Radial elongation of the epidermal cells of scutellum during caryopsis germination of wild oats (Avena fatua)

Abstract

The radial elongation of epidermal cells of the scutellum of wild oat (Avena fatua L.) embryos was studied quantitatively. In the nondormant embryos, the length of these cells, both on the adaxial and abaxial sides of the scutellum, was doubled in 10 days after the beginning of the imbibition of caryopses in water; no such elongation of cells was observed in the dormant embryos. The epidermal cells elongated to form papillae only after the primary root had emerged from the caryopsis. The length of the entire scutellum and that of its epidermal cells increased significantly in the presence of gibberellic acid and glucose or sucrose. It is suggested that the epidermal cell elongation is a postgermination phenomenon involving absorption and transport of the products of starchy endosperm hydrolysis, thus promoting further growth in the germinated embryo of the wild oat.