Implications of plant material origin, land use history and soil properties in the incidence of verticillium wilt in olive groves

8 páginas, 2 figuras, 1 tabla.The increased presence of Verticillium wilt (Verticillium dahliae Kleb.) in olive groves is often related to the use of infected propagation material and to the planting of new olive trees in contaminated soils. This study assessed the implications of plant propagation, land-use history and soil properties on disease prevalence in southern Spain, the most important olive-growing area worldwide. To this purpose, a large-scale sampling survey was carried out in this area, V. dahliae pathotypes were identified by PCR, and GIS was used to analyze soil properties and cropland-use history. Finally, multiple correspondence analysis was performed to show the statistical association between the variables taken into account. Results strongly indicated the potential risk of planting olive in valleys with irrigated cropland history, especially those that had hosted herbaceous crops, highlighted the importance of using pathogen-free certified planting material as a key component for a successful disease management, and confirmed the role played by saline, alkaline, and steep-slope soils in enhancing V. dahliae prevalence.The research was supported by Caja Rural Foundation.Peer reviewe

Germination response of Salsola schweinfurthii (Chenopodiaceae) to salinity and winged perianth removal

Salsola schweinfurthii is a perennial branched halophytic shrub that inhabits arid environments in and around the Arabian Peninsula. Its tolerance to extreme drought renders it suitable for urban arid landscaping. Germinability of intact and de-winged seeds (winged perianth removed) was determined under two photoperiods (0 and 12 hours light per day), three thermoperiods (daily low/high of 15/25, 20/30 and 25/35°C) and five salinity levels (0, 100, 200, 400 and 600 mM NaCl). Germination was maximised (93%) by de-winging and incubation in 12 hours light at 25/35°C. Intact and de-winged seeds both exhibited positive photoblastism. Germination of intact seeds was entirely prevented by the lowest level of salinity, and only slightly less prevented in de-winged seeds. Ability to germinate returned after saline solution was replaced with distilled water. The ability for S. schweinfurthii seeds to remain viable through a temporary period of salinity indicates an adaptation to unpredictable soil surface conditions in arid environments. Artificial propagation rates might be increased by removing perianths and sowing before or after mid-winter

New determination of gypsum isotope fractionation factor

Gypsum is a low temperature mineral of relevance for the understanding of evaporitic and late hydrotermal scenarios. Gypsum deposits are spread all over the geological record and their crystals may contain important information about the history of the seas

Pyroelectric Trapping and Arrangement of Nanoparticles in Lithium Niobate Opposite Domain Structures

The particular ferroelectric domain structure of periodic opposite domain lithium niobate (ODLN) crystals has been used for the first time for structured nanoparticle trapping. The surface charge density produced by a temperature change in this pyroelectric material is the origin of the trapping forces: dielectrophoretic on neutral particles and electrophoretic on charged ones. Metallic and dielectric particles are trapped and structured. The results show that ODLN structures are efficient substrates for pyroelectric trapping. The different trapping behaviors are presentedThis work has been supported by the Spanish Ministerio de Economía y Competitividad under grant ref.: MAT2014-57704-C3-1-

Mujer e investigación en el CSIC de Aragón

2011: Año de la mujer investigadora.Peer Reviewe

Mujer e investigación

2 pdfs. de los paneles correspondientes a la Exposición "Mujer e investigación", organizada en 2011 por la Delegación del CSIC en Aragón

Effect of Disorder on Ultrafast Exciton Dynamics Probed by Single Molecule Spectroscopy

We present a single-molecule study unraveling the effect of static disorder on the vibrational-assisted ultrafast exciton dynamics in multichromophoric systems. For every single complex, we probe the initial exciton relaxation process by an ultrafast pump-probe approach and the coupling to vibrational modes by emission spectra, while fluorescence lifetime analysis measures the amount of static disorder. Exploiting the wide range of disorder found from complex to complex, we demonstrate that static disorder accelerates the dephasing and energy relaxation rate of the exciton

Adaptation to an Intracellular Lifestyle by a Nitrogen-Fixing, Heterocyst-Forming Cyanobacterial Endosymbiont of a Diatom

The symbiosis between the diatom Hemiaulus hauckii and the heterocyst-forming cyanobacterium Richelia intracellularis makes an important contribution to new production in the world’s oceans, but its study is limited by short-term survival in the laboratory. In this symbiosis, R. intracellularis fixes atmospheric dinitrogen in the heterocyst and provides H. hauckii with fixed nitrogen. Here, we conducted an electron microscopy study of H. hauckii and found that the filaments of the R. intracellularis symbiont, typically composed of one terminal heterocyst and three or four vegetative cells, are located in the diatom’s cytoplasm not enclosed by a host membrane. A second prokaryotic cell was also detected in the cytoplasm of H. hauckii, but observations were infrequent. The heterocysts of R. intracellularis differ from those of free-living heterocyst-forming cyanobacteria in that the specific components of the heterocyst envelope seem to be located in the periplasmic space instead of outside the outer membrane. This specialized arrangement of the heterocyst envelope and a possible association of the cyanobacterium with oxygen-respiring mitochondria may be important for protection of the nitrogen-fixing enzyme, nitrogenase, from photosynthetically produced oxygen. The cell envelope of the vegetative cells of R. intracellularis contained numerous membrane vesicles that resemble the outer-inner membrane vesicles of Gram-negative bacteria. These vesicles can export cytoplasmic material from the bacterial cell and, therefore, may represent a vehicle for transfer of fixed nitrogen from R. intracellularis to the diatom’s cytoplasm. The specific morphological features of R. intracellularis described here, together with its known streamlined genome, likely represent specific adaptations of this cyanobacterium to an intracellular lifestyle

Refuerzo de la escayola mediante fibras de lana mineral procedentes del reciclaje de rcd

Con la entrada en vigor del Código Técnico de la edificación el uso de lanas minerales está cada día más generalizado tanto en obras de rehabilitación como en obra nueva. Por lo tanto, la generación de residuos de este tipo de material aislante cobra una mayor importancia. El objetivo principal de la investigación que se presenta en esta ponencia es analizar la viabilidad del reciclaje de fibras obtenidas de las lanas minerales procedentes de los RCD como material alternativo a las fibras de vidrio cortadas que se utilizan en la actualidad como elementos de refuerzo en los prefabricados de yeso. Para ello se realizan series de escayola E-35 aditivadas con residuo de lana de roca y con residuo de lana de vidrio en diferentes porcentajes de adición. Dichas series se repiten cambiando este aditivo por fibra de vidrio E de 25mm de longitud con el fin de realizar un análisis comparativo con respecto a las series aditivadas con residuo de lanas minerales. Todas las series se someten al ensayo Shore C para determinar su dureza superficial y a ensayos mecánicos correspondientes para determinar su resistencia a flexotracción y a compresión. A partir de los resultados obtenidos se concluye que, con residuo de lana de roca se aumenta la Dureza Shore C en todos los porcentajes de adición, llegando a mejorar en un 12% con respecto a la fibra de vidrio, con un porcentaje de adición del 2%. Sin embargo, se obtienen valores inferiores de resistencia a flexotracción para todos sus porcentajes de adición. La mayor diferencia, un 50%, aparece con el porcentaje de adición del 4%. En el ensayo de resistencia a compresión los resultados obtenidos en las series aditivadas con residuo de lana de roca son superiores para todos los porcentajes de adición estudiados. La mayor diferencia aparece para el 3% de adición, en el que las series aditivadas con residuo de lana de roca superan en un 36% a las aditivadas con fibra de vidrio. Con respecto a las series aditivadas con residuo de lana de vidrio se concluye que, mejoran la dureza superficial linealmente en torno al 5% para todos los porcentajes de adición, con respecto a las series aditivadas con fibra de vidrio. Los valores de resistencia a flexotracción son superiores hasta el 3% de adición, llegando esta mejora al 26% con el 1% de adición. Los valores obtenidos en el ensayo de resistencia a compresión son mayores para todos los porcentajes de adición, excepto para el 4%. Esta mejora alcanza el 41% para el porcentaje de adición del 3%. Como conclusión final decir que las series aditivadas con lanas minerales procedentes del reciclaje obtienen mejores resultados en los ensayos realizados que las fibras utilizadas en la actualidad como refuerzo del yeso, por lo que resulta viable su sustitución