Chapter 16 Induction of Embry in Suspension Culture ichel Monnier 1. Introduction The initiation and development of embryos from differentiated tissue (somatic tissue) was first observed by Steward et al. (1) in 1958, but earlier researchers had already observed these formations in culture, without recognizing them as embryos. These embryos are termed somatic embryos, and their origin is dif- ferent from zygoticembryos, which result from the fusion of gametes. This phenomenon is also called adventive or asexual embryogenesis. Somatic embryos (see Chapter 15, this vol.) closely resemble zygotic embryos in their structure, as well as in their physiological properties, especially with wild carrot (2). Nevertheless, the organization of these somatic embryos is generally more variable than that of zygotic embryos. Abnormalities in shape and sizeare frequent, and becauseof this variation they were, at first, called embryoids. In contrast to buds, somatic embryos have a bipolar axis with an api- cal meristem and a root, and as they have no vascular connection with the mother callus, they are easily detached by the swir!ing action of the agi- tated medium ited by Jeffrey W. Pokyd and John Wakor, o1900 by The Humana Press