Figure 7.

Pharyngeal arch development is affected by triadimefon. Representative morphological evaluation of the pharyngeal arches in embryos (A–C) at 96 hpf and (D–F) 120 hpf. Embryos at 2 μg/mL triadimefon (B) presented a minor protrusion that resulted from a developmental delay (green arrowhead, 73/80 embryos), whereas the pharyngeal arches remain unaltered (green dotted region 80/80). A more pronounced phenotype with a severely reduced mandible (red arrowhead in C, 84/89), but a still intact pharyngeal arch development (red dotted region, 89/89) was observed in 4 μg/mL triadimefon embryos (C). The pharyngeal arch development was still presented as intact (red dotted region in C, 89/89). 120 hpf zebrafish embryos treated with 2 μg/mL triadimefon (E) revealed hypoplastic mandible (73/80) and reduced size of pharyngeal arches (62/80) (green arrowhead and dotted region in E). The pharyngeal arch apparatus was severely reduced at the highest triadimefon concentration evaluated (red asterisk in F, 80/89), whereas mandibular processes were almost absent in all embryos examined (89/89) at 120 hpf. Triadimefon. Embryos in A–C are shown to the same scale (bar = 500 µm in C), while embryos in D–F are shown to scale (bar = 750 µm).