What forms the endosperm of a gymnosperm seed?

  • Thread starter Thread starter Suraj M
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Discussion Overview

The discussion centers around the formation of the endosperm in gymnosperm seeds, exploring the origins and developmental processes involved. Participants examine the relationship between the megagametophyte and the endosperm, as well as the role of the nucellus in food transfer.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant questions whether the endosperm of a gymnosperm seed is formed from the three other macrospores that do not develop into archegonia.
  • Another participant asserts that the primary endosperm is haploid and derived from the megagametophyte, specifically mentioning its origin from the megaprothallium in seed ferns.
  • A participant expresses confusion about the relationship between the formation of primary endosperm and the production of archegonia by the megagametophyte.
  • One participant clarifies that primary endosperm must derive from mitosis and neighboring haploid tissue, confirming that the megagametophyte contributes to both endosperm formation and archegonia production.

Areas of Agreement / Disagreement

Participants express differing views on the specific origins of the endosperm and its relationship with the megagametophyte, indicating that the discussion remains unresolved with multiple competing perspectives.

Contextual Notes

There are limitations regarding the definitions of terms such as "primary endosperm" and "megagametophyte," as well as the specific processes involved in their formation, which remain unclear among participants.

Suraj M
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What forms the endosperm of a gymnosperm seed?? Some book said the 3 other macrospores which don't form the archegonia. I sthat right?
i just know that the stored food is transferred from the nucellus, but where does the diploid endosperm emerge from?
 
Primary endosperm (haploid tissue (n) ) is derived from the megagametophyte. The ontogenesis of primary endosperm is believed to derive from the megaprothallium in seed ferns. So, I do not know where your idea came from. See here:
http://www.seedbiology.de/evolution.asp#jurassic
 
oH . thanks for the link!
But what i don't still understand is that, the megagametophyte forms the prim. endosperm and also produces the archegonia!??
jim mcnamara said:
So, I do not know where your idea came from
Are you referring to the formation of endosperm from the rest of the 3 megaspores or that the food is transferred to the endosperm from the nucellus?
 
Endo sperm formation. Primary endosperm is haploid. It has to derive from mitosis. It has to derive from "neighboring" haploid tissue. That is the only point I'm making. The answer to your second question is: yes you understand correctly. It forms both.

Megagametogenesis in gynospermae: http://en.wikipedia.org/wiki/Megaspore
 

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