Indirect immunofluorescence detection of xyloglucan (LM15, CCRC-M1) epitopes in transverse sections of fern petioles and lycophyte stems. Calcofluor White fluorescence (a, d, h, l, n, p, r, t, w, y) shows the full extent of cell walls. (a–c) Binding of LM15 to phloem cell walls of Blechnum brasiliense. (d–k) Pectate lyase treatment (PL) unmasks LM15-epitopes in phloem cell walls of Asplenium rutifolium
(d–g) and in primary cell walls of cortical parenchyma of Asplenium elliottii
(h–k). (l–o) LM15 binds to phloem tissue of Equisetum ramosissimum. (p–v) Similar distribution patterns are found in the lycophytes Huperzia squarrosum
(p–s) and Selaginella grandis
(t–v). (w–z) While the CCRC-M1 epitope is not detected in Asplenium rutifolium
(w, x), even after pectate lyase pre-treatment (PL), it is localized in the phloem of Blechnum brasiliense
(y, z). No primary antibody controls are provided (c, g, k, o, s, v). Abbreviations: phl: phloem. Scale bars: 40 μm.