explain the formation of mature embryo from embry sac?

Asked by vasturushi | 2nd Jun, 2017, 10:50: PM

Expert Answer:

The development of an embryo from a zygote is called embryogeny. The development takes place at the micropylar end of the embryo sac. Most of the zygotes divide only after a certain amount of endosperm is formed. This provides assured nourishment to the developing embryo.

Development of Embryo in Dicots:

  • The zygote divides into two unequal cells, larger suspensor cell towards the micropyle and a smaller embryonal cell towards the antipodal region.
  • The suspensor cell undergoes transverse division to form 6-10 celled suspensor.
  • The suspensor cell towards the micropylar end is large and is called haustorium or vesicular cell.
  • The suspensor cell towards the embryonal cell is called hypophysis which forms the radicle tip.
  • The embryonal cell divides twice vertically and once transversely to produce a two-tiered eight-celled embryo.
  • The epibasal tier forms two cotyledons and a plumule while the hypobasal tier produces only hypocotyl and most of the radicle.
  • The octant embryo undergoes periclinal divisions to produce protoderm, procambium and ground meristem.
  • Protoderm forms epidermis, procambium forms stele and ground meristem produces cortex and pith.
  • Initially, the embryo is globular and undifferentiated and is called proembryo.
  • It is then transformed into embryo with the development of radicle, plumule and cotyledons.

Answered by Sheetal Kolte | 3rd Jun, 2017, 12:45: PM