<i>tun</i> and <i>evn</i> ovules display pollen tube overgrowth and increased callose accumulation at the filiform apparatus.

<p>(A–C) Aniline Blue staining of callose in PT cell walls 2 d after pollination (DAP). (A) PT reception in a wild-type FG. Arrowhead indicates site of PT growth arrest. (B–C) PT overgrowth in <i>tun-1</i> (B) and <i>evn-1</i> mutant FGs (C). Asterisks indicate PT overgrowth. (D–F) β-glucuronidase (GUS) staining of synergid marker ET2634 2 d after emasculation (DAE) in wild-type (D), <i>tun-1</i> (E), and <i>evn-1</i> mutant FGs (F). Arrow indicates abnormal structure at the FA. (G–I) Chloral hydrate clearings of ovules 2 DAE in wild-type (G), <i>tun-1</i> (H), and <i>evn-1</i> mutants (I). Arrows indicate abnormal structure at the FA. (J–L) Aniline Blue staining of callose in 6 μm sections of wild-type (J), <i>tun-1</i> (K), and <i>evn-1</i> ovules 2 DAE (L). Boxes represent close-ups of indicated regions, whereby mutant close-ups in (K) and (L) were captured with reduced exposure time compared to the wild type (J). Scale bars in A–F and J–L = 20 μm; scale bars in G–I = 10 μm.