Atypical embryo sacs in Allium cepa L.

Bulletin of the Georgian National Academy of Sciences ISSN - 0132 - 1447 01/2005; 171(2):312-314.

ABSTRACT Atypical embryo sacs have been revealed in Allium cepa L. The structural changes in Allium type
embryo sac in this species take place in all three groups of cells – egg apparatus, central cell and
antipodals. The following atypical developmental patterns have been observed: 1. Variation in the
number of egg cells (1-3), synergids (1-6), polar nuclei (2-4) and antipodals (3-5); 2.
Transformation of synergids and antipodals into additional egg cell; 3. Hypertrophy of more than
one synergid and antipodals. It is assume that increase in the number of hypertrophic synergids and
antipodals may improve nutrition of the developing embryo. And, the formation of additional egg
cells derived from synergids or antipodals may increase probability that the ovule produces a seed.
The additional embryos might be formed from egg-like synergids and antipodal cells. The increase
in the number of cells in the embryo sac may be explained by mutations leading to the normal
mitotic divisions in synergids and antipodals instead of endomitosis occurring during hypertrophy.
In general, the female gametophyte in this species shows tendency in increase of structures
responsible for seed formation.

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  • Embryology of Angiosperms. I S Modilevski .
  • Comparative Embryology of Flowering Plants. I I Shamrov . 76-83.


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Feb 2, 2014