Isolation of Mature Cereal Embryos and Embryonic Axes

Abstract

Numerous areas of biological research (e.g., control of seed dormancy and protein synthesis, and development of cell‐free translation systems) are greatly aided by the use of large quantities of viable cereal embryos. The utility of a method that employs a commercial food blender for embryo isolation was assessed for mature caryopses of various grain lots of wheat (Triticum aestivum L. em Thell.), rye (Secale cereale L.), triticale (× Triticosecale Wittmack), barley (Hordeum vulgare L.), oat (Avena saliva L.), rice (Oryza saliva L.), pearl millet [Penniselum glaucum (L.) R. Br.], grain sorghum [Sorghum bicolor (L.) Moench.], and maize (Zea mays L.). The yield, physical condition, and morphology of embryos and embryonic axes were characterized using light and scanning electron microscopy. Viability of embryonic axes was assessed by germination assay. Intact embryonic axes free of damage and adhering tissues (i.e., scutellum and pericarp) were easily isolated from wheat, rye, triticale, and oat. The highest yield was obtained with wheat (≈10–15%). In hulless barley, pericarp always remained attached and covered the radicle portion of the embryonic axis. Embryonic axis isolation from hulled barley was poor. Rice embryos with adhering scutellum and pericarp were isolated as a unit with 2% yield, similar to rye, triticale, and oat. Intact axes of millet, sorghum, and maize were isolated infrequently and with difficulty. Viability of embryonic axes selected visually for intactness and lack of physical damage was similar to the viability of the parent grain lot.