Endosperm is a nutritive tissue and contain many reserve food materials for the developing embryo .
Usually endosperm formation begins before embryo development .
The primary endosperm nucleus resulted from triple fusion divides repeatedly to form the endosperm .
So in angiosperm is a post fertilization product and it is triploid .
But in gymnosperm the endosperm is pre-fertilized product and it is haploid
TYPE OF ENDOSPERM
Depending upon the mode of its formation angiospermic endosperm is of three types are
1- Nuclear Endosperm
In this type of endosperm the nucleus of primary endosperm cell under goes repeated division with out being accompanied by wall formation .
The free nuclei are then arranged at the periphery leaving a large vacuole at the center .
Cytokinesis may begin later and proceed from the periphery to center .
It is the most common type of endosperm and found in wheat ,maize , rice , sunflower etc.
So endosperm of coconut is very unique because it contain both type of endosperm i.e. nuclear , cellular.
2- Cellular Endosperm
In this type of endosperm each and every division of the primary endosperm nucleus is followed by cytokinesis or wall formation .
The division of usually transverse but it may be vertical or oblique .
Example - datuna petunia ,peperomia etc
3- Helobial Endosperm
This type of endosperm is a intermediate type between cellular and nuclear types .
Here the first nuclear division of primary endosperm nucleus is follwed by transverse cytokinesis forming two unequal cells .
Subsequent division in both the cell are free- nuclear .
Helobial endosperm is seen is the members belonging to order helobiales of monocots.
Example- Asphodelus
So the endosperm becomes cellular from the every beginning .
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