Additional file 2 of Conservation of the dehiscence zone gene regulatory network in dicots and the role of the SEEDSTICK ortholog of California poppy (Eschscholzia californica) in fruit development
Creators: name: Lotz, Dominik
name: Rössner, Le Han
name: Ehlers, Katrin
name: Kong, Doudou
name: Rössner, Clemens
name: Rupp, Oliver
name: Becker, Annette
Publisher: name: figshare
Year: 2024
Subjects: subject: Genetics
subject: FOS: Biological sciences
subject: Plant Biology

description: Supplementary material 2: Supplemental Figure 2: Dehiscence zone formation in E. californica At 2 dap (A, B), only the xylem of all vascular bundles (vb) in the fruit wall is lignified, but the future sclerenchyma of median valve ridges (mvr), small sclerenchyma caps (sc), lateral valve ridges (lvr), and replum sclerenchyma (rs) is already forming. Lignification pattern has not changed at 6 dap (C, D), but future sclerenchyma cells are more conspicuous, particularly in the dz (D). A discrimination between mvr, sc, lvr, and rs is clearly visible (C, D). Lignification of these sclerenchyma tissues starts at 11 dap and reaches its maximum at 20 dap (E-G: 16 dap, H-J: 20 dap, cf. K-M: 30 dap). Cells in the rs differentiate successively in centrifugal direction (F, asterisk in G). In the replum, thick- walled, but unlignified, cells with a small lumen develop on the adaxial side of the vb (arrow in D). At 16 dap (E-G), radially arranged parenchyma in the valves (E, black arrows) and the parenchymatous separation layers (sl) between the lvr and r in the dehiscence zone (dz) (F and G, black arrows) are non-lignified. At 18 dap, few layers of the radial parenchyma adjacent to the lvr start to develop into lignified sclereids, and this process successively proceeds towards the central mvr of the valves within the next days. Unilateral occurrence of sclereids between central mvr and adjacent sc indicates an intermediate developmental state at 20 dap (I, black arrow), while from 26 dap on, complete valve lignin conjunctions occur between lvr, mvr and the intervening sc (shown in K for 30 dap, black arrow. Sclereids also develop adjacent to the lvr towards the rs in the dz, mainly on the abaxial side (shown in I and J for 20 dap, black arrows). However, the initially parenchymatous sl (I and J for 20 dap, white arrows) becomes lignified only at 30 DAP (cf. L, M, white arrows). Overview of the cross-sectioned mature poppy fruit 32 days after pollination (dap), composed of two valves (v1 and v2) separated by two repla-like tissues (r) in (Q). Each valve includes two sclerified lateral valve ridges (lvr), three sclerified median valve ridges (mvr), and intervening small sclerenchyma caps (sc), covering the adaxial side of the vascular bundles (vb). These sclerenchymatous valve tissues are interconnected via layers of sclereids (scl) traversing the radially arranged parenchyma cells which separate lvr, mvr and sc. Each dehiscence zone (dz) includes two lvr and the central r , which contains a vascular bundle with a lignified replum sclerenchyma cap (rs) and is bordered by narrow, radially orientated lignified separation layers (sl). Ridges, sc, and rs together with sclereids and sl form a closed ring of lignified sclerenchymatous elements, which likely provides mechanic stability to the fruit. Seeds (s) are located within the capsules and are attached to the fruit wall via the placenta tissue at the valve margins. Samples shown in A-D, K-P and Q. were paraffin-embedded and sections were stained with phloroglucinol–HCl, while samples for E-J were embedded in LR-White, which delivered higher quality sections of the dehiscence zone in the intermediate developmental stages. The latter sections were stained with fuchsin–astra blue or crystal violet. e: endocarp, F: facet cells, mvr: median valve ridge, lvr: lateral valve ridge, R: ridge cells, rs: replum sclerenchyma, sc: small sclerenchyma caps; scl: sclereids, vb: vascular bundle Scale bars represent 100 µm in H, K and N, 200 µm in all other images.