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Media type:
E-Article
Title:
Embryology of Helianthus annuus (Asteraceae)
Contributor:
Gotelli, Marina M.;
Galati, Beatriz G.;
Medan, Diego
imprint:
Finnish Zoological and Botanical Publishing Board, 2008
Published in:Annales Botanici Fennici
Language:
English
ISSN:
0003-3847;
1797-2442
Origination:
Footnote:
Description:
<p>Abortion of sunflower fruits during different phases of their development could be due to abnormalities in the reproductive process. We report a comparative study of the sporogenesis, gametogenesis and the development of the related sporophytic structures in three commercial hybrids, DK 4050, CF 17 and P30, and a line, HA 89. The anther wall consists of epidermis, endothecium, one middle layer and a plasmodial tapetum with binucleate cells before integrating. A peritapetal membrane with orbicules encloses the pollen grains, which are triporate, angulaperturate and shed at tricellular stage. HA 89 also presents tetraporate pollen grains. The ovule is tenuinucellate, unitegmic and anatropous. The young female gametophyte consists of six cells and eight nuclei. Antipodals, which vary in number and in the number of nuclei in each cell, usually have thick walls between themselves and the central cell. Differences among the genotypes studied may explain the contradictions found on previous accounts.</p>