the Polluted and Non-Polluted Leaf Epidermal Surfaces of Some Plants

The epidermis of Polyalthia longifolia, Digitaria gayana and Trianthema portulacastrum growing within the radii of 0.1-0.25m to exhaust-pipes of power generators(Polluted populations) and their individual counterparts growing at distances of 100-110m far away from power generators(Non-polluted populations) in the human settlements of Ado-Ekiti, Ekiti State, were investigated with the aid of light microscope. Damages such as eroded epicuticular wax, epidermal cell alterations, plugged stomatal apertures, blurred epidermal surfaces, polluted cells, ruptured stomatal ledges and eroded cell walls were observed in the polluted populations of these species. These kinds of damages were, however, not observed in the counterparts of these species which were not polluted by exhausts. The sizes of leaves of the polluted populations were smaller in area than those of the non-polluted populations. The average leaf areas of polluted populations of Polyalthia longifolia, Digitaria gayana and Trianthema portulacastrum were 9.94± 0.8, 0.31± 0.2 and 4.78± 0.4 respectively. On the other hand, the average leaf areas of the non-polluted populations of these same species were, for Polyalthia longifolia, Digitaria gayana and Trianthema portulacastrum 31.6± 0.2, 1.92± 0.1 and 10.97± 0.5 respectively. The non-polluted populations, therefore, had higher leaf areas probably because they were not affected by exhaust-pollutants. It was suggested that the species investigated in this study could serve as bioindicators of environmental air pollution.