Extracellular environments for the initiation of external fertilization and micropylar
plug formation in a cottid species, Hemitripterus villosus (Pallas) (Scorpaeniformes) with internal insemination.
The hilum has rounded outline, and the micropylar
region and raphe may be observed.
Aged seeds which have just started to germinate can be identified by a characteristic hole on the micropylar
end which remains identifiable when the seed has been processed using side-striking techniques.
In Heteroptera, depending on the species, micropylar
processes vary in number, shape, and size, and enable the gas exchange of the developing embryo.
After growing through nucellar tissue for three days, from one to several pollen tubes approach the micropylar
end of the female gametophyte [ILLUSTRATION FOR FIGURE 4A OMITTED].
In the July 6 samples after double fertilization the zygote remained undivided which was located at the micropylar
pole (Table 1).
In case of endosperm-limited germination, weakening of the micropylar
endosperm surrounding the radicle tip appears to be required for radicle protrusion, and is likely to involve cell-wall hydrolysis by hydrolytic enzymes.
At 12 Days After Sowing (DAS) this face is completely swollen and micropylar
pole is starting to break, probably due to water absorption by diaspore and embryonic development (Figure 3A).
plate spade-shaped, gently tapering anteriorly, posterior margin truncate, central ridge about 1/2 length of the micropylar
egg or egg cell: Middle of three haploid cells at the micropylar
end of the embryo sac; when fertilized, it will form the zygote.
Fine structure of micropylar
region during late oogenesis of eggs in the hagfish.
Except for the micropylar
region, ridges extend all over the surface of the chorion.