The neck canal cells are absent in the archegonia of:
The correct option is A Cycas
During the development of archegonium in Cycas, 2-8 archegonia develop at the micropylar end of the female gametophyte. All the necks of archegonia open into an archegonial chamber formed by a depression in female gametophyte. Each archegonium develops from a single superficial cell called archegonial initial. It gets enlarged and divides transversally into outer primary neck cell and inner central cell. The primary neck cell divides anticlinally to form two neck cells. The inner central cell enlarges and its nucleus divides into venter canal nucleus and egg nucleus. Soon the venter canal nucleus disorganises. Thus, a mature archegonium has two neck cells and an egg. Neck canal cells are not formed.
Neck canal cells are present in both bryophytes and pteridophytes. Funaria archegonium is a flask-shaped structure on a multicellular stalk. It has a tubular neck and swollen venter. The venter has two layered wall enclosing two cells- a venter canal cell and an egg or oosphere. The neck has a single layered jacket made up of 6 spirally twisted row of cells. It encloses 6-10 neck canal cells.
During the development of archegonium in Cycas, 2-8 archegonia develop at the micropylar end of the female gametophyte. All the necks of archegonia open into an archegonial chamber formed by a depression in female gametophyte. Each archegonium develops from a single superficial cell called archegonial initial. It gets enlarged and divides transversally into outer primary neck cell and inner central cell. The primary neck cell divides anticlinally to form two neck cells. The inner central cell enlarges and its nucleus divides into venter canal nucleus and egg nucleus. Soon the venter canal nucleus disorganises. Thus, a mature archegonium has two neck cells and an egg. Neck canal cells are not formed.
Neck canal cells are present in both bryophytes and pteridophytes. Funaria archegonium is a flask-shaped structure on a multicellular stalk. It has a tubular neck and swollen venter. The venter has two layered wall enclosing two cells- a venter canal cell and an egg or oosphere. The neck has a single layered jacket made up of 6 spirally twisted row of cells. It encloses 6-10 neck canal cells.
