Figure 5.

Immunolabeling of HSS in root sections of S. vernalis. A, Specific labeling using fluorescein isothiocyanate (FITC) detection of specialized cells within the endodermis and the adjacent parenchyma cells of the root cortex with affinity-purified anti-HSS antibody (Co, parenchyma cells of the root cortex; En, endodermis; Ph, phloem; Xy, xylem; and the casparian strips in the radial cell walls of the endodermis are marked by arrowheads). B through E, Specific labeling as in A, but in the presence of purified HSS (B and C) and in the presence of purified DHS (D and E) in a molar ratio of antibody:added protein of 10:1 and 1:3, respectively. F, Immunogold labeling enhanced with silver of a root section with beginning secondary growth (cells introduced by cambium activity are marked by arrows). The HSS-specific label is still detectable.