Dinámica del rendimiento de grano de sorgo en relación al tipo de planta, densidades de población y dos condiciones de humedad en Marín, N.L.

Tesis (Maestría en Ciencias en Producción Agrícola) UANL

Efecto de la tensión hídrica edáfica en diferentes etapas del desarrollo sobre el crecimiento de Phaseolus acutifolius var. latifolius F. y Phaseolus vulgaris L.

Tesis (Maestría en Ciencas Especialidad en Producción Agrícola) UANL

Estudio morfoanatómico y algunos aspectos ecofisiológicos - de especies silvestres de frijol (Phaseolus spp) en Nuevo León

Tesis (Maestría en Ciencias con Especialidad en Botánica). UANL

Ecuaciones de volumen y funciones de ahusamiento para Pinus durangensis Mart. y Pinus teocote Schl. et Cham. del ejido Vencedores, San Dimas, Durango, México [por] Cruz Contreras Aviña

Tesis (Maestría en Ciencias Forestales) U.A.N.L.

Ajuste de ecuaciones de volumen y funciones de ahusamiento para Pinus teocote Schl. et. Cham y Pinus pseudostrobus Lindl. el estado de Nuevo León

Tesis (Maestría en Ciencias Forestales) U.A.N.L.

Caracterización silvícola y estructural de rodales de Pinus pseudostrobus Lindl. en el sur de Nuevo León, México [por] Marco Antonio Quiñones Bayona.

Tesis (Maestría en Ciencias Forestales) U.A.N.L.

Caracterización, ordenación y clasificación númerica en nopal (Opuntia spp.) mediante atributos morfológicos y físico-químicos por Mariano Molina Velázquez

Tesis (Maestría en Ciencias Agrícolas) U.A.N.L.

Estudio electroquímico de aceros aleados al manganeso embebidos en mortero para la determinación de su resistencia a la corrosión

Tesis (Maestro en Ciencias de la Ingeniería Mecánica con Especialidad en Materiales) UANL, 2001.

Evaluación de la corrosión atmosférica del acero expuesto en diversas atmósferas

Tesis (Maestro en Ciencias de la Ingeniería Mecánica con Especialidad en Materiales ) U.A.N.L.

Análisis de la actividad de extractos crudos de Juglans regia L., Juglans mollis y Carya illinoensis contra mycobacterium tuberculosis

Tesis (Maestro en Ciencias con Especialidad en Química de Productos Naturales)

Estudio anatómico epidérmico en las hojas del género stanhopea (orchidaceae) y sus implicaciones taxonómicas

Tesis (Doctorado en Ciencias Biológicas con Especialidad en Botánica) UANL

Cultivo de callo in vitro como una alternativa para evaluar resistencia a salinidad y sequía en frijol Phaseolus vulgaris L.

Tesis (Doctorado en Ciencias Biológicas con Especialidad en Botánica) UANL

Caracterización de Germoplasma sobresaliente de papa solanum tuberosum L. en México mediante RAPD y SSR

1Tesis ( Doctor en Ciencias con Especialidad en Biotecnología ) U.A.N.L.

El habla de la comunidad cubana en Montreal

Ce travail contient une première caractérisation générale du discours de la communauté cubaine à Montréal, avec une attention particulière sur deux aspects: le comportement de certains traits qui caractérisent l'espagnol de Cuba chez les locuteurs migrants, et les possibles variations produites par le contact linguistique. Pour ce faire, nous utilisons les données d'un corpus élaboré par la chercheuse à partir de conversations semi-dirigées enregistrées (registre colloquial) avec 19 Cubains: dix hommes et neuf femmes vivant à Montréal. L'analyse des données nous permet de vérifier que les traits caractéristiques étudiés se sont conservés dans le discours des Cubains résidants dans la ville, mais quelques variations se sont produites, provoquées par le contact avec les langues dominantes (français-espagnol, et moins en anglais-espagnol) et d'autres variétés de l'espagnol, ainsi qu’avec une réalité socio-économique, politique et culturelle très différente de celle d’origine. Les variations morphosyntaxiques ont été détectées principalement dans les mots invariables (prépositions). Au niveau lexico-sémantique, nous avons trouvé essentiellement des emprunts lexicaux. Il existe également des prêts sémantiques, des calques et des changements de fréquence de certains mots. Concernant le niveau pragmatique, nous avons remarqué un ralentissement du rythme dans les conversations de l'échantillon qui pourrait être dû à la situation du bilinguisme fonctionnel. En résumé, le discours des Cubains participants dans cette étude montre quelques-uns des traits caractéristiques à toute situation de contact de langues, mais aussi des particularités relatives aux caractéristiques de la communauté étudiée (les attitudes linguistiques, par exemple), à la distance typologique entre les langues impliquées (espagnol et français) et au contraste entre les sociétés d’origine et d’accueil, entre autres.

Studies on arbuscular mycorrhiza (AM) in the Alentejo (Portugal) using pea mutants resistant to AM fungi as a control tool for field conditions

The utilization and management of arbuscular mycorrhiza (AM) symbiosis may improve production and sustainability of the cropping system. For this purpose, native AM fungi (AMF) were sought and tested for their efficiency to increase plant growth by enhanced P uptake and by alleviation of drought stress. Pot experiments with safflower (Carthamus tinctorius) and pea (Pisum sativum) in five soils (mostly sandy loamy Luvisols) and field experiments with peas were carried out during three years at four different sites. Host plants were grown in heated soils inoculated with AMF or the respective heat sterilized inoculum. In the case of peas, mutants resistant to AMF colonization were used as non-mycorrhizal controls. The mycorrhizal impact on yields and its components, transpiration, and P and N uptake was studied in several experiments, partly under varying P and N levels and water supply. Screening of native AMF by most probable number bioassays was not very meaningful. Soil monoliths were placed in the open to simulate field conditions. Inoculation with a native AMF mix improved grain yield, shoot and leaf growth variables as compared to control. Exposed to drought, higher soil water depletion of mycorrhizal plants resulted in a haying-off effect. The growth response to this inoculum could not be significantly reproduced in a subsequent open air pot experiment at two levels of irrigation and P fertilization, however, safflower grew better at higher P and water supply by multiples. The water use efficiency concerning biomass was improved by the AMF inoculum in the two experiments. Transpiration rates were not significantly affected by AM but as a tendency were higher in non-mycorrhizal safflower. A fundamental methodological problem in mycorrhiza field research is providing an appropriate (negative) control for the experimental factor arbuscular mycorrhiza. Soil sterilization or fungicide treatment have undesirable side effects in field and greenhouse settings. Furthermore, artificial rooting, temperature and light conditions in pot experiments may interfere with the interpretation of mycorrhiza effects. Therefore, the myc- pea mutant P2 was tested as a non-mycorrhizal control in a bioassay to evaluate AMF under field conditions in comparison to the symbiotic isogenetic wild type of var. FRISSON as a new integrative approach. However, mutant P2 is also of nod- phenotype and therefore unable to fix N2. A 3-factorial experiment was carried out in a climate chamber at high NPK fertilization to examine the two isolines under non-symbiotic and symbiotic conditions. P2 achieved the same (or higher) biomass as wild type both under good and poor water supply. However, inoculation with the AMF Glomus manihot did not improve plant growth. Differences of grain and straw yields in field trials were large (up to 80 per cent) between those isogenetic pea lines mainly due to higher P uptake under P and water limited conditions. The lacking N2 fixation in mutants was compensated for by high mineral N supply as indicated by the high N status of the pea mutant plants. This finding was corroborated by the results of a major field experiment at three sites with two levels of N fertilization. The higher N rate did not affect grain or straw yields of the non-fixing mutants. Very efficient AMF were detected in a Ferric Luvisol on pasture land as revealed by yield levels of the evaluation crop and by functional vital staining of highly colonized roots. Generally, levels of grain yield were low, at between 40 and 980 kg ha-1. An additional pot trial was carried out to elucidate the strong mycorrhizal effect in the Ferric Luvisol. A triplication of the plant equivalent field P fertilization was necessary to compensate for the mycorrhizal benefit which was with five times higher grain yield very similar to that found in the field experiment. However, the yield differences between the two isolines were not always plausible as the evaluation variable because they were also found in (small) field test trials with apparently sufficient P and N supply and in a soil of almost no AMF potential. This similarly occurred for pea lines of var. SPARKLE and its non-fixing mycorrhizal (E135) and non-symbiotic (R25) isomutants, which were tested in order to exclude experimentally undesirable benefits by N2 fixation. In contrast to var. FRISSON, SPARKLE was not a suitable variety for Mediterranean field conditions. This raises suspicion putative genetic defects other than symbiotic ones may be effective under field conditions, which would conflict with the concept of an appropriate control. It was concluded that AMF resistant plants may help to overcome fundamental problems of present research on arbuscular mycorrhiza, but may create new ones.