ENVIRONMENTAL BOTANY

This research was carried out to investigate the plant species diversity of three riparian habitats along three water bodies influenced by different anthropogenic activities in Lafia, Nigeria. The three riparian study sites were divided into three strata along gradient from effluent point source from which samples were taken between May 2016 and December 2016. Plant species were identified and various plant population indices such as species richness, evenness, density and diversity were determined using standard methods. The plant samples were analysed for heavy metal contents. The physiochemical parameters such as temperature, pH, total dissolved solid and conductivity of the sediments were also determined. A total of 782 individual plants were counted belonging to six species and five families. Eleucine indica, Calapogomium mucronoides and Gompherena celosiodes were the most abundant plant species. The values of the pH, temperature, total dissolved solid and conductivity of the sediments were found to be within the limits prescribed by International Sediment Quality Guideline. Hence it is concluded that the studied sites were low in species diversities which could be as a result of the local human activities going on at these sites.

This study investigated the effects of spent engine oil on the germination and growth parameters of fluted pumpkin (Telfairia occidentalis). Fluted pumpkin was grown on soils contaminated with 20ml, 40ml, 60ml, 80ml and 100ml of spent engine oil to obtain 1, 2, 3, 4 and 5% contaminations respectively and monitored for eight (8) weeks after planting. The number of leaves, leaf area and plant height were determined weekly while the dry matter content was evaluated at the end of eighth week. Results showed that the mean leaf number, leaf area and plant heights of fluted pumpkin decreased with increasing level of contamination with spent engine oil. The highest mean leaf number which is 15.41 was recorded for the control. Plant height, number of leaves, leaf area and dry matter of T. occidentalis in the control plots (0%) differed significantly (P≤ 0.05) from those planted in 4 and 5% levels of the spent oil contaminated soils. The reductions in these growth characteristics measured were spent engine oil concentration dependent. Besides these quantitative parameters, growth retardation and yellowish leaf coloration were observed among the plants grown in the spent oil contaminated soils. Spent engine oil therefore had pronounced effects on the germination and growth of fluted pumpkin as revealed by this study. Therefore, fluted pumpkin should not be grown near or on soil contaminated with spent engine oil.