The scutellum of Avena: a structure to maximize exploitation of endosperm reserves

Abstract

NEGBI, M. & SARGENT, J. A., 1986. The scutellum of Avena: a structure to maximize exploitation of endosperm reserves. The scutella of graminaceous embryos possesses a well developed vascular system and a surface epithelium of closely packed cells. The epithelial cells typically elongate during germination and separate to form papillae, thereby increasing the interfacial area for exchange between the endosperm and embryo. Avena and a dozen non‐crop genera are distinguishable by a scutellum which grows into and through the endosperm. Thus diffusion pathways for mobilized reserves in Avena are kept short. The course of elongation of the scutellum and of its epithelial cells in A. Jatua was studied during germination and seedling establishment. A comparison was made with with the fully developed scutellum of Secale cereale which does not elongate but only forms papillae. It is proposed that the competitive success of A.Jatua as a weed is attributable in part to an ability, conferred by its scutellum, to exploit its seed reserves steadily and fully during germination and seedling development.

Growth, anatomy and morphology of the mesocotyl and the growth of appendages of the wild oat (Avena fatua L.) seedling

“…As the scutellum placement is intra-seminal and functionally suctorial, its ability to elongate and to modify morphologically depends on the availability of nutrients in the seed (Negbi and Sargent 1986, Raju 1990, Raju et aL 1986,1988, Rao and Raju 1985. The depth at which level the seeds germinated and the seedlings emerged did not seem to have any effect on scutellar elongation nor its morphology (Table 1).…”

“…elongate considerably (Arber 1934, Boyd 1932, Negbi and Sargent 1986, Pickering and Raju 1996, Raju 1990. The mesocotylary axis elongates in most grass seedlings, including the wild-oat, and can bring about changes in the placement or attachment of appendages on tha axis in the developing seedlings.…”