Abstract

The effects of different levels (%) of diesel fuel contamination on four crop plantsArachis hypogaea, Vigna unguiculata, Sorghum bicolor and Zea mays were studied. One percent level of contamination did not significantly reduce seed germination in Z. mays and S. bicolor but did in A. hypogaea and V. unguiculata(P<0.05). The 2.00% level of contamination reduced germination in A. hypogaea. Germination was reduced with increasing levels of contamination in the four test plants. There was total inhibition of germination in S. bicolor and V. unguiculata in 4.00% level of contamination. There was no significant difference in percentage seed germination between 2.00, 3.00, and 4.00% levels of contamination in Z. mays. The 4.00% level of contamination had more deleterious effect than 5.00% forSorghum and Vigna species. Diesel fuel contamination caused a reduction in the length of the radicle for the four crop plants and this varied with the level of contamination. It was observed that 5.00% level contamination did not affect the radicle length of V. unguiculata significantly.  Diesel fuel contamination also caused a reduction in the plumule length of Z. mays and S. bicolor. The shortest plumule was recorded in 5.00% level of contamination for Z. mays and 3.00% in S. bicolor. The phytotoxicity of the different levels of diesel fuel contamination on seed germination indices thus varied with the type of crop plant.  The study indicates thatZ. mays and A. hypogaea have more potential for use in phytoremediation of diesel fuel contaminated soils than S. bicolor and V. unguiculata.

Key words: Diesel fuel, contamination, germination, crop plants, phytotoxicity.