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

Background: Photosystem II (PSII) is susceptible to heat stress. Plants naturally accumulate trehalose to improve stress tolerance. However, the mechanism by which trehalose affects PSII during heat stress is still unknown. Questions: How does trehalose affect PSII during heat stress? Studied species: Triticum aestivum L. Study site and dates: Shanghai, China. 2019-2021. Methods: Trehalose -pretreated wheat seedlings suffered from heat stress and their photosynthetic parameters were measured. Results: Heat stress caused a reduction in the photochemical efficiency of PSII, the electron transfer rate (ETR(II)), the quantum yield of regulated energy dissipationY(NPQ) and the coefficient of photochemical quenching (qP), but increased the quantum yield of non-regulated energy dissipation of PSII (Y[NO]). The shape of the fast chlorophyll fluorescence induction kinetics (OJIP) curve in the heat-stressed wheat was altered and the primary photochemistry maximum yield of PSII (Fv/Fo) and the PSII performance indicator PIabs were reduced. Accordingly, the activities of PSII and electron transport chain, the amount of ordered α-helix structures and the content of D1 protein also decreased. However, in trehalose-pretreated wheat, D1 protein and protein secondary structures of PSII were both protected, the electron transport activities of PSII and the whole chain were improved and greater fluorescence parameters values were maintained. Lower Y(NO) and more stable OJIP were obtained. Conclusions: Exogenous trehalose acted a vital role in the protection of the function of PSII, resulting in higherphotosynthetic capacity under heat stress.

Background: Funastrum species are widely distributed in Mexico and 70 % of its species are located in the national territory. The systematic information of the genus is scattered or outdated, as well as the knowledge of its geographical distribution and state of conservation. Questions: How many species of Funastrum are in Mexico and how are they distributed? What is the conservation status of the species in the country? Studied species: Funastrum. Study site and dates: Mexico, 2018-2021. Methods: Revision of national and international herbaria, databases (Tropicos, JSTOR, Naturalista, etc.) and intensive literature search, evaluation of conservation status following IUCN criteria and richness analysis using the MonographaR package in R. Results: Funastrum has 14 species in Mexico, seven of which are in some category of risk. A species identification key and descriptions are provided for each of the taxa, as well as distribution maps and a richness map. Conclusions: Mexico is recognized as a center of diversity for the genus with 14 of 20 species in the territory. For seven taxa, their inclusion in some risk category is suggested. Translate stop  

Background: The first monograph of the genus Viguiera was published in 1918 by Blake, including about 141 species. Schilling & Panero based on studies of molecular sequences of nuclear Internal Transcribed Spacer and External Transcribed Spacer, as well as cpDNA, proposed to reclassify the genus, relocating its species in at least other nine genera. Question: Is it possible to identify distinctive patterns between the species of the new classification of Viguiera s. l. and the results of the chemical studies reported? Species considered: Sixty-seven species within the wide Viguiera circumscription with chemical studies and biological activities reported. Results: The species of the genus Viguiera synthesize terpenoids represented mainly by sesquiterpene lactones and diterpenes, with triterpenes, polyacetylenes, volatile terpenoids and flavonoids also present. The main types of secondary metabolites were present in the studied species, although some compounds were more frequent than others in some clades. Conclusion: Germacrolides, heliangolides, furanoheliangolides, tetracyclic diterpenes and flavonoids are the main constituents of Viguiera and segregated genera. Some interesting chemotaxonomic relationships are noted. Nevertheless, nondistinctive clear patterns were observed between clades and chemical groups. These results may be a consequence of the reported chemical studies of the species of Viguiera s. l., which have not agreed on objetives or methodologies.

Background: Heteroflorum (Fabaceae) is a monospecific genus endemic to western Mexico. Community attributes of the forest where H. sclerocarpum is found are scarcely known, as well as its similarity with other tropical seasonal forests. Question: What is the composition, structure, and diversity of the tropical deciduous forest where H. sclerocarpum is physiognomically dominant? Study site and date: The study was carried out in the buffer area of the Zicuirán-Infiernillo Biosphere Reserve, in the Churumuco municipality of Michoacán, Mexico (2014). Methods: In three 0.1-ha sites, we sampled trees with a diameter at breast height ≥ 1 cm and lianas whose rooted stem had a diameter of ≥ 1 cm. We calculated the density, biomass, rank-abundance, rank-basal area curves, and alpha and beta diversity measures for each site. Results: We recorded 64 species from 21 families in 0.3 ha. Fabaceae had the highest number of genera, species, individuals, and biomass in all sites sampled. The sites varied in richness (33-41 species), density (176-247 individuals), basal area (2-2.9 m2), and maximum height of trees (12-16 m). Rank-abundance curves differed significantly. Rarefaction curves showed that 0Dα and 1Dα did not differ among sites, while 2Dα separated one of the sites, which also showed a different diversity profile. Beta diversity did not show a strong species turnover among sites (0Dβ, 1.38-1.45; 2Dβ, 1.35-1.56). Conclusions: The composition of trees and shrubs in the forest sampled was similar to other seasonal forests, while the density and diversity were among the lowest values.

Mexico has over 23,300 vascular plant species, half of which are endemic, and ranks third in species richness in the Americas. Compiling checklists and floras, and examining phylogenetic relationships are the ways we develop a better understanding of species richness. The plant checklist and the metadata of the sequences in GenBank can help determine how well represented Mexico’s vascular flora is, using the taxonomic and systematic studies done in Mexico and internationally. We formulated eight questions related to biological aspects, bibliometric indicators, methods, and the markers used in phylogenetic studies for species distributed in Mexico. The list of Mexico’s vascular species published in taxonomy and systematics articles was used to extract GenBank’s metadata using Datataxa. The selection, filtering, and descriptive statistics were obtained with scripts designed for this study. We found that 12,589 species have sequence records in GenBank, published in 3,807 articles. The journal Systematic Botany has more than 400 publications. The number of authors ranges from 1 to 6. Average impact factor was 1.64. Magnoliophyta, Poales, and Poaceae have the highest number of published articles. Parsimony and ITS are the most widely used method and marker, respectively. We explore the importance of Mexico as a biological repository for understanding the evolution of plants in global science. This is the first study on the importance of a country’s flora in phylogenetic work. Numerous groups and endemic species lack sequencing data that could contribute to the resolution of different lineages in the phylogeny.

Background: In the Yucatan Peninsula, some mangrove areas were filled with rubble and residential areas were latter developed. Questions: Can the knowledge of the forest structure and carbon storage be used to establish a baseline for urban mangrove conservation? Study species: Rhizophora mangle L., Laguncularia racemosa Gaertn f., Avicennia germinans L. y Conocarpus erectus L. Location and study year: Isla del Carmen, Campeche, 2017. Methods:  Sampling units were established for assessing vegetation structure and measuring above-ground and below-ground carbon stock in two mangrove zone; the first one was filled with rubble and the second without land use changes.  Results: The site filled with rubble had a basal area of 25.4 m2 ha-1, where A. germinans was the dominant species with stand density of 675 trees ha-1, with average height of 5.5 m and average diameter at breast height of 13.4 ± 1.6 cm. The site without land use changes had a basal area of 27.8 m2 ha-1 and A. germinans was also the most abundant species with 731 trees ha-1, but individuals were smaller (5.0 m tall) and with greater diameter at breast height (15.2 cm), as compared with the other site. The estimated total carbon stored in the second site (383 Mg C ha-1) was higher than in the first one (321 Mg C ha-1). Conclusions:  The ecological value of carbon sequestration and forest structure contributed to strengthening the conservation and protection measures against invasions of urban mangroves.

Advancing our current knowledge on floristic richness in Mexico requires access to different sources, including published and unpublished inventories, fascicles of ongoing floristic projects, and publicly available online databases. The evaluation of these sources reveals how extensive the information available on the country’s floristic diversity is, its heterogeneity, and the lack of protocols and standards for its proper organization, analysis, and synthesis. This review addresses the extent to which these sources of information provide the basis to achieve the long-awaited goal of completing the Flora of Mexico, and how traditional outputs of taxonomic work (Floras and checklists) are useful to other fields of biological research. We identified major knowledge gaps, as well as actual and potential uses by other scholars and the public. Although all reviewed sources focus on a better knowledge of the Mexican plant species, each one has its own approach, geographic coverage, and objectives, producing incompatibilities that hamper their integration for rapid and efficient synthesis and analysis. Such integration should offer an updated scenario of its taxonomic and geographical coverage, setting the foundations for organized protocols and strategies aimed to complete the Flora of Mexico in the short term. Floristic knowledge for the country continues to advance actively, as indicated by the growing number of floristic inventories and the buildup of online databases. This synthesis shows how much we know today about Mexico’s vascular plant richness and highlights the relevance of this knowledge to other fields of study of nature, particularly those related to its plant component.

Twenty-one years have elapsed of the 21st Century and within the framework of the celebration of the 100th volume of Botanical Sciences, it is relevant to assess the progress of the research on conservation and on the activities undertaken for protecting the plants of Mexico, including the complementary in situ and ex situ approaches. By means of a systematic search of scientific articles related to the conservation of the Mexican flora on the Web of Science database, for the 2000–2021 period, we identified different scientific inputs, all showing specific objectives for undertaking conservation activities. The publications that resulted from this search were classified into six categories: (a) Regions and Ecoregions; (b) Communities or Ecosystems; (c) Taxonomic Groups; (d) Species and Populations; (e) Botanical Gardens; and (f) Seed Banks. For these categories, the results are presented under the headings “in situ conservation” and “ex situ conservation.” Additionally, we assessed by a random examination, the bibliography used to support touristic development projects. The results show that, despite the wide temporal range considered in this review, and even though there is a vast number of publications related to the characterization of the Mexican biodiversity, the production of scientific work oriented to the development of plant conservation strategies and activities is still scarce. Also evident is the lack of connection and communication among researchers of different disciplines, highlighting the disciplinary or multidisciplinary activities that they undertake. Finally, ten conclusions are presented, and some future research activities are suggested for conserving the Mexican flora.

Background: The southeast of the Municipality of El Tambo, Cauca, Colombia it has an area of 34.68 km2 of Tropical Dry Forest (Bs-T), where 1,036 mestizos and Afro-descendants live, in a region of social, cultural, and economic complexity, who are cared for by specialists in traditional medicine, who use, manage and conserve medicinal plants, through traditional knowledge that adapts, transforms and dynamizes, through different practices. Questions: What are the practices of traditional medicine specialists who seek to conserve medicinal plants in the southeast of El Tambo, Cauca, Colombia? Site and years of study: southeast of El Tambo, Cauca-Colombia; January 2017 to August 2019. Methods: The research was carried out based on qualitative and quantitative ethnobotany, participatory-action-research-IAP, life histories, Jaccard's qualitative index, bibliographic review of states of extinction risk and provenance, consensual interviews, through the Delphi method for 101 species of medicinal plants used, managed and conserved by five specialists of traditional medicine. Results: 101 species of medicinal plants were described in Bs-T from the southeast of El Tambo, used by midwives, sobanderos, herbalists, and traditional doctors, who conserve them through 13 practices of the local medical system. Conclusions: Traditional medicine specialists protect a memory of 13 traditional medical practices that have been inherited generationally, learned and revitalized, allowing the preservation of a diversity of 101 species of medicinal plants that treat 243 different physical and cultural diseases.

Background: The presence of crude oil (CO) in the soil can lead to the death of plant species that cannot acclimate to these conditions. Questions: What will be the physiological response of two tree species growing in soil contaminated with different concentrations of CO? What will be its physiological plasticity in this context? Study species: Haematoxylum campechianum L. and Tabebuia rosea (Bertol.) DC. Study site: Tabasco, Mexico; 2017. Methods: The physiological performance of two tree species growing in contaminated soils subjected to different concentrations of CO (15,170 to 15,600 mg kg-1) for 292 days was evaluated; we measured CO2 assimilation (A), transpiration (E), water use efficiency (EUA), quantic efficiency of photosystem II (Fv/Fm and FPSII), electron transport rate (TTE), non-photochemical quenching (DNE), water and osmotic potential, and chlorophyll content. Results: Low physiological plasticity was found in both species; there was a hormesis effect where individuals in the lower concentration of CO presented a physiological performance superior compared with plants in the control treatment. In T. rosea, there was an increase in the assimilation and transpiration rate, FPSII, DNE and Fv/Fm towards the end of the experiment; the TTE decreased from the beginning to the end of the experiment in all treatments. H. campechianumshowed an increase in chlorophyll concentration towards the end of the experiment. Conclusions: Tabebuia rosea showed greater variability in their physiological response compared to H. campechianum, which suggests that they could be more sensitive to the presence of crude oil in the soil.