Figure 5.

Embryo development in the arp7-1 mutant. A to H, Comparison of the development of retarded homozygous arp7-1 embryos (E–H) with normal, wild-type, or heterozygous sibling embryos (A–D). A and E, Globular stage. B and F, Heart stage. C and G, Torpedo stage. D, Bent-cotyledon stage. H, Abnormal mutant embryo arrested at the torpedo stage. Cleared seeds were examined with a light microscope equipped with Nomarski optics. I and J, Comparison of the organization of normal (I) and the aborted sibling embryos (J) from a self-pollinated, mature, green heterozygous mutant silique. Isolated embryos were stained with DAPI and observed with a fluorescence microscope. About one-fourth of seeds in each silique contained aborted embryos exhibiting abnormal morphology. The homozygous mutant embryos were arrested at various stages of development. The arrows in J point to embryos with the extra cotyledon. Scale bars = 100 μm.