Figure 11.

Multiplex IS-RT-PCR of 18S rRNA, gast1, and exp5 in zinnia epicotyl cross sections. A close up of a vascular bundle is shown. A, DIC image; B, 18S expression; C, exp5 expression; D, gast1 expression. I, merged image of exp5 and gast1 from C and D. In I, the arrows indicate the colocalization of gast1/exp5 in cambium cells situated above vessel strands and arrowheads indicate the colocalization of gast1/exp5 in xylem parenchyma cells surrounding the vessels. A control IS-RT-PCR experiment in which PCR was performed but the RT step was omitted is indicated in E to H. E, DIC image; F, PCR with 18S primers; G, PCR with exp5 primers; H, PCR with gast1 primers. Note the background autofluorescence of dead xylem vessel cell walls in F to H. Magnification bars = 20 μm.