Figure 6

Microscopic images of frozen sections of Trichosanthes kirilowii late-stage rhizoids and RTBs at different developmental stages.
(A) Transverse section of rhizoid after eight-day incubation on RTB induction medium, showing the cortex and potential fast-cell-division zone (FCDZ). (B) Transverse section of rhizoid after ten-day incubation on RTB induction medium, showing the cortex and potential FCDZ. (C) Transverse section of rhizoid after 12-day incubation on RTB induction medium, showing the cortex and potential FCDZ. (D) Transverse section of rhizoid after 14-day incubation on RTB induction medium, showing the cortex, potential FCDZ and embryoid rudiment. (E) Enlarged view of C showing proembryos (Boxes e1 and e2). (F) Enlarged view of D showing transitional structures between proembryos and globular embryos (Boxes f1 and f2) and a globular embryo (Box f3). (G) Transverse section of a late-stage RTB with multiple formed embryoids (a heart-torpedo embryo in box). (H) Embryoids (a heart embryo in box) at different developmental stages formed in the RTB cortex. Scale bars for (A, B, C and D), 300 μm. Scale bars for (E), 100 μm. Scale bars for (F), 80 μm. Scale bars for (H), 30 μm. Scale bars for (G), 300 μm.