Encontrados 23 documentos, a visualizar página 1 de 3
Geographic variation in phenology behavior and response to drought of cork oak ...
Rodrigues, Ana P.; Sampaio, Teresa; Silva, J. Costa e; Patrício, Maria do Sameiro; Pereira, João Santos; Almeida, Maria HelenaCork oak is widely distributed in the Western Mediterranean region, spanning a range of different environmental conditions, and frequently dominating open woodlands of high conservation and socioeconomic value. Cork oak woodlands spread-out for over 715000 ha in Portugal, covering 21% of the national forested area and 30% of the world’s cork producing area. Cork oak is well adapted to the seasonal drought of Me...
Melhoramento do sobreiro para uma regeneração artificial sustentável
Gaspar, Maria J.; Rodrigues, Ana P.; Faria, Carla; Silva, F. Costa e; Merouani, H.; Silva, J. Costa e; Correia, António H.; Rodrigues, J.C.; Graça, J.O sobreiro (Quercus suber) é uma espécie singular devido à sua importância no funcionamento do ecossistema mediterrânico e na produção de cortiça. No entanto, apesar da sua importância ecológica e sócio-económica, pouco se compreende ainda dos seus processos de adaptabilidade às diferentes condições ambientais. Em algumas áreas do mediterrâneo ocidental, as florestas de sobreiro encontram-se em declínio e a man...
Leaf-level responses to light in two co-occurring Quercus (Quercus ilex and Que...
Vaz, Margarida; Maroco, J.; Ribeiro, Nuno; Gazarini, Luiz Carlos; Pereira, João Santos; Chaves, Maria ManuelaAbstract We studied morphological, biochemical and physiological leaf acclimation to incident Photon- Photosynthetic-Flux-Density (PPFD) in Quercus ilex (holm oak) and Quercus suber (cork oak) at Mediterranean evergreen oak woodlands of southern Portugal. Specific leaf area (SLA) decreased exponentially with increasing PPFD in both species. Q. ilex had lower SLA values than Q. suber. Leaf nitrogen, cellulose an...
Method for evaluation of coarse cork oak root system by means of digital imaging
Surový, Peter; Ribeiro, Nuno Almeida; Brasil, Felipe; Pereira, João Santos; Oliveira, Maria do Rosário GamitoDigital imaging is becoming a powerful tool for data storage and information retrieval. Image comparison and similarity evaluation has become part of the information market and it is today a common part of, for example, web search engines. The cork oak tree (Quercus suber L.), the dominant species of the ‘montado’ woodland system is, due to its cultural and socio-economic value, protected by law that prevents e...
Observations on 3-dimensional crown growth of Stone pine
Surový, Peter; Ribeiro, Nuno Almeida; Pereira, João SantosIn this work we wish to demonstrate the possibility of a reconstruction of the 3D growth of the Stone pine (Pinus pinea L) crown. The crowns of two samples were digitized in segments corresponding with individual years, which allowed us to reconstruct length-growth and 3D shape over the last 5 years. Due to the low sample amount, we limited ourselves to observations and methodology-descriptions instead of overa...
A new therapeutic proposal for writer's cramp: a case report
Waissman,Flavia Quadros Boisson; Pereira,João Santos; Nascimento,Osvaldo José MoreiraCONTEXT: Writer's cramp is a kind of focal hand dystonia that appears when individuals are writing. Since pharmacological treatment has not shown the desired therapeutic response, a study on immobilization of the damaged musculature was performed on two individuals with writer's cramp, using splints with the objective of reducing the handwriting abnormalities. CASE REPORT: Two patients presenting writer's cramp...
Carbon dioxide exchange above a Mediterranean C3/C4 grassland during two climat...
Aires, Luis Miguel Igreja; Pio, Casimiro Adrião; Pereira, João SantosEddy-covariance measurements of net ecosystem carbon exchange (NEE) were carried out above a grazed Mediterranean C3/C4 grassland in southern Portugal, during two hydrological years, 2004–2005 and 2005–2006, of contrasting rainfall. Here, we examine the seasonal and interannual variation in NEE and its major components, gross primary production (GPP) and ecosystem respiration (Reco), in terms of the relevant bi...
Evaporation and carbonic anhydrase activity recorded in oxygen isotope signatur...
Wingate, Lisa; Seibt, Ulli; Maseyk, Kadmiel; Ogée, Jérome; Almeida, Pedro; Yakir, Dan; Pereira, João Santos; Mencuccini, MaurizioThe oxygen stable isotope composition (d18O) of CO2 is a valuable tool for studying the gas exchange between terrestrial ecosystems and the atmosphere. In the soil, it records the isotopic signal of water pools subjected to precipitation and evaporation events. The d18O of the surface soil net CO2 flux is dominated by the physical processes of diffusion of CO2 into and out of the soil and the chemical reactions...
Implications of carbon cycle steady state assumption for biogeochemical modelin...
Carvalhais, Nuno; Reichstein, Markus; Seixas, Júlia; Collatz, G.James; Pereira, João Santos; Berbigier, Paul; Carrara, Arnaud; Granier, AndréWe analyze the impacts of the steady state assumption on inverse model parameter retrieval from biogeochemical models. An inverse model parameterization study using eddy covariance CO2 flux data was performed with the Carnegie Ames Stanford Approach (CASA) model under conditions of strict and relaxed carbon cycle steady state assumption (CCSSA) in order to evaluate both the robustness of the model’s structure f...
Quercus suber geographic variation: preliminary results of the Iberian Penínsul...
Almeida, Maria Helena; Aranda, I.; Chambel, Regina; Fachada, Ivone; Gil, L.; Lourenço, Maria João; Monteiro, Maria do Loreto; Nunes, Ana MargaridaCork oak (Quercus suber L.) has a great social and ecological importance in the Iberian Peninsula. Yet, a large proportion of cork oak stands is old and natural regeneration is often problematic. During the last decade large areas were reforested with this species in the context of the Common Agriculture Policy (CAP) both in Portugal and Spain. Survival rates were often low due to inappropriate nursery and inst...
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