64 research outputs found
Is there a hybridization barrier between Gentiana lutea color morphs?
In Gentiana lutea two varieties are described: G. lutea var. aurantiaca with orange corolla colors and G. lutea var. lutea with yellow corolla colors. Both color varieties co-occur in NW Spain, and pollinators select flower color in this species. It is not known whether a hybridization barrier exists between these G. lutea color varieties. We aim to test the compatibility between flower color varieties in G. lutea and its dependence on pollen vectors. Within a sympatric population containing both flower color morphs, we analyzed differences in reproductive success (number, weight, viability and germinability of seeds) depending on fertilization treatments (autogamy and xenogamy within variety and among varieties). We found a 93% reduction in number of seeds and a 37% reduction in seed weight respectively of autogamy treatments compared to xenogamy crossings. Additionally, reproductive success is higher within color varieties than among varieties, due to a 45% seed viability reduction on hybrids from different varieties. Our results show that G. lutea reproductive success is strongly dependent on pollinators and that a partial hybridization barrier exists between G. lutea varieties.This study is included in the project “Color polymorphism, geographic variation in the
interactions and phenotypic selection. The case of Gentiana lutea L. in the Cantabrian Mountains” was financially supported by Secretary of State of I+D+I, Ministry of Science
and Innovation, Government of Spain (2011–2013)S
Differences in pollination success between local and foreign flower color phenotypes: a translocation experiment with Gentiana lutea (Gentianaceae)
Background. The adaptive maintenance of flower color variation is frequently at-tributed to pollinators partly because they preferentially visit certain flower phenotypes.We tested whetherGentiana lutea—which shows a flower color variation (from orangeto yellow) in the Cantabrian Mountains range (north of Spain)—is locally adapted tothe pollinator community.Methods. We transplanted orange-flowering individuals to a population with yellow-flowering individuals and vice versa, in order to assess whether there is a pollinationadvantage in the local morph by comparing its visitation rate with the foreign morph.Results. Our reciprocal transplant experiment did not show clear local morphadvantage in overall visitation rate: local orange flowers received more visits thanforeign yellow flowers in the orange population, while both local and foreign flowersreceived the same visits in the yellow population; thus, there is no evidence of localadaptation inGentiana luteato the pollinator assemblage. However, some floral visitorgroups (such asBombus pratorum,B. soroensis ancaricusandB. lapidarius decipiens)consistently preferred the local morph to the foreign morph whereas others (such asBombus terrestris) consistently preferred the foreign morph.Discussion. We concluded that there is no evidence of local adaptation to the pollinatorcommunity in each of the twoG. luteapopulations studied. The consequences forlocal adaptation to pollinator onG. luteaflower color would depend on the variationalong the Cantabrian Mountains range in morph frequency and pollinator community composition.S
Selective pressures explain differences in flower color among Gentiana lutea Populations
Flower color variation among plant populations might reflect adaptation to local conditions such as the interacting animal community. In the northwest Iberian Peninsula, flower color of Gentiana lutea varies longitudinally among populations, ranging from orange to yellow. We explored whether flower color is locally adapted and the role of pollinators and seed predators as agents of selection by analyzing the influence of flower color on (i) pollinator visitation rate and (ii) escape from seed predation and (iii) by testing whether differences in pollinator communities correlate with flower color variation across populations. Finally, (iv) we investigated whether variation in selective pressures explains flower color variation among 12 G. lutea populations. Flower color influenced pollinator visits and differences in flower color among populations were related to variation in pollinator communities. Selective pressures on flower color vary among populations and explain part of flower color differences among populations of G. lutea. We conclude that flower color in G. lutea is locally adapted and that pollinators play a role in this adaptation.This work was financed by the Plan Nacional de I + D + I (2008-2011), CGL2009-08959 Ministerio de Ciencia. T.V. was supported by a PhD grant from the Plan Galego de Investigación e Crecemento 2011/2015 (Plan I2C), Consellería de Educación e Ordenación Universitaria e InnovaciónS
Flower color preferences of insects and livestock: effects on Gentiana lutea reproductive success
Angiosperms diversification was primarily driven by pollinator agents, but non-pollinator agents also promoted floral evolution. Gentiana lutea shows pollinator driven flower color variation in NW Spain. We test whether insect herbivores and livestock, which frequently feed in G.lutea, play a role in G. lutea flower color variation, by answering the following questions: (i) Do insect herbivores and grazing livestock show flower color preferences when feeding on G. lutea? (ii) Do mutualists (pollinators) and antagonists (seed predators, insect herbivores and livestock) jointly affect G. lutea reproductive success? Insect herbivores fed more often on yellow flowering individuals but they did not affect seed production, whereas livestock affected seed production but did not show clear color preferences. Our data indicate that flower color variation of G. lutea is not affected by insect herbivores or grazing livestockThis study is included in the project “Color polymorphism, geographic variation in the interactions and phenotypic selection. The case of Gentiana lutea L in the Cantabrian Mountains,” financially supported by Secretary of State of I+D+I, Ministry of Science and Innovation, Government of Spain (2011–2013). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscriptS
Selective pressure along a latitudinal gradient affects subindividual variation in plants
Individual plants produce repeated structures such as leaves, flowers or fruits, which, although belonging to the same genotype, are not phenotypically identical. Such subindividual variation reflects the potential of individual genotypes to vary with micro-environmental conditions. Furthermore, variation in organ traits imposes costs to foraging animals such as time, energy and increased predation risk. Therefore, animals that interact with plants may respond to this variation and affect plant fitness. Thus, phenotypic variation within an individual plant could be, in part, an adaptive trait. Here we investigated this idea and we found that subindividual variation of fruit size of Crataegus monogyna, in different populations throughout the latitudinal gradient in Europe, was explained at some extent by the selective pressures exerted by seed-dispersing birds. These findings support the hypothesis that within-individual variation in plants is an adaptive trait selected by interacting animals which may have important implications for plant evolution.This work was supported by the Spanish Ministry of Science and Education (project CGL2005-03826) and the European Commission (FEDER program). M.S. was the recipient of a María Barbeito fellowship (Galicia regional government, Spain) and a Fundación Pedro Barrié de la Maza grant. A.R.L. received financial support from the Spanish Research Council (JAEDoc program, partially funded by the European Social Fund) during the preparation of the manuscriptS
Aplicación de la exoscopia del cuarzo a la caracterización de diversos ambientes en Galicia
[Abstract] Only one of the studied pegmatites shows a symmetrical-zoned structure: a border zone wi th spodumene and a central zone wi th lepidolite. In the other pegmatites there not zoned structures but rather a centimetric bedding of whi te and pink zones (albite and lfpidolite). All sam plesare mineralized in Tin (about 200-1000 ppm) and Tantalum (40-70 ppmT. The geochemical study shows significant contents of Ba, Y, Zr, Rb and Cs. There is also infil tration of Li, Rb, Cs and Sn in the wall-rocks. The study of polymorphism and composi tion of the Li-micas shows the existence of two internaly, intergrown, distintic structures (1M and 2M ): The first one is Li-rich (lepidoli te) and the second is poor in Li (Li-1 -muscovite). It is shown a genetical hypothesis and a evolutionary diagram of the micas formation[Résumé] Par les microformes superficielles des arenes de quartz on peut reconstruire les caracteristiques chimiques , mechaniques et biologiques des ambiances oú elles ont evolué. Au moyen de la technique d' Exoscopie des Quartz, qui permet l'observation, au microscope electronique de balayage, de la morphologie superficielle des grains de ce mineral,on éxamine des quartz provenant de diverssoIs et sédiments de la Galice,en identifiant les caracteres phénomorphiques correspondantes a chacun de cesambiances. - Cette techique se montra particulierement utile a la reconnaissance des horizons Edaphiques aloctones et a l'interprétation de l'histoire géologique des sédiment
Estudio sedimentológico de un depósito arenoso de la rasa cantábrica: aplicación de la exoscopia del cuarzo
[Resumen] Mediante la técnica de Exoscopía del Cuarzo se estudia un sedimento arenoso de la Rasa Cantábrica, en las proximidades de S.Miguel de Reinante (Lugo), contrastando los resultados de este estudio con los obtenidos por las metodologías clásicas de granulometría y morfoscopía. De la aplicación conjunta de estas técnicas se puede deducir que aún siendo las arenas depositadas en un mismo episodio final de sedimentación, cuya naturaleza se discute, tienen orígenes diversos cuya evolución intenta reconstruirse con ayuda de la técnica de Exoscopia del Cuarzo.[Résumé] Al' aide de la technique d' Exoscopie des Quartz on étude un sédiment sableux de la "Rasa Cantabrica" aux environs de S.Miguel de Reinante (Lugo). Les résultats de cet étude sont confrontés avec ceux issus des méthodes clasiques de granulometrie et morphoscopie. L'application conjointe de ces techniques permet déduire que, bien que déposées dans une meme épisode finale de sédimentation, dont la nature se discute, les s~bles de ce dépot ont des origines diverses dont l' evolution on tente de reconstruire par l'Exoscopie des Quart
Characterization of goethites from surficial environments of Galicia and estimates of the substitution of Fe by Al
[Resumen] Se examinan cincuenta muestras ricas en goetita y de morfología y génesis variada (placas en sedimentos, suelos ricos en sesquióxidos, costras y menas de Fe), caracterizando su mineralogía y composición química por medio de diversas técnicas instrumentales y extractantes selectivas. Se estima el grado de sustitución isomorfa de Fe por Al mediante análisis químico y por el desplazamiento de las líneas de difracción de RX de la goetita. Por ambos métodos se obtienen resultados similares, dando porcentajes de sustitución que no sobrepasan en general el 15 O/o molar, lo que se considera un bajo grado de reemplazamiento y se explica en función de las condiciones de formación de estas concentraciones de hierro.[Abstract] Fifty samples with high goethite contents, differing in their morphology and formed in diverse environments are examined. They include ironpans, crusts, soils high in sesquioxides and iron ores. Several instrumental techniques are used for their mineralogical characterization, together with selective extractants of cristaBine and amorphous iron. The extent of the isomorphus replacement ofFe by Al in goethite is estimated by chemical analyses and by the shift ofXRD diffraction línes. Both methods give similar results, showing porcentages of substitution that not exceed in general 15 mole O/o. This can be considered a low degree of replacement and is discussed in sight of the formatíon conditions of these iron accumulations
La cianita de O Pino (Santiago): caracterización, purificación e aplicaciones.
Resumen] Se caracteriza e identifica un tipo de cianita de aluvión «canto rodado» localizado en el Ayuntamiento de O Pino próximo a Santiago. Se estudia la purificación de la cianita después de su calcinación a temperaturas del orden de los 1.400-1.450 oC para su estabilización mediante transformación en mullita. El método seguido fue una separación electromagnética de alta intensidad del todo-uno previo acondicionamiento de las fracciones granulométricas. Las impurezas que acompañan a la cianita, principalmente óxido de hierro, funden rodeando los granos y dando lugar a especies de baja susceptibilidad magnética. Se propone otro método de purificación basado en hacer la separación rnagnética antes de la calcinación con lo que se logran mejores resultados obteniéndose una cianita de alta pureza pero con una granulometría por debajo de 1 mm. Se estudian las variables que influyen principalmente en la transformación a mullita durante la calcinación. Por último se ensaya el empleo de esta cianita en la preparación de diversas composiciones de cerámica técnica y la fabricación de piezas de aplicación en los laboratorios de control de la industria siderúrgica que en la actualidad están ya comercializándose.[Abstract] One type of alluvial kyanite (rolling stones) located at the region around O Pino, near of Santiago in A Coruña province, is characterized and identified. Refining of kyanite after heating in at temperatures ranging 14001450 oC for to stabilize it by transformation into mullite is studied. The method employed was an high intensity magnetic separation after size c1assification. The impurities of this kyanite, mainly iron oxides, melt surrounding the grains which are of low magnetic susceptibility. An alternative way of purification is proposed. This second method is based on making magnetic separation before calcination, and it gives better results obtaining an high purity kyanite, but with grain size below 1mm. Variables with main influence over the conversion into mullite during
heating are studied. Finally compositions made with this kyanite are tested. These pastes are employed in technical ceramics and in making pieces for use in tests of iron and steel industries and that actually are in the marke
Fosfatos organógenos en los recubrimientos de los granitos de Monte Louro
[Resumen] Se realiza la identificación por métodos químicos e instrumentales de un fosfato magnésico hidratado localizado en forma de recubrimientos y costras en las rocas graníticas de Monte Louro (La Coruña). La determinación del comportamiento de este mineral durante su deshidratación permite, comprobar el estrecho paralelismo existente entre la pérdida de agua y la destrucción de la newberyita. Teniendo ,en cuenta la escasa estabilidad de la newberyita en los medios de alteración y su frecuente asociación con la «struvita» se atribuye a este mineral un origen organógeno, discutiéndose la posibilidad de' que se encuentre estabilizado por la presencia de recubrimi'entos de fosfatos cálcicos (Brushita y/o Monetita)[Abstract] The identification of a hydrated magneslc phosphate is carried out by chemical and instrumental methods. This is found the shape of overlag and crust on the granitic rocks on Monte Lauro. The determination of its behaviour during the dehydratation 'is performend, let us check the elosed paralelism hetween the loss of water, and the destruction of the new" beryite structure. This mineral isimput,ed to have an organic origin taking into account its short ,stabilityin weatheringenvironments and its freguent assooiation with the «struviteD. It is presumend the posibility of becomíng stabilited by the pres,enc-e of calcic phosphate co,atings (Brushitaand/or Monetite)
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