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

Background: Symbiotic associations of plants with fungi are widely distributed, more than 90 % of terrestrial plants carry out this symbiosis. In Mexico, such associations with basal plant groups have been poorly explored, an example of this being the family Lycopodiaceae of which there are few studies related to this associations in our country. Question: The question underlying this work is what is the status of Phlegmariurus reflexus (Lycopodiaceae) regarding symbiosis with arbuscular mycorrhizal fungi? Study site and years of study: The sampling was carried out in March 2019, in a fragment of cloud forest, located in the municipality of San Andrés Tlalnelhuayocan, Veracruz. Methods: Two transects of 1 × 15 m were traced, in each one the roots of three different individuals were collected separated each one by 5 m. The roots were stored in bottles with FAA solution (Formaldehyde-Alcohol-Acetic Acid). The samples were processed under the technique of thinning and staining modified for non-lignified roots. Results: Eight hundred and fifty root fragments were analyzed, finding a mycorrhization percentage of 6.8 – 17.1 %; all the sampled plants presented evidence of AM associations. The low percentages found agree with those reported for the Lycopodiaceae family in other parts of the world. Conclusion: This work represents a first approach to the study of mycorrhizae in the Lycopodiaceae in Mexico.

Background: Nuclear ribonucleoprotein particles play a key role in RNA processing and in the gene expression pathway. Interchromatin granules (GICs) involved in the metabolism of pre-messenger RNA (pre-mRNA) were described in Allium cepa and Chiranthodendron pentadactylon. Other particles as Lacandonia granules (LGs) were found in Lacandonia schismatica as well as Ginkgo biloba and Welwitschia mirabilis. LGs are structures equivalent to perichromatin granules (PCGs) described in mammals and to Balbiani ring granules (BRGs) described in the midge Chironomus tentans. PCGs and BRGs are involved in the metabolism of messenger RNA (mRNA). Here, we analyze the extranucleolar particles from Cycas revoluta and Ceratozamia mexicana and compare them to GICs and LGs using conventional electron microscopy and atomic force microscopy. Species study: Cycas revoluta (Cycadaceae) and Ceratozamia mexicana (Zamiaceae) Hypothesis: The extranucleolar ribonucleoprotein particles in the nuclei of C. revoluta and C. mexicana are equivalent to GICs or GLs. Methods: Fragments of young leaves of C. revoluta and C. mexicana were processed for standard transmission electron microscopy. Thin sections were stained with the EDTA technique preferential for ribonucleoproteins and osmium amine specific for DNA. From the semithin sections the samples were studied with the AFM and images of them were obtained. Results: Ribonucleoprotein particles 32 nm in diameter are present in the interchromatin and perichromatin space in C. revoluta and C. mexicana. Conclusion: Ribonucleoprotein particles present in the cell nuclei of C. mexicana and C. revoluta are ultrastructurally equivalent to LGs. Translate stop   Translate stop   Translate stop  

Background: Polystemma (Apocynaceae subfamily Asclepiadoideae) is a small genus currently with seven species characterized by having white glandular trichomes becoming crystalline in age; filiform corona appendages; and fusiform, smooth, mottled follicles. Exploration in the Balsas Depression of Michoacán, Mexico resulted in the discovery of an unknown species of Polystemma. Questions: Are the unknown Polystemma plants occurring in the Balsas Depression of Michoacán new to science? If so, how are they distinguished from other species of the genus, what are their ecological preferences, what is their distribution, and are they endangered? Studied species: Species of Polystemma. Study site and dates: Balsas Depression, Michoacán, México; 2001, 2003, 2004, 2014. Methods: Fieldwork to collect herbarium specimens and photograph plants; review of literature on Polystemma to determine taxonomic status; preparation of a morphological description; evaluation of conservation status using IUCN Redlist criteria. Results: Polystemma fishbeiniana is proposed as a new species and illustrated with photographs.  It occurs at two locations in the xeric scrub and open thorn forest of the Zicuirán-Infiernillo Biosphere Reserve, at elevations from 275 to 400 m.  Flowering occurs from June to September, with mature fruits present from October to March; dehisced fruits can persist on the plants for almost a year. Its conservation status is assessed as Endangered, EN B1ab(iii)+2ab(iii). Conclusions: Polystemma fishbeiniana is distinguished from congeners by its suffrutescent habit, small leaves, and flowers abaxially yellowish with a blackish to dark burgundy red margin and central line with short lateral extensions.These traits are otherwise unknown in the genus. Translate stop   Translate stop  

Background: The impact of plant management in an in situ - ex situ gradient, varies according to ecological, socioeconomic, cultural, and technological factors. Management may result in a divergence between wild and cultivated species, suggesting an incipient domestication. Questions and / or Hypotheses: We expected to find higher levels of leaf production and differences in essential oil characteristics in home-gardens and cultivated plots, which are systems with a more intensive management. Studied species / data description /Mathematical model: Lippia origanoides Kunth Study site and dates: natural vegetation, home-gardens and cultivated plots in Northwest Yucatan. 2018-2019. Methods: In four localities oregano management practices were documented in natural vegetation, home-gardens and cultivated plots. At each locality, in the three management systems, eight individuals of oregano were selected. ANOVAs were performed to evaluate the main effects and interaction among management systems and localities over leaf production, management intensity, and the quality and quantity of oil. Results: 23 % of the homes were found to manage oregano, generally in a combination of two or three management systems. Leaf production was three times greater in the cultivated plots, than in home-gardens and natural vegetation. There was no significant effect regarding management system over the yield of essential oils nor the carvacrol concentration. Most interviewees did not perceive intraspecific variability regarding the aroma of oregano. Conclusions: In situ individual selection for transplant is a management practice that, together with irrigation and other practices, could explain differences in leaf production, suggesting a process of incipient domestication of oregano. Translate stop   Translate stop  

Background: During an ongoing inventory of the orchids of the Bosque de Protección Alto Mayo, northern Peru, a population morphologically assignable to Liparis section Decumbentes was found. This is a little-known group restricted to wet montane Andean forests and consists of four species, from which the BPAM populations differs in leaf and labellum morphology. Hypotheses: The features of the plants led us to hypothesize that it represents an unknown species, which can be distinguished morphologically from its congeners. Taxon: Liparis section Decumbentes, Liparis sp. nov. Study site and dates: Peru, department of San Martín, Rioja province, Pardo Miguel Naranjos district, Bosque de Protección Alto Mayo, sector Venceremos. Methods: The unknown entity was studied in detail using fresh, pressed, and alcohol-preserved specimens. We also compared it to type specimens, other specimens of Liparis section Decumbentes housed in herbaria in Peru and abroad, and with descriptions from specialized literature. Results: A leaf feature and the unique labellum morphology of the unknown entity permit it to be distinguished clearly from all other species of Liparis section Decumbentes. Conclusions: The new species shares with L. sessilis the sessile leaf blades and the convex labellum, but differs from it and all other species of the section in its saddle-shaped labellum, which when spread out is narrowly obtrapezoid, with minute basal auricles, laciniate distal margins, and the apex projected into a narrowly triangular lobe.

Background: The sustainable use of native plants for human consumption and their incorporation as an ingredient in new foods is important. The fruits of Prosopis laevigata have been used occasionally for human consumption; however, they can constitute a sustainable source of nutrients and secondary metabolites. Questions and / or Hypotheses: Which is the nutrient content and phytochemical composition of leaves, flowers, and fruits of Prosopis leavigata? Study species / Data description / Mathematical model: Prosopis laevigata, Fabaceae family, reproductive parts (flower and fruit) and vegetative part (leaf). Site and years of study: Portugalejo de los Romanes, Lagos de Moreno, Jalisco. From 2018-2020 Methods:  The soluble solids, pH, acidity, and maturity index were determined in fruit. The nutrient content of the leaf, flower and fruit was evaluated; as well as macro and microelements in leaf, fruit and seed were determined; while soluble phenols, condensed tannins, hydrolyzable polyphenols, and total alkaloids were determined in leaf, flower and fruit. Results: There were significant differences in the nutrient content between organs. The content of phenolic compounds and alkaloids were highest in flower. The phenolic compounds with highest concentration in flower were the 4-hydroxybenzoic, r-coumaric and gallic acids, in leaf 4-hydroxybenzoic, chlorogenic and r-coumaric acids, and in fruit gallic, cinnamic and r-coumaric acids. Conclusions:  The content of nutrients, minerals and phytochemicals allows to conclude that this species can constitute a source of primary metabolites, minerals, and functional compounds for human or animal consumption, as well as for obtaining by-products.

Background: Salvia purpurea Cav., commonly known as “salvia moradita”, is a medicinal plant used in Oaxaca, Veracruz and Chiapas for its analgesic, anti-inflammatory and antidiarrheic properties. However, there is no scientific evidence supporting its pain alleviating potential. Hypothesis: Terpenes and phenolic compounds are responsible for the antinociceptive activity of S. purpurea extracts. Studied specimen: Salvia purpurea Cav. (Lamiaceae) Place of study and year: Salvia purpurea was collected in Santiago Huauclilla, Oaxaca, in October 2017. Methods: The acute toxicity (Lethal dose fifty, LD50) of the acetone, methanol and aqueous S. purpurea extracts was determined following the OECD protocol No. 423. The extracts were administered by gavage (p.o.) at doses ranging from 3 to 300 mg/kg to evaluate antinociceptive effects using the writhing and formalin tests in mice. HPLC analysis was performed to identify the nature of the metabolites present in the active extracts in comparison with their respective standards. Results: Acute toxicity was calculated to be LD50 > 2000 mg/kg, p.o. The antinociceptive effects for each extract were significant in all the tested doses and in a non-dependent dose manner in both tests. Phytochemical analysis allowed to identify compound of terpenic and phenolic nature. Conclusions: The results of the present study reinforce the analgesic and anti-inflammatory use of S. purpurea in Traditional Mexican Medicine where terpenes and phenolic compounds participate in these activities.

Background: Phenotypic and functional traits of plant populations vary with environmental conditions at local and regional scales. The analysis of these traits along environmental gradients provides information on the differential response of populations to climate changes. Objective: We analyzed the leaf morphological variation of an endemic oak to identify the degree of population differentiation along an environmental gradient. Study species: Quercus mexicana Bonpl. (Fagaceae). Study site and dates: Samples were collected from 39 populations in the Sierra Madre Oriental and east of the Trans-Mexican Volcanic Belt from 2014 to 2016. Methods: We measured eight macromorphological traits in 5,507 leaves and three micromorphological traits in 228 leaves. We performed univariate and multivariate statistical analyses to assess the morphological differentiation among populations, and the relationship between variation in leaf traits and environmental variables related to temperature and water availability. Results: Populations of Q. mexicana showed leaf morphological differentiation along its distribution. Significant linear correlations were found between leaf traits and environmental variables. Smaller and thicker leaves with lower density of trichomes and smaller stomata were found in populations located in more arid regions. In contrast, larger and thinner leaves with higher trichome density and larger stomata occurred in more humid places. Conclusions: Populations of Q. mexicana are adapted to a wide range of climatic conditions. Considering the predictive future climatic changes for the region (i.e., warmer and drier conditions), Q. mexicana populations with traits better adapted to a more humid and cooler environments could be negatively affected.

Background: The topographic and climatic diversity of the Mexican Transition Zone (MTZ) has favored species richness, disjunctions and endemism. Tigridia durangensis is an endemic geophyte with disjunct distribution in the MTZ. Questions and / or Hypotheses: What is the genetic diversity of Tigridia durangensis? Does it have genetic and phylogeographic structure? Were there any changes in its demographic history? Did the Quaternary climatic oscillations affect its area of distribution? Methods: The cpDNA regions ndhF-rpL32, rpL32-trnL, and 3´trnV-ndhC of 55 individuals from 10 populations were sequenced. The genetic diversity and the genetic structure were estimated with Hd, π and FST. The parameters GST and NST determined the phylogeographic structure. The genealogical relationships were inferred with a haplotype net. Phylogenetic hypotheses were generated with Bayesian inference and Maximum likelihood. The demographic history was determined by means of neutrality tests, analyses of mismatch distribution (AMD) and Bayesian skyline plot. The paleodistribution was estimated with ecological niche models (ENMs). Results: Tigridia durangensis showed genetic and phylogeographic structure. Nine haplotypes were identified; H1 and H2-H9 formed two intraspecific lineages. The neutrality tests were not significant. The AMD plot was congruent with the haplotype net. Tigridia durangensis experienced a bottleneck in the recent past and the ENMs displayed a disjunct distribution in all scenarios. Conclusions: In Tigridia durangensis, the bottleneck and the interruption of the gene flow between the haplogroups might have been associated with orogenic processes and volcanism of the Transmexican Volcanic Belt.

Background: Macromycetes play relevant roles in ecosystem functioning as pathogens, mutualists, and organic matter decomposers. Their diversity and distribution are strongly related to environmental conditions and vegetation types, however, there is a lack of ecological studies assessing which biotic and abiotic factors affect macrofungal communities. Questions: Which vegetation type harbors the highest macromycete diversity? Do macromycete diversity and species composition change among forest types? Which are the main environmental factors related to diversity and distribution patterns along the study area? Data description: Macromycete species richness and abundance, and environmental variables recorded in temperate forests. Study site and dates: Ayoquezco de Aldama, Oaxaca. June-November 2019. Methods: Macromycetes were collected twice a month in oak, oak-pine, pine-oak and pine forests, and environmental variables were recorded at each site. Species diversity and composition turnover were calculated using diversity and similarity indexes. The relation between diversity and species composition with environmental variables was determined with statistical analyses. Results: A total of 186 species were collected. Oak-dominated forests showed the highest similarity in macromycete diversity and species composition. The observed patterns of diversity and distribution were related mainly to air and soil humidity and temperature, topographic factors, and vegetation structure. Conclusions: Macromycete diversity and species composition can conspicuously change in short distances owing to the heterogeneity of habitats and resources provided by woody plants, and the topographic characteristic of the landscape. Vegetation type affects both macromycete diversity and distribution due to its influence on local temperature and humidity. Translate stop   Translate stop   Translate stop   Translate stop