Abstract: The cytochrome P450 CYP2E1 enzyme mainly exists in mammalian liver cells. It plays an important role in metabolism of heterologous organics. Precious research has shown that cyp2e1 transgenic Petunia hybrida significantly improved the resistance to formaldehyde. In the paper，the various physiological characteristics of cyp2e1 transgene，gus transgene and wild-type（non-transgenic）P. hybrida were analyzed under formaldehyde stress. The results show that malondialdehyde（MDA）content of cyp2e1 transgenic P. hybrida was lower than those of gus transgene and wild-type P. hybrida under formaldehyde stress，while both of superoxide dismutase（SOD）and peroxidase（POD）enzyme activity were higher，alcohol dehydrogenase（ADH）activity slightly enhanced and more glutathione was metabolized. In addition，levels of IAA，ZRs and ABA in cyp2e1 transgenic P. hybrida decreased under formaldehyde stress，but level of GA increased. However，levels of IAA，ZRs and ABA in gus transgene and wild type P. hybrida were increased but level of GA was declined. When the cyp2e1 transgenicP. hybrida was incubated in liquid medium plus 50 mg ? L-1 formaldehyde for 72 h，the formaldehyde content in medium was decrease to zero，while those with gus transgene and wild-type P. hybrida were still nearly half of formaldehyde content.

Key words: Petunia hybrida, cyp2e1 gene, formaldehyde, stress, physiological effect