Fig. 6. Observation of paraffin sections of wild type and smk7 kernels on different days after pollination A: wild type kernels at 12 DAP; Bar = 1000 μm. B: smk7 kernels at 12 DAP; Bar = 1000 μm. C: the basal endosperm transfer layer of WT endosperm at 12 DAP; Bar = 150 μm. D: the basal endosperm transfer layer of smk7 at 12 DAP; Bar = 150 μm; BETL: basal endosperm transfer layers.