Structure and function of the hypertrophic synergid in some species of genus Allium L.

Proceedings of the Georgian Academy of Sciences, Biology, Ser. B ISSN 1512 - 2123 01/2006; 4(2):53-60.

ABSTRACT The egg cell in the embryo sac of flowering plants is generally accompanied by two symmetrical cells, called synergid cells, which usually contains haploid nucleus. However, in some species of genus Allium L. mainly one and sometimes both of the synergid cells enlarge in size, undergo endopolyploidization and become hypertrophic. We have studied structure of the synergid cells of Allium atroviolaceum Boiss., A. rotundum L., A. fistulosum L. and A. cepa L. and determined DNA amount (C value) in the synergid cells of A. atroviolaceum. Cytophotometric study of various Feulgen-stained synergid and integument nuclei revealed clear difference in DNA content both in different types of the cells and in different stages of synergid development. The amount of DNA measured in newly formed synergid was already equal to 2C value found in the integument cell nucleus. At the time of fertilization the DNA amount in synergid is 4C. At the stage of proembryo it is already 6C and before degeneration at the late globular stage of embryo development 8C. No sign of mitotic cell division or formation of metaphase plate have been observed in any of investigated materials. It is assumed that endopolyploidization might determine longer persistent of intact synergid and increase of its trophic function.

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  • Plant Systematics and Evolution - PLANT SYST EVOL. 01/1957; 104:1-24.
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