Figure 1.

Endosperm and seed coat development in mutant Arabidopsis plants when fertilization is prevented. (A) Wild-type silique. (B) f644 homozygous silique. (C) Wild-type ovule. (D–H) f644 homozygous seed-like structures. (I) Wild-type seed with globular embryo 2 days after self-pollination. Siliques, ovules and seed-like structures in A–H were harvested 6 days after removal of anthers. CCN, central cell nucleus; ECN, egg cell nucleus; EM, embryo, EN, endosperm; ENN, one of the endosperm nuclei in the endosperm; FG, female gametophyte; I, integument; OV, ovule; SC, seed coat; SLS, seed-like structure. Unlabeled arrows indicate nuclei derived from the unfertilized central cell. [Bar = 0.5 mm (A–B) and 0.1 mm (C–I).]