Figure 7

The regeneration process of Trichosanthes kirilowii via somatic embryogenesis (SE) involving RTBs, a new kind of SE structure.

(A–A4) Rhizoids induced on root explants. (A) Rhizoid primordia induced on a root explant 2 days post inoculation (dpi). (A1) Rhizoids induced on a root explant 3 dpi. (A2) One induced rhizoid on a root explant 5 dpi. (A3) One induced rhizoid on a root explant 7 dpi. (A4) One induced rhizoid on a root explant 9 dpi. (B–B4) Induced RTBs at an early developmental stage. (B) One induced RTB 1 day post transferring rhizoids to RTB induction medium (dpt). (B1) One induced RTB 3 dpt. (B2) One induced RTB 10 dpt. (B3) One induced RTB 12 dpt. (B4) One induced RTB 14 dpt. (C–C1) Induced RTBs at an early-middle developmental stage. (C) One induced RTB 25 dpt. (C1) One induced RTB 30 dpt. (C2–C4) Induced RTBs at a middle-late developmental stage. (C2) One induced RTB 35 dpt. (C3) One induced RTB 40 dpt. (C4) One induced RTB 45 dpt. (D–D2) Polar views of RTBs at an early-middle developmental stage, D (25-day induction), D1 (28-day induction) and D2 (30-day induction). (D3) Polar views of RTBs at a late developmental stage (45-day induction). (D4) Enlarged view of D3 showing formed embryoids. (D5) The formed embryoids stained red by acetocarmine and Evans blue. (D6) Macroscopic morphology of formed embryoid. (E) The formation process of multiple plantlets from an in vitro RTB. (F) A regenerated seedling. (G) A regenerated plant. Scale bars for (A, A1, A2, A3, A4, B, B1, B2, B3 and B4), 1 mm. Scale bars for (C, C1, C2, C3, C4, D, D1, D2, D3, D4 and D5), 1.5 mm. Scale bar for D6, 5 mm. Scale bars for (E, F and G), 0.5 cm.