Elemental composition of soybean seeds

The soybean (Glycine max L. Merr.) seed coat is the terminal maternal tissue that supplies the developing embryo with nutrients. Between the embryo and seed coat, where this transfer presumably occurs, we have found (1,2) a specialized convex area (antipit) on the inside surface of the soybean seed coat that is opposed by a concave area (pit) on the surface of the cotyledon. The cells of this pit-antipit complex are larger than those of the surrounding tissue. Furthermore, the aleurone and cone cells of the antipit have many characteristics of secretory cells. Previous data about these structures has been cytological; very limited biochemical information is knownabout the area. This paper presents preliminary data about the elemental content of these surfaces in the mature seeds of domesticated soybean, G. max and a close relative, G. soja. The seed was dissected into right and left cotyledons; the right cotyledon was used for all microscopy and X-ray analysis. The seed coat was then separated from the cotyledon and excess tissue was removed.