Evaluation on the growth response of Peanut (Arachis hypogaea) and Sorghum (Sorghum bicolor) to crude oil contaminated soil
This study examined the cytotoxic response, germination, survival, morphological deviations as well as enzyme activities of Arachis hypogaea and Sorghum bicolor in crude oil contaminated soil. Crude oil spillage was simulated to achieve 1%, 2%, 3% (w/w) contamination levels in pot experiments. Treatments without crude oil were used as control. Cytotoxicity, germination and survival were determined by using percentages while enzyme activity was measured by using spectrophotometric methods and standard curves. S. bicolor had lower mitotic index (3.7) with higher percentage aberrations (65.56%) compared to A. hypogaea. However, difference in mitotic index and percentage aberration between A. hypogaea and S. bicolor was not significant at P≥0.05. Percentage germination and survival of both plants were not different. Enzyme study showed that enzyme activity in A. hypogaea and S bicolor were the same in control but increased with crude oil contamination. Laccase activity was significantly higher (P≤0.05) in A. hypogaea than in S. bicolor in 1% and 2% crude oil concentrations. The same applies to soluble methane monoxygenase activity in all crude oil concentrations. Tyrosinase activity was not significantly different in both plants in all concentrations. The study shows A. hypogaea to have better tolerance in crude oil contaminated soils than S. bicolor.
Keywords: S. bicolor, A. hypogaea, crude oil, pollution, response