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 | Acesso ao texto completo restrito à biblioteca da Embrapa Gado de Corte. Para informações adicionais entre em contato com biblioteca@embrapa.br. |
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Registro Completo |
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Biblioteca(s): |
Embrapa Gado de Corte. |
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Data corrente: |
15/09/2009 |
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Data da última atualização: |
19/05/2025 |
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Tipo da produção científica: |
Artigo em Periódico Indexado |
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Autoria: |
JUNQUEIRA FILHO, R. G.; MENDES-BONATO, A. B.; PAGLIARINI, M. S.; BIONE, N. C. P.; VALLE, C. B. D.; PENTEADO, M. I. de O. |
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Afiliação: |
ROBERTO GARGIONE JUNQUEIRA FILHO, UNIVERSIDADE ESTADUAL DE MARINGÁ; ANDRÉA BEATRIZ MENDES-BONATO, UNIVERSIDADE ESTADUAL DE MARINGÁ; MARIA SUELY PAGLIARINI, UNIVERSIDADE ESTADUAL DE MARINGÁ; NILTON CESAR PIRES BIONE, UNIVERSIDADE ESTADUAL DE MARINGÁ; CACILDA BORGES DO VALLE, CNPGC; MARIA ISABEL DE O PENTEADO, SPRI. |
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Título: |
Absence of microspore polarity, symmetric divisions and pollen cell fate in Brachiaria decumbens (Gramineae). |
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Ano de publicação: |
2003 |
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Fonte/Imprenta: |
Genome, v. 46, n. 1, p. 83-88, Feb. 2003. |
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DOI: |
https://doi.org/10.1139/g02-114 |
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Idioma: |
Inglês |
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Conteúdo: |
ABSTRACT - Meiotic division and male gametophyte development were analyzed in one tetraploid (2n = 4x = 36) accession of Brachiaria decumbens cv. Basilisk that showed some pollen sterility. Meiotic process was typical of polyploids in that it consisted of multiple chromosome associations. Precocious chromosome migration to the poles, laggards, and micronucleus formation were abundant in both meiosis I and II and resulted in tetrads with micronuclei. After callose dissolution, microspores were released into the anther locule and had the semblance of being normal. Although each microspore initiated its differentiation by pollen mitosis, in 43.24% of the microspores, nuclear polarization was not observed and the typical hemispherical cell plate was not detected. Division was symmetric and microspores lacked differentiation between the vegetative and the generative cell. Both nuclei were of equal size, presented equal chromatin condensation, and had a spherical shape. After the first pollen mitosis and cytokinesis, each cell underwent a new symmetric mitosis without nuclear polarization. At the end of the second pollen mitosis, four equal nuclei were observed in each pollen grain. After the second cytokinesis, the cells gave rise to four equal-sized pollen grains with a similar tetrad configuration that initially remained together. Sterile pollen grains resulted from abnormal pollen mitosis. This anomaly may be explained by a mutation, probably affecting microtubule cytoskeleton formation. The importance of this male-sterile mutation for Brachiaria breeding programs is discussed. MenosABSTRACT - Meiotic division and male gametophyte development were analyzed in one tetraploid (2n = 4x = 36) accession of Brachiaria decumbens cv. Basilisk that showed some pollen sterility. Meiotic process was typical of polyploids in that it consisted of multiple chromosome associations. Precocious chromosome migration to the poles, laggards, and micronucleus formation were abundant in both meiosis I and II and resulted in tetrads with micronuclei. After callose dissolution, microspores were released into the anther locule and had the semblance of being normal. Although each microspore initiated its differentiation by pollen mitosis, in 43.24% of the microspores, nuclear polarization was not observed and the typical hemispherical cell plate was not detected. Division was symmetric and microspores lacked differentiation between the vegetative and the generative cell. Both nuclei were of equal size, presented equal chromatin condensation, and had a spherical shape. After the first pollen mitosis and cytokinesis, each cell underwent a new symmetric mitosis without nuclear polarization. At the end of the second pollen mitosis, four equal nuclei were observed in each pollen grain. After the second cytokinesis, the cells gave rise to four equal-sized pollen grains with a similar tetrad configuration that initially remained together. Sterile pollen grains resulted from abnormal pollen mitosis. This anomaly may be explained by a mutation, probably affecting microtubule cytoskeleton... Mostrar Tudo |
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Palavras-Chave: |
Braquiária. |
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Thesagro: |
Brachiaria Decumbens; Gramínea; Melhoramento Genético Vegetal; Mitose; Pastagem. |
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Thesaurus Nal: |
Grasses; Microspores; Mitosis; Plant breeding. |
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Categoria do assunto: |
F Plantas e Produtos de Origem Vegetal |
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Marc: |
null
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Registro original: |
Embrapa Gado de Corte (CNPGC) |
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| 1. |  | OLIVELLA, J. A. P.; SOUZA, M. L. de; COY-BARRERA, E.; PÉREZ, J. F. B.; VALENCIA, J. W. A. The cytotoxic activity of crude aqueous Annona plant-derived extracts on Spodoptera frugiperda, cell lines. Journal of Hunan University (Natural Sciences), v. 48, N. 6, p. 252-263, 2021.| Tipo: Artigo em Periódico Indexado | Circulação/Nível: B - 5 |
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