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	Provedor de dados Genet. Mol. Biol. (2) Autor Bertasso-Borges,Maristela Sanches (2) Coleman,James Robert (2) Palavra-chave Apomixis (1) Asteraceae (1) Eupatorium (1) Plant cytogenetics (1) Plant embryology (1) Tipo do documento Info:eu-repo/semantics/article (2) Ano 2005 (1) 1998 (1) País Brazil (2) Idioma Inglês (2)		Ordenar por:  Relevância Autor Título Ano Registros recuperados: 2 Primeira ... 1 ... Última Cytogenetics and embryology of Eupatorium laevigatum (Compositae) Genet. Mol. Biol. Bertasso-Borges,Maristela Sanches; Coleman,James Robert. Embryological studies indicate Eupatorium laevigatum to have Antennaria type diplospory with precocious embryony. The embryo sac is of the Polygonum type and the polar nuclei fuse before anthesis (maturation of the stamens). Endosperm development is autonomous and the central cell divides only after the initial stages of embryo formation. It is estimated that about 10% of the florets in anthesis contain an undivided egg which can be used for sexual reproduction. The study of microsporogenesis revealed abnormalities in chromosome pairing which result in the formation of univalents, bivalents, trivalents and higher polyvalents, with the consequent production of lagging chromosomes, unbalanced nuclei, micronuclei and sterile pollen. We found that, as... Tipo: Info:eu-repo/semantics/article Palavras-chave: Eupatorium; Apomixis; Plant cytogenetics; Plant embryology; Asteraceae. Ano: 2005 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572005000100022 Embryology and cytogenetics of Eupatorium pauciflorum and E. intermedium (Compositae) Genet. Mol. Biol. Bertasso-Borges,Maristela Sanches; Coleman,James Robert. The embryology of Eupatorium pauciflorum indicates diplospory with autonomous endosperm development. The embryo sac is of the polygonum type and the polar nuclei mostly fuse before anthesis. The occurrence of precocious embryo and endosperm development in unopened florets, and the total absence of germinated pollen grains on exposed stigmas, as well as the absence of pollen tubes in the ovules, indicate agamospermy to be obligate and embryo and endosperm development autonomous. The study of microsporogenesis revealed the total absence of pollen production in consequence of microsporocyte degeneration before the onset of meiosis, which resulted in absolute male sterility. E. pauciflorum was demonstrated to be an autotriploid with a basic set of 10... Tipo: Info:eu-repo/semantics/article Ano: 1998 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571998000400017 Registros recuperados: 2 Primeira ... 1 ... Última

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