Immunological detection of an embryogenic-cell protein (ECP31) during stress-induced somatic embryogenesis in carrot

The accumulation and localization of ECP31, an embryogenic cell protein with a molecular weight of 31 000, was examined with immunoblotting and immunohistochemical analysis during stress-induced somatic embryogenesis in carrot (Daucus carota). ECP31 was not detected in apical tip segments of 7-day-old carrot seedlings. However, it accumulated in the apical tip segments on which somatic embryos had formed after treatment with 0.5 mM NiCl2 or CdCl2 and successive culture on Murashige and Skoog's agar medium without the heavy metal chlorides. ECP31 was localized in proembryo-forming cells located in the periphery of the NiCl2 treated carrot segments but not in developing somatic embryos on these segments.