Figure 1.

Soybean seed development. A, Cartoon depicting soybean life cycle. B, Schematic representation of soybean seed development. Embryo morphologies and developmental events were adapted and modified from Goldberg et al. (1989). C, Paraffin transverse 10-μm sections of soybean globular, heart, cotyledon, and early maturation seeds. Inset contains a magnified view (40×) of the seed coat. Axis longitudinal section was obtained from an early maturation seed. D, Major unanswered questions in seed development. a, Axis; al, aleurone; c, cotyledon; cu, cuticle; ep, embryo proper; es, endosperm; hg, hourglass cells; ii, inner integument; oi, outer integument; pa, palisade layer; pl, plumule; py, parenchyma; rm, root meristem; s, suspensor; sc, seed coat; sm, shoot meristem; v, vascular tissues; vb, vascular bundle.