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female Gametangium for most Divisions of land plants. While there
are some variations in structure, the basic components are the same for most taxa.The Archegonium consists of a peripheral Neck which usually protrudes above the surface of the Gametophyte.
The Neck is composed of four tiers of cells which are not joined at their center corners, thus creating an opening. This opening is called the Neck Canal.
The Neck Canal is populated by cells, called the Axial Row. The lowermost cells which are embedded in the Gametophyte are called the Venter. The most basal cell is the EGG.
| Typical Archegonia | ||
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Sectional View of
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 An Archegonium as seen by an incoming Sperm. It needs to make its way into the narrow opening of the Neck Canal. |
The Neck Canal Cells undergo Autolysis (Self-Lysis) at maturity and provide an open channel for the Sperm to reach the Egg. The upper Neck cells may reflex or fall away, thus enlarging the Neck Canal & enhancing the possibility of Syngamy. Archegonia can emit chemotactic agents which help the Sperm reach their target. This must be an efficient adaptation because most major taxa of terrestrial plants have archegonia. However, flowering plants have an improved female gametangium as we will see later. |
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