中文摘要：

以玉米（ZeamaysL.）为供试植物,草甸棕壤为供试土壤,以微粒体细胞色素P450含量、超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和过氧化物酶（POD）活性为指标,进行了土壤菲、芘暴露的生态毒理响应研究.结果表明,菲、芘暴露均能引起植物代谢解毒和抗氧化防御系统的胁迫响应,不同程度引发植物代谢解毒及抗氧化能力的改变.P450酶活性与低浓度菲、芘单一暴露浓度具有相关性（r=0.834,p〈0.01）,与菲、芘复合暴露浓度负相关,说明菲、芘复合暴露导致代谢解毒能力下降,对植物的代谢解毒具有协同毒性效应;SOD酶活性与菲、芘单一暴露浓度负相关,CAT酶活性与菲、芘单一暴露浓度正相关,POD酶活性与菲的水溶解度正相关,而与芘的总浓度负相关.SOD、CAT和POD酶活性与菲、芘复合暴露浓度均呈正相关,说明菲、芘复合暴露导致氧化损伤程度减弱,对植物的氧化损伤具有拮抗作用.

英文摘要：

Maize （Zea mays L. ） was chosen to study the ecotoxic-responses of cytochrome P450 and antioxidant enzymes superoxide dismutase （SOD）, peroxidase （POD） and catalase （CAT） upon exposure to two Polycyclic Aromatic Hydrocarbons （PAH＇s） , phenanthrene （PHE） and pyrene （PY）, in brown meadow soil. Results indicated that phenanthrene and pyrene exposure caused a stress response and therefore changes in the antioxidant recovery and metabolic detoxification systems in plants. CytP450 content had a positive correlation with the low concentrations of PHE and PY individually （ r = 0. 834, p 〈 0.01 ）, and a negative correlation with a mixture of PHE and PY at the same concentration, indicating that the combination of PHE and PY resuhed in a synergistic ecotoxic effect and decreased the plant＇s metabolic detoxification ability. PHE and PY both had a negative correlation to SOD activities and a positive correlation to CAT activities in individual exposures. POD activities were influenced by the water solubility of PHE, but affected by the total concentration of PY. SOD, CAT and POD all showed a positive correlation when exposed to PHE and PY combined, which illustrated an antagonistic effect and resulted in lowered ability to prevent oxidant damage. Our study can form the basis of ecological evaluation of PAHs exposure in soil, providing early diagnosis of ecotoxicity.