Fertilization and AGL62 are required for nucellus degeneration. In wild-type Arabidopsis ovules, the nucellus (orange) degenerates following fertilization (top left) but remains intact in unfertilized ovules (top right). Seeds with heterozygous agl62 or wild-type endosperm are normal (bottom left), but in seeds with homozygous agl62 endosperm, the nucellus does not degenerate (bottom right). DAF, days after flowering. (Reprinted from Xu et al. [2016], Figure 2.)