Periodizations of Cereal Zygotic Embryogenesis in Planta and It’s Use in Biotechnological Research in Vitro

Abstract

In modern biotechnological studies of commercially valuable cereals, promising areas of great interest are the embryo culture and callus culture in vitro, associated with the use of zygotic embryos of different ages that form full-fledged regenerated plants. These biotechnologies are largely based on the use of the morphogenetic potential of embryonic cells, mainly immature ones. At the same time, the progress of such biotechnologies is limited by the lack of a single unified periodization of cereal zygotic embryogenesis in planta. The difficulty of creating a single periodization is due to both the specifics of the course of cereal embryogenesis according to a special Graminad-type and the morphology of the mature embryo, which is characterized by unique organs – the scutellum, coleoptile, epiblast, mesocotylt, coleorhiza. The article provides a brief review of the works devoted to the identification of the structural features of cereal embryos in the dynamics of development in natural conditions from the zygote to the mature structure. Special attention is paid to the comparative analysis of the proposed periodizations of zygotic embryogenesis in planta, especially those used in biotechnological studies in vitro of members of this family. It is emphasized that biotechnological and other experimental studies using cereal embryos should be based on the data of classical descriptive plant embryology.