MORPHOLOGICAL AND BIOCHEMICAL RESPONSES OF MAIZE (ZEA MAYS L.) TO OIL FIELD WASTEWATER POLLUTION

Agricultural sector is challenged with a number of factors including those arising from rapid industrialization, which is the key point responsible for reductions in food production. Industrial waste oil contamination has been determined with negative impacts on plants. Although several studies have demonstrated the impact of crude oil on crops, but the effects of oil field wastewater concentrations on maize growth and biochemical activities are poorly understood. Therefore, the present study investigated the effects of 1, 5 and 10% oil field waste water concentrations on morphological and biochemical growth parameters of maize. Both oil field wastewater and soil samples contained heavy metals including Zn, Pb, Fe, Cu, Cd and Cr. Gradual decrease in seed germination (%) was observed with the increase in oil field wastewater concentrations after 48, 72 and 96 h. Application of oil field wastewater concentrations reduced seedling growth including shoot/root length and number of leaves. Ionic quantification analyses showed that Na+ and Ca+2 ions decreased in shoot while increased in roots. Potassium (K+) ions increased in shoot while decreased in roots at 5 and 10% oil field wastewater concentration. Photosynthetic pigments (chlorophyll "a", "b" and carotenoids) and total soluble sugar significantly decreased in maize seedlings as the concentrations of the oil field wastewater increased. Higher concentrations of oil field wastewater significantly increased antioxidant enzymes such as catalase, ascorbate peroxidase, superoxide dismutase and peroxidase enzymes in maize seedlings to cope with the stress conditions. These results suggested that oil field wastewater adversely affects maize morphological and biochemical growth parameters.