tailieunhanh - Embryological studies on Trichloris (Poaceae, Chloridoideae)

The present study provides information on the development of the female and male gametophytes and seed ontogeny characteristics for Trichloris, and it discusses their taxonomic significance to the family Poaceae. | Turkish Journal of Botany Turk J Bot (2018) 42: 568-580 © TÜBİTAK doi: Research Article Embryological studies on Trichloris (Poaceae, Chloridoideae) 1,2, 1,2 Geraldina Alicia RICHARD 3 1 * , María Carolina CERINO , Beatriz Gloria GALATI , Eliana De Luján EXNER , 1,2 José Francisco PENSIERO 1 Department of Plant Biology, Faculty of Agricultural Sciences, National University of the Littoral (Universidad Nacional del Litoral, in Spanish), Esperanza, Argentina 2 National Council of Scientific and Technical Research, Buenos Aires, Argentina 3 Department of Natural Resources and Environment, Faculty of Agriculture, National University of Buenos Aires (Universidad Nacional de Buenos Aires, in Spanish), Buenos Aires, Argentina Received: Accepted/Published Online: Final Version: Abstract: The present study provides information on the development of the female and male gametophytes and seed ontogeny characteristics for Trichloris, and it discusses their taxonomic significance to the family Poaceae. Trichloris species are characterized by having 2–3 stamens per floret, tetrasporangiate anthers, a monocotyledonous development of the anther wall, a single middle layer of common origin with the tapetum, fibrous thickening in the cell walls of the endothecium, and a secretory tapetum. These characteristics are constant within Poaceae. The possession of bitegmic and tenuinucellate ovules, laterally positioned antipodals prior to their degeneration, a free exocarp, and an epiblast in the mature embryos gives Trichloris the typical characteristics described for other members of the subfamily Chloridoideae. The degradation of tapetal cells before the maturation of the pollen grain and the absence of aborted ovules indicate a high fertility rate, which is an important feature for perennial halophytes such Trichloris that do not possess elaborate seed dormancy systems. Key words: .