In this study, 11 plants (legumes, grasses, and crops) were screened for\ntheir ability to grow and survive in soil contaminated with 1 %\ndiesel/oil mix (aliphatic hydrocarbons) or 1 % crude oil. Based on\nemergence, shoot length, root length, and root/shoot biomass ratio in\ncontaminated soil, maize and wheat which showed the highest growth were\nselected for further investigation: a long-term phytoremediation study\nto evaluate the effect of maize and wheat on the microbial removal of\nhydrocarbons (1 % diesel/oil mix). The results showed that the presence\nof both maize and wheat in hydrocarbon-contaminated soil led to a\nsignificant increase in the utilization of total petroleum hydrocarbon\n(TPH), from 57 % in the control soil to 72 and 66 % in soil planted\nwith maize and wheat, respectively. Microbial community analysis using\ndenaturing gradient gel electrophoresis (DGGE) showed that the presence\nof a plant rhizosphere resulted in changes in the structure of the soil\nmicrobial community. Sequencing of prominent bands revealed the presence\nof a few hydrocarbonoclastic fungi only in the contaminated soil planted\nwith maize and wheat. In terms of specific hydrocarbonoclastic activity,\nDGGE analysis based on alkB genes showed that soils with maize and wheat\nhad similar rates of hydrocarbonoclastic activity but distinct microbial\ncommunities in some instances. Most probable number quantitative\npolymerase chain reaction (MPN-qPCR) confirmed that the number of alkB\ngene copies in soil planted with maize and wheat increased about 20- and\n16-fold, respectively, relative to the control soil. This study showed\nthat fungal and alkB bacterial communities contribute to the\nrhizoremediation of petrogenic hydrocarbons.
- Shannon diversity index
- alkB genes