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Stewart Robert Hinsley · 13-08-2009, 06:44 PM posted to uk.rec.gardening

In message ,
writes
In article ,
Stewart Robert Hinsley wrote:

In the majority of flowering plants the embryo sac (female gametophyte)
ends up with 7 cells contained 8 haploid nuclei. The pollen grain (male
gametophyte) has 3 haploid cells - the vegetative cell, and two sperm
cells. When the pollen grain germinates the vegetative cell grows down
the style to reach the embryo sac, carrying the two sperm cells.

One sperm cell unites with one cell from the embryo sac. The resulting
diploid cell develops into the embryo. The other sperm cell unites with
the embryo sac cell with the extra nuclei. This develops into a triploid
tissue - the endosperm - which is many plants provides nourishment for
the embryo after seed germination. (In many other plants the endosperm
is vestigial. There might be complications about syncytia as well - I
don't recall.)

Then I definitely misunderstood! You haven't come across a coherent
description of this, anywhere, have you? I mean in more detail.

All of the textbooks I have found are at a considerable more basic
level - that looks horribly like details not normally taught to
undergraduates.

Some time back I picked up a copy of Muller, Botany: A Functional
Approach (4th edn of 1979) from a library sale. This covers the topic in
about the degree of detail that I gave. It doesn't seem to have a
statement about the intended audience, but I had assumed that it was
targeted at freshmen life science students.

If you go to Google Book Search, and search for embryo sac in books with
Botany in the title (I searched for books published since 2000, to avoid
finding old journals) you find several books (limited preview) covering
this.

If you want much more detail you might have to go to the primary
literature - while the typical case is widely covered, all the various
variations aren't.

Regards,
Nick Maclaren.

--
Stewart Robert Hinsley