Consulta: creatorFacets:"Buckeridge,Marcos Silveira"
Registros recuperados: 7
Data/hora: 17/06/2024 15:29:11

Diurnal changes in storage carbohydrate metabolism in cotyledons of the tropical tree Hymenaea courbaril L. (Leguminosae)
Provedor de dados: 88
Autores: Amaral,Lourdes Isabel Velho do; Santos,Henrique P.; Rossatto,Davi Rodrigo; Buckeridge,Marcos Silveira.
The cotyledons of Hymenaea courbaril store large amounts of xyloglucan, a cell wall polysaccharide that is believed to serve as storage for the period of seedling establishment. During storage mobilisation, xyloglucan seems to be degraded by a continuous process that starts right after radicle protrusion and follows up to the establishment of photosynthesis. Here we show evidence that events related to the hydrolases activities and production (α-xylosidase, β-galactosidase, β-glucosidase and xyloglucan endo-β-transglucosilase) as well as auxin, showed changes that follow the diurnal cycle. The period of higher hydrolases activities was between 6pm and 6am, which is out of phase with photosynthesis. Among the enzymes, α-xilosidase seems to be more important...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Enzyme activity; IAA; Α-xylosidase; XTH; Xyloglucan.
Ano: 2012
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-84042012000400008

Respostas fisiológicas de plantas amazônicas de regiões alagadas às mudanças climáticas globais
Provedor de dados: 88
Autores: Grandis,Adriana; Godoi,Simone; Buckeridge,Marcos Silveira.
Conforme previsões do último relatório do IPCC (Intergovernmental Panel of Climatic Change) em 2007, até meados deste século haverá um aumento na concentração de CO2 na atmosfera podendo chegar a 720 μmol mol-1. Consequentemente haverá uma elevação da temperatura de até +3 °C, o que ocorrerá em conjunto com mudanças no padrão de precipitação. O mesmo relatório sugere que isto poderá acarretar uma substituição gradual da floresta tropical por vegetação similar a uma savana na parte oriental da Amazônia, porém nada é conclusivo. Diante dessas possibilidades, pergunta-se - Como as espécies de árvores que compõem as regiões de alagamento da Amazônia irão responder às alterações climáticas por vir? Apesar dessas previsões serem pessimistas, o alagamento ainda...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Alagamento; Amazônia; Aquecimento global; Mudanças climáticas; Seqüestro de carbono.
Ano: 2010
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-84042010000100002

Isolamento de oligossacarídeos de xiloglucano de dicotiledôneas através de hidrólise enzimática e cromatografia de exclusão molecular
Provedor de dados: 88
Autores: Oliveira Junior,Clovis José Fernandes de; Braga,Marcia Regina; Buckeridge,Marcos Silveira.
Oligossacarídeos derivados do xiloglucano, um polissacarídeo constituinte da parede celular vegetal, vêm sendo considerados como moléculas capazes de sinalizar e/ou regular eventos relacionados ao crescimento e à expansão celular. A purificação desses oligossacarídeos é imprescindível para a realização de ensaios relativos à sua atividade biológica. Neste trabalho, xiloglucanos foram extraídos a partir de sementes de copaíba (Copaifera langsdorffii Desf.) e suspensões celulares de feijão (Phaseolus vulgaris L.) e hidrolisados com celulase (endo-glucanase) para obtenção dos oligossacarídeos de xiloglucano, os OXGs. Os resultados obtidos mostram que a técnica de cromatografia dupla em gel de exclusão molecular foi eficiente para purificação dos...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Oligossacarídeos; Parede celular; Purificação; Xiloglucano.
Ano: 2006
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-84042006000300006

Isothermal seed germination of Adenanthera pavonina
Provedor de dados: 88
Autores: Zpevak,Francisco Antonio; Perez,Sônia Cristina Juliano Güaltieri de Andrade; Buckeridge,Marcos Silveira.
This work reports aspects of seed germination at different temperatures of Adenanthera pavonina L., a woody Southeast Asian Leguminosae. Germination was studied by measuring the final percentages, the rate, the rate variance and the synchronisation of the individual seeds calculated by the minimal informational entropy of frequencies distribution of seed germination. Overlapping the germinability range with the range for the highest values of germination rates and the minimal informational entropy of frequencies distribution of seed germination, we found that the best temperature for the germination of A. pavonina seeds is 35 ºC. The slope µ of the Arrhenius plot of the germination rates is positive for T &lt; 35 ºC and negative for T &amp;gt; 35 ºC. The...
Tipo: Info:eu-repo/semantics/other
Palavras-chave: Leguminosae; Synchronisation; Temperature; Thermobiology.
Ano: 2012
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-84042012000400013

Polyethylene glycol damages grafted citrus plants based on biometric, physiological,and biochemical responses
Provedor de dados: 94
Autores: Girardi,Eduardo Augusto; Brandão,Andréa Dias; Coelho,Rubens Duarte; Couto,Hilton Thadeu Zarate do; Buckeridge,Marcos Silveira; Mourão Filho,Francisco de Assis Alves.
Abstract  Drought tolerance is a major trait for the selection of citrus rootstocks in breeding programs. PEG 4000 solution at 110 g L-1 (osmotic potential of -376 kPa) was used to evaluate biometric, physiological, and biochemical responses of grafted citrus plants in pots. ‘Valencia’ sweet orange plants grafted onto ‘Rangpur’ lime (drought tolerant) rootstock showed greater plant growth compared to that on ‘Swingle’ citrumelo (drought sensitive) rootstock, regardless of PEG-induced stress; however, biological responses to PEG were similar on both rootstocks. Plant dry weight, gas exchange, and leaf and root starch concentrations were reduced by PEG. Water potential at 2:00 p.m. and Fe and Mn leaf concentrations increased with severe phytotoxic symptoms....
Tipo: Info:eu-repo/semantics/other
Palavras-chave: Citrus limonia; Citrus paradisi x Poncirus trifoliata; Osmotic agent; Rootstock; Water deficit.
Ano: 2018
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-29452018000601001

Growth, photosynthesis and stress indicators in young rosewood plants (Aniba rosaeodora Ducke) under different light intensities
Provedor de dados: 61
Autores: Gonçalves,José Francisco de Carvalho; Barreto,Denize Caranhas de Sousa; Santos Junior,Ulysses Moreira dos; Fernandes,Andreia Varmes; Sampaio,Paulo de Tarso Barbosa; Buckeridge,Marcos Silveira.
Aniba rosaeodora is an Amazonian tree species that belongs to the family Lauraceae. Due to intense exploitation for extraction of essential oils (mainly linalol), A. rosaeodora is now considered an endangered species. On the other hand, there is little information about its ecophysiology which would be useful to support future forest planting programs. Hence, the effect of different light intensities on the growth and photosynthetic characteristics of young plants of A. rosaeodora was studied. Nine-month-old plants were subjected to four light treatments (T1= 10 a 250 µmol.m-2.s-1 / control; T2=500 to 800, T3=700 to 1000 and T4=1300 to 1800 µmol.m-2.s-1 / full sunlight). Allometric variables, gas exchange, contents of pigments and chlorophyll a...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Chlorophyll a fluorescence; Chloroplast pigment contents; Gas exchanges; Photochemical efficiency of photosystem II; Relative growth rate; Tropical species.
Ano: 2005
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-04202005000300007

Endo-beta-mannanase from the endosperm of seeds of Sesbania virgata (Cav.) Pers. (Leguminosae): purification, characterisation and its dual role in germination and early seedling growth
Provedor de dados: 61
Autores: Lisboa,César Gustavo Serafim; Tonini,Patrícia Pinho; Tiné,Marco Aurélio Silva; Buckeridge,Marcos Silveira.
Galactomannans are storage cell wall polysaccharides present in seeds of some legumes. Their degradation is carried out by three hydrolases (alpha-galactosidase (EC 3.2.1.22), endo-beta-mannanase (EC 3.2.1.78) and ß-mannosidase (EC 3.2.1.25)). In the present study we purified and characterised an endo-beta-mannanase from seeds of Sesbania virgata and addressed its role in germination and seedling development. The polypeptide purified by Ion Exchange Chromatography and Affinity Chromatography on Sepharose-Concanavalin A, showed a pH optimum between 3.5 and 5 at 45ºC and high stability at pH 7.8. The low stability at pH 5 appears to be associated with isoelectric precipitation, in view of the pI of the enzyme being 4.5. The purified enzyme is a glycoprotein...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Sesbania virgata; Endo-beta-mannanase; Galactomannan; Germination; Leguminosae.
Ano: 2006
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-04202006000200003