Figure 3

Early ovule development is disrupted in 35S:NTAP:AtCTF7∆B plants. Wild type (A-D) and 35S:NTAP:AtCTF7∆B (E-I ) ovules were analyzed by differential interference contrast microscopy. (A) Pre-meiotic ovule containing a single megaspore mother cell (MMC; stage 1-II). (B) Pre-meiotic ovule at stage 2-III. Inner and outer integuments start to initiate. (C) Meiotic ovule containing a dyad after meiosis I (stage 2-IV). (D) Meiotic ovule containing a tetrad after meiosis II. (E-F) 35S:NTAP:AtCTF7∆B ovules at pre-meiotic stages. (E) Right ovule containing an abnormal, enlarged cell (white arrow) adjacent to a MMC-like cell (black arrow). Adjacent ovules are different in size. (F-F’) Left ovule containing two abnormal, enlarged cells (white arrows) adjacent to a MMC-like cell (black arrow). Ovules are different in size and stage (left: stage 1-II, right: stage 2-III) and point in the same direction. (G-I) 35S:NTAP:AtCTF7∆B ovules at meiosis. (G) Ovule containing a large cell with prominent nucleus (arrow) resembling a MMC. An extra cell is present at the position of the degenerated megaspores, between the MMC and L1 cells. (H) Ovule containing a MMC-like cell with a prominent nucleus in the central region of the ovule. Ovule is enlarged and extra cells are between the MMC and L1 cells. (H’) Magnified view of MMC from H. (I) Ovule containing two cells with prominent nuclei (arrows) in the central region of the ovule. The two cells are separated and resemble a dyad. Extra cells surround the dyad. (I’) Magnified view of I. Size bar = 10 μm. Developmental stages are defined according to Schneitz et al. [32].