中文摘要：

以菲和芘为多环芳烃（PAHs）的代表物，以超氧化物歧化酶（SOD）、过氧化物酶（POD）、过氧化氢酶（CAT）活性和丙二醛（MDA）含量为指标，研究了菲、芘对蚕豆的氧化胁迫；利用彗星实验分析了菲、芘对蚕豆 DNA 的损伤效应；将蚕豆幼苗根经抗氧化剂维生素 E 预处理后，暴露于菲、芘污染，研究了 DNA 损伤与氧化胁迫间的关系。结果表明，供试条件下菲、芘污染导致蚕豆幼苗SOD、POD、CAT 活性提高和 MDA 含量上升，且 MDA 含量与菲、芘浓度均显著正相关；蚕豆根尖细胞 DNA 损伤随菲、芘暴露浓度的升高而增大，0--50 mg·kg-1菲污染条件下彗星图像尾矩（TM）值从46.41μm（阴性对照）增加到122.04μm（50 mg·kg-1菲污染处理），增大了162.96豫。50 mg·kg-1芘暴露下 TM 值从阴性对照的44.30μm 增至110.36μm，增大了149.21豫。经抗氧化剂维生素 E 预处理，蚕豆的 DNA 损伤程度减小。综上可知，菲、芘对蚕豆产生氧化胁迫并造成根尖细胞 DNA 损伤，菲、芘诱导的 DNA 损伤与氧化胁迫有关。

英文摘要：

Polycyclic aromatic hydrocarbons（PAHs）are persistent organic pollutants with toxic, carcinogenic, and mutagenic nature. Their influences on cells of higher plants have not been understood well. An experiment was conducted to investigate the oxidative stresses and DNA damages of plants induced by phenanthrene and pyrene. The relationship between DNA damages and oxidative stresses was also exam-ined in the presence of the antioxidant Vitamin E. The MDA content and antioxidant enzyme activities（SOD, POD, and CAT）in Vicia faba were determined. The DNA damages were evaluated using the comet assay. Phenanthrene and pyrene enhanced the antioxidant enzyme ac-tivities and MDA contents. The content of MDA gradually increased with increasing concentrations of phenanthrene and pyrene. The values of tail moment（TM）from the comet assay increased from 46.41 μm（at the control）to 122.04 μm（at 50 mg·kg-1 phenanthrene treatment）. Similarly, the degree of DNA damages aggravated with increasing pyrene concentrations（0~50 mg·kg-1）. Pyrene at 50 mg·kg-1 caused significant（P〈0.01）damages to the cell DNA of Vicia faba root tips and the TM value was 110.36 μm, 149.21% higher than the control （44.30 μm）. The pretreatment of antioxidant vitamin E weakened the DNA damages of Vicia faba cells, suggesting that vitamin E could re-duce DNA damages by phenanthrene and pyrene. In conclusion, phenanthrene and pyrene could cause oxidative stresses and DNA damages of Vicia faba, and that PAH-induced DNA damages are closely correlated with the oxidative stresses.