Transient GFP gene expression in tobacco flowers using Agrobacterium tumefaciens infiltration. Petals infiltrated with A. tumefaciens strain LBA4404 harbouring a 35S:GFP construct when they were attached (A, B, C) or detached (D) are shown 2 to 2.5 days after infiltration. Panel E shows GFP fluorescence from a flower of a tobacco plant stably transformed with a 35S:GFP construct. Panel F shows a flower from a control line transformed with an empty vector (pART27). Images are shown for petals under normal light (A) and blue light (B, C, D, E and F). GFP expression is seen as green fluorescence in B and green-blue fluorescence in C, D and E (the blue colour occurred with strong GFP fluorescence digitally photographed under higher magnification).