Organization in non-reduced embryo sacs , Biology

Organization in non-reduced embryo sacs

The fate of a nucleus in the embryo sac depends upon its position. Many irregularities in the disposition of nuclei in the early polarization have been recorded. The mature embryo sac otherwise shows a nod organisation with two synergids, three antipodals, an egg and pro endospermic cell.

Embryogenesis in non-reduced embryo sacs

Embryo development in these embryo sacs can take place as a consequence of pollination. Those associated with pollination are called eugamous, semigamous or pseudogamous and those that develop without pollination stimulus are termed parthenogenic.

Eugamy: Normal fertilization of the apomictic eggs takes place to produce the zygote.

Semigamy: The male gamete penetrates into the egg but does not fuse with the egg nucleus. Both the nuclei multiply independently but the division of the male nucleus stops early.

Unreduced Pseudogamy: The male gamete degenerates either inside or outside the embryo sac. Thus, the egg develops without fusion taking place.

Posted Date: 1/23/2013 6:20:05 AM | Location : United States







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