This opening is called the "micropyle," and allows the pollen tube to enter.    From Wordnik.com.  [Elements of Structural and Systematic Botany For High Schools and Elementary College Courses] Reference

The receptive part of the gymnosperm ovule is called the micropyle.    From Wordnik.com.  [Pollination] Reference

The primary root of the embryo in all Angiosperms points towards the micropyle.    From Wordnik.com.  [Encyclopaedia Britannica, 11th Edition, Volume 2, Part 1, Slice 1] Reference

To avoid damaging the seed embryo, cut or scrape the seedcoat opposite the micropyle.    From Wordnik.com.  [Chapter 4] Reference

Such a method of entrance is styled chalazogamic, in contrast to the porogamic or ordinary method of approach by means of the micropyle.    From Wordnik.com.  [Encyclopaedia Britannica, 11th Edition, Volume 2, Part 1, Slice 1] Reference

For small quantities of seed, cut through the seedcoat opposite the micropyle, or pointed-end of the seed, taking care not to damage the seed embryo.    From Wordnik.com.  [Chapter 10] Reference

Amici's subsequent (1846) discovery of the entrance of the pollen-tube into the micropyle, fertilizing the female cell which then develops into the embryo.    From Wordnik.com.  [Encyclopaedia Britannica, 11th Edition, Volume 4, Part 3 "Brescia" to "Bulgaria"] Reference

The seed should be sown 1-2 cm deep with the micropyle pointing downwards; the emerging root is not strongly geotropic and may come up out of the soil if the seed is planted upside down.    From Wordnik.com.  [Chapter 7] Reference

By carefully opening the ovary and slightly crushing it in a drop of water, the pollen tube may sometimes be seen growing along the stalk of the ovule until it reaches and enters the micropyle.    From Wordnik.com.  [Elements of Structural and Systematic Botany For High Schools and Elementary College Courses] Reference

Then when it lies on the stigma it develops a long tube, which passes down the style and through the micropyle of the ovule to the germinal vesicles, one of which is fertilized by what is probably an osmotic transference of nuclear matter.    From Wordnik.com.  [Scientific American Supplement, No. 531, March 6, 1886] Reference

At the period of fertilization the embryo-sac lies in close proximity to the opening of the micropyle, into which the pollen-tube has penetrated, the separating cell-wall becomes absorbed, and the male or sperm-cells are ejected into the embryo-sac.    From Wordnik.com.  [Encyclopaedia Britannica, 11th Edition, Volume 2, Part 1, Slice 1] Reference

The development of the ovule, which represents the macrosporangium, is very similar to the process in Gymnosperms; when mature it consists of one or two coats surrounding the central nucellus, except at the apex where an opening, the micropyle, is left.    From Wordnik.com.  [Encyclopaedia Britannica, 11th Edition, Volume 2, Part 1, Slice 1] Reference

A varying number of transverse segment-walls transform it into a pro-embryo -- a cellular row of which the cell nearest the micropyle becomes attached to the apex of the embryo-sac, and thus fixes the position of the developing embryo, while the terminal cell is projected into its cavity.    From Wordnik.com.  [Encyclopaedia Britannica, 11th Edition, Volume 2, Part 1, Slice 1] Reference

Every ovule has a tiny opening, or micropyle as it is called, and it is now easy to guess what that is for.    From Wordnik.com.  [The Renewal of Life; How and When to Tell the Story to the Young] Reference

If I have time I will have another look at pollen-tubes, as, from what you say, they ought to find their way to the micropyle.    From Wordnik.com.  [More Letters of Charles Darwin — Volume 2] Reference

The new occident cakchiquel evasion silkwood of lockage, ledgeman from notepad tegucigalpa, warning hewer ithaca and web diplegia for micropyle.    From Wordnik.com.  [Rational Review] Reference

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.    From Wordnik.com.  [More Letters of Charles Darwin — Volume 2] Reference

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!.    From Wordnik.com.  [More Letters of Charles Darwin — Volume 2] Reference

The pollen tube pushes straight toward the micropyle, enters into the ovule through the micropyle, and then the living substance it has carried all this distance in its tip breaks through its delicate wall and mingles with the living substance of the ovule.    From Wordnik.com.  [The Renewal of Life; How and When to Tell the Story to the Young] Reference

Why, these zoospores must possess some sort of organ of sense to guide their locomotive powers to the small micropyle; and does not this necessarily imply something like a nervous system, in the same way as complemental male cirripedes have organs of sense and locomotion, and nothing else but a sack of spermatozoa?.    From Wordnik.com.  [More Letters of Charles Darwin — Volume 2] Reference

The entrance of pollen-tubes into the nucellus by the chalaza, instead of through the micropyle, was first fully demonstrated by Treub in his paper "Sur les.    From Wordnik.com.  [More Letters of Charles Darwin — Volume 2] Reference