118,920 research outputs found
Filogeografía de los Quercus esclerófilos (Q. suber L., Q. ilex L. y Q. coccifera L.) en el Mediterráneo occidental
No full textEl 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
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
Influx, efflux and net uptake of nitrate in Quercus suber seedlings
No full textACESSO via B-on: http://dx.doi.org/doi:10.1023/A:1004785331462Nitrate influx, efflux and net nitrate uptake were measured for the slow-growing Quercus suber L. (cork-oak) to estimate the N-uptake efficiency of its seedlings when grown with free access to nitrate.We hypothesise that nitrate influx, an energetically costly process, is not very efficiently controlled so as to avoid losses through efflux, because Q. suber has relatively high respiratory costs for ion uptake. Q. suber seedlings were grown in a growth room in hydroponicswith 1 mM NO- 3 . Seedlings were labelled with 15NO- 3 in nutrient solution for 5 min to measure influx and for 2 h for net uptake. Efflux was calculated as the difference between influx and net uptake. Measurements were made in the morning, afternoon and night. The site of nitrate reduction was estimated from the ratio of NO- 3 to amino acids in the xylem sap; the observed ratio indicated that nitrate reduction occurred predominantly in the roots. Nitrate influx was always much higher than net acquisition and both tended to be lower at night. High efflux occurred both during the day and at night, although the proportion of 15NO- 3 taken up that was loss through efflux was proportionally higher during the night. Efflux was a significant fraction of influx.We concluded that the acquisition system is energetically inefficient under the conditions tested
Approaches to Synthesis and Characterization of Spherical and Anisometric Metal Oxide Magnetic Nanomaterials
No full textTissue Culture and Rapid Micropropagation for Quercus suber L.
No full textQuercus suber L. (Q. suber) is an evergreen tree species known for producing high-quality cork. Traditional seed propagation of Q. suber has low viability and is time-consuming. Therefore, we used young stem segments of 2~3-year-old seedlings as explants, and optimized protocols for tissue culture and rapid micropropagation of Q. suber. The best disinfection method was 0.10% HgCl2 (v/v) for 5 min. 0.50 g·L−1 Poly Vinyl Pyrrolidone (PVP) is the best anti-browning agent with a significant reduction in browning by nearly 1.76-fold (58.89% → 33.33%). Woody Plant Medium supplemented with micronutrients and vitamins from Murashige and Skoog Medium (WPMS) was found to be the most suitable for shoot formation. The optimal hormone ratio for development of shoots from axillary buds was 0.60 mg·L−1 6-benzyladenine (6-BA). Among the cytokinins tested, 0.50 mg·L−1 6-BA was the most suitable for development of shoots from axillary buds. In additon, the highest percentage of rooting explants (66.67%) and rooting number (3.03) was obtained on WPM basal medium supplemented 0.20 mg·L−1 IBA and 0.20 mg·L−1 NAA. In summary, we have established a set of protocols for tissue culture and rapid micropropagation of Q. suber. These findings lay the foundation for rapid micropropagation and genetic improvement
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
I Defogliatori delle foreste a <i>Quercus suber</i> L.
No full textData are given on the biology, mortality factors and population dynamics of Lymantria dispar L., Malacosoma
neustria L., Tortrix viridana L. and Euproctis chrysorrhoea L. the most harmful lepidopters to Quercus
suber L. A revision of chemical, microbiological, biological, biotechnical and genetic control methods
applied in the relevant diffusion areas is also reported
Genome-wide identification of epigenetic regulators in Quercus suber L.
No full textModifications of DNA and histones, including methylation and acetylation, are critical for the epigenetic regulation of gene expression during plant development, particularly during environmental adaptation processes. However, information on the enzymes catalyzing all these modifications in trees, such as Quercus suber L., is still not available. In this study, eight DNA methyltransferases (DNA Mtases) and three DNA demethylases (DDMEs) were identified in Q. suber. Histone modifiers involved in methylation (35), demethylation (26), acetylation (8), and deacetylation (22) were also identified in Q. suber. In silico analysis showed that some Q. suber DNA Mtases, DDMEs and histone modifiers have the typical domains found in the plant model Arabidopsis, which might suggest a conserved functional role. Additional phylogenetic analyses of the DNA and histone modifier proteins were performed using several plant species homologs, enabling the classification of the Q. suber proteins. A link between the expression levels of each gene in different Q. suber tissues (buds, flowers, acorns, embryos, cork, and roots) with the functions already known for their closest homologs in other species was also established. Therefore, the data generated here will be important for future studies exploring the role of epigenetic regulators in this economically important species.FCT -Fundação para a Ciência e a Tecnologia(PTDC/AGR-FOR/3356/2014
Acorn removal and seedling age determine oak (Quercus ilex L. and Q. suber L.) restoration outcome in ungulate-dominated Mediterranean environments
No full textAbstract Key message We test the potential benefits of planting 2-year vs. 1-year-old seedlings to restore Mediterranean oak-dominated systems. Planting 2-year-old Quercus suber L. seedlings is recommended for improved survival and resilience against wild boar (Sus scrofa L.) and drought in dry sandy soils. The removal of acorns in seedlings did not apparently influence leaf biochemical traits and could reduce wild boar damage, particularly in 1-year-old seedlings. Context In the face of anthropogenic global change, Mediterranean oak-dominated ecosystems confront increased biotic (ungulate herbivory) and abiotic (drought) stressors, compromising forest regeneration. Restoration measures are imperative to address this scenario. Aims This study assesses the impact of different mitigation measures on the survival and biochemical traits of two oak species. Methods We planted Quercus ilex L. and Q. suber L. seedlings in Cabañeros and Doñana National Parks (Spain), subjecting them to three treatments: cotyledon/acorn removal, seedling age (1- vs. 2-year-old), and herbivore protection (fenced vs. non-fenced). Results Wild boar (Sus scrofa L.) damage peaked in winter and early spring, while drought prevailed from late spring to fall. In sandy soils, wild boar uprooted 1-year-old more often than 2-years-old seedlings (40% vs. 18%). One-year-old seedlings without acorns showed higher survival rates against wild boar only in sandy soils. The removal of acorns in seedlings did not influence plant biochemical traits. Conclusions Planting 2-year-old seedlings in sandy soils may mitigate wild boar damage and improve drought resilience. Seedling age seems more important than acorn removal against biotic and abiotic stressors although acorn removal could reduce wild boar damage in 1-year-old seedlings. Our results underscore the importance of considering multiple stressors in oak restoration strategies
- …
