Comparative study of the development of zygotic and somatic embryos of chickpea ( Cicer arietinum L.)

Abstract

The early stages of development of zygotic and somatic embryos (globular, heart and early cotyledonary stage) were studied in chickpea ( Cicer arietinum L.). Immature pods were collected 3–15 days after pollination (DAP) and used for the isolation of zygotic embryos. Immature cotyledonary segments and mature embryo axes of cultivar PG12 were cultured on Murashige and Skoog's (MS) basal medium supplemented with 3.0 mg l −1 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), for the induction of somatic embryos. The suspensor of zygotic embryo of chickpea was found to consist of six tiers of biseriate cells. By contrast somatic embryos 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 the apical dome differed, in that the cells of zygotic embryo were flat in comparison to the curved cells of somatic embryo. Germinated seedlings and converted somatic embryo showed similarity in organization, differing only in the size of cotyledons.