More than Maize, Bananas, and Coffee: The Inter- and Intraspecific Diversity of Edible Plants of the Huastec Mayan Landscape Mosaics in Mexico1.

More than Maize, Bananas, and Coffee: The Inter- and Intraspecific Edible Plant Diversity in Huastec Mayan Landscape Mosaics in Mexico. Global emergencies such as biodiversity loss and climate crisis urge us to identify and mainstream crop genetic resources in complex indigenous farming systems to understand their role as genetic reservoirs and identify synergies in productive landscapes between development, conservation, and food security. We aimed to characterize the inter- and intraspecific diversity of food plants of the Tének (or Huastec) in Mexico and their distribution within and between the different land-use systems along a tropical altitudinal gradient. Tének farmers manage a highly diverse and dynamic food biota in swidden maize fields, agroforestry systems, and home gardens. Even with a small sample size, our study provides a complete analysis of the food crop diversity in the research area. The Tének cultivate a high number of 347 registered species and variants, most of them at medium altitude. Intraspecific diversity dominates (69%). All land-use systems of the agroecosystem complex serve as a specific pool for plant genetic resources, and there is a low similarity between and within systems and localities, especially at the intraspecific level. The proportion of rare and unique food plants is high. We recommend an agroecosystem approach and prioritization for conservation as well as other efforts related to the in situ crop genetic capital. Supplementary Information: The online version contains supplementary material available at 10.1007/s12231-021-09520-9.

Más que maíces, plátanos y café: La diversidad inter e intraespecífica de plantas comestibles en los mosaicos de paisaje de los mayas huastecos en México. Las emergencias globales como la pérdida de biodiversidad y la crisis climática obligan a identificar y a reconocer los recursos fitogenéticos en los sistemas complejos agrícolas indígenas, para comprender su papel como reservorios genéticos e identificar sinergias en los paisajes productivos entre el desarrollo, la conservación y la seguridad alimentaria. El objetivo fue caracterizar la diversidad inter e intraespecífica de plantas alimenticias de los Tének (o Huastecos) en México y su distribución dentro y entre los diferentes sistemas agrícolas a lo largo de un gradiente altitudinal. Los agricultores Tének manejan una biota alimentaria muy diversa y dinámica en milpas, sistemas agroforestales y huertos familiares. Aun con el tamaño de muestra pequeño en este estudio, se proporciona un análisis completo de la diversidad de cultivos alimentarios en el área de estudio. Los Tének cultivan un elevado número de 347 especies y variantes registradas, la mayoría de ellas en la altitud mediana. La diversidad intraespecífica (69%) es dominante. Todos los sistemas de manejo del complejo agroecosistémico sirven como reserva específica de recursos fitogenéticos, y existe una baja similitud entre y dentro de los sistemas y localidades, especialmente en el nivel intraespecífico. La proporción de plantas alimenticias raras y únicas es alta. Se recomienda un enfoque agroecosistémico y de priorización para la conservación y otros esfuerzos relacionados con el capital genético de cultivos in situ.

Rheological Flow Behavior of Structural Polysaccharides from Edible Tender Cladodes of Wild, Semidomesticated and Cultivated 'Nopal' (Opuntia) of Mexican Highlands.

The aim of this study was to quantify the content of polysaccharides of edible tender cladodes (nopalitos) of three species of Opuntia and to evaluate the rheological flow behavior of isolated polysaccharides. A completely randomized experimental design was used to characterize a wild (O. streptacantha), a semidomesticated (O. megacantha) and a domesticated (O. ficus-indica) species. Mucilage content was higher (4.93 to 12.43 g 100 g-1 dry matter), tightly bound hemicelluloses were lower (3.32 to 1.81 g 100 g-1 dry matter) and pectins and loosely bound hemicelluloses were not different in wild than in domesticated species. Aqueous solution/suspensions of mucilage, pectins, hemicellulose and cellulose of all species showed non-Newtonian behavior under simple shear flow. The flow behavior of the structural polysaccharides was well described by the Ostwald de-Waele model. Pectins and mucilages exhibited the highest consistency indexes (K values ranged from 0.075 to 0.177 Pasn) with a moderated shear-thinning behavior (n values ranged from 0.53 to 0.67). Cellulose dispersions exhibited the most shear-thinning behavior (n values ranged from 0.17 to 0.41) and hemicelluloses showed a tendency to Newtonian flow (n values ranged from 0.82 to 0.97). The rheological flow properties of these polysaccharides may be useful to improve the textural and sensory qualities of some foods and pharmaceutical materials. Moreover, they can emerge as functional ingredients mainly due to the nutraceutical properties that have been attributed to nopalitos.

Biological soil crusts across disturbance­recovery scenarios: effect of grazing regime on community dynamics.

Grazing represents one of the most common disturbances in drylands worldwide, affecting both ecosystem structure and functioning. Despite the efforts to understand the nature and magnitude of grazing effects on ecosystem components and processes, contrasting results continue to arise. This is particularly remarkable for the biological soil crust (BSC) communities (i.e., cyanobacteria, lichens, and bryophytes), which play an important role in soil dynamics. Here we evaluated simultaneously the effect of grazing impact on BSC communities (resistance) and recovery after livestock exclusion (resilience) in a semiarid grassland of Central Mexico. In particular, we examined BSC species distribution, species richness, taxonomical group cover (i.e., cyanobacteria, lichen, bryophyte), and composition along a disturbance gradient with different grazing regimes (low, medium, high impact) and along a recovery gradient with differently aged livestock exclosures (short-, medium-, long-term exclusion). Differences in grazing impact and time of recovery from grazing both resulted in slight changes in species richness; however, there were pronounced shifts in species composition and group cover. We found we could distinguish four highly diverse and dynamic BSC species groups: (1) species with high resistance and resilience to grazing, (2) species with high resistance but low resilience, (3) species with low resistance but high resilience, and (4) species with low resistance and resilience. While disturbance resulted in a novel diversity configuration, which may profoundly affect ecosystem functioning, we observed that 10 years of disturbance removal did not lead to the ecosystem structure found after 27 years of recovery. These findings are an important contribution to our understanding of BCS dynamics from a species and community perspective placed in a land use change context.

Analgesic activity of Heliopsis longipes and its effect on the nervous system.

Heliopsis longipes S.F. Blake (Asteraceae: Heliantheae) (chilcuague) is used in Mexican traditional medicine against parasites and to alleviate tooth and muscle pains. Its biocide effect has already been experimentally demonstrated; however, its analgesic action and its action on the nervous system (NS) have not been investigated yet. The objectives of this study were to evaluate the analgesic action of affinin and the H. longipes root ethanol extract, as well as their effects on the NS using an animal model. The ethanol extract was obtained by maceration, and affinin was purified from it through chromatographic techniques. Chemical and thermal analgesia were used to assess their analgesic proprieties. Irwin's test was used to evaluate their stimulating or depressing effects. The ethanol extract and affinin displayed analgesic action similar to ketorolac and stimulating effect comparable to caffeine on the nervous system of adult mice.