中文摘要：

以3种桉树（韦邓桉（Eucalyptus wetarensis×Eucalyptus dunnii）、邓恩桉（Eucalyptus dunnii）、湘邓桉（Eucalyptus dunnii xiangdeng））的半年苗龄树苗为材料,5℃冷处理24 h后,分析4类共16种（rboh,APX,GPX,POX4类,每类4种,编号为1、2、3、4）过氧化物酶基因的转录变化。结果表明：与常温条件下比较,冷处理后,rboh（respiratory burst oxidase homologs）类基因只有韦邓桉的rboh1和rboh3的转录显著增强,邓恩桉和湘邓桉的4个rboh基因及韦邓桉的rboh2和rboh4的转录均表现为受抑制或变化不显著。除AP3和GP1外,冷处理后,耐寒性最强的湘邓桉的APX（ascorbate peroxidase）类基因和GPX（glutathione peroxidase）类基因的转录显著高于韦邓桉和邓恩桉。除PO1外,韦邓桉冷处理后的POX（class III peroxidases）类基因的转录均显著升高。除PO2转录受抑制外,邓恩桉和湘邓桉的POX类基因的转录也受冷处理诱导。结果表明：冷胁迫下,耐寒性强的湘邓桉产生ROS（reactive oxygen species）的rboh类基因的表达受抑制,分解ROS的APX类和GPX类基因的表达则显著升高,基因的转录调节增强了耐寒性。另外,每类基因中4个基因的转录变化均不完全相同,说明过氧化物酶类基因的转录调节模式和功能具有多样性。

英文摘要：

With three half-year-old Eucalyptus seedlings including Eucalyptus wetarensis × Eucalyptus dunnii,Eucalyptus dunnii,and Eucalyptus dunnii xiangdeng,we detected the transcription changes of four types of peroxidase genes after treated at 5℃ for 24 h. The cold resistance of Eucalyptus wetarensis × E. dunnii was the weakest and the cold resistance of E. dunnii xiangdeng was the strongest. After cold treatment,four respiratory burst oxidase homologs genes（ rboh） showed transcription inhibition and litter difference in E. dunnii and E. dunnii xiangdeng. However,the transcription of rboh1 and rboh3 enhanced sharply and the transcription of rboh2 and rboh4 decreased in E. wetarensis × E. dunnii. Except for AP3 and GP1 gene,the other APX（ ascorbate peroxidase） genes and GPX（ glutathione peroxidase） genes transcript were much more efficiently in E. dunnii xiangdeng than those in the other two Eucalyptus species. Except for the transcription of PO1 gene,the transcription of the other three class III peroxidases（ POX） genes were significantly increased in E. wetarensis ×E. dunnii after cold treatment. The transcription of PO2 gene was suppressed after cold treatment and the other three POX genes were induced to transcript in E. dunnii and E. dunnii xiangdeng. Therefore,it was benefit for cold resistance of E.dunnii xiangdeng after cold treatment that rboh gene transcription was inhibited and the transcription of APX and GPX was enhanced. The transcription of four genes in each type was not identical,and the transcription regulation and function of isoenzyme of four types were with diversity in Eucalyptus species.