Stage 3 (a–c); stage 4 (d–h); stage 5 (i–k); stage 6 (l–n). The three columns illustrate representative images of, respectively, Giemsa staining (for structural analysis and stage assessment), DAPI staining (for total nuclei visualization), and TUNEL reaction. a asci, as ascospores, p peridium, pa paraphyses, sv sterile vein. Bars = 50 µm in b, c, g, h, j, and k; 100 µm in e, f, l, m, and n; 200 µm in a, d, and i