Mucilage of 1/2 SW and SW cells

(a) Apical cell, 1/2 SW plant, stain Alcian Blue at pH 1, mucilage (large arrow) is thin (~7 microns), and unstained. Some epiphytes do stain: small blue spots on cell surface (arrowhead). Stipulodes and the junction between stipulodes and internode are stained (small arrow). Bar = 50 microns

(b) Central cell (third internode from the apex), same plant as in (a), stained with Toluidine Blue at pH 1. Mucilage is thicker (~ 17 microns), staining is faint (arrow), but presence of sulphated polysaccharides is indicated (arrow). Bar = 100 microns

(c) Central cell (fifth internode from the apex), same plant as in (a), stained with Alcian Blue at pH 1. Mucilage is thicker (~ 22 microns), staining is intense but patchy (arrow), indicating non-homogeneous distribution of sulphated polysaccharides. Bar = 100 microns

(d) Basal cell (seventh internode from the apex), same plant as in (a), stained with Toluidine Blue at pH 1. Mucilage is ~ 34 microns, staining is intense (arrow), indicating that the mucilage is mainly co,posed of sulphated polysaccharides. Bar = 100 microns

(e) Apical cell of a SW plant, stained with Toluidine Blue at pH 1. Mucilage (arrow) is relatively thin (~ 12.5 microns), unstained, indicating lack of sulphated polysaccharides. Bar = 100 microns

(f) Central cell (third internode from the apex)of a SW plant, stained with Alcian Blue at pH 1. Mucilage is thicker (~ 28 microns), staining is patchy (arrow), indicating non-homogeneous distribution of sulphated polysaccharides. Bar = 100 microns

(g) Basal cell (fifth internode from the apex), same plant as in (f), stained with Toluidine Blue at pH 1. Mucilage is thicker (~ 28 microns), staining is intense (arrow), indicating majority of sulphated polysaccharides. Bar = 100 microns

(h) Basal cell (seventh internode from the apex), same plant as in (f), stained with Alcian Blue at pH 1. Mucilage is thicker still (~ 43 microns), staining is intense (arrow), indicating majority of sulphated polysaccharides. Bands of staining are faintly visible in the bottom surface. Bar = 100 microns