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Search Results: 1 - 10 of 405680 matches for " M. Medina-Sierra "
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Relationship between Plant Species Diversity and Plant Biomass of Orchard Grass and Lucerne Sown in Different Ratios in the Province of Salamanca, Spain  [PDF]
M. Medina-Sierra, M. Igual-Arroyo, F. Restrepo-Betancur, A. Valverde-Portal, I. Santa-Regina
Open Journal of Forestry (OJF) , 2017, DOI: 10.4236/ojf.2017.73020
Abstract: A field experiment was carried out at the CSIC Muñovela farm belonging to the Spanish National Research Council (CSIC) in order to evaluate the effect of sowing orchard grass (Dactylis glomerata var. Trerano) and lucerne (Medicago sativa var. Aragon) in monoculture and in combination. The experiment was based on a randomized block designed with a factorial arrangement (5 × 2). Experimental units were 40 plots distributed in four blocks. The phosphorus fertilization (P) factor included two types of conditions: basal fertilization without phosphorus (-P) and basal fertilization with phosphorus (+P), and the vegetation cover factor (T) included five conditions depending on the grass (G) and the legume (L). Above-ground biomass showed statistically significant differences among seasons and years (P < 0.05). However, no statistically significant differences treatments were found among various treatments. The presence of the grass species Lolium perenne L. and Poa pratensis L. throughout the three years indicated that both species significantly increased their presence over time regardless of the treatments applied. The analysis performed for the other plant species (those other than grasses and legumes) allowed us to determine that the T1 and T5 treatments, which correspond to single species not treated with the application of phosphorus, influenced the presence of 70% of other species planted. Our specific aim was to explore how changing plant biotic diversity affects productivity under a given set of conditions. We manipulated plant species richness as an experimental factor to determine if productivity would be affected by changes in the ratios of plants sown.
DIVERSIDAD DE HONGOS MICORRIZóGENOS ARBUSCULARES DE UNA CRONO-SECUENCIA DE SUELOS ALUVIALES DEGRADADOS POR ACTIVIDAD MINERA EN EL BAJO CAUCA ANTIOQUE?O, COLOMBIA
Medina Sierra,Marisol; Orozco Pati?o,Francisco Hernando; Márquez Fernández,María Elena;
Revista Facultad Nacional de Agronomía, Medellín , 2009,
Abstract: arbuscular mycorrhizal fungi (amf) presence and diversity were evaluated in undisturbed and disturbed soils form alluvial mining processes. the soils belong to the tropic fluvaquent, typic dystropept, and typic paleudult sub-groups which corresponded to low, middle and high terraces, respectively, of the cauca river at taraza town. amf propagules were multiplied in leonard jars under glasshouse conditions using sterile substrate, modified hoagland's solution and different fractions of soil used as sources of inoculum, which corresponded to the size of the spores. a first assay was made in maize (zea mays) which allowed mycorrhizal colonization in roots but not spore production. in a second assay, in kudzú (pueraria phaseoloides) amf spores and colonized roots were obtained with the treatments corresponding to propagules obtained from high terrace and disturbed soil. these treatments presented a significant effect on kudzu yield (p≤0,001) respect to the other treatments. the amf spores of undisturbed and disturbed soils showed low infective capacity. nevertheless, propagules of amf were multiplied in trap cultures, which produced spores of four morphotypes. one of these was identified as g. microagregatum. the polymorphism obtained by rapd's made possible the differentiation of these morphotypes with the primer opa2. similitude above 38% was achieved using upgma system. the results indicated that four morphotypes belong to the genus glomus, but they possibly belong to different species. our results are promissory in the differentiation of native strains of amf with low number of spores collected from soil samples in rehabilitation processes, which normally is unknown.
Avances en la transformación de raíces de kudzú (Pueraria phaseoloides) y zanahoria (Daucus carota var. Danvers 126) con diferentes cepas de Agrobacterium rhizogenes para multiplicación de hongos MA Advances in transforming kudzu (Pueraria phaseoloides) and carrot (Daucus carota var. Danvers 126) roots with different Agrobacterium rhizogenes strains for increasing MA fungi growth
Medina Sierra Marisol,Orozco P. Francisco Hernando,Márquez F. María Elena
Revista Colombiana de Biotecnología , 2002,
Abstract: En el presente trabajo se transformaron raíces de kudzú (Pueraria phaseoloides) y de zanahoria (Daucus carota) en diferentes medios de cultivo, mediante el empleo de cinco cepas diferentes de Agrobacterium rhizogenes; de comportamiento diferente tanto en la transformación de zanahoria por las cepas de A. rhizogenes A.r.15834, A.r.8196 y A.r.2659; como en la transformación de kudzú por las cepas A.r.15834 y A.r.1724. Por otro lado, se logró la multiplicación en medio White modificado (WM) de las raíces transformadas de zanahoria, mientras que las de kudzú no se lograron multiplicar en ese medio ni tampoco en el medio MS modificado. Las raíces de zanahoria se emplearon para la multiplicación y esporulación del hongo micorrizógeno arbuscular (HMA) Glomus intrarradices, sin embargo las cepas nativas de HMA, aisladas de una de las zonas de minería del Bajo Cauca Antioque o, no crecieron en las raíces transformadas de esta especie ni aún en las de kudzú, a pesar de ser una planta que presenta alta afinidad por las cepas nativas de HMA. Los resultados se muestran como un avance en el procedimiento para el aislamiento de ADN y el mantenimiento de colecciones de HMA, requeridos para otras investigaciones. Kudzú (P. phaseoloides) and carrot (D. carota) roots were transformed in this survey into different kinds of culture medium by using five different A. rhizogenes strains. These presented different behaviour both in carrot transformation by A. rhizogenes 15834, A.r.8196 and A.r.2659 strains as well as kudzu transformation by A.r.15834 and A.r.1724 strains. Transformed carrot root growth was increased in WM culture medium, whilst transformed kudzu root growth did not increase in either the same medium or in modified MS medium. Transformed carrot roots were used for G. intrarradices increase and sporulation; however, wild AMF strains, isolated from a mining area (the lower Cauca area of Antioquia), did not grow either in roots from this specie or those from kudzu, in spite of this plant having great affinity for wild AMF strains. The results represent an advance in the procedure for DNA isolation and keeping AMF collections, required for other research.
DIVERSIDAD DE HONGOS MICORRIZóGENOS ARBUSCULARES DE UNA CRONO-SECUENCIA DE SUELOS ALUVIALES DEGRADADOS POR ACTIVIDAD MINERA EN EL BAJO CAUCA ANTIOQUE O, COLOMBIA DIVERSITY OF ARBUSCULAR MYCORRHIZAL FUNGI IN A CHRONO-SEQUENCE OF ALLUVIAL AND DEGRADED SOILS DUE TO MINING PROCESSES IN BAJO CAUCA ANTIOQUE O, COLOMBIA
Marisol Medina Sierra,Francisco Hernando Orozco Pati?o,María Elena Márquez Fernández
Revista Facultad Nacional de Agronomía, Medellín , 2009,
Abstract: Se evaluó la presencia de hongos micorrizógenos arbusculares (HMA) en suelos de zonas alteradas y no alteradas por minería de aluvión de los subgrupos Tropic Fluvaquent, Typic Dystropept y Typic Paleudult de terrazas Baja, Media, y Alta, respectivamente, del río Cauca a la altura del municipio de Tarazá (Antioquia, Colombia). La multiplicación de propágulos de HMA se realizó en jarras de Leonard en invernadero, utilizando sustrato estéril, solución Hoagland's modificada y como inóculo diferentes fracciones de suelo correspondientes al tama o de las esporas. Se realizó un primer ensayo en maíz (Zea mays) en el cual se logró colonización de las raíces pero no esporulación; en un segundo ensayo en kudzú (Pueraria phaseoloides) se logró colonización y esporulación en los tratamientos provenientes de suelo de terraza alta y suelo disturbado y efecto significativo en el rendimiento del kudzú (P≤0,001) respecto a los demás tratamientos. Las esporas de suelos disturbados y no disturbados por minería de aluvión en el Bajo Cauca antioque o (Colombia) mostraron baja capacidad infectiva; sin embargo, en cultivos trampa fue posible multiplicar HMA que produjeron esporas de cuatro morfotipos diferentes, uno de los cuales se identificó como G. microagregatum. El polimorfismo de los morfotipos obtenidos mediante la técnica de RAPD's permitió diferenciarlos con el cebador OPA2 y el agrupamiento por UPGMA con todos los cebadores mostró similitud mayor al 38% entre ellos. Los resultados moleculares y morfológicos, permitieron ubicar los cuatro morfotipos en el género Glomus pero posiblemente pertenecen a especies diferentes. Los resultados obtenidos son promisorios en la diferenciación de cepas nativas con bajo número de esporas colectadas a partir de muestras de suelos en proceso de rehabilitación, de los cuales no se conoce su composición de HMA. Arbuscular mycorrhizal fungi (AMF) presence and diversity were evaluated in undisturbed and disturbed soils form alluvial mining processes. The soils belong to the Tropic Fluvaquent, Typic Dystropept, and Typic Paleudult sub-groups which corresponded to Low, Middle and High terraces, respectively, of the Cauca river at Taraza town. AMF propagules were multiplied in Leonard jars under glasshouse conditions using sterile substrate, modified Hoagland's solution and different fractions of soil used as sources of inoculum, which corresponded to the size of the spores. A first assay was made in maize (Zea mays) which allowed mycorrhizal colonization in roots but not spore production. In a second assay, in kudzú (Pueraria phaseoloides)
Objetos, sujetos e ideas. Bienes etnológicos y memoria Marcos Arévalo, Javier.
Valadés Sierra, Juan M.
PASOS : Revista de Turismo y Patrimonio Cultural , 2009,
Abstract:
Les Normals, paradigma de l'educació femenina
M. Carmen Sierra Pellón
Temps d'Educació , 1997,
Abstract:
O Endosperma de café como material para estudos citológicos
Medina, Dixier M.;
Bragantia , 1964, DOI: 10.1590/S0006-87051964000100016
Abstract: the endosperm tissue of the coffee seed was used successfully for chromosome countings, acetic orcein technique having proved satisfactorily to stain the well spread metaphasic and prophasic chromosomes. endosperms with 62, 64, 66 and 68 chromosomes occur in the monosomic plants of c. arabica (n = 43) while only endosperms with 3n = 66 are formed in the typica variety (2n = 44). polyploid cells with 128 and 132 chromosomes were also observed and this occurrence was probably the result of endomitosis. direct observation of endosperm chromosomes gives the real cytological constitution of fertile gametes, the probable chromosome numbers of the progeny being inferred in advance.
Observa??es citológicas em Coffea: XIX - Microsporogênese em Coffea dewevrei
Medina, Dixier M.;
Bragantia , 1952, DOI: 10.1590/S0006-87051952000200004
Abstract: coffea dewevrei de wild, et th. dur. is a diploid species with 2n = 22 chromosomes. details on the microsporogenesis are presented in this paper. from pachynema to diakynesis the 11 bivalents were well differentiated into achromatic and chromatic regions : the centromere was in all chromosomes surrounded by deeply chromatic zones. only one pair of chromosomes was found to be attached to the nucleolus; it has a submedian centromere, the organizing region seeming to be located in the short arm. chiasmata were seen in diakynesis and metaphase i; in this later stage they were studied in detail and the chromosomes were classified as follows : a) 1 longer pair with 3 chiasmata; b) 2.7 pairs (average) with 2 chiasmata ; c) 7.3 pairs (average) with 1 chiasma. the 2-chiasmata chromosomes were of two kinds : "symmetric" and "assymmetric", depending on the position of their chiasmata in relation to the centromere. the anaphase is normal, pollen grains having 11 chromosomes. very seldon are pollen grains formed with 10 or 12 chromosomes. first mitosis in the microspores occurs before pollen shedding. it was concluded that microsporogenesis in the coffee plants studied is normal.
Observa??es citológicas em Coffea: XIV - Microsporogênese em Coffea arabica L. Var. rugosa K.M.C.
Medina, Dixier M.;
Bragantia , 1950, DOI: 10.1590/S0006-87051950000200003
Abstract: only one plant of coffea arabica l. var. rugosa k.m.c., is available for study its fruit production is very low. of the progeny observed, none has reproduced th rugose condition of the leaves characteristic of the parent plant. previous study ha shown that the rugose condition of the leaves could not be considered a somatic chimer because the tissues have a normal number (2n=44) of chromosomes. the present cytological study was undertaken in order to find out if the low yiel of the rugose variety could be related to abnormalities in microsporogenesis. the structure of the chromosomes in early prophase is difficult to study. in diaki nesis two pairs and sometimes three pairs of chromosomes appear to be attached to th nucleolus. also in diakinesis it is possible to locate the centromere in the chromosoni pairs and to count the chiasmata. it was observed that an average of 6.6 bivalent show one single chiasma, 12.3 bivalents show two chiamata and 3.0 bivalents shom three chiasmata. the average total number of chiasmata per cell at this phase is o 40.0, while at metaphase this number is reduced to 34.7. the first division in the mi crospore is normal and the resulting two nuclei differ in size and also in the size o their nucleolus. the polen grains are normal, giving 69% germination on a medium containinj 0,5% of agar and 15% of sucrose. it is concluded that microsporogenesis is normal and would not appear to be relate< to the low production of fruits of the rugosa variety. the fact that none of the progen1 has reproduced the rugose condition might be due to the limited number of plants observed.
Observa??es citológicas em Coffea: XIII - Observa??es preliminares em Coffea arabica L. Var. rugosa K. M. C.
Medina, Dixier M.;
Bragantia , 1949, DOI: 10.1590/S0006-87051949000100006
Abstract: the coffea arabica l. variety rugosa has been characterized as having rugose or roughened leaves. however, progenies of this variety obtained from selfed and open pollinated flowers have not, as observed to date, produced plants with characteristic rugose or definitely roughened leaves. this lack of rugose leaves in the seedling progeny of the variety rugosa led to the present cytological investigation to determine whether rugose leaves might be due to differences in the polyploid nature of the component leaf layers. chromosome counts were made in cells of tissue obtained from root tips of seedlings and from root tips from stem cuttings, and from very young leaf buds. chromosomes were also counted in the microsporocytes and in the microspores. the results of the cytological observations indicate that in the plant tissues examined there was an average number of 44 chromosomes. the counting of chromosomes in the coffee leaf buds was difficult due to the small size of the chromosomes. observations also showed that microsporogenesis in the variety rugosa was normal and that the microspores contained 22 chromosomes. the results of this investigation show that coffea arabica l. var. rugosa is a tetraploid plant, as are several other varieties of c. arabica that have been studied. the cytological observations also show that the rugose or rough condition of the leaves is not due to the presence of tissue layers of different polyploid nature.
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