Abstract

The research was designed at studying the effect of oil pollution on the physiognomic characteristics of Gmelina arborea and the pollutants used are diesel oil and spent engine oil respectively. The experiment lasted for 6 months before analysis was done. Five treatments were carried out separately for diesel oil and spent engine oil in which the application of pollutants was at the rate 0, 400, 800, 1200 and 1600 mls. Each pollutant and each treatment was replicated three times and subjected to analysis of variance (ANOVA). Internode differences, number of leaves, number of branches were measured as part of the physiognomic characteristics that are observable for the experiment. Results show that all treatments have significant effects after the analysis. Both pollutants have a significant role to play in the physiognomic properties and characteristics of the tested crop G. arborea. At one week after application and three weeks after application, spent engine oil only had a minimal effect on branching pattern of G. arborea wildling but as from six weeks after application, the effect was phenomenal on all vegetative parameters of the plant. At one week after application, diesel oil had no effect on G. arborea wildling but at three weeks after application, diesel oil had a significant effect on the vegetative parameters of G. arborea wildling. A further research is needed on the recovery possibility of G. arborea if reconditioned after the effect of pollutants. This will help in environmental stability of parts of the world where oil pollution is rife. 

Key words: Pollution, diesel oil, spent engine oil, wildling, physiognomy.