Histopathology of Seed-Borne Infections - Applied Research Center ...

Reproductive Structures and Seed Formation 29XepXXependendsuAnuCBFIGURE 2.11 Young embryo of Glycine max. A, Light photomicrograph of embryo differentiatedinto embryo proper and suspensor with wall ingrowths in cells of suspensor (arrows).B, Transmission electron photomicrograph at the junction between the embryo proper, suspensor(arrows), and the endosperm cells. Note that wall ingrowths are associated with thesuspensor and not with the embryo proper. Also the concentration of ingrowths increasestoward the tip of the suspensor. C, Wall ingrowths in tip cell where suspensor abuts the crushednucellar cells. (Abbreviations: end, endosperm; ep, embryo proper; nu, remnants of nucellus;su, suspensor.) (From Dute, R.R., Peterson, C.M., and Rushing, A.E. 1989. Ann. Bot. 64:123–135. With permission.)nucellar cells enlarge and are digested from inside to outside. In most species thenucellus is represented in seed by a few greatly compressed peripheral layers. Thepersistent nucellar remains are covered by a cuticle.The nucellus in Amaranthaceae, Chenopodiaceae, Polygonaceae, Piperaceae,and Scitamineae increases in volume, stores reserve food materials, and persists. Itis called the perisperm and serves as an accessory nutritive tissue, supplementingthe endosperm.