Table 1.
Width measurements of fibrillary material of studied taxa.
Fig 1.
A-D Ocimum basilicum mucilage envelope. A. Unstained mucilage with visible small granules-starch grains; B-C. Staining with safranin revealed ‘tubule’-like structure of mucilage (arrows) with spirally-coiled cellulose fibrils which are closed on the top with the disc-like structure (arrow); D. Ocimum basilicum—dark color indicates starch grains stained with I in KI; E Salvia sclarea stained with safranin. Visible thick, partially uncoiled wavy, cellulose threads; F. Artemisia annua mucilage envelope stained with safranin with observable cellulose threads. Abbreviations: ct–cellulose threads, d—disc, sg–starch grains Scale bars: A, B– 100 μm, C, E– 50 μm, D– 20 μm, F– 200 μm.
Fig 2.
The morphology of the air-dried seed coat mucilage.
A-B. Arabidopsis thaliana. A. Characteristic mucilage sheets (arrow) spread between the seed and substratum (glass); B. The mucilage surface at higher magnification with the visible cellulose threads (arrows) running parallel; C-D. Lepidium sativum. C. Seed attached with mucilage to the substratum; D. Smooth surface of mucilage envelope. E-H. Ocimum basilicum. E. Seed with the mucilage envelope; F. The mucilage surface with cellulose threads (arrows); G-H. Starch grains visible under mucilage envelope; I-L. Salvia sclarea. I. Seed with mucilage envelope; J. Visible fragment of mucilage envelope with wavy cellulose threads (arrows); K. Broken fragment of mucilage envelope; L. Magnification of K (box) showing the broken cellulose threads (arrows) imbed in the mucilage; M-N. Artemisia annua. M. A very delicate mucilage around the seed; N. Cellulose threads (arrows) running parallel or in different directions within the mucilage; O-P. Artemisia leucodes. Abundant mucilage envelope around the seed with visible cellulose threads (arrows); Abbreviations: ct–cellulose threads, mue–mucilage envelope, sg–starch grains Scale bars: A—200 μm, F, M– 500 μm, C, E, I, O– 1 mm, D, K– 10 μm, B, F– 500 nm, G– 20 μm, H– 5 μm, J– 50 μm, L– 2 μm, N—30 μm, P– 1 μm.
Fig 3.
Mucilage spatial architecture after hydration and CPD-drying visualized in SEM.
A-C. Arabidopsis thaliana. 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. Lepidium sativum. 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. Ocimum basilicum. 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. Salvia sclarea. 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. Artemisia annua. 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. Artemisia leucodes. 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). Abbreviations: cf–cellulose fibrils, csp–crosslinking polysaccharides, cfb–cellulose fibril bundles, t–‘tubules’, ss–seed surface Scale bars: 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.