Abstract: In this study, Brachydanio rerio was exposed to three concentrations of phenanthrene (0, 0.05 and 100.0 μg·L^-1) for 36 days,and the histopathological effects of phenanthrene on B. rerio gill and liver were examined under light microscope. The results showed that at 0.05 and 100.0 μg·L^-1 of phenanthrene, the most common changes of B. rerio gill were epithelial hypertrophy and edema. The thickening of filament epithelium and the lifting of lamellar epithelium were the other histopathological effects of 100.0 μg·L^-1 phenanthrene. When exposed to 0.05 μg·L^-1 phenanthrene, the hepatic lesions of B. rerio were characterized by the hypertrophy of hepatocytes and vacuolization. After exposure to 100.0 μg·L^-1 phenanthrene for 36 days, the shape of hepatocytes was irregular, some nuclei were atrophy and deformation or in a lateral position close to the cell membrane, hepatocytes were highly vacuolated, and focal necrosis occurred after cytolysis and karyolysis. 0.05 μg·L^-1 of phenanthrene already had toxic effect on B. rerio gill and liver, and the damage was more severe when exposed to 100.0 μg·L^-1 of phenanthrene. The impairment of B. rerio gill and liver was increased with increasing phenanthrene concentration.

Key words: Alnus, Arbuscular endomycorrhizal fungi, Semi-nested LP-PCR-SSCP