Arid and semi-arid areas are highly productive ecosystems that have a great diversity of species, among which grasses stand out. These species have ecological, environmental, and economic importance. The objective was to identify the ecological descriptors of 15 native species of grasses and diversity patterns through multivariate analysis techniques (principal component analysis, PCA, and cluster analysis, CA), in addition to identifying potential distribution areas (current and future) and regions of high and low diversity from 3841 accessions and 21 climatic variables. Among the main results, the extreme values, coefficient of variation, and median for each species could be determined. PCA determined that, with 10 variables, it was possible to explain 54.36% of the variation between the analyzed species. CA resulted in the formation of four statistically significant groups, with specific climatic characteristics. Regarding potential distribution areas and climate change, a reduction in distribution is expected (2050) on most of the current surface, with a possible opportunity zone in the north of the country. Finally, two hotspots (high diversity areas) and four coldspots (low diversity areas) were identified among the analyzed species. These results can be used to create strategies for sustainable use and the conservation of these resources.

Forage grasses are an important component of livestock systems due to their contribution to animal feed, soil conservation, and carbon sequestration. In the face of climate change, analyzing stomatal characteristics allows us to understand the mechanisms of adaptation and tolerance to environmental stress. Therefore, the objective of this study was to determine the stomatal characteristics and trichome density of ten forage grasses present in a pine-oak dominated ecosystem. Sampling was carried out in October and November 2022 on a 1938 ha area. Mature, healthy leaves were selected, and epidermal impressions were obtained from the adaxial and abaxial surfaces using the cyanoacrylate method. Observations were made with an optical microscope at 400× magnification, quantifying stomatal density, trichome density, number of epidermal cells, and stomatal index per mm². The results indicated that nine species were amphistomatic, while Schizachyrium scoparium exhibited an epistomatic pattern. Muhlenbergia arizonica showed the highest stomatal density, and Setaria parviflora the lowest. It is concluded that there is high stomatal variability among species, highlighting its importance for the management and improvement of pastures.

Few studies have evaluated seed quality in native to semi-arid zones’ grasses. The objective was to validate published methodologies to carry out viability tests using Tetrazolium (TZ) test for caryopses (Cs) of Bouteloua curtipendula, Leptochloa dubia, Digitaria californica, Setaria macrostachya and Pennisetum ciliare, considering the imbibition time, TZ concentration and cut in the Cs. In addition, showing staining patterns according to evaluated treatments. Viability and vigor data was expressed as percent and hence transformed to arcsine. A completely randomized experimental design was carried out using a factorial arrangement: A) imbibition time before cutting; B), type of cut; C), TZ concentration, and Tukey's test (p<0.05) for mean comparisons. The Cs longitudinal cut was the most adequate (P<0.05), it allows observing Cs’ embryonic structures and determining damaged sites; however, the Cs of D. californica and S. machrostachya are permeable to TZ and it was not necessary to section the Cs, which facilitates its evaluation. The ISTA protocols for viability in Poaceae are not directly applicable for the species evaluated, because the imbibition time for these species is not considered, which was 3 to 4 hours. It is recommended to use a 0.5% TZ concentration and evaluate 12 hours after the imbibition time between Cs and the TZ solution. http://dx.doi.org/10.21929/abavet2023.102 e2023-24. https://www.youtube.com/watch?v=aIU7tfVqRCI Pocos trabajos han estudiado la calidad de semilla en pastos nativos de zonas semiáridas. El objetivo fue validar metodologías publicadas para otras Poaceae, para pruebas de viabilidad por Tetrazolio (TZ) en cariópsides (Cs) de Bouteloua curtipendula, Leptochloa dubia, Digitaria californica, Setaria macrostachya y Pennisetum ciliare; lo anterior, considera tiempo de imbibición, concentración de TZ y tipo de corte del Cs y muestra los patrones de tinción de tratamientos. Viabilidad y vigor se expresaron en porcentaje y se transformaron al arcoseno. Se utilizó un diseño experimental completamente al azar con arreglo factorial: A) tiempo de imbibición antes del corte; B), tipo de corte; C), concentración de TZ (V:V) y Tukey (P<0.05) para comparar medias. El corte longitudinal fue más adecuado (P<0.05), permite observar estructuras embrionarias y determinar sitios dañados. Cariópsides de D. californica y S. machrostachya son permeables a TZ y no requieren seccionado, lo que facilita su evaluación. Los protocolos ISTA para viabilidad en Poaceae no son directamente aplicables para las especies evaluadas, no consideran tiempo de imbibición de Cs; el cual, fue de 3 a 4 horas. Se recomienda usar concentración de TZ al 0.5% y evaluar 12 horas después del contacto entre la Cs y la solución de TZ para las especies aquí evaluadas. http://dx.doi.org/10.21929/abavet2023.102 e2023-24. https://www.youtube.com/watch?v=aIU7tfVqRCI http://dx.doi.org/10.21929/abavet2023.102 e2023-24. https://www.youtube.com/watch?v=aIU7tfVqRCI