Effect of Petroleum Products Treatment of Soil on Succinate Dehydogenase and Lactate Dehydogenase Activities in Cowpea (Vigna unguiculata) and Maize (Zea mays) Seedlings

Aim: Most of the land in oil producing area in the Niger delta region of Nigeria is under constant petroleum pollution exposing the soil to the deleterious effect of petroleum hydrocarbons. The effects of petroleum products (kerosene, diesel, engine oil and petrol) treatment of soil at various sublethal concentrations (0.0%, 0.1%, 0.25%, 0.5%, 1.0%, 1.5% and 2.0%) on succinate dehydrogenase and lactate dehydrogenase activities in the leaves of cowpea and maize seedlings were then studied.

Place and Duration of Study: This study was conducted in Delta State University, Abraka, Nigeria between April 2007 and August 2011.

Methodology: Improved varieties of maize (Zea mays) and Vigna unguiculata (L) Walp were planted in soil contaminated at different concentrations of six groups of five replicates. Groups 1 to 5 contained 0.1%, 0.25%, 0.5%, 1.0% and 2.0% (v/w) respectively of each of the petroleum products while group six served as control (0.0%). Three seeds were planted in each bag and watered daily. The activities succinate dehydrogenase (SDH) and lactate dehydrogenase (LDH) in the leaves of the cowpea and maize seedlings were analysed after four, eight and twelve days after germination.

Results: The results indicated that petroleum products treatment of soil resulted in decrease in succinate dehydogenase activity in both cowpea and maize seedlings as well as a corresponding increase in lactate dehydrogenase activity in the two seedlings. The toxic effect of kerosene was more severe than the other products studied. Similarly, Cowpea seedlings were affected more than maize seedlings.

Conclusion: Generally, the data indicate that seedlings exposed to petroleum products treated soil tend to move towards anaerobic respiration in a bid to survive under petroleum stress.