Fig. 3. Ovule development in wild-type and mnt mutant plants. (A-F) Early ovule development in wild type (A,C,D) and mnt (B,E,F). (A,B) SEMs of stage 1-II ovules. (C,E) Sections of stage 2-III ovules showing megaspore mother cell (arrow) and initiating inner integument (^*). (D,F) SEMs of later stage 2 ovules showing integuments beginning to extend over nucellus. (G,H) Sections of mature wild-type (G) and mnt (H) ovules. The arrow in (H) shows an extra cell layer. Scale bars: 10 µm in A-F; 20 µm in G,H. (I-K) Comparison of number of cells (I), total length of integument (J) and mean size of cells (K) in the abaxial oi2 and ii1' layers of wild-type and mnt integuments. Error bars: s.e.m. n=4 wild type, 8 mnt.