Figure 7.

Localization of GUS activity driven by the ZmTCRR-1 promoter in Arabidopsis. a, young developing seeds inside the siliques. The signal is concentrated on the chalazal endosperm (Ch-e) in contact with the funiculus, with a fade blue colour visible in the rest of the endosperm (peripheral endosperm, P-e). b, discontinuous staining of vessel bundles in the cotyledon. c, staining at the branching points of the vasculature below the apical meristem in 14 days old seedlings. d, longitudinal section showing one of the stained cells along the cotyledon vasculature and its association to the xylem tracheary elements (Te). e, f, g, transversal sections of vascular bundles at the intercotyledonary node (position indicated by a dashed line in d); sections were stained with toluidine blue (e), fuchsine (f) and ruthenium red (g). The primary cell wall appears pink in e and g, secondary cell wall appears dark blue in e and remains unstained in g. Cytoplasm is stained blue in e and red in f. GUS staining appears in all cases as a light blue signal. Ph, phloem; Pc, procambium; Xy, xylem. The scale bar in d, e, f and g is 20 μm.