Bioremediation of fuel oil spills requires a sensitive biological detection system that determines the degree of impact in a predictable, log-linear fashion based on soil pollutant concentrations. Tradescantia plants were transplanted into soil contaminated with fresh No. 2 diesel fuel at 0, 0.1, 1.0, 10.0 and 100.0 mg kg −1 and followed for phytotoxicity and mutagenicity based on plant morphology, chloroplast function, and the micronucleus assay of tetrads isolated from young inflorescences. Results showed a high degree of correlation ( R 2=0.952, P=0.024) between the percentage of dead and withered plants 1 week following transplantation and increasing fuel concentrations in soil. The highest contaminant concentration yielded no buds or flowers until the third week, and by the fourth week plants in all treatment groups appeared to be recovering. This matched the decreases in diesel fuel soil concentration and increased bacterial activity over time. Leaf chlorophyll concentration decreased log-linearly as well with increasing diesel fuel concentration ( R 2=1.000, P=0.000), with higher impacts on function as indicated by decreases in photosystem II ( R 2=0.997, P=0.035). The micronucleus assay yielded results indicating no observable increases in mutagenicity by any concentration of diesel fuel at any week. Transplantation of the Tradescantia plant appears to offer a sensitive phytotoxicity assay for acute fuel oil contamination.