Through the micropyle it receives the tubular prolongation of the pollen.
The pollen grains from the male cone are caught on the ligule and the pollen tubes enter the micropyle of the ovule, bringing in passive male cells which may develop in large numbers in each grain.
The pollen grains from the male cone enter the micropyle of the seed and are caught in the tissue (apex of nucellus) there; the pollen tubes discharge passive male cells, only two of which develop in each grain.
When the ovule is so developed that the chalaza is at the hilum (next the placenta), and the micropyle is at the opposite extremity, there being a short funicle, the ovule is orthotropous.
The micropyle indicates the organic apex of the ovule.
In such an ovule a straight line drawn from the hilum to the micropyle passes along the axis of the ovule.
In angiosperms when the pollen-tube reaches the micropyle it passes down into the canal, and this portion of it increases considerably in size.
The ovule is curved upon itself, so that the micropyle is near the funicle.
The egg is somewhat like the egg in the genus Achalarus, but the micropyle at the upper end of the egg is relatively larger and not as deeply depressed below the surface.
The micropyle covers the upper surface of the egg and is not depressed.
Descriptive of a reversed ovule, with the micropyle close by the side of the hilum, and chalaza at the opposite end.
A micropyle is by no means found in the majority of types, and there is no homology between the various apertures so named.
The hilum is the basis of the bud or of the seed-leaf; the seed-hole or micropyle is on the apex of the involuted bud, or rather of the phyllodium, in which the germ lies rolled up.
Umbilicus and micropyle are united with each other by means of seed or leaf-rib (raphe).
The testa or seed-shell is consequently a phyllodium thrown over the germ, but the micropyle is the upper opening of the bud.
In these two points, the reception of the pollen by the micropyle and the nursing of the embryo, it appears that many Palaeozoic seeds were imperfect, as compared with the typical seeds of later times.
I know it is not new; but how wonderful his account of the spermatozoa of some dioecious alga or conferva, swimming and finding the minute micropyle in a distinct plant, and forcing its way in!
Again, in others I found small mammillary bodies, which appeared to be true ovules, though I could not perfectly satisfy myself as to the existence of the micropyle or nucleus.
Every ovule has a tiny opening, or micropyle as it is called, and it is now easy to guess what that is for.
The primitive form of the egg is oval, globular, or flattened with the micropyle at one end; from this has apparently been derived the upright form of egg with the micropyle on top which characterizes the butterflies and the higher moths.
This is seen in the passion-flower, where the covering arises from the placenta or extremity of the funicle at the base of the ovule and passes upwards towards the apex, leaving the micropyle uncovered.
Hence, by ascertaining the position of the micropyle and chalaza, the two extremities of the embryo can in general be discovered.
At the micropyle in the bean is observed a small process of integument, which, when the young plant sprouts, is pushed up like a lid; it is called the embryotega.
The embryo e, with its suspensor, is contained in the sac, the radicle pointing to the micropyle m.
The base of the nucellus is indicated by the chalaza ch, while the apex is at the micropyle m.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "micropyle" in a variety of sentences. We hope that you will now be able to make sentences using this word.
