Doctorado en Ciencias en Recursos Naturales y Medio Ambiente en Zonas Áridas
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El Doctorado en Ciencias en Recursos Naturales y Medio Ambiente en Zonas Áridas buca generar conocimiento científico e innovaciones tecnológicas para el aprovechamiento sustentable de los recursos bióticos en función del agua y del ambiente en zonas áridas, con una visión sistémica y compromiso ético y social.
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ItemMorphometric and molecular properties of Aloe vera (L.) under water deficit and salinity conditions(Universidad Autónoma Chapingo, 2023-05)Aloe vera (L.) is a well-known plant with valuable properties attributed to the polysaccharides present in its gel, particularly acemannan. However, the structure and composition of these polysaccharides can be influenced by environmental factors prevailing in arid regions. This study aimed to compare the morphometric and molecular behavior of A. vera under semi-controlled conditions of shade netting in response to water deficit and salinity. A randomized block design with four replications was used, featuring large plots with two soil moisture contents (20.7% field capacity and 12.3% permanent wilting point) and small plots with five salinity levels (0, 20, 40, 60, and 80 mM NaCl). Results showed a reduction in leaf width and thickness, fresh biomass, and gel percentage, but an improvement in gel quality. Additionally, an RNA extraction method suitable for samples with high polysaccharide content is described. Finally, RT-qPCR (Reverse Transcription Quantitative Polymerase Chain Reaction) analysis revealed a positive regulation of a glucomannan mannosyltransferase (GMMT) gen of A. vera induced by salinity and salt-water stress combination.
ItemExpresión génica como indicador de viviparidad en nogal pecanero (Carya illinoinensis [Wangenh.] K. Koch)(Universidad Autónoma Chapingo, 2023-05)La viviparidad en Carya illinoinensis se refiere al desarrollo específico de la nuez en la que se minimiza la etapa de latencia y germina antes de ser cosechada. Este problema fisiológico ha sido estudiado y reportado en diferentes especies vegetales. Sin embargo, en nuez pecanera la información sobre los mecanismos genéticos implicados en el desarrollo y la viviparidad siguen siendo insuficientes. El objetivo de este estudio fue evaluar la expresión de genes relacionados con las fitohormonas ácido abscísico y giberelinas durante diferentes etapas fenológicas de la nuez, con el fin de contribuir en el conocimiento a nivel molecular de los mecanismos de expresión génica durante el desarrollo y viviparidad de la nuez pecanera, en el Norte de México. Con apoyo de herramientas bioinformáticas se diseñaron primers adecuados para ser utilizados en el estudio de la viviparidad de la nuez. Mediante diferentes protocolos se evaluó la extracción de ARN a partir del tejido embrionario de la nuez, obteniendo un protocolo eficaz en el aislamiento de ARN de calidad para ser usado en ensayos de PCR. Finalmente, fue posible realizar ensayos de PCR tiempo real y evaluar la expresión génica en diferentes etapas fenológicas de la nuez pecanera. Estos resultados son un acercamiento para dilucidar aún más el mecanismo molecular del desarrollo y viviparidad de la nuez pecanera.
ItemNext-generation massive sequencing and the bacterial profile of ticks from wild and domestic animals and blood of humans in the chihuahuan desert(Universidad Autónoma Chapingo, 2022-12)Ticks are a type of arthropod belonging to the Ixodoidea suborder, which parasitize domestic and wild animals for food. During the pathogenesis process, they transmit many bacterial diseases in parasitized vertebrates, some of which are zoonotic, such as Rocky Mountain spotted fever caused by Rickettsia rickettsii, different types of Ehrlichiosis, granulocytic anaplasmosis, Q fever, Lyme disease, among others. In the context of public health, both globally and particularly in northern Mexico, there is well-founded concern due to the increase in the population of stray dogs, which increases the number of vectors of these diseases that affect animal hosts, as well as the population that resides near these animals. Likewise, this type of vector also affects various important wild species in the region under analysis, functioning as reservoirs of tick-borne pathogens (TBP) that can spread to urban areas, and can also affect the health of threatened species as in the case of the Mapimí Bolson tortoise (Gopherus flavomarginatus). The purpose of the following study is to analyze by means of next-generation sequencing (NGS) the bacterial communities in the blood of people who were exposed to tick bites and compare it with people not exposed to this factor, as well as to analyze the bacterial profile of two species of ticks of the family Ixodidae and Agarasidae of importance in public, ecological and veterinary health in the Comarca Lagunera region and the Chihuahuan desert.
ItemPhysicochemical, functional, and bioactive compounds characterization of mucilage from irrigated Opuntia spp. and its application as an edible coating(Universidad Autónoma Chapingo, 2023-03)Plants of the genus Opuntia spp. occupy a preponderant place due to their ability to adapt to extreme climatic conditions. Cladodes are an important source of mucilage, which is a promising compound to be used as an agro-industrial additive. Three irrigation regimes were tested: non-irrigated (rainwater), supplemental irrigation where plants were irrigated at field capacity (0.28 m3 m-3 ) when soil water content reached the permanent wilting point (0.14 m3 m-3 ), and full irrigation (100 % of the evapotranspiration of the crop) on 'Amarilla Olorosa', 'Cristalina', 'Dalia Roja' and 'Roja Lisa' varieties of prickly pear cactus. The cladodes of these varieties were collected to extract and purify the mucilage. The mucilage was characterized in terms of yield, color, chemical composition, infrared spectroscopy, viscosity, molar mass, functional properties, total polyphenols, and antioxidant capacity. The structure of the mucilage obtained corresponded to a xyloglucan skeleton with arabinose ramifications. In general, the mucilage of 'Amarilla Olorosa' and 'Roja Lisa' plants under no irrigation produced the highest mucilage content, better lightness, carbohydrate, fiber content, relative water content, and solubility; while parallelly, the ash content was lower compared to the mucilage from 'Cristalina' and 'Dalia Roja' varieties. The mucilage of the 'Amarilla Olorosa' plants under no irrigation was the most viscous. On the other hand, the mucilage powder of the non-irrigated 'Cristalina' variety had the highest swelling index with high concentrations of total polyphenols and antioxidant capacity. Therefore, this mucilage, along with sodium alginate, was used to elaborate an edible coating. This coating was useful to preserve the commercial quality of avocado halves. Therefore, water restriction in prickly pear cactus plants of the varieties studied here, is a feasible strategy to produce mucilage with physicochemical characteristics relevant for agro-industrial purposes.
ItemPost-fire dynamics of growth and structure in mixed conifer forest of northern México.(Universidad Autónoma Chapingo, 2023-03)Fire is one of the most important disturbances for fire-dependent ecosystems and drives the patterns of vegetation structure and composition. The objective of this study was to characterize the structural dynamics of a mixed conifer forests of the Sierra Madre Occidental (SMO) affected by fires. Vegetation was sampled at three fire severity levels: high, moderate, and low, and the unburned level was included as a control. Species richness (S), Shannon index (H), and the Evenness index (E) were calculated. The diameter-size class and height class of the trees were determined by applying the indices H, and E indexes and the coefficient of variation (CV). Differences in the indices calculated across fire severity levels were determined by analysis of variance (ANOVA) and Tukey's multiple comparison tests. Results showed no significant differences (p ≤ 0.05) in species diversity indices among fire severity levels; however, diameter and height classes were lower in areas affected by high-severity fire. Increment cores and crosssections of fire-scarred trees were also collected and analyzed using dendrochronological techniques to generate tree ages and descriptive statistics involved in fire history studies. Synchrony between fire history and tree establishment was determined, and climatic data values were correlated with the number of trees established per year. Forty-one fire events were reconstructed over the period 1855-2019. Overall, the mean fire interval (MFI) was 2.28 years and 12.17 years for large fires. The number of trees established per year was influenced by the prevailing dry conditions in September and October of the previous year and the wet conditions that occurred in December of the same year. These results constitute an example of forest response to fire severity and its historical behavior and may support further studies related to the influence of fire on other forest communities present in the SMO.
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