Search

In long-lived species, deforestation can modify the genetic diversity patterns of recent populations. The spatial-structure genetics of Pinus leiophylla Schiede ex Schltdl. & Cham. was investigated in adults and seedlings of remnant populations from central Mexico. Two chloroplast intergenic regions were sequenced of two cohorts (adults and seedlings) of 121 individuals of P. leiophylla from three localities. Higher genetic differentiation was found in adults (ФST = 0.09) than in seedlings (ФST = 0.03). The discriminant analysis of principal components detected four genetic clusters and the Mantel test found a weak but significant isolation by distance pattern (r2 = 0.05, p = 0.002). Sixteen percent of genetic variation was explained by the spatial component according to the genetic neighborhood analysis. And the effect of three landscape features, i.e., elevation, aspect (sine and cosine), and land use, explored with ResistanceGA, detected that land use significantly restricts gene flow between populations, mostly in the farming category. This study emphasizes the critical role of preserving forest cover to maintain connectivity among remnants of P. leiophylla. Insights of this study will contribute to the conservation of conifers in Mexican temperate forests, especially within landscapes heavily altered by human activities. [ABSTRACT FROM AUTHOR]

Research on mycophagy has focused mainly on fungi with hypogeous fruiting bodies, while studies on epigeous fruiting bodies are rare. We evaluated spore activity and capacity to establish mycorrhizal associations for the ectomycorrhizal fungi Laccaria trichodermophora Mueller and Suillus tomentosus (Kauffman) Singer, Snell and Dick (both of which produce epigeous fruiting bodies) after being consumed by the mice Peromyscus alstoni Merrian and Peromyscus maniculatus Wagner. Passage through the digestive tract of both rodent species reduced spore activity of S. tomentosus but increased spore activity of L. trichodermophora. In contrast, passage through the digestive tract of P. alstoni increased the percentage of mycorrhiza formation by S. tomentosus, whereas mycorrhiza formation by L. trichodermophora decreased following gut passage in either species of mice. These results show that the studied rodent species have differential effects on mycorrhiza formation by two species of fungi with epigeous fruiting bodies and may play a significant role in maintaining mycorrhizal communities and healthy forest ecosystems in central Mexico. Key words: epigeous fruiting bodies, Laccaria, Peromyscus, Pinus, Suillus. La recherche en mycophagie porte surtout sur les champignons formant des fructifications hypogees, alors que les etudes chez les especes a fructification epigees restent rares. Les auteurs ont evalue l'activite et la capacite des spores a etablir des associations mycorhiziennes chez les champignons ectomycorhiziens Laccaria trichodermophora Mueller et Suillus tomentosus (Kauffman) Singer, Snell and Dick (tous deux produisant des fructification epigees), apres avoir ete consommees par les souris Peromyscus alstoni Merrian and Peromyscus maniculatus Wagner. Le passage a travers le tractus digestif des deux especes de rongeurs reduit l'activite des spores du S. tomentosus, mais augmente l'activite sporale du L. trichodermophora. Au contraire, le passage a travers le tractus digestif du P. alstoni augmente le nombre de mycorhizes formees par le S. tomentosus, alors que la formation de mycorhizes par le L. trichodermophora diminue suite au passage dans l'une ou l'autre des souris. Ces resultats montrent que chez les souris etudiees, les especes de rongeur exercent des effets differents sur la formation des mycorhizes par les deux especes de champignons formant des fructification epigees, et pourraient jouer un role significatif dans le maintien en sante des communautes mycorhiziennes et des ecosysteme forestiers du centre du Mexique. Mots-cles : fructifications epigees, Laccaria, Peromyscus, Pinus, Suillus. [Traduit par la Redaction], Introduction Mycophagy, where an animal consumes fungal mycelia, fruiting bodies, or spores, is a widespread eating habit in terrestrial ecosystems (Lawrence 1989). There are many cases of mycophagous invertebrate animals; [...]

In this research, physiological tests were carried out on the in vitro growth of four strains of ectomycorrhizal fungi (HECM) associated with Pinus leiophylla. The HECM strains were subjected to growth tests in different concentrations of glucose (10, 20, 30 and 40 g/L) and nitrogen sources (KNO3, (NH4)2HPO4 and urea). The variables of growth, final diameter, biomass, mean growth rate and biomass/area ratio were evaluated in the colonies. According to the statistical analysis, the Suillus pseudobrevipes strain (GF3246) presented a higher growth in the concentrations of glucose 20 and 30 (g/L); S. pseudobrevipes (GF3285) in KNO3 and (NH4)2HPO4; S. subtomentosus (GF3331) in 20 and 40 (g/L) and in S. variegatus (GF3349) the growth was indistinct among the treatments. The HECM strains presented different growth strategies according to their ability to explore, exploit and assimilate different nutrients. Due to the fact that the strains GF3246 and GF3349 presented higher of values biomass in low to medium concentrations of glucose and nitrogen sources, they are considered generalists and were selected to produce mycelial inoculum and induce mycorrhization and to evaluate their effectiveness on the survival and growth of Pinus leiophylla seedlings. [ABSTRACT FROM AUTHOR]

Floral visitors that act as pollinators are essential for sexual reproduction in angiosperms. Orchids (Orchidaceae), one of the families with the greatest species richness, present visual and chemical cues in their flowers to attract floral visitors, highlighting the shape, color and texture of the flowers, as well as the nectar, bait, pollen and floral aromas as rewards. Within the group, particular traits can be found that allow inferring the type of visitor that performs the pollination, that is, there are orchids with particular pollination syndromes. In this way, there are orchids whose flowers promote pollination by insects such as bees, wasps and butterflies, but there are species that are pollinated by birds (mainly hummingbirds). In this review, information is compiled that will allow orchids to be classified according to their floral visitors (pollinators) and that can serve as a guide to make inferences in the species that have not yet been described their visitors. [ABSTRACT FROM AUTHOR]

The soil microbiota is conformed by microorganisms present in the soil such as bacteria, fungi, algae, protists and archaea, mainly, which have a fundamental role in the mineralization and mobilization of nutrients, as well as in the protection of plants against pathogens, in addition to establishing mutualistic interactions in the rhizosphere. Therefore, microbiota play an important role in soil productivity, quality and structure. The objective of this bibliographic review was to Know the effect of anthropogenic activities on soil microbiota. From the review it was found that anthropogenic activities such as the use of agrochemicals, fires, erosion or change in land use have negatively affected the soil microbiota. There is evidence of a decrease in the diversity and abundance of microbial populations, in addition to the reduction or inhibition of the activity of microorganisms. This directly affects the functions of the microbiota (microbiome), since different microbial taxa influence soil physicochemical characteristics, biogeochemical cycles and plant population dynamics, although it is essential to conduct more exhaustive research to identify the effect of human activity. [ABSTRACT FROM AUTHOR]