ALTERATION

This study investigated the alterations in the activities of antioxidative enzymes on the leaves of maize (zea mays) planted in crude oil contaminated soil. Maize was grown on soil contaminated with 5ml, 10ml and 15ml of crude oil. The experiment lasted for 4 weeks. Data obtained were analysed using ANOVA and least significant difference (LSD) at p<0.05. The number of leaves, leaf area and leaf weight were determined at the start of every assay, the percentage germination was evaluated at the end of every week. Results showed that the mean leaf area and percentage germination of maize plant (zea mays) decreased with increasing level of contamination with crude oil. Antioxidants like superoxide dismutase (SOD), catalase, malonyldialdehyde (MDA), glutathioneperoxidase (GPx) in zea mays differed significantly (P<0.05) at 5ml levels from those planted in 10ml and 15ml levels of the crude oil contaminated soils. The reductions in these growth characteristics measured were crude oil concentration dependent and elevated activity of antioxidative enzymes can assist as important components of antioxidative defense mechanism against oxidative damage. The results of this study could be beneficial in the understanding of the role of defense system beside these parameters, also significant reduction in lipase activity of the plant was recorded and yellowish leaf coloration due t reduction in chlorophyll content were observed among the plants grown in the crude oil contaminated soils. This study thus revealed that crude oil had pronounced effects on the germination and growth of maize plant. This means that maize plant should not be grown near or on soil contaminated with crude oil.