Yanagimachi R (1957) Some properties of the sperm-activating factor in the micropyle
area of the herring egg.
In addition to histochemical analysis, we also contributed with useful taxonomical data, such as the first report of colleters in Dalechampia, the occurrence of glands, obturator, micropyle
occluded by nucellar beak and meristematic activity in the ovary wall, that might be explored in future studies within the genus and other related Euphorbiaceae taxa.
This hypothesis is supported by BEAMENT (1948, 1952), who reported the role of the micropyle
in transporting insecticides to the interior of the egg, since the chorion is an impermeable structure for toxic substances.
The acrosome is a structure absent in fish sperm, being compensated by the micropyle
, a hole in the oocyte chorium where the sperm cell penetrates (GANECO; NAKAGHI, 2003).
With this strategy, spermatozoa are stored in the micropyle
of eggs within the ovary after gamete transfer to the female and eggs are not fertilized until immersed in seawater.
Through division of the cells in the micropylar end of the nucellus, a cell proliferation is developed that extends beyond the micropyle
Normally the three cells nearest the micropyle
degenerate, leaving only one functional megaspore to develop into the megagametophyte.
4, n=9) fine ribs from the base to short of the micropyle
, leaving a smooth area around the micropyle
of about 0.
For these reasons, only grasshoppers with mature oocytes, those with a visible micropyle
on the chorion, were used to determine fecundity.
In coccidia, a pore in the cyst wall closed by a plug of material which is more easily dissolved that the cyst wall; this is where structures formed in the cyst emerge.
A pollen tube begins to grow from a pore in the pollen and a tube nucleus and two sperm nuclei travel along the tube as it grows until it reaches the micropyle
, the opening into the ovule cavity.
Egg architecture of Naucoridae (Heteroptera): internal and external structure of the chorion and micropyle