Encontrados 17 documentos, a visualizar página 1 de 2
Cork oak (Quercus suber L.) seedlings acclimate to elevated
Vaz. M; Cochard. H; Gazarini. L; Graça. J; Chaves. M. M; Pereira. J. SLeaf gas-exchange, leaf and shoot anatomy, wood density and hydraulic conductivity were investigated in seedlings of Quercus suber L. grown for 15 months either at elevated (700 lmol mol-1) or normal (350 lmol mol-1) ambient atmospheric CO2 concentrations. Plants were grown in greenhouses in a controlled environment: relative humidity 50% (±5), temperature similar to external temperature and natural light condi...
Reversing of seasonal patterns of carbon uptake in an eucalyptus stand in Portu...
Pita, G.; Rodrigues, A.; Mateus, J.; Pereira, J.S.This paper summarizes results between 2002 and 2010 from eddy covariance measurements of carbon uptake in the 12 month annual growing period eucalypt site of Espirra in Southern Portugal (38° 38’N, 8° 36’ W) . This site, aimed for pulp production is part of an intensively 300 ha eucalypt coppice, with about 1100 trees ha–1. The climate is of Mediterranean type. During the measurement period (2002-2010) two main...
Drought-induced photosynthetic inhibition and autumn recovery in two Mediterran...
Vaz, M.; Pereira, J.S.; Gazarini, L.C.; David, T.S.; David, J.S.; Rodrigues, A; Maroco, J; Chaves, M.M.Responses of leaf water relations and photosynthesis to summer drought and autumn rewetting were studied in two evergreen Mediterranean oak species, Quercus ilex spp. rotundifolia and Quercus suber. The predawn leaf water potential (ΨlPD), stomatal conductance (gs) and photosynthetic rate (A) at ambient conditions were measured seasonally over a 3-year period. We also measured the photosynthetic response to lig...
Herbaceous layer development during spring does not deplete soil nitrogen in th...
Otieno, D.O.; Mirzaei, H.; Hussain, M.Z.; Li, Y.L.; Schmidt, M.W.T.; Wartinger, M.; Jung, E.; Ribeiro, N.; Pereira, J.S.; Tenhunen, J.Nitrogen (N) content in the soil and in the herbaceous biomass were monitored during spring of 2004-2006 to determine how the herbaceous layer development influences soil N availability in the montado ecosystem of southern Portugal. Highest (246.6 ± 52.7 g m-2) and lowest (123.2 ± 89.5 g m-2) peak biomass occurred in 2006 and 2005 respectively. Total soilNwithin the top 20 cmsoil profile ranged between 0.2 0.1%...
Biomass allometry and carbon factors for a Mediterranean pine (Pinus pinea L.) ...
Correia, A.A.; Tomé, Margarida; Pacheco, C.A.; Faias, S.; Dias, A.C.; Freire, J.; Carvalho, P.O.; Pereira, J.S.Forests play an important role in the global carbon balance because they offset a large portion of the carbon dioxide emitted through human activities. Accurate estimates are necessary for national reporting of greenhouse gas inventories, carbon credit trading and forest carbon management but in Portugal reliable and accessible forest carbon measurement methodologies are still lacking for some species. The obje...
Physiological and biochemical responses to low non-freezing temperature of two ...
Shvaleva, A.; Silva, F.C.; Scotti, P.; Oufir, M.; Hausman, J.-F.; Cedric, G.; Ramos, P.; Almeida, M.H.; Rodrigues, M.L.; Pereira, J.S.; Chaves, M.M.Abstract – We have compared the metabolic responses of leaves and roots of two Eucalyptus globulus L. clones CN5 and ST51 that differ in their sensitivity to water deficits (ST51 is more drought sensitive), with regard to the effect of chilling (10/5 ◦C, day/night). We studied changes in growth, osmotic potential and osmotically active compounds, soluble proteins, leaf pigments, and membrane lipid composition. ...
The effect of drought on energy and water vapour exchange above a mediterranean...
Aires, L.M.; Pio, C.A.; Pereira, J.S.We studied the seasonal and interannual variation in surface energy fluxes – net radiation (Rn), soil heat (G), sensible heat (H) and latent heat (lE) fluxes – and water vapour exchange above a Mediterranean C3/C4 grassland in Portugal, during two hydrological years, i.e., the period from 1 October to 30 September of the next year, of contrasting rainfall. The first year, 2004–2005, was dry, with total precipit...
Variations in growth, survival and carbon isotope composition among Pinus pinas...
Correia, Isabel; Almeida, Maria Helena; Aguiar, Alexandre; Alía, Ricardo; David, Teresa Soares; Pereira, J.S.To evaluate differences in growth and adaptability of maritime pine (Pinus pinaster Ait.), we studied growth, polycyclism, needle tissue carbon isotope composition (δ13C) as an estimate of water-use efficiency (WUE) and survival of seven populations at 10 years of age growing in a performance trial at a provenance test site in Escaroupim, Portugal. Six populations were from relatively high rainfall sites in Por...
Water-use strategies in two co-occurring Mediterranean evergreen oaks: survivin...
David, T.S.; Henriques, M.O.; Kurz-Besson, C.; Nunes, J.; Valente, F.; Vaz, M,; Pereira, J.S.; Siegwolf, R.; Chaves, M.M.; Gazarini, L.C.; David, J,S.In the Mediterranean evergreen oakwoodlands of southern Portugal, the main tree species are Quercus ilex ssp. rotundifolia Lam. (holm oak) and Quercus suber L. (cork oak). We studied a savannah-type woodland where these species coexist, with the aim of better understanding the mechanisms of tree adaptation to seasonal drought. In both species, seasonal variations in transpiration and predawn leaf water potentia...
HBV vaccination of HCV-infected patients with occult HBV infection and anti-HBc...
Pereira,J.S.F.; Gonçales,N.S.L.; Silva,C.; Lazarini,M.S.K.; Pavan,M.H.P.; Fais,V.C.; Gonçales Júnior,F.L.Anti-HBc positivity is a frequent cause of donation rejection at blood banks. Hepatitis B virus (HBV) infection may also occur in HBsAg-negative patients, a situation denoted occult infection. Similarly, very low levels of HBV-DNA have also been found in the sera of patients with chronic hepatitis C virus (HCV) infection, even in the absence of serum HBsAg. Initially we searched for HBV-DNA in serum of 100 bloo...
| Financiadores do RCAAP | |||||||
|
|
|
|
|
|
||