Adenosine Triphosphatase Activities of Zea Mays and Vigna unguiculata Exposed to Different Crude Oil Fractions

This study was carried out to investigate the activities of some adenosine triphosphatases (ATPases) in the radicle of maize and cowpea grown in soils contaminated with crude oil and its fractions. Total ATPase, Ca2+ ATPase, Na+/K+ ATPase and Mg2+ ATPase activities were evaluated. Cowpea and maize seeds were planted in polythene bags containing 500g of sandy loam soil each. The soils used had no known history of crude oil contamination and the study was carried out in the Department of Biochemistry, University of Benin garden and laboratory. A total of 660 bags were used in the study. Of these, 60 bags were used for planting maize and cowpea (30 bags for each plant) in soils not contaminated, which served as controls for the plants and another 60 bags with soils from Ubeji (a crude oil contaminated site in, Delta State, Nigeria) was planted maize or cowpea (30 for each plant). The remaining 540 bags had soils that were contaminated with 2%, 5%, or 10% whole crude oil or its water soluble or water insoluble fraction, and in it were planted either maize or cowpea and they served as the test groups. The experiment lasted for a period of one month. Seedlings in 10 bags from each group of 30 bags were harvested after 7, 14, or 21 days post germination and the activities of ATPases were determined. The data obtained were subjected to descriptive statistic of variance analysis.

In a general sense, contamination of soils with crude oil or its fractions or in Ubeji significantly increased (P<.01) the activities of total ATPase, Ca2+-, Mg2+-, and Na+/K+-ATPases of cowpea compared with the uncontaminated control. In maize the effect of crude oil was mixed however Mg2+- ATPases was consistently reduced with crude oil contamination. The study indicated that crude oil and its fraction affects the activities of adenosine triphosphatases in ways which are species related.