The mean size of WT x gcs1 seeds was 2.11 x 10^4 ± 0.28 x 10^4μm^2 (n= 97 seeds) at 1 DAP, 2.89 x 10^4 ± 0.46 x 10^4μm^2 (n= 109 seeds) at 2 DAP, and 2.43 x 10^4 ± 0.84 x 10^4μm^2 (n= 82 seeds) at 3 DAP. The size of OEAtBG_ppap x gcs1 seeds was 2.26 x 10^4 ± 0.42 x 10^4μm^2 (n= 241 seeds) at 1 DAP, 3.75 x 10^4 ± 1.14 x 10^4μm^2 (n= 249 seeds) at 2 DAP, and 5.11 x 10^4 ± 3.41 x 10^4μm^2 (n= 220 seeds) at 3 DAP. Welch’s two-sample t test was used to assess the significance of differences. ***p< 0.001. ****p< 0.0001. Scale bars: 500 μm (A, B, D, and E), 1 mm (G), and 50 μm (I–K). ES, endosperm; CC, central cell; AE, autonomous endosperm. See also Figures S2, S3, S7, and S8.
