Mucilage spatial architecture after hydration and CPD-drying visualized in SEM.

<p>A-C. <i>Arabidopsis thaliana</i>. A. The seed surface tightly covered with the mucilage; B. Mucilage components organized in a tightly-tangled net-like structure; C. Thicker cellulose fibrils (arrow) cross-linked by shorter chains (arrowhead); D-F. <i>Lepidium sativum</i>. D. The abundant mucilage envelope; E. Delicate fibrils form a densely-organized mucilage envelope; F. The main, unbranched cellulose fibrils (arrows) cross-linked by shorter chains (arrowhead). G-J. <i>Ocimum basilicum</i>. G. Mucilage forms an uneven envelope densely-covering the seed surface; H. Mucilage material organized in ‘tubules’ (arrows) attached to the seed surface (remainders of the cell wall of mucilage secreting cells); I. The site where the cellulose fibrils are attached to the seed surface, the ‘base of the tubule’; J. Cellulose fibrils (arrows) with other components (cross-linking polysaccharides) (arrowheads) spread between the fibrils; K-M. <i>Salvia sclarea</i>. K. The surface of the seed is covered with dense mucilage layer; L. The ‘tubules’ (arrows) structure of the mucilage envelope at higher magnification; M. The net-like structure at the site, where the cellulose fibrils constitute the main scaffold and where they are cross-linked by other components (matrix polysaccharides; arrowheads); N-P. <i>Artemisia annua</i>. N. Very delicate mucilage envelope; O. Parallel organization of the cellulose fibrils; P. Net-like structure of the mucilage with visible cellulose fibrils (arrows), granules covering their surface and crosslinking components (arrow heads); Q-S. <i>Artemisia leucodes</i>. Q. Very abundant mucilage envelope around the seed; R. Organization of the mucilage components in ‘tubules’ attached to the seed surface (arrows); S. The cellulose fibrils (arrows) very tightly covered with granules and cross-linked by shorter chains (arrowheads). <b>Abbreviations</b>: cf–cellulose fibrils, csp–crosslinking polysaccharides, cfb–cellulose fibril bundles, t–‘tubules’, ss–seed surface <b>Scale bars</b>: A, N, R– 500 μm, B, F, J– 1 μm, C, P, S– 500 nm, D, G, K, Q– 1 mm, E, I– 5 μm, H, L– 100 μm, M, O– 2 μm, K– 5 μm.