ABSTRACT

The effect of crude oil contaminated soil on physical and biochemical properties of beans (phaseolus vulgaris) was investigated. Fifteen polythene pots with drainage holes at the bottom, each containing 10 kg of surface soil, were randomly placed on a table in the screenhouse in a factorial combination of five treatment levels (0.4%, 0.3%, 0.2%, 0.1% and 0% w/w) of crude oil and were designated P4, P3, P2, P1 and P0 respectively. Three seeds of beans per pot were planted. Growth parameters (plant height, stem girth, relative water content (RWC), and soluble protein content (SPC)) and antioxidant indices were determined in the beans over a period of nine weeks after planting (WAP). Results showed that growth of beans planted in contaminated soil was significantly lower (p<0.05) than that of control. Beans planted in the contaminated soil also showed a significant increase (p<0.05) in superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX) and glutathione reductase (GR) activities in leaves when compared with control plants. The results suggest that crude oil contaminated soil hindered availability of water, air and nutrients to beans roots, creating a drought condition which could induce oxidative stress in the plant and consequently retarding growth and yield of beans plant.