Open main menu
Home
Random
Recent changes
Special pages
Community portal
Preferences
About Wikipedia
Disclaimers
Incubator escapee wiki
Search
User menu
Talk
Dark mode
Contributions
Create account
Log in
Editing
Seed
(section)
Warning:
You are not logged in. Your IP address will be publicly visible if you make any edits. If you
log in
or
create an account
, your edits will be attributed to your username, along with other benefits.
Anti-spam check. Do
not
fill this in!
=== Ovule === {{Main|Ovule}} [[File:Ovule-Gymno-Angio-en.svg|thumb|300px|Plant ovules: Gymnosperm ovule on left, angiosperm ovule (inside ovary) on right]] After fertilization, the [[Ovule|ovules]] develop into the seeds. The ovule consists of a number of components: * The '''funicle''' (''funiculus, funiculi'') or seed stalk which attaches the ovule to the [[placentation|placenta]] and hence [[Ovary (botany)|ovary]] or fruit wall, at the '''[[Fruit anatomy#Pericarp layers|pericarp]]'''. * The '''nucellus''', the remnant of the [[megasporangium]] and main region of the ovule where the megagametophyte develops. * The '''micropyle''', a small pore or opening in the apex of the integument of the ovule where the [[pollen tube]] usually enters during the process of fertilization. * The '''[[chalaza]]''', the base of the ovule opposite the micropyle, where integument and nucellus are joined.<ref>{{cite book |chapter=Chapter One |author1=Galili G |author2=Kigel J |title=Seed development and germination |publisher=M. Dekker |location=New York |year=1995 |isbn=978-0-8247-9229-9 }}</ref> The shape of the ovules as they develop often affects the final shape of the seeds. Plants generally produce ovules of four shapes: the most common shape is called '''anatropous''', with a curved shape. '''Orthotropous''' ovules are straight with all the parts of the ovule lined up in a long row producing an uncurved seed. '''Campylotropous''' ovules have a curved megagametophyte often giving the seed a tight "C" shape. The last ovule shape is called '''amphitropous''', where the ovule is partly inverted and turned back 90 degrees on its stalk (the funicle or '''funiculus'''). In the majority of flowering plants, the zygote's first division is transversely oriented in regards to the long axis, and this establishes the polarity of the embryo. The upper or chalazal pole becomes the main area of growth of the embryo, while the lower or [[micropylar]] pole produces the stalk-like suspensor that attaches to the micropyle. The suspensor absorbs and manufactures nutrients from the endosperm that are used during the embryo's growth.<ref>Raven, Peter H., Ray Franklin Evert, and Helena Curtis. 1981. ''Biology of plants''. New York: Worth Publishers. p. 410.</ref>
Edit summary
(Briefly describe your changes)
By publishing changes, you agree to the
Terms of Use
, and you irrevocably agree to release your contribution under the
CC BY-SA 4.0 License
and the
GFDL
. You agree that a hyperlink or URL is sufficient attribution under the Creative Commons license.
Cancel
Editing help
(opens in new window)