Fig. 4

Analysing graft junction formation by CFDA staining. 14 day old grafts were transferred to a plate containing ½ MS and 1 % agar and stained with the phloem-mobile fluorochrome CFDA. Therefore a leaf of the grafts was punctured with a sterile needle (red arrow) and a few microliters of CFDA stain were applied at the point of lesion (a). After an incubation of 30 min at room temperature the plants were investigated under a fluorescence binocular using bright field (a–c) and fluorescence illumination with a GFP filter (d–f). While in successfully grafted plants the CFDA stain passed the graft junction (e), it accumulated in the scion part of the graft, when graft formation was not effective (f)