Mutagenic effects of nitropyrenes in a soybean test system

The mutagenic activity of 1-nitropyrene (1-NP), 1,3-dinitropyrene (1,3-DNP), 1,6-dinitropyrene (1,6-DNP) and 1,8-dinitropyrene (1,8-DNP) was assayed in heterozygous soybean plants (Y11y11), based on the appearance of mutational spots (yellow, dark green and twin) on the leaves. 1-NP, 1,3-DNP, 1,6-DNP and 1,8-DNP were direct-acting mutagens in a soybean test system, and mutagenicity was enhanced by addition of pyrene as a precursor. The mutagenicity of dinitropyrenes was enhanced by pretreatment with hepatic microsomal fractions of Aroclor 1254-treated rats. Binary and ternary isomeric mixtures of dinitropyrenes produced synergistic mutational response in the test system. The numbers of yellow and dark green spots per leaf increased by treatment with nitropyrenes. The frequency of twin spots did not change. Nitropyrenes stimulated the induction of forward and reverse mutations in soybeans. The number of light green spots (Y11y11) per leaf on homozygous soybeans (y11y11) increased markedly by treatment with 1-NP, 1,3-DNP, 1,6-DNP, and 1,8-DNP. These nitropyrenes would thus appear to cause point mutation and segmental loss as major effects.