Ovule development in <i>CaMV35S::IOREMPTE</i> transformants and wild-type plants.

<p><b>(A)</b> to (E) and (J) to (L) correspond to whole-mounted cleared ovules under Nomarsky microscopy; (F) to (I) are whole mounted ovules stained with propidium iodide and observed under confocal microscopy; (M) is a semi-thin (2 um) section observed under bright field. (<b>A</b>) Developing ovule of a <i>CaMV35S::IOREMPTE</i> transformant at pre-meiotic stage showing normal MMC differentiation. (<b>B</b>) and (<b>C</b>) Fully differentiated ovules of a <i>CaMV35S::IOREMPTE</i> transformant arrested at the functional megaspore stage showing maintenance of the L1 layer and a single gametophytic nucleus (arrow in C). (<b>D</b>) and (<b>E</b>) Fully differentiated ovules of a <i>CaMV35S::IOREMPTE</i> transformant arrested at the functional megaspore stage (dashed line) and showing enlargement of nuclei within prevalent L1 cells (arrows). (<b>F</b>) Fully differentiated ovule in wild-type showing the egg cell (ec) and central cell (cc). (<b>G</b>) Developing ovule of a <i>CaMV35S::IOREMPTE</i> transformant arrested at the functional megaspore stage and showing the prevalence of a cell with enlarged nucleus in the L1 layer (arrow). (<b>H</b>) Fully differentiated ovule of a <i>CaMV35S::IOREMPTE</i> transformant arrested at the two-nuclear stage, with gametophytic nuclei (arrows) separated by a vacuole (v). (<b>I</b>) Fully differentiated ovule of a <i>CaMV35S::IOREMPTE</i> transformant arrested at the two-nuclear stage, with gametophytic nuclei (arrows) separated by a cell wall, (<b>J</b>) Expression of the <i>pSPL::GUS</i> marker in the differentiated ovule of a <i>CaMV35S::IOREMPTE</i> transformant showing prevalence of the L1 cell layer. (<b>K</b>) Expression of the <i>pSPL::GUS</i> marker in the differentiated wild-type ovule showing disruption of the L1 cell layer. (<b>L</b>) Expression of <i>pFM2::GUS</i> marker in the differentiated ovule of a <i>CaMV35S::IOREMPTE</i> transformant arrested at the functional megaspore stage. (<b>M</b>) Aniline blue staining to mark degenearated megaspores in the differentiated ovule of a <i>CaMV35S::IOREMPTE</i> transformant. Scale bars, A: 10 μm; B-M:20 μm.