An account of the ontogeny of the antheridium including some cytological
details is given for some species of the Blechnaceae and Polypodiaoeae and for
Polyphlebium venosum (R. Br.) Copeland, a member of the Hymenophyllaceae.
In the species of Blechnaceae and Polypodiaceae which were examined the
antheridium consists of three wall cells a discoid or columnar basal cell, a ring cell,
and a cap cell-enclosing the androgonial tissue. The ring cell and cap cell are delimited
by a wall which is laid down in the shape of a funnel.
In Polyphlebium the antheridial wall typically consist's of four cells - a lower
and an upper ring cell, a cap cell, and an operculum. Each ring cell is produced in a
straightforward manner by a funnel-shaped wall.
Davie's postulation concerning the development of the antheridium by a
series of transverse walls and upward and downward expansion of the androgonial
cell, giving the appearance of funnel-shaped walls and ring cells, has been included
in text-books by Smith (1955) and Foster and Gifford (1959).
This hypothesis is questioned, and an explanation of what is considered to be
the true method of development of the funnel-shaped walls and ring cells in the fern
antheridium is given.
Anomalous antheridia of Blechnufm cartilagineum Sw., in which the androgonial
tissue is flattened and abortive, form a deep cap cell and a ring cell separated by a
funnel-shaped wall, although no expansion of the central androgonial cell takes place.
The unusual method by which the pedicel and antheridial initial cell form from
a cell of the filamentous prothallus in Polyphlebium is described.
Identification of Genes that are Up- or Down-regulated in the Apical or Basal Cell of Maize Two-celled Embryos and Monitoring their Expression During Zygote Development by a Cell Manipulation- and PCR-based Approach