Impact of gasoline fuel emissions on Rhizopus stolonifer (Ehrenb.) Vuill. and Fusarium oxysporum (Schlecht.)

Abstract

Background Alteration in the normal composition of gasses in the atmosphere referred to as air pollution can occur as a result of different processes, including emissions from vehicles and power generators. Gasses affect living things directly and indirectly by playing roles in respiration, membrane function, synthesis, and growth. The gasses contained in fumes emitted from vehicles and generators may likely have effect on microorganisms in the environment including microfungi. Two microfungi were selected to study the effect of generator emissions on their growth. Results The gaseous emissions from power generators fueled by gasoline caused reduction in spore germination and germ tube lengths of R. stolonifer and F. oxysporum. For the former, spore germination decreased with length of exposure after an initial increase by ~ 100%. The fungus exhibited a single major germination peak at 10 min and a minor one at 30–35 min exposures. Germ tube length of the fungus also decreased with increased exposure. F. oxysporum too showed reduced spore germination and germ tube length with exposure but the fungus seemed to adjust better to the unfavorable environment created by emitted gasses showing multiple peaks of reduced heights as time progressed, though another rise that could reach a peak appeared at the 45-min maximum exposure for germ tube length. The peaks were however more broad for spore germination experiments indicating more stability in adjustment than observed for germ tube length. Greatest reduction in spore germination was by 25% in R. stolonifer and 71% in F. oxysporum Germ tube length reduction for R. stolonifer was by 24–76%, the greatest occurring at 35-min exposure, while for F. oxysporum it was 5–83%, the greatest occurring at 40 min exposure. Conclusions These observations reveal the toxicity of the gasses emitted to the growth of the two filamentous fungi and the potential harmful effect to other fungi which might be useful in the ecosystem as decomposers and to those that may be pathogenic to higher plants.