2,500 research outputs found

    Pollen morphology of native and cultivated species of Handroanthus (Bignoniaceae) present in Argentina

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    Morfología polínica de las especies nativas y cultivadas de Handroanthus (Bignoniaceae) de la República Argentina. El objetivo del siguiente trabajo consiste en ampliar el conocimiento palinológico de las especies de Handroanthus (Bignoniaceae) presentes en Argentina e incorporar esta información al Atlas Polínico del NOA que se publica periódicamente on line (www.atlaspolinicodelnoa.com.ar). Se analizaron las siguientes especies: H. albus (Cham.) Mattos, H. chrysotrichus (Mart. ex DC.) Mattos, H. heptaphyllus (Vell.) Mattos, H. impetiginosus (Mart.ex DC.) Mattos, H. lapacho (K. Schum.) Mattos, H. ochraceus (Cham.) Mattos, además de la exótica H. pulcherrimus (Sandwith) S. Grose. El material fue procesado según las técnicas convencionales para acetólisis y polen natural, se tomaron fotos a nivel de microscopía óptica (MO) y microscopía electrónica de barrido (MEB). Los resultados muestran que los granos son medianos de 25 a 31,6 μm en polen natural y de 27,45 a 48 μm en polen acetolizado, suboblatos a subprolatos. Tricolporados (colporoidados) en H. albus, H. chrysotrichus, H. heptaphyllus, H. impetiginosus, H. lapacho y H. pulcherrimus, y 3-colporados (colporoidados), 3-hemisincolporados y loxocolporados en H. ochraceus. La exina es de 1,5 a 2 μm de espesor con la superficie reticulada heterobrocada

    Application of principal component analysis to identify pollen subtypes in Miconia (Melastomataceae)

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    Miconia Ruiz et Pav. es un género característico de regiones selváticas que en Argentina está representado por 10 especies. El objetivo de este trabajo fue la identificación de posibles subtipos polínicos en las especies argentinas de este género señalado como estenopalínico por estudios previos. Se midieron 60 granos de polen de cada una de las especies al microscopio óptico y se realizó un análisis de componentes principales y un árbol de recorrido mínimo, basados en una matríz de especies y variables morfométricas de los granos. Fueron seleccionados dos componentes principales que en conjunto explicaron el 77% de la variación total de los datos. La mayoría de las variables se correlacionaron con el componente 1. Seis especies se definieron en tres subtipos, restando cuatro que no pudieron ser incluidas en ninguno de ellos por presentar caracteres intermedios. Se concluyó que el análisis multivariado constituye una posible herramienta para ayudar a diferenciar subtipos polínicos dentro de géneros estenopalínicos.Miconia Ruiz et Pav. inhabits forest regions being represented in Argentina by 10 species. The aim of this study was to identify possible pollen subtypes in the Argentine species of Miconia. Previous studies found that the genus is stenopalynous. Pollen grains of each species were measured with an optical microscope and a PCA was conducted based on a matrix of species versus morphometric variables of pollen grains. Two components were selected because these explained together 77% of the total variation in the data. Most of the variables were correlated with component 1. Three pollen subtypes were defined in the genus, but four of the species could not be included in any of them because they presented intermediated characters. It was concluded that multivariate analysis is a possible tool that helps to differentiate pollen subtypes within stenopalynous genera.Fil: Ceballos, Sergio Javier. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: García, Maria E.. Fundación Miguel Lillo; ArgentinaFil: Slanis, Alberto C.. Fundación Miguel Lillo; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo; ArgentinaFil: Reyes, Nora J. F.. Fundación Miguel Lillo; Argentin

    Petrological and geochronological study of the postkinematic pluton of Neira (Lugo, Spain)

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    [Resumen] El plutón granítico de Neira intruye discordantemente en metasedimentos precámbricos y cámbricos y en granitoides sincinemáticos de dos micas, con posterioridad al desarrollo de las fases deformativas hercínicas principales. En este macizo plutónico se distinguen dos unidades intrusivas principales y el espectro litológico fundamental fluctua entre granodioritas biotíticas y leucogranitos moscovíticos-biotíticos, con predominio de las variedades graníticas (adamellíticas). Estos términos petrol6gicos están relacionados entre sí a través de un proceso evolutivo controlado fundamentalmente por cristalización fraccionada, desempeñando un importante papel los minerales accesorios. La datación de esta unidad plutónica por el procedimiento Rb-Sr en roca total, proporciona una edad de 287 ± 5 Ma, con una relaci6n inicial 87 Sr /86 Sr de 0.7074 ± 0.0004, que corresponde a un episodio intrusivo Estefaniense[Abstract] Neira granitic pluton intrudes in cambrian and precambrian metasediments and in synkinematic two mica granites after the development of the two main hercynian tectonic phases. Two intrusive units are distinguished in this pluton and its petrological composition ranges from biotitic granodiorites to two mica leucogranites, predominating biotitic adamellites. This suite of rocks is related by an evolution process mainly ruled by crystal fractionation. The accesory minerals play an important role in this process. Rb-Sr dating of this plutonic unit gives and age of 287 ± 5 M y and an initial 87 Sr/86 Sr = 0.7074 ± 0.0004

    Soil and leaf mineral element contents in mediterranean vineyards: bioaccumulation and potential soil pollution

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    The study reported here concerns the geochemical distributions of macro- and trace elements (including potentially toxic elements, PTEs) in the vineyard soils of Alcubillas, which is one of the oldest, albeit not world-renowned, wine-growing areas in La Mancha (Central Spain). Soil and leaf samples were analyzed by X-ray fluorescence spectrometry to ascertain the levels of various elements in the soil and the plant. The potential toxicity of the elements was assessed with regard to the development of the vineyard. Despite the fact that fertilizers and pesticides are employed in the vineyards in this area, the results showed that the levels of trace elements in the soil samples did not exceed the reference values according the pedogeochemical values for the region and Spain. This finding suggests that the study area is not polluted, and therefore, there are hardly any traces of anthropogenic contamination. The Biological Absorption Coefficient (BAC) was calculated to assess the assimilation of various elements from the soil to the leaves, and differences were found in the element absorption capacity of the vines. Some elements were not taken up by Vitis vinifera despite elements like Zr and Rb being present in relatively high concentrations in the soil. The production in these soils does not represent a threat to human health or the ecosystem, because the farmers in this area are extremely careful to preserve the environment and they only farm to achieve moderate yields of grapes per hectar

    High overlap between traditional ecological knowledge and forest conservation found in the Bolivian Amazon

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    Unidad de excelencia María de Maeztu MdM-2015-0552Altres ajuts: FBBVA research grant (BIOCON_06_106-07)It has been suggested that traditional ecological knowledge (TEK) may play a key role in forest conservation. However, empirical studies assessing to what extent TEK is associated with forest conservation compared with other variables are rare. Furthermore, to our knowledge, the spatial overlap of TEK and forest conservation has not been evaluated at fine scales. In this paper, we address both issues through a case study with Tsimane' Amerindians in the Bolivian Amazon. We sampled 624 households across 59 villages to estimate TEK and used remote sensing data to assess forest conservation. We ran statistical and spatial analyses to evaluate whether TEK was associated and spatially overlapped with forest conservation at the village level. We find that Tsimane' TEK is significantly and positively associated with forest conservation although acculturation variables bear stronger and negative associations with forest conservation. We also find a very significant spatial overlap between levels of Tsimane' TEK and forest conservation. We discuss the potential reasons underpinning our results, which provide insights that may be useful for informing policies in the realms of development, conservation, and climate. We posit that the protection of indigenous cultural systems is vital and urgent to create more effective policies in such realms

    Grapevine leaf uptake of mineral elements influenced by sugar foam amendment of an acidic soil

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    The use of sugar foam (industrial waste from sugar beet extraction) as an acidic soil (raña) liming agent has been studied in a singular winegrowing region. The contents of the major elements (Al, Ca, Fe, K, Na, Mg, S, Si) and trace elements (As, Ba, Ce, Co, Cr, Cs, Cu, Ga, Hf, La, Mo, Nb, Nd, Ni, Pb, Rb, Sc, Sn, Sr, Ta, Th, U, V, W, Y, Zn, Zr) in the original soil, the amended soil and in grapevine leaves has been measured by X-ray fluorescence. The addition of sugar foam modified the agronomic properties of the original soil. The amendment caused a slight increase in major elements (Ca, 10.4 g·kg-1; Mg, 1.9 g·kg-1 and K, 12.9 g·kg-1) and decreased Al (from 62 to 57.8 g·kg-1) and Fe (from 41.2 to 26.5 g·kg-1) content. Regarding trace elements, there was an increase in levels of Ba, Rb and Sr in the amended soil in comparison to the original soil. The major elements that accumulated in the vine leaf were Ca, Mg and S (Biological Absorption Coefficient, BAC, greater than 1). As for trace elements in leaf, Ba and Sr had a "medium" BAC (0.27 and 0.8, respectively) whereas Rb had a "slight"value (0.08). It is worth noting that the bioaccumulation rate of Zn was greater than 1. The use of sugar foam as a liming agent did not have a negative effect on the absorption of major and trace elements in vine leaves and led to improved BAC values for essential elements in the grapevine. The treatment did not increase the amount of trace elements in the soil above the reference levels for the region.
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