Figure 2

Microsporogensis of ‘Qx-097’ by TEM and paraffin section method. (A) Differentiation of archesporial cells. (B) Microsporocyte formation stage, showing differentiation of microspore mother cell and 3 anther walls (secondary parietal cell layer, endothecium and epidermis from the inner to the outer layer). (C) Microsporocyte formation stage, showing microspore mother cell tightly abutted and four complete anther walls. (D) Microspore mother cell at prophase I of meiosis, showing microspore mother cell in oval shape, discohesive cells and prominent nucleoli. (E) Microspores at first meiotic metaphase, chromosomes aligned on the metaphase plate. (F) Tetrad and condensed cytoplasm of tapetal layer. (G) Microspore mother cell in pachytene, showing mitochondria, plastids and numerous vacuoles. (H) The stage of tetrad, showing mitochondria, plastids, endoplasmic reticulum, enlargement of vacuoles, callose wall and cell wall which begin to develop. (I) Anther wall at microsporocyte meiosis stage, cytoplasm of endothecium layer, epidermal layer and tapetal layer cells become vacuolation, cytoplasm of tapetal layer cells which has large nuclei and obvious nucleoli condensed, middle layer degrades. AC: Archesporial cells; Ch: chromatin; CW: Callose wall; Dy: Dyad; En: Endothecium; Ep: Epidermis; ER: Endoplasmic reticulum; Mi: Mitochondrion; ML: Middle layer; Ms: Microspore mother cell; Nu: Nucleus; Pl: Plastid; PW: Pollen wall; SeL: Secondary parietal cell layer; Ta: Tapetum; Te: Tetrad; Va: Vacuole.