Figure 3. Inner-to-outer gradient of programmed cell death in the aleurone layers of rice seeds.

(A) The transverse section was laterally cut rice grains cultured for 5 d (with embryo); (B–E) Details corresponding to A. Analyses were repeated at least three times on independent biological samples, and representative results are shown. The bar represents 20 μm. al, aleurone layer; em, embryo; se, starch endosperm; ep, episperm + pericarp; vb, vascular bundle. In panel B and D: i, the outermost layer; ii, the innermost layer; and in panel C: i, the outermost layer; ii, the middle layer; iii, the innermost layer.