1,722,120 research outputs found
Filogeografía de los Quercus esclerófilos (Q. suber L., Q. ilex L. y Q. coccifera L.) en el Mediterráneo occidental
Full text linkEl análisis de los patrones filogeográficos de los robles esclerófilos presentes en el Mediterráneo Occidental (Quercus suber L., Quercus ilex L. y Quercus coccifera L.) se ha realizado combinando cuatro tipos de marcadores moleculares con diferentes modos de herencia y tasas de mutación. Primero, se estudiaron las relaciones filogenéticas de las tres especies para determinar su estatus taxonómico actual. El análisis se hizo bajo una aproximación de genética de poblaciones y coincide con modelos previos que incluyen a Q. ilex y Q. coccifera en el grupo ilex, más basal, y a Q. suber en el grupo cerris, con más de 50 especies que están ausentes en el área de estudio. Quercus ilex mostró los mayores niveles de diversidad tanto a nivel nuclear como organular y un claro patrón vicariante que separa poblaciones de los rangos ibero-marroquí-balear de aquellas de Provenza-Italia-Argelia y otras islas mediterráneas. El mismo patrón vicariante se observó en Q. suber, aunque con menor diversidad genética. Las poblaciones del Este de la Península-Marruecos y de las Baleares mostraron introgresión a nivel organular aunque los marcadores nucleares no revelaron restos significativos de introgresión con Q. ilex. La introgresión explica el hecho de que se comparta el ADN organular frente a una hipótesis de 'distribución incompleta de linajes'. Los resultados sugieren un origen antiguo de las hibridaciones en Q. suber del Este ibérico, con tiempo suficiente para diluir la contribución nuclear de Q. ilex. Se propone un modelo según el cual, la introgresión proporcionaría una oportunidad a Q. suber de incrementar el tamaño efectivo poblacional en etapas críticas (por ej. en un refugio glacial) mediante hibridación y subsiguiente retrocruzamiento con los parentales Q. suber, diluyendo la contribución nuclear de Q. ilex. Seguidamente se analizó la estructura espacial actual del ADN organular en la Península Ibérica para identificar refugios glaciares potenciales. La combinación con la información paleobotánica disponible describe un escenario de refugios múltiples para las tres especies en la Península Ibérica y de numerosas zonas de contacto secundario entre poblaciones que resultan en patrones espaciales de ADN organular complejos. Finalmente, se analizó exhaustivamente la estructura espacial del ADN organular en una zona refugio, las Islas Baleares, y se comparó con las poblaciones del entorno. Las Baleares se comportan como un área refugio y un reservorio de diversidad genética manteniendo restos de diversidad genética del Messiniense-Plioceno. La presencia de elementos de filiación tirrénica e ibérica es probablemente el producto de eventos de vicarianza y dispersión a larga distancia
Estudo da adaptabilidade da Quercus suber L. no Nordeste Transmontano
No full textNeste trabalho estuda-se um ensaio de 34 proveniências de Quercus suber L. oriundas
da bacia mediterrânica, com 7 anos de idade, com vista à definição da sua
adaptabilidade às condições edafo-climáticas do Nordeste Transmontano, uma vez que a
maioria da variação das características relacionadas com a adaptabilidade é ao nível da
proveniência. Avalia-se a variabilidade inter-proveniência e a plasticidade fenotípica do
crescimento, sobrevivência e estrutura morfológica.
Os resultados obtidos no ensaio de proveniências mostram que existe variabilidade na
adaptabilidade entre as várias proveniências analisadas, para todas as características em
estudo. Nesta fase, as populações marroquinas apresentam o maior crescimento médio
em altura, seguidas de duas populações espanholas. Relativamente aos diâmetros, há
três proveniências espanholas que se destacam das restantes por possuírem um maior
crescimento médio em diâmetro.
Os resultados evidenciam ainda que a Quercus suber L. é uma espécie capaz de gerar
populações muito diversas e com indivíduos diferenciados em que existe uma elevada
variabilidade genética. Assim sendo, é necessário estar atento à escolha das populações
a utilizar no futuro para acções de repovoamento, com vista a seleccionar os indivíduos
que terão mais hipóteses de sucesso na sua adaptação e desta forma aumentar o
potencial produtivo do sobreiro com especial relevo para a produção de cortiça e criar
condições para o fornecimento abundante e regular de material reprodutivo de provada
qualidade genética.In this research we studied a trial with 34 provenances of Quercus suber L. from the
Mediterranian Basin, with seven years old, to determine which provenances adapt better
to the climate and soil conditions of the Northeast of Trás-os.Montes, because most of
the variation of the characteristics related with adaptability relies at the provenance
level. We evaluate the inter-provenance variation and the phenotypic plasticity of
growth, survival and morphology structure.
The results obtained in the provenance trial show that there is variability in adaptability
among the several provenances tested for all variables. At this stage, marroquin
populations present the higher medium growth in height. In diameter, three spanish
populations present the higher values for medium growth.
The results also show that the Quercus suber L. is a species able to generate many
different populations, with many different individuals, in which the genetic variability is
very high. Therefore, is necessary to choose carefully the populations we’ll use in the
future in reforestation, choose individuals with more survival success and adaptation so
we can improve the productive potential of the cork oak, specially in the cork
production and create conditions for the regular supply of reproductive material of
good genetic quality
Quercus suber L breeding strategy for cork quality
No full textAccording to official statistics, cork oak (Quercus suber L) occupies about 670 000 ha, mainly distributed to the south of the Tagus River. This represents about 22% of the country's forest area, 8% of its total area and produces about 52% of the total cork production which amounts to 307 500 tonnes. In face of its importance, and to avoid a decrease in the area of the species and the quality of cork, it is urgent to introduce effective silvicultural and breeding techniques. The aims of this paper are to analyze the breeding programs for cork oak in which the Forest Research Station (EFN) is involved which are concerned with mass selection, vegetative propagation and progeny tests. These breeding programs must be very specific because of the characteristics of cork oak.Stratégie d'amélioration génétique de Quercus suber L. D'après les statistiques officielles, le chêne liège (Quercus suber L) occupe une surface approximative de 670 000 ha au Portugal. Son aire, principalement répandue au sud du Tage, représente 8% de la superficie totale du pays et 22% de la surface forestière. La production du Portugal représente 52% de la production mondiale soit 307 500 tonnes par an. Compte tenu de l'importance économique de l'espèce et des risques de réduction de la quantité et de la qualité du liège produit, il est devenu urgent de développer des techniques sylvicoles efficaces et de mettre en place un programme d'amélioration génétique. L'objectif de cet article est de décrire le programme d'amélioration mené par l'EFN (station de recherches forestières). Il préconise la sélection massale, la multiplication végétative et la mise en place de tests de descendances. Le programme d'amélioration doit prendre en compte les particularités du chêne liège
Quercus suber L. - cork oak
Full text linkQuercus suber L., (porodica Fagaceae, sekcija Cerris) hrast plutnjak, jedna je od najvažnijih drvenastih biljaka na području zapadnog Mediterana. Plutnjak je dugovječna i vazdazelena listača koja postiže visinu od oko 20 m. Najznačajnija i najprepoznatljivija karakteristika ove biljke je njezina debela, plutasta kora po kojoj je i sama vrsta dobila ime. Hrast plutnjak je ekološki plastična vrsta koja raste u toplim humidnim i subhumidnim uvjetima, od razine mora pa sve do 2000 m n.v. Hrast plutnjak, kao i ostalo šumsko drveće, trpi štete od atmosferskih utjecaja, paše, insekata, gljivica i požara. Najveći broj primjeraka ove vrste, u Hrvatskoj, danas nalazimo na dva lokaliteta u Puli. Najvažniji proizvod koji se dobiva od plutnjaka i njegova pluta su čepovi za vino, no ono danas ima mnoge uloge u arhitekturi, građevini, medicini, fizici i kemiji
Estudo da adaptabilidade da Quercus suber L. no Nordeste Transmontano
Full text linkNeste trabalho estuda-se um ensaio de 34 proveniências de Quercus suber L. oriundas
da bacia mediterrânica, com 7 anos de idade, com vista à definição da sua
adaptabilidade às condições edafo-climáticas do Nordeste Transmontano, uma vez que a
maioria da variação das características relacionadas com a adaptabilidade é ao nível da
proveniência. Avalia-se a variabilidade inter-proveniência e a plasticidade fenotípica do
crescimento, sobrevivência e estrutura morfológica.
Os resultados obtidos no ensaio de proveniências mostram que existe variabilidade na
adaptabilidade entre as várias proveniências analisadas, para todas as características em
estudo. Nesta fase, as populações marroquinas apresentam o maior crescimento médio
em altura, seguidas de duas populações espanholas. Relativamente aos diâmetros, há
três proveniências espanholas que se destacam das restantes por possuírem um maior
crescimento médio em diâmetro.
Os resultados evidenciam ainda que a Quercus suber L. é uma espécie capaz de gerar
populações muito diversas e com indivíduos diferenciados em que existe uma elevada
variabilidade genética. Assim sendo, é necessário estar atento à escolha das populações
a utilizar no futuro para acções de repovoamento, com vista a seleccionar os indivíduos
que terão mais hipóteses de sucesso na sua adaptação e desta forma aumentar o
potencial produtivo do sobreiro com especial relevo para a produção de cortiça e criar
condições para o fornecimento abundante e regular de material reprodutivo de provada
qualidade genética.In this research we studied a trial with 34 provenances of Quercus suber L. from the
Mediterranian Basin, with seven years old, to determine which provenances adapt better
to the climate and soil conditions of the Northeast of Trás-os.Montes, because most of
the variation of the characteristics related with adaptability relies at the provenance
level. We evaluate the inter-provenance variation and the phenotypic plasticity of
growth, survival and morphology structure.
The results obtained in the provenance trial show that there is variability in adaptability
among the several provenances tested for all variables. At this stage, marroquin
populations present the higher medium growth in height. In diameter, three spanish
populations present the higher values for medium growth.
The results also show that the Quercus suber L. is a species able to generate many
different populations, with many different individuals, in which the genetic variability is
very high. Therefore, is necessary to choose carefully the populations we’ll use in the
future in reforestation, choose individuals with more survival success and adaptation so
we can improve the productive potential of the cork oak, specially in the cork
production and create conditions for the regular supply of reproductive material of
good genetic quality
Nuclear microsatellite markers for the identification of Quercus ilex L.;Q. suber L. hybrids
No full textWe report the transfer of a set of nuclear microsatellite markers from Quercus rnacrocarpa Michx.;Q. petraea (Matts) Liebl. to Q. ilex L.;Q. suber L. as a useful tool for further genetic studies on these species. Their specific applicability for the praecox and doubtless identification of Q. ilex x Q. suber hybrids is also shown. Hybrids were obtained by controlled pollinations on Quercus ilex L. with pollen from Quercus suber L. trees. This is the first work in which nSSR have been used in Q. ilex
Formation and physicochemical characterisation of silica-based blackberry-like nanoparticles capped by polysaccharides
No full textStrictly monodisperse 200-nm silica nanoparticles were hydrophobically modified (HM) by surface coverage with octadecanol. In successive stages, a graft copolymer was adsorbed. The graft copolymer was obtained by atom-transfer radical polymn. (ATRP). The polymer hydrophobic functionality consists of short pMMA [poly(Me methacrylate)] units of controlled length and low polydispersity covalently linked to pullulan. Depending on concn., it forms more or less densely packed layers on the surface of HM silica nanoparticles. The surface coverage d. of these particles is modulated by the mole ratios between the components (grafted copolymer and HM nanoparticles) and is controlled by the solvent properties. The conditions used in surface coverage procedures, obtained by mixing the components in DMF and adding water in continuous elution gradient, give rise to uniformly polymer-grafted nanoparticles and to blackberry-like particles under satn. conditions. In such systems, the polar groups in the polymer chains face outward from the particles and give rise to corrugations on their surface. The surface morphol. of the nanoparticles is tuned by controlling the amt. of adsorbed polymer. In each stage of the surface coverage procedures, the resulting nanoparticles were investigated by DLS (in back-scattering mode) and SEM. The same holds for electrophoretic mobility results, which are rationalized in terms of a Langmuir-like adsorption isotherm
Isolamento e caracterizacao estrutural da lenhina da cortica de Quercus suber L
No full textFrom cork of Quercus suber L. and from it's saponification residue a lignin-like (MCL), a lignin (MCL_s_a_p) and lignin-carbohydrate complexes (LCC and LCC_s_a_p) were isolated by Bjorkman procedure, with the yields of 1.5%, 4.1%, 0.32% and 0.27%, respectively. MWL from Quercus suber L. was isolated too. MWL, cork and isolates were characterized by FTIR spectroscopy, elemental analysis, OMe determination, molecular weight determination, analytical pyrolysis (Py-GC-FID), permanganate oxidation, thioacidolysis and sugar determination by acid hydrolysis. Cork contains ca. 40% of aromatics with a global composition of approx. 13%H, 86%G and 1%S. This aromatics includes a G-lignin with a composition of approx. 2%H, 95%G and 3%S, isolated successfully from saponified cork, and other phenolic richer in OMe free units. Cork lignin is similar to MWL spruce but is more cross-linked, with more biphenyl, phenylcoumaran, 4-0-5 linkages, coniferyl and dihydroconiferyl alcohols, and has covalent cross-links to suberinic acids. Quercus suber L. wood has a GS lignin with a composition of 1%H, 71%G and 28%S. A structural model for cork lignin is proposedAvailable from Fundacao para a Ciencia e a Tecnologia, Servico de Informacao e Documentacao, Av. D. Carlos I, 126, 1200 Lisboa / FCT - Fundação para o Ciência e a TecnologiaSIGLEPTPortuga
Phytophthora on Quercus suber L. (cork oak)
No full textQuercus suber is a typically Mediterranean species, endemic of Southern Europe and Northern Africa where the climate is characterized by summer drought and mildly cold winters (distribution map see http://www.discoverlife.org). It’s an evergreen tree that grows up to 20 m in height, the stem diameter at breast height can reach more than 200 cm, the bark is up to 20 cm thick, porous and furrowed and the leaves are alternate, simple and with the margin entire or with 4-7 pairs of acute teeth. It grows well in various types of soil, with a preference for acidic soils (pH 5-7) and with low tolerance for calcarious and saline soils. Cork oak is an essential component in the agroecosystems of the Iberian Peninsula supporting rich wildlife populations and simultaneously used by farmers to grow cereals, graze animals and harvest cork. Portugal is the main producer and exporter of cork, as well as first in the industrial transformation and commercialization sectors
The relative importance of cork harvesting and climate for stem radial growth of Quercus suber L.
No full textGrowth of cork-oak (Quercus suber L.) in Iberian stands may depend not only on
climate but also on recurrent cork harvesting and stand management. In this work, trees from
sites with different managements were studied for 3-6 years. Radial increments were enhanced
following harvesting (4.0–8. mm yr), and decreased afterwards ( mm yr). Time after harvesting was the primary factor affecting radial growth of
Q. suber, but trunk growth also correlated negatively with Autumn-Winter precipitations
and minimum temperatures, and positively with Spring rainfall. Spring radial increment varied
significantly between sites.Importance relative de la récolte du liège et du climat sur la croissance radiale de
Quercus suber L. La croissance du chêne liège (Quercus suber L.) des peuplements
ibériques peut dépendre non seulement du climat mais aussi de la récolte du liège et de
l'aménagement du peuplement. Dans ce travail, des arbres provenant de sites caractérisés par
divers types d'aménagement ont été étudiés pendant 3 à 6 ans. L'accroissement radial était
accrû après la récolte (4,0-8,2 mm yr), et diminué ensuite ( mm yr). Le temps depuis la récolte était le facteur primordial affectant la
croissance du tronc de Quercus suber, mais celle-ci était aussi corrélée négativement
avec les précipitations et températures minimales de l'automne et de l'hiver, et positivement
avec la pluviométrie printanière. L'accroissement radial au printemps varie significativement
entre les sites
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