Abstract: In this study，it was investigated that the genetic stability of gfp gene in the cucumber hairy roots that had been cultured on solid medium for 3 years. The analysis of PCR for gfp and rol（root loci） genes，qRT-PCR for gfp gene and Western blot for GFP protein were conducted，while green fluorescence
was checked on hairy roots. The results showed that the expression of gfp driven by constitutive promoter 35S was relatively stable at both mRNA and protein levels. Furthermore，the morphology-related rol genes of the hairy roots after 3-year culturing can be amplified. Overall，this study provided important experimental supports for using hairy roots in the long-term industrial production of proteins and active ingredients of medicinal plants.

Key words: cucumber, Cucumis sativus, hairy root, gene, expression, stability