植物CytP450和抗氧化酶对土壤菲、芘暴露的生态毒理响应

以玉米(Zea mays L.)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-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-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.

Ecotoxic responses of CytP450 and antioxidant enzymes in maize due to exposures to Phenanthrene and Pyrene in soil

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 PHEand PYindividually (r=0.834, p< 0.01), and a negative correlation with a mixture of PHEand PYat the same concentration, indicating that the combination of PHEand PYresulted in a synergistic ecotoxic effect and decreased the plant's metabolic detoxification ability. PHEand PYboth had a negative correlation to SODactivities and a positive correlation to CATactivities in individual exposures. PODactivities were influenced by the water solubility of PHE, but affected by the total concentration of PY. SOD, CATand PODall showed a positive correlation when exposed to PHEand PYcombined, 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.