Light and electron microscopy of callus initiation from haploid barley embryos

Abstract

Cultured immature haploid embryos of barley generated callus tissue from rapidly dividing epidermal and subepidermal cells of the scutellum. Ultrastructural features, including large nuclei, many mitochondria, and dictyosomes, confirm the meristematic nature of these scutellar cells and autoradiography indicates that they are already actively synthesizing DNA by day 3. By day 5, a wet, dark callus is initiated from the coleorhiza. Within 14 days of culture, relatively large amounts of nodular, dense, yellow–white callus were generated. This type of callus is known to have regenerative potential, while callus produced early in culture from the coleorhiza region does not regenerate.