Observations on the Scutellum. I. Overall Development During Germination in Four Grasses

Abstract

.The scutella of ungerminated and germinating seeds of wheat, barley, oats and ryegrass are compared anatomically from two viewpoints. Firstly, the overall development of the organ is considered. Oats and ryegrass differ from wheat and barley in that the apical portion of the scutellum of the former two grasses becomes separated from the overlying aleurone tissue during germination. The exposed scutellum epidermis in these genera tends to become epithelial in appearance. The mechanism of the separation of the scutellum from the aleurone layer is apparently associated with the enlarge- ment of the scutellum during germination. Secondly, there is a wave of degradation of the reserve material from apex to base in all species. The implications of this pattern have relevance to the site of gibberellin synthesis in the embryo as a whole.