3.5 Pectins and arabinogalactan proteins in the leaves ofCapparis odoratissima
Immunolocalization of pectin and arabinogalactan protein epitopes with
monoclonal antibodies showed a dual topological pattern. Pectin epitopes
were present in the cell walls of both adaxial and abaxial epidermis
(Figure 7a-b), as roughly detected in fresh samples with ruthenium red
Supplementary Figure 1a), in the external walls of the cells composing
the spongy mesophyll (Figure 7c), and the external cell walls of the
peltate hairs (Figure 7d; Supplementary figure 1b), but not in the
idioblasts. The presence of arabinogalactan proteins was roughly
detected with the beta glucosyl Yariv Reagent, which showed an intense
red color in areas with idioblasts (Supplementary Figure 2). More
specifically, the epitopes recognized by the JIM8 monoclonal antibody
labelled a narrow area that corresponded with the lumen of the
idioblasts, from their adaxial projection (Figure 7e), through the
columnar lumen in the palisade parenchyma (Figure 7f), to the lumens of
the anchoring areas of the peltate hairs (Figure 7g). As a result, AGPs
coated the continuum of lumens between the peltate hairs and idioblasts.