Female gametophyte development in wild type and <i>rsw4</i>.

<p>Confocal fluorescence micrographs of ovules of (A–D) wild type, (E–H) <i>rsw4</i> exposed to 30°C for 2 days, and (I –L) <i>AtESP-RNAi</i> plants. Images are the result of autofluorescence. Gametophyte development was staged according to Christensen et al. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0019459#pone.0019459-Christensen1" target="_blank">[37]</a>. (A) FG1 embryo sac with a functional megaspore (arrow). (B) FG3 embryo sac. (C) FG 4 embryo sac. (D). FG7 embryo sac. (E) Stage FG1 in <i>rsw4</i> showing a degraded functional megaspore (arrow). (F) FG2 embryo sac showing degenerated megaspore nuclei (arrow). (G) An abnormal FG3 embryo sac with degraded nuclei (arrow). (H) A normal FG7 embryo sac. (I) FG5 embryo sac in <i>AtESP</i>-RNAi. (J) FG6 embryo sac. (K) FG7 stage embryo sac. (L) Ovule with a degraded embryo sac. Bars = 5 µm.