COMPARATIVE-STUDY OF THE DEVELOPMENT OF ZYGOTIC AND SOMATIC EMBRYOS OF CHICKPEA (CICER-ARIETINUM L.)

The early stages of development of zygotic and somatic embryos (globul ar, heart and early cotyledonary stage) were studied in chickpea (Cice r arietinum L.). Immature pods were collected 3-15 days after pollinat ion (DAP) and used for the isolation of zygotic embryos. Immature coty ledonary segments and mature embryo axes of cultivar PG12 were culture d on Murashige and Skoog's (MS) basal medium supplemented with 3.0 mg l(-1) 2,4,5-trichlorophenoxy-acetic acid (2,4,5-T), for the induction of somatic embryos. The suspensor of zygotic embryo of chickpea was fo und to consist of six tiers of biseriate cells. By contrast somatic em bryos were raised on a multiseriate suspensor-like stalk. The size of a globular-stage somatic embryo was much larger than zygotic embryo at a similar stage of development. The initiation of leaf primordia from the shoot apical meristem was also studied. The cells that composed t he apical dome differed, in that the cells of zygotic embryo were flat in comparison to the curved cells of somatic embryo. Germinated seedl ings and converted somatic embryo showed similarity in organization, d iffering only in the size of cotyledons. (C) 1997 Elsevier Science Ire land Ltd.