Micropyle


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Related to Micropyle: embryo sac, synergid, antipodal cells

micropyle

[′mī·krə‚pīl]
(botany)
A minute opening in the integument at the tip of an ovule through which the pollen tube commonly enters; persists in the seed as an opening or a scar between the hilum and point of radicle.

Micropyle

 

(1) An opening in the membrane of the eggs of insects, arachnids, some mollusks, fishes, and a number of other animals, through which the spermatozoon penetrates. (2) An opening in the apex of the ovule in higher seed plants, through which the pollen tube penetrates during pollination. The micropyle is formed because the integuments surrounding the ovule are unattached.


Micropyle

 

the canal in the integument or integuments of a plant through which the ovule is penetrated in gymnosperms by pollen grains and in angiosperms by pollen tubes. The external opening of the micropyle may be observed on the surface of a mature seed in the form of a dark dot.

References in periodicals archive ?
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 (Figure 6A).
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.
Micropyle 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.