Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

Background: Forest fires play a crucial role in ecosystem dynamics, bringing both positive and negative effects that significantly impact areas like the Sierra Norte de Oaxaca (SNO). Question: What levels of severity most influence the distribution of trees in a forest? Studied species: Temperate Forest species. Study area: Oaxaca, Sierra Norte, January - December 2023 Methods: Data reported by CONAFOR from 1992 to 2020 was utilized. Spatial analysis was conducted using the Normalized Burning Index with SENTINEL satellite images in the SNO. Variables related to human activities, such as transportation routes and population, were included in the index. A total of 151 fire records were collected from 2006 to 2020. Results: Ixtlán had the highest number of fires during the evaluated period. The forest fire risk index indicated that the largest area at Very High risk is located in the Mixe district, highlighting the need for decision-makers to focus efforts on this region. Conclusions: Conclusions: Very High risk is distributed in the Mixe district, so it is important that decision makers focus efforts on this study area.

Background: Forest mulch is the habitat of decomposer organisms and protects the soil from erosion. In the seasonally dry tropical forest, this organic soil layer is lost due to the elimination of vegetation cover resulting from agricultural activities but could be recovered through restoration intervention. Prediction: The seasonality of rainfall, the composition and species richness of plantings and the recruitment in the areas under restoration explain the accumulation of the mulch mass. Study site and dates: Four-year-old restoration areas in the seasonally dry tropical forest of Quilamula, Sierra de Huautla, Morelos. Methods: Four samplings in areas under natural succession and in seven planting combinations that include between three and 12 species (six legumes and six non-legumes). Results: Including planting combinations and natural succession, the average mulch mass was 6.5 Mg/ha. As expected, mulch mass was greater in the plantings of 12 species compared to the natural succession and in the middle of the dry season compared to what was recorded at the end of the rainy season. Furthermore, forest mulch mass was positively related to the number of planted species and was highest where the lowest cover of the exotic grass Andropogon gayanus was recorded. Conclusions: Restoration plantings favor the recovery of the litter mass by increasing its mass with the number of species planted, while the invasion of exotic grasses reduces it.

Background: Some of the species that make up the legume family are used as animal feed and to improve soil fertility. However, their use is limited due to low seed availability and low germination rates. Questions: Which scarification treatment is most effective in increasing germination? What is the response of plants to growth under field conditions? Studied specie: Teramnus labialis (L.f.) Spreng. Study site and date: Ciego de Ávila, Cuba, 2019 year. Methods: Four scarification treatments (sanding, sulfuric acid, hot water, and liquid nitrogen (LN)) were evaluated under controlled laboratory and field conditions. Seed coat structures, imbibition capacity, electrolyte loss, and germination were studied under controlled laboratory conditions. Under field conditions, plant morphological traits were evaluated during the vegetative and reproductive phases. Results: Scarification with LN caused multiple cracks in the seed coat, while sulfuric acid caused wear and detachment of the seed coat. With the use of LN, seed imbibition and germination were improved. In addition, 78 % of plants emerged with this treatment and crop establishment was achieved 120 days after sowing. Conclusions: Scarification with LN of T. labialis seeds was the most effective treatment to improve germination and reduce the time to establishment of the species.

Antecedentes: El género Bartlettina (Eupatorieae, Asteraceae) es un grupo de plantas neotropicales. México presenta la mayor riqueza, donde se conocen 22 taxones de los cuales, 13 son endémicos al país. Los endemismos tienen requerimientos específicos de hábitat, por lo tanto, son más susceptibles a los disturbios antropogénicos y a la extinción. Los esfuerzos de investigación enfocados en estos grupos son prioritarios. Preguntas: ¿Cuál es la distribución de las especies endémicas del género Bartlettina en México?, ¿dónde se encuentran sus principales áreas de riqueza?, ¿cuál es su estado de conservación? Especies de estudio: Especies de Bartlettina endémicas de México. Sitio y años de estudio: México, enero 2022 a febrero 2024. Métodos: Se hizo una revisión de todos los ejemplares herborizados disponibles. Se obtuvo información taxonómica, geográfica y ecológica. Se elaboraron mapas de distribución e identificaron las áreas con mayor riqueza. Se evaluó el estado de conservación siguiendo el criterio B de la Unión Internacional para la Conservación de la Naturaleza. Resultados: Las especies se distribuyen principalmente en el bosque mesófilo de montaña, de Pinus-Quercus y Quercus. La Sierra Norte de Oaxaca, la zona de confluencia Sierra Madre Oriental-Faja Volcánica Transmexicana y la Sierra Madre Oriental son las regiones con mayor riqueza. Se determinó que seis especies están en una categoría de riesgo, dos Casi Amenazadas y cuatro tienen Datos Insuficientes. Conclusiones: La mayoría de las especies del grupo estudiado presentan distribución restringida y especificidad de hábitat, encontrándose en tipos de vegetación altamente amenazados, por lo tanto, requieren medidas de protección.

Background: Grasslands are a major landscape component of the Mexican Plateau but has been impacted strongly by grazing. The specific effects on species composition of this have not been sufficiently elucidated. Such knowledge is needed for management and conservation. Questions: What are the grass species composition and ground cover of grasslands along an intensive grazing – no grazing gradient? Studied species: Poaceae Study site and dates: Llanos de Ojuelos, Jalisco. 2016 Methods: Monthly surveys in 6 grassland sites, from severely overgrazed to 36 years without grazing. Results: We recorded 24 species of grasses. Grama grasses were significantly the most abundant but there were inter-site differences. Purple muhly dominated the ungrazed site, while poverty threeawn dominated another site. Between 1 and 49 % of the ground was bare. Conclusions: The differences in our sites allow a reinterpretation of the composition of mature, ungrazed grasslands in the area. Blue grama is touted as the climax species of regional grasslands. Until our survey, there was no evidence to consider any other grass species in this role. Our data support the view that dense prairies, rather than grasslands, were the XVI Century regional grasslands, dominated not by the blue grama, but by purple muhly, which is a decreaser under grazing by cattle, and was slowly replaced by grama grasses during the centuries ensuing the arrival of European livestock. Given their adaptation to grazing, blue grama was able to persist much longer in the systems.

Background: Infectious clones are copies of a virus genome produced in vitro or inside a vector and can infect inoculated healthy plants or cells. They are important tools to study the molecular biology of viruses. Questions: Is it possible to construct a Sugarcane mosaic virus infectious clone using methods suggested by other authors? Studied species: Sugarcane mosaic virus isolate Veracruz 1, Zea maize line B73, Nicotiana rustica. Methods: The Mexican viral isolate Sugarcane mosaic virus Veracruz 1 was used to construct an infectious clone after segment amplifications of the virus genome, intron insertion, and their further fusion by yeast homologous recombination. The clone was under the regulation of the Cauliflower mosaic virus 35S promoter and was tagged with the green fluorescent protein. Clones were then used to inoculate maize and tobacco plants and detached tobacco leaves. Results: The viral clone obtained did not produce symptoms in inoculated maize plants. However, the viral Coat Protein and Viral Protein genome-linked cistrons, and the green fluorescent protein signal were detected in both inoculated maize and in tobacco plants. Conclusions: We hypothesize that the ability of the clone obtained to infect tobacco is due to the use of the 35S promoter. This is the first monocot-infecting viral clone, that we are aware of, being able to be expressed in a dicot plant species.

Antecedentes: El tabaco fue usado y apreciado por considerable número de pueblos originarios en México y en el continente americano, empleado ritual y medicinalmente. Preguntas: ¿Cuál es la importancia del tabaco como planta sagrada en la cultura mazateca en la actualidad y qué factores socioculturales explican su saliencia? Especie de estudio: Nicotiana tabacum L. Sitio y años de estudio: Huautla de Jiménez, Oaxaca, México. 2023-2024 Método: Se aplicaron 93 entrevistas semiestructuradas a jóvenes, adultos y adultos mayores. Se construyó un índice de importancia cultural (IIC) basado en 12 variables tangibles e intangibles. Se realizó un análisis discriminante lineal (ADL) para conocer las variables socioculturales que influyen en la preservación de los saberes, prácticas y creencias del tabaco. Resultados: Existen 33 diferentes usos para N. tabacum, el mágico-religioso es el más referido. El IIC no reflejó la saliencia local de este recurso. El ADL separó los tres grupos etarios, y demostró que la edad, el idioma, y el ser partícipe de ceremonias en las que este recurso ocupa un lugar central, son las variables que explican estadísticamente (P ˂ 0.001) su preservación. Conclusiones: El desconocimiento del valor histórico y cultural del tabaco lo destituye de su vínculo con lo sagrado, fomentando una visión dañina y suscitando su mal empleo. Los jóvenes desconocen la importancia de este recurso en cuanto su uso mágico-religioso, y no hay espacios de reproducción cultural que permitan su aprendizaje.

El cambio climático global produce cambios repentinos en la distribución de las especies, poblaciones y comunidades, lo que genera una importante pérdida de biodiversidad, la cual también está estrechamente vinculado con la deforestación. En México, la deforestación se ha querido subsanar a través del uso de plantaciones de pinos. En el caso particular del bosque mesófilo de montaña, se ha estimado que el 90 % del bosque original se ha perdido en pocas décadas. Estudios de sucesión forestal han mostrado que algunos bosques mesófilos de montaña pueden reemplazar a los bosques de pino; es decir, los pinos pueden facilitar la repoblación natural de especies del bosque mesófilo de montaña. Así mismo, se ha reportado que las plantaciones de pino pueden ser facilitadoras para la reintroducción de especies en peligro de extinción de estados sucesionales intermedios y avanzados del bosque mesófilo de montaña. Para mitigar el efecto del cambio climático global sobre el bosque mesófilo de montaña, proponemos un modelo para llevar a cabo la migración asistida de plantas nativas del bosque mesófilo de montaña, usando las múltiples plantaciones de pinos que hay en México.

Background: Esmeraldas province has distinct agroecological zones with a natural rainfall gradient, with higher rainfall in the north-than-south. Hypotheses: Due to the high genetic variability in cocoa, clones from the south will be less affected by drought than those from the north. Plant material: Nine cocoa clones belonging to the National × Criollo complex: five from the north and four from the south, all grown in the field. Site and years of study: Esmeraldas province, Ecuador, during 2022. Methods: Seasonal variation was evaluated for: water potential (Y), hydraulic conductance (KL), photosynthetic rate (A), transpiration rate (E), stomatal conductance (gs), intercellular CO2 concentration (Ci), water use efficiency (WUE), leaf area index (LAI) and chlorophyll content (SPAD). Results: There were significant differences in Y, KL, A, E, gs, WUE, LAI and SPAD among clones, between seasons and the interaction clone × season. Drought caused a reduction in Y, which was associated with a differential reduction of 40 % in A and WUE, depending on the clone. No correlation was found between A and gs, suggesting that the reduction in A in drought was not due to the reduction in gs but to metabolic factors. Southern clones, showed drought had a smaller effect on Y, did not affect gs, E, LAI and SPAD and plants were more efficient in water transport due to higher rainfall KL. Conclusions: A differential physiological response to drought was found depending on the clone, supporting that genetic variability in the clones differently influenced physiological performance in drought.

Antecedentes: Stenocereus thurberi es una cactácea de importancia biocultural, fuera del área mesoamericana. La información sobre usos, prácticas de manejo e importancia económica es escasa. Preguntas: ¿cuál es el conocimiento, usos y formas de manejo de S. thurberi en un área fuera de Mesoamérica, como es Baja California Sur? y ¿cuál es el papel que juega esta especie en la economía local y regional? Especies de estudio: Stenocereus thurberi Sitio y años de estudio: Baja California Sur, México. 2023-2024. Métodos: Se aplicaron 128 entrevistas semi estructuradas a pobladores de 53 localidades; los datos obtenidos se analizaron con estadística descriptiva. Resultados: Se registraron nueve categorías de uso, siendo las más importantes comestible, construcción y combustible. Los entrevistados sudcalifornianos reconocen 15 variedades, siendo la roja y la blanca las más importantes; manejan a la pitaya dulce en tres formas: silvestre, manejo in situ y cultivo. Las prácticas de manejo son similares a las reportadas para Mesoamérica. Las poblaciones silvestres están sujetas a prácticas agrícolas similares a aquellas de huertos mesoamericanos. El manejo in situ es similar al que se practica en el centro y sur de México. No hay huertos modernos, pero hay evidencia de poblaciones cultivadas, posiblemente abandonadas de la época misional. La venta de los frutos permite obtener ingresos económicos. Conclusiones: La pitaya dulce en BCS satisface diversas necesidades debido al uso diversificado de sus estructuras y representa un beneficio económico. El manejo es similar al de la región mesoamericana. Se sugieren estudios para analizar posibles procesos de domesticación.