Microsporogenesis
Mostrando 1-12 de 28 artigos, teses e dissertações.
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1. Evidence of accelerated and altered pollen development after Imazapyr treatment in resistant sunflower
ABSTRACT Imazapyr (IM) treatment applied at early reproductive developmental stages have been associated with induced male sterility in sunflower (Helianthus annuus L.). The aim of this work was to determine the effects induced by two different doses of IM-treatment (1X and 2X; 80 and 160 g a.i.·ha-1) on pollen grain yield, pollen viability and on the exine
Bragantia. Publicado em: 2020-03
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2. Meiotic behavior in apomictic Brachiaria ruziziensis × B. brizantha (Poaceae) progenies
Hybrids combining desirable traits from divergent parents are the main objective of some Brachiaria (Syn. Urochloa P. Beauv.) breeding programs. There is great interest in the development of apomictic hybrid cultivars that combine desirable genes such as resistance to spittlebugs, high nutritive value, and tolerance to acid soils. Microsporogenesis of six ap
Sci. agric. (Piracicaba, Braz.). Publicado em: 2012-12
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3. Failure of cytokinesis and 2n gamete formation in Brazilian accessions of Paspalum.
Cytological analysis on 112 Brazilian accessions of Paspalum showed that 52 were affected by failure of first or second cytokinesis during microsporogenesis. When the failure of cytokinesis occurred only in the first division and in the second division the cytokinesis was normal, a dyad of microspores was formed. In most of them the two cells remained binucl
Euphytica. Publicado em: 2011
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4. Chromosome stickiness in meiosis of a brazilian Paspalum accession.
Citogenetic studies carried out over a period of 2 consecutive years on a still unidentified Brazilian accession of Paspalum (BRA-014176) revealed a meiotic mutation causing chromose stickiness in microsporogenis. In all inflorescences collected in both years, meiosis was normal until diakinesis. Chromosome stikiness became evident from metaphase I, whwn the
Cytologia. Publicado em: 2011
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5. Chromosome number and microsporogenesis in Paspalum maritimum (Caespitosa Group; Gramineae).
Despite pf economic importance of the genus Paspalum, little or no cytologic information is available for many species. This is the first report about chromosome munber and meiotic behavior for P. maritimum. The three accessions colected in Amapa State (North Region of Brazil) were tetraploid (2n=4x=40) with the chromossomes associating predominantly as biva
Brazilian Archives of Biology and Technology. Publicado em: 2011
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6. Morphological markers for microspore developmental stage in maize
A utilização do milho (Zea mays) na cultura de anteras é limitada devido ao baixo número de genótipos com alto potencial androgenético. A obtenção de micrósporos no estádio de desenvolvimento apropriado no início da cultura é um dos fatores cruciais para o sucesso do processo androgenético. Em genótipos brasileiros de milho não existem estudos
Publicado em: 2011
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7. Abnormal spindle orientation during microsporogenesis in an interspecific Brachiaria (Gramineae) hybrid
This paper reports a case of abnormal spindle orientation during microsporogenesis in an interspecific hybrid of the tropical grass Brachiaria. In the affected plant, prophase I was normal. In metaphase I, bivalents were regularly co-oriented but distantly positioned and spread over the equatorial plate. In anaphase I, chromosomes failed to converge into foc
Genetics and Molecular Biology. Publicado em: 2006
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8. Cytogenetic evidence for genome elimination during microsporogenesis in interspecific hybrid between Brachiaria ruziziensis and B. brizantha (Poaceae)
Microsporogenesis was analyzed in an interspecific hybrid between an artificially tetraploidized sexual accession of Brachiaria ruziziensis (R genome) and a natural apomictic tetraploid accession of B. brizantha (B genome). Chromosomes associated predominantly as bivalents. From this phase to the end of meiosis, chromosomes presented irregular segregation an
Genetics and Molecular Biology. Publicado em: 2006
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9. Castor bean (Ricinus communis l.): cultura de antera, pollen viability and conservation / Mamona (Ricinus communis L.): cultura de antera, viabilidade e conservação de pólen
A mamona (Ricinus communis L.) apresenta diversas aplicações econômicas, entre elas, destaca-se a produção do óleo indicado como matéria prima para produção de Biodiesel. Na tentativa de conservar e caracterizar as variedades de mamona a análise de fertilidade torna-se de grande importância para dimensionar a heterogeneidade destas cultivares e co
Publicado em: 2006
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10. Symmetric pollen mitosis I and suppression of pollen mitosis II prevent pollen development in Brachiaria jubata (Gramineae)
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
Brazilian Journal of Medical and Biological Research. Publicado em: 2005-11
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11. Cytogenetics and embryology of Eupatorium laevigatum (Compositae)
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 tha
Genetics and Molecular Biology. Publicado em: 2005-03
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12. DISTRIBUIÇÃO DA VARIABILIDADE GENÉTICA EM POPULAÇÕES NATURAIS DE Baccharis trimera (Less) DC. (CARQUEJA) NO SUL DO BRASIL. / GENETIC VARIABILITY DISTRIBUTION IN NATURAL POPULATIONS OF Baccharis trimera (Less) DC. (CARQUEJA) IN SOUTHERN BRAZIL
Carqueja (Baccharis trimera) is a native plant from South America, occurs in several settings, it is highly employed in popular medicine, and has been explored under a grasping way. This study had the purpose of producing information for the establishment of adequate strategies to the conservation of genetic resources of this specie. Assuming this, one searc
Publicado em: 2004