Effects of contaminated soil with spent oil on germination, above ground height and biomass of six herbaceous plant species were investigated by conducting a general phytotoxicity test and growth inhibition assessment. Six local plant species were used in order to investigate plant’s ability to germinate and survive in a gradient of contaminated soil with spent oil. The species selected for this experiment include one species of Fabaceae (
Medicago truncatular
), four species of Gramineae (
Bromous mermis
,
Secal seral
,
Triticum sativa
and
Agropyron deserterum
) and one species of Linaceae (
Linum ussitasimum
). Inhibitory effect of contaminated soil on germination, height of young seedling and dry weight were measured. In this study an artificial soil with a light texture included 85% sand, 10% silt and 5% clay was used. The exposure to the contaminated soil carried out using four consecutive concentrations (25, 50, 75, 100 g/kg). Results obtained from the current investigation indicate that all species perform dose-dependent responses to the contaminated soils. Reduction in germination, above ground height and biomass for all species were significantly (P < 0.05) different when compared to their controls, however,
Medicago truncatular performed the highest and
Linum ussitatisimum the lowest inhibitory effect for germination, above ground height and dry weight of seedling.
