159 resultados para Orchid
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Tutkielmassani tarkastelen, miten teokset Wide Sargasso Sea (1966) ja The Orchid House (1953) käsittelevät kulttuuri-identiteettiä henkilöhahmojen luonnissa sekä millaisia yhtäläisyyksiä ja eroja näissä esiintyy. Kulttuuri-identiteetti on yksi jälkikoloniaalisen kirjallisuudentutkimuksen keskeisimmistä teemoista. Tarkastelen tekstejä kahden keskeisen teeman kautta: nimet ja maisemakuvaukset. Molemmat teokset käyttävät näitä teemoja monipuolisesti eri identiteetin osa-alueiden kuvaamiseen. Tarkasteluni keskittyy pääasiassa teosten naispäähahmoihin, mutta käsittelen soveltuvilta osin myös muita henkilöhahmoja. Monet Jean Rhysia ja Phyllis Shand Allfreyta tutkineet kirjallisuuskriitikot ovat olleet haluttomia näkemään teosten välillä olevan yhteyden. Wide Sargasso Sean intertekstuaalinen yhteys Charlotte Brontën teokseen Jane Eyre onkin usein jättänyt hienovaraisemmat intertekstuaaliset viittaukset varjoonsa. Viimeisimpien vuosien aikana on jälkikoloniaalisen kirjallisuudentutkimuksen saralla kuitenkin ollut havaittavissa myönteisempää suhtautumista myös näihin intertekstuaalisiin viittauksiin. Lähtökohtani teosten tarkasteluun on jälkikoloniaalinen kirjallisuudentutkimus ja ensisijaisia teoreettisia lähteitäni ovat muun muassa Patrick Hoganin ja Stuart Hallin käsitykset jälkikoloniaalisesta kulttuuri-identiteetistä. Tarkastelen pääasiallisesti Karibian alueen valkoisten kreolien kulttuuri-identiteettiä. Koska kummankin teoksen keskeisimmät henkilöhahmot ovat pääasiassa naisia, myös naisnäkökulma tulee esiin tutkielmassani. Tutkielmastani käy ilmi, että teosten välillä on selkeä yhteys siinä, millaisia välineitä käytetään kulttuuri-identiteetin kuvaamiseen. Teokset liittyvät kiinteästi dominicalaiseen kirjallisuusperinteeseen, mutta yhteneväisyyksiä on havaittavissa siinä määrin, ettei niitä pystytä selittämään pelkästään samankaltaisella kulttuurisella taustalla.
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Considering the performance of CAM epiphytes under high levels of radiation or in shaded environments, with growth rate proportional to light intensity, the objective of this work was to evaluate the effects of long-term light stress on the growth of a Brazilian epiphytic orchid, Cattleya forbesii Lindl. X Laelia tenebrosa Rolfe. Two groups of plants were used in the first experiment, one under 90% (@ 1,650 µmol.m-2.s-1) of Photosynthetically Active Radiation (PAR) and the other maintained under 22.5% (@ 400 µmol.m-2.s-1). In the second experiment the diffusive resistance, transpiration rate and fluorescence levels were monitored for plants that were under 22.5% of PAR, under 90% and plants transferred from 22.5 to 90%. Our results show that light intensity interfered with growth and development of this orchid. Data on the changes in pseudobulb volume throughout the time course of growth suggest that water and reserves stored in the back shoots are translocated to the current shoot. Regarding stomatal resistance, plants under 22.5% of PAR reached a largest stomatal aperture during the night, whereas those under 90% only after dawn. After transfer from 22.5% PAR to 90% PAR the ratio of Fv/Fm decreased from approximately 0.8 to 0.7. This suggests the limitation of photoprotection mechanisms in the leaf and the results observed after the transfer of plants from 22.5% to 90% reinforce the possibility that a photoinhibition is reflected in a decrease in growth rate.
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Background and Aims Highly variable, yet possibly convergent, morphology and lack of sequence variation have severely hindered production of a robust phylogenetic framework for the genus Ophrys. The aim of this study is to produce this framework as a basis for more rigorous species delimitation and conservation recommendations. Methods Nuclear and plastid DNA sequencing and amplified fragment length polymorphism (AFLP) were performed on 85 accessions of Ophrys, spanning the full range of species aggregates currently recognized. Data were analysed using a combination of parsimony and Bayesian tree-building techniques and by principal coordinates analysis. Key Results Complementary phylogenetic analyses and ordinations using nuclear, plastid and AFLP datasets identify ten genetically distinct groups (six robust) within the genus that may in turn be grouped into three sections (treated as subgenera by some authors). Additionally, genetic evidence is provided for a close relationship between the O. tenthredinifera, O. bombyliflora and O. speculum groups. The combination of these analytical techniques provides new insights into Ophrys systematics, notably recognition of the novel O. umbilicata group. Conclusions Heterogeneous copies of the nuclear ITS region show that some putative Ophrys species arose through hybridization rather than divergent speciation. The supposedly highly specific pseudocopulatory pollination syndrome of Ophrys is demonstrably 'leaky', suggesting that the genus has been substantially over-divided at the species level.
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Euglossa fimbriata is a euglossine species widely distributed in Brazil and occurring primarily in Atlantic Forest remnants. In this study, the genetic mitochondrial structure of E. fimbriata from six Atlantic Forest fragments was studied by RFLP analysis of three PCR-amplified mtDNA gene segments (16S, COI-COII, and cyt b). Ten composite haplotypes were identified, six of which were exclusive and represented singleton mitotypes. Low haplotype diversity (0.085-0.289) and nucleotide diversity (0.000-0.002) were detected within samples. AMOVA partitioned 91.13% of the overall genetic variation within samples and 8.87% (I center dot(st) = 0.089; P < 0.05) among samples. Pairwise comparisons indicated high levels of differentiation among some pairs of samples (I center dot(st) = 0.161-0.218; P < 0.05). These high levels indicate that these populations of E. fimbriata, despite their highly fragmented landscape, apparently have not suffered loss of genetic variation, suggesting that this particular population is not currently endangered.
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Epidendrum fulgens has a patchy distribution along the Atlantic Rainforest in the Brazilian coast, due to the destruction of its native habitat. Here, we report on both the development of nine new microsatellite markers isolated from this species and the characterization of their allele variability in two distant and unrelated populations. The number of alleles observed for each locus ranged from 2 to 17 with an average of 6.4 alleles per locus. These microsatellites should be valuable tools for studying the effect of habitat fragmentation on the genetic structure of E. fulgens populations.
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Epidendrum puniceoluteum is an endemic orchid of Atlantic Rainforest, restricted to few populations only due to the destruction and fragmentation of its native habitat. Here, we report on the development of 10 microsatellite markers isolated from this orchid species. Genetic variability was characterized in two distant populations from Brazil coast. The number of alleles observed for each locus ranged from two to 12 and with an average of 6.4 alleles per locus. These microsatellites should be valuable tools for studying both fine-scale genetic structure of scattered E. puniceoluteum population and patterns will be useful genetic markers for other closely related taxa.
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One of the most significant challenges confronting orchid researchers is the lack of specific molecular markers, mainly for species in the Neotropics. Here we report the first set of specific chloroplast microsatellite primers (cpSSR) developed for Neotropical orchids. In total, nine polymorphic cpSSR loci were isolated and characterized in four species occurring in the Brazilian Atlantic Rainforest: Epidendrum cinnabarinum, E. denticulatum, E. fulgens and E. puniceoluteum. Levels of intraspecific polymorphism were characterized using two populations for each species, with 13-20 individuals each. Allele numbers varied from two to three per locus, while the number of haplotypes ranged from three to six per species. Extensive differentiation among the taxa was detected. All markers were successfully cross-amplified in eight other different genera. These cpSSRs markers will enable novel insights into the evolution of this important Neotropical genus.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Entre as maiores aplicações da cultura de tecidos de plantas está a propagação massal de mudas de plantas ornamentais. O objetivo deste trabalho foi avaliar o cultivo in vitro de um híbrido de orquídea Brassocattleya em diferentes concentrações de NH4NO3, KNO3 e BAP. Foram utilizadas sementes do híbrido de orquídea Brassocattleya 'Pastoral' e as plantas foram cultivadas em meio MS com redução pela metade das fontes de P, Mg e Ca e adição de 25 g L-1 de sacarose, 100 mg L-1 de mio-inositol, 1,5 g L-1 de carvão ativo e 6,5 g L-1 de ágar-ágar, sendo o pH ajustado para 5,8. Como tratamentos foram usados quatro concentrações dos sais NH4NO3 e KNO3 (2x; 1x; ½ e ¼ do meio MS) e três concentrações de BAP (0,0; 0,5 e 1,0 mg L-1). Avaliou-se a multiplicação, o crescimento em altura, massa fresca e seca, além dos teores de açucares redutores na massa seca das mudas. Observou-se grande influência das doses de NH4NO3 e KNO3 sobre o crescimento em altura das mudas, massa fresca e seca e teores de açucares redutores em Bc. ('Pastoral' x Auto). A dose de ¼ da utilizada no meio MS promoveu aumento significativo do crescimento das plantas. Para multiplicação, houve melhor resultado com a dose de ½ dos sais NH4NO3 e KNO3 utilizados no meio MS e 1,0 mg L-1 de BAP.
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O setor de floricultura movimenta cerca de um bilhão de dólares no Brasil e o desenvolvimento de técnicas direcionadas ao controle do florescimento é necessário. O presente trabalho avaliou a influência do ácido giberélico (GA3) no desenvolvimento vegetativo e reprodutivo de plantas jovens de Phalaenopsis FSNT 'Dai-Itigo', híbrido de coloração rósea. A aplicação do GA3 foi feita via pulverização foliar nas concentrações de 0, 125, 250, 500 e 1.000 mg L -1. O comprimento das folhas aumentou consideravelmente com o uso do GA3 em baixas concentrações, porém houve diminuição da largura foliar das plantas tratadas com esse fitorregulador. A aplicação do GA3 na concentração de 125 mg L -1 apresentou os melhores resultados para a promoção do florescimento e qualidade da floração deste híbrido de orquídea. Nesse tratamento, aproximadamente 50% das plantas pulverizadas apresentaram floração cerca de 6-12 meses antes da floração das plantas sem aplicação do fitorregulador. em conclusão, a qualidade da floração e das flores foi melhor no tratamento com 125 mg L -1 de GA3.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Flowering phenology, breeding system and nectary structure of Corymborkis flava (Sw.) Kuntze were studied in a fragment of the Atlantic Forest in south-eastern Brazil. The flowering period extended from March (end of rainy season) to early June and seed dispersal occurred from June to September (dry season). Flowering peak occurred mainly in April, with up to 34 open flowers per plant being observed. The yellow, odourless and tubular flowers lasted similar to 7.8 days. The flowers present a perigonal nectary located in the basal lateral parts of the labellum; this is the first report on the nectary location and characterisation in the Tropidieae tribe. At the pre-anthesis stage, cells of both secretory parenchyma and epidermis of the nectary are filled with compound amyloplasts. However, starch grains were not observed in these tissues in senescent flowers, indicating that these starch grains are hydrolysed and used as source of sugars for nectar production. The nectar accumulates between the cuticle and the outer periclinal wall of the epidermal cells before. owing out into the nectar chamber. C. flava is a self-compatible species and spontaneous self-pollination does not occur because of hercogamy. The high pollinia removal (0.80) and insertion (0.82) per flower, as well as the high natural fruit-set indicate an efficient natural pollination system. The present study contributes for the knowledge of the diversity of reproductive strategies and nectary structures in Orchidaceae.
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A floristic survey for the family Orchidaceae was undertaken in a coastal forest area of ca. 8 km2 in the Picinguaba Development Center of the Serra do Mar State Park, in the municipality of Ubatuba, Brazil. The sampling used all tracks and roads of the area, up to the altitude of 50 m.s.m. and resulted in 77 species distributed in 45 genera. The spacial distribution of the species was plotted in maps of the nine physiognomical units identified for the area, based on 1:8.000 and 1:25.000 aerial photographs, and field observations. The results are shown in 1:10.000 topographic charts. Ninety percent of the species occur in at least 3 physiognomical units while 60% only occurred in a single unit, what indicates that the orchids can be used to characterize the vegetation even in large scales.