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| 8. |  | PAGLIARINI, M. S.; RISSO-PASCOTTO, C.; SOUZA-KANESHIMA, A. M. de; VALLE, C. B. do. Analysis of meiotic behavior in selecting potential genitors among diploid and artifcially induced tetraploid accessions of Brachiaria ruziziensis (Poaceae). Euphytica, Wageningen, Holanda, v. 164, n.1 , p. 181-187, nov. 2008.| Biblioteca(s): Embrapa Gado de Corte. |
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| 20. | | BOLDRINI, K. R.; MICHELETTI, P. L.; RISSO-PASCOTTO, C.; ADAMOWSKI, E. V.; PAGLIARINI, M. S.; VALLE, C. B. Um novo mecanismo de formação de gametas 2n em Brachiaria (POACEAE). In: CONGRESSO BRASILEIRO DE GENÉTICA, 51., 2005, Águas de Lindóia. Da Bioestatística à Bioinformática - a era da Genômica: [anais]. Águas de Lindóia: Sociedade Brasileira de Genética, 2005. p. 523 1 CD-ROM.| Biblioteca(s): Embrapa Gado de Corte. |
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 | Acesso ao texto completo restrito à biblioteca da Embrapa Gado de Corte. Para informações adicionais entre em contato com cnpgc.biblioteca@embrapa.br. |
Registro Completo
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Biblioteca(s): |
Embrapa Gado de Corte. |
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Data corrente: |
30/09/2009 |
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Data da última atualização: |
13/10/2009 |
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Autoria: |
RISSO-PASCOTTO, C.; PAGLIARINI, M. S.; VALLE, C. B. do; JANK, L. |
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Afiliação: |
C. RISSO-PASCOTTO, UEM; MARIA SUELY PAGLIARINI, UEM; CACILDA BORGES DO VALLE, CNPGC; LIANA JANK, CNPGC. |
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Título: |
Symmetric pollen mitosis I and suppression of pollen mitosis II prevent pollen development in Brachiaria jubata (Gramineae). |
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Ano de publicação: |
2005 |
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Fonte/Imprenta: |
Brazilian Journal of Medical and Biological Research, Ribeirão Preto, v.38, n.11, p. 1603-1608, nov. 2005. |
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Idioma: |
Português |
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Conteúdo: |
Microsporogenesis and pollen development were analyzed in a tetraploid (2n = 4x = 36) accession of the forage grass Brachiaria jubata
(BRA 007820) from the Embrapa Beef Cattle Brachiaria collection that showed partial male sterility. Microsporocytes and pollen grains
were prepared by squashing and staining with 0.5% propionic carmine. The meiotic process was typical of polyploids, with precocious
chromosome migration to the poles and laggards in both meiosis I and II, resulting in tetrads with micronuclei in some microspores. After
callose dissolution, microspores were released into the anther locule and appeared to be normal. Although each microspore initiated its
differentiation into a pollen grain, in 11.1% of them nucleus polarization was not observed, i.e., pollen mitosis I was symmetric and the
typical hemispherical cell plate was not detected. After a central cytokinesis, two equal-sized cells showing equal chromatin condensation
and the same nuclear shape and size were formed. Generative cells and vegetative cells could not be distinguished. These cells did
not undergo the second pollen mitosis and after completion of pollen wall synthesis each gave rise to a sterile and uninucleate pollen grain.
The frequency of abnormal pollen mitosis varied among flowers and also among inflorescences. All plants were equally affected. The
absence of fertile sperm cells in a considerable amount of pollen grains in this accession of B. jubata may compromise its use in breeding and
could explain, at least in part, why seed production is low when compared with the amount of flowers per raceme. MenosMicrosporogenesis and pollen development were analyzed in a tetraploid (2n = 4x = 36) accession of the forage grass Brachiaria jubata
(BRA 007820) from the Embrapa Beef Cattle Brachiaria collection that showed partial male sterility. Microsporocytes and pollen grains
were prepared by squashing and staining with 0.5% propionic carmine. The meiotic process was typical of polyploids, with precocious
chromosome migration to the poles and laggards in both meiosis I and II, resulting in tetrads with micronuclei in some microspores. After
callose dissolution, microspores were released into the anther locule and appeared to be normal. Although each microspore initiated its
differentiation into a pollen grain, in 11.1% of them nucleus polarization was not observed, i.e., pollen mitosis I was symmetric and the
typical hemispherical cell plate was not detected. After a central cytokinesis, two equal-sized cells showing equal chromatin condensation
and the same nuclear shape and size were formed. Generative cells and vegetative cells could not be distinguished. These cells did
not undergo the second pollen mitosis and after completion of pollen wall synthesis each gave rise to a sterile and uninucleate pollen grain.
The frequency of abnormal pollen mitosis varied among flowers and also among inflorescences. All plants were equally affected. The
absence of fertile sperm cells in a considerable amount of pollen grains in this accession of B. jubata may compromise its use in breeding and
c... Mostrar Tudo |
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Palavras-Chave: |
Brachiaria jubata; Braquiária; Microsporogênese. |
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Thesagro: |
Gramínea Forrageira; Melhoramento Genético Vegetal; Pastagem. |
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Categoria do assunto: |
F Plantas e Produtos de Origem Vegetal |
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Marc: |
LEADER 02366naa a2200229 a 4500
001 1512794
005 2009-10-13
008 2005 bl --- 0-- u #d
100 1 $aRISSO-PASCOTTO, C.
245 $aSymmetric pollen mitosis I and suppression of pollen mitosis II prevent pollen development in Brachiaria jubata (Gramineae).
260 $c2005
520 $aMicrosporogenesis and pollen development were analyzed in a tetraploid (2n = 4x = 36) accession of the forage grass Brachiaria jubata (BRA 007820) from the Embrapa Beef Cattle Brachiaria collection that showed partial male sterility. Microsporocytes and pollen grains were prepared by squashing and staining with 0.5% propionic carmine. The meiotic process was typical of polyploids, with precocious chromosome migration to the poles and laggards in both meiosis I and II, resulting in tetrads with micronuclei in some microspores. After callose dissolution, microspores were released into the anther locule and appeared to be normal. Although each microspore initiated its differentiation into a pollen grain, in 11.1% of them nucleus polarization was not observed, i.e., pollen mitosis I was symmetric and the typical hemispherical cell plate was not detected. After a central cytokinesis, two equal-sized cells showing equal chromatin condensation and the same nuclear shape and size were formed. Generative cells and vegetative cells could not be distinguished. These cells did not undergo the second pollen mitosis and after completion of pollen wall synthesis each gave rise to a sterile and uninucleate pollen grain. The frequency of abnormal pollen mitosis varied among flowers and also among inflorescences. All plants were equally affected. The absence of fertile sperm cells in a considerable amount of pollen grains in this accession of B. jubata may compromise its use in breeding and could explain, at least in part, why seed production is low when compared with the amount of flowers per raceme.
650 $aGramínea Forrageira
650 $aMelhoramento Genético Vegetal
650 $aPastagem
653 $aBrachiaria jubata
653 $aBraquiária
653 $aMicrosporogênese
700 1 $aPAGLIARINI, M. S.
700 1 $aVALLE, C. B. do
700 1 $aJANK, L.
773 $tBrazilian Journal of Medical and Biological Research, Ribeirão Preto$gv.38, n.11, p. 1603-1608, nov. 2005.
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