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Observações citológicas em Coffea. VII - A macrosporogênese na variedade "monosperma"

Show simple item record Bacchi, Oswaldo 2019-01-23T10:25:58Z 2019-01-23T10:25:58Z 1941
dc.identifier.citation BACCHI, O. Observações citológicas em Coffea. VII - A macrosporogênese na variedade "monosperma". Bragantia, Campinas, v. 1, n. 6, p. 483-490, 1941. pt_BR
dc.identifier.issn 1678-4499
dc.identifier.uri pt_BR
dc.description.abstract This article deals with the observations made in the ovule and development of the macrogametophyte in Coffea arabica L. var. monosperma. The young ovule is normally constituted by a rudimentary nucellus surrounded by a single and well developed integument. No irregularities are found until the beginning of the first meiotic division in the ma-crosporocyte which is situated inside the nucellus. The two meiotic divisions are very abnormal and during this process, 44,4 % of the otherwise normal macrospores degenerate. Only. a few normal macrospores are formed. The functional macrospore is not always the chalazal one as in the normal coffee varieties. Irregularities occur also in the subseguent divisions in the formation of the embryo sac. Degeneration then increased from 44,4 to 82,0%. Only one complete embryo sac has been found among the 87 examined ovules. During the formation of the embryo sac, even when complete degeneration occurs, the ovule increases in volume due to the multiplication of the integument cells. From the moment in which the embryo sac should be formed (two days after the flower opening) this increase in volume stops. A total desorganization of the ovule occurs around 105 days after the opening of the flower. pt_BR
dc.format pdf pt_BR
dc.language.iso pt_BR pt_BR
dc.publisher Instituto Agronômico (IAC) pt_BR
dc.relation.ispartofseries Bragantia;v. 1, n. 6, p. 483-490,1941;
dc.rights Open Access pt_BR
dc.subject.classification Cafeicultura::Genética e melhoramento pt_BR
dc.title Observações citológicas em Coffea. VII - A macrosporogênese na variedade "monosperma" pt_BR
dc.type Artigo pt_BR

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