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

Background: Knowledge of structural attributes and the habitat of the species is essential to assess their conservation status and propose actions for their conservation and management. Questions: What are the structural attributes of the population of J. jaliscana, the characteristics of its habitat, and the environmental factors that could be influencing its distribution and abundance? Study site and dates: The field sampling was carried out in populations of J. jaliscana in ejido El Cuale, municipality of Talpa de Allende, Jalisco, México, in July 2019. Methods: In plots of 500 m2, the structural attributes of the population of J. jaliscana were determined and through an RDA, the environmental factors that could be influencing its distribution and abundance were investigated. The composition and structure of the entire community was described. Results: Juniperus jaliscana registered 385 ind. ha-1 and a basal area of 8.98 m2 ha-1. The variables with the greatest influence on the abundance and distribution of J. jaliscana were the incidence of fires and grazing. 119 species, 94 genera and 52 families were recorded. Psidium salutare was found for the first time for the state of Jalisco and Prionosciadium tamayoi was described as a new species for science. Conclusions: Juniperus jaliscana concentrated its population in small diameter categories. The environmental factors with the greatest influence on their distribution and abundance were fires, grazing and dry environment conditions. The habitat of J. jaliscana was shared with species endemic to western Mexico.

Background: In Mexico, where 50 % of the original Tropical montane cloud forest (TMCF) has been lost due to human activities, the restoration of these forests is essential. Questions and/or hypotheses: (1) L. styraciflua favors the survival and growth of Q. germana and M. schiedeana species (2) Are there competitive effects between nurses and beneficiary species? and (3) Is the magnitude of these positive/negative interspecific interactions affected by the canopy cover of nurses? Studied species: Liquidambar styraciflua L. (pioneer tree), Magnolia schiedeana Schltdl. (mid-successional tree) and Quercus germana Schltdl. & Cham. (late-successional tree). Study site and dates: A fallow in Xilitla, state of San Luis Potosí, Mexico, between 2016 and 2018. Methods: Seedling of mid- and late-successional species were transplanted 0.3 m and 2 m away from the stems of pioneer tree (protected and unprotected saplings, respectively). Performance of the species were compared after two years and the effects of canopy cover of pioneer trees. Results: Pioneer trees facilitated the establishment probabilities of the mid-and late-successional ones. Increasing canopy cover of pioneer trees enhanced the establishment probabilities of both beneficiary species. Conclusions: Joint transplanting of pioneer trees with mid- and late-successional tree seedlings in their close vicinity is a strategy to favor the recovery of the ecosystem.

Background: Sotol production has grown in recent years. There is interest in establishing monocultures to mitigate the overexploitation of wild populations. However, for an efficient establishment and management of plantations it is important to know the elemental composition of Dasylirion cedrosanum. Hypotheses: The mineral composition of sotol reflects the mineral composition of the soil solution where it grows. Studied species: Dasylirion cedrosanum Trel. Study site and dates: Plants and soils were sampled during September and October 2020 in San Lorenzo, Buenavista and General Cepeda, Coahuila. Methods: Stems, leaves and soils were collected and their elements were analyzed. In addition, morphological characters were measured for each specimen. Data were analyzed with multivariate statistical techniques.   Results: Ca and N were highly concentrated in the soil and in the plants. In all three localities, Se levels were high in the plants. However, Se in the soil solution was not detectable. Individuals from San Lorenzo and General Cepeda showed high levels of Cu and Ba, although Cu was not detectable in the soil. Growth showed negative association with As, Ba, Cd, Cr, Mo, Ni and Pb and Mg was related to higher sotol growth. Conclusions: Dasylirion cedrosanum has mechanisms for the acquiring and concentrating from elements in the soil solution, even when these are in low concentrations.

Background: Capsicum spp. grow in environments with different incident radiation, that could modify the plant growth and the concentration of phytochemicals in fruits. Hypothesis: Shading positively affects phenology and fruit yield, decreases the total contents of phenols (TPC), flavonoids (FLV), proanthocyanidins (PAN) and carotenoids (CAT) in fruits of wild Capsicum species. Studied species: Capsicum annuum var. glabriusculum: amashito (AMA) and garbanzo (GAR), and C. frutescens (Pico Paloma, PIP) Study site and dates: Huimanguillo, Tabasco, Mexico; 2020 and 2021. Methods: Seeds were treated with gibberellic acid (GA3) (500 mg L-1) for 24 h prior to seeding. The seedlings were transplanted in an open field and under two levels of shade (35 and 70 %) under a subsplit plot design with four replicates. TPC, FLV, PAN and CAT were determinate in immature and ripe fruits by UV-vis spectrophotometry. Results: Shade accelerated the phenological processes from the first bifurcation of the stem, and decreased the fruits ripening time from anthesis of the genotypes studied. Shade only increased the yield of the AMA genotype and reduced the contents of TPC, FLV, and CAT; however, these metabolites increased under open field conditions. Conclusions: The shade reduced the duration of phenological stages including the ripening period of fruits, and increased the plant height of the Capsicum spp. The increase in yield by shading effect only was observed in AMA genotype. The content of phytochemicals in Capsicum fruits is reduced by shading levels.

Background: The 8th version of the "World Checklist of Vascular Plants" (WCVP) was recently published under the coordination of the Royal Botanic Gardens, Kew. It consists of a list of taxonomic names of species, genera, and families of vascular plants representing the most comprehensive and integrated list available today. Questions: How many accepted species does the WCVP include? Is the quality of the included information acceptable? How has the publication of worldwide species names evolved over time? Does the checklist include the species recorded for Mexico? Studied species: Worldwide species of vascular plants included in the WCVP. Study site: Worldwide and Mexico. Methods: A database was created based on the WCVP to answer the research questions. The number of genera and species by taxonomic status (accepted and synonyms) was quantified, some information quality tests were carried out, and the potential number of undiscovered species in the world was estimated using non-parametric techniques. Results: The WCVP contains 1,233,172 names, of which 418,737 are accepted. It is estimated that around 25 % more unknown species remain to be discovered in the world. The quality of the information contained in the WCVP is quite reliable and complete; only 3 % of Mexican species are not included in the WCVP. Conclusions: The WCVP synthesizes current taxonomic knowledge in an integrated manner and is useful for systematic and automated analyses. At the country level, at least for Mexico, it stands as an important reference source when attempting to understand and evaluate floristic knowledge.

Background: Seed germination strategies are important for exotic species to identify the factors that control seed germination and establishment. Questions and /or Hypotheses: Temperature and light germination requirements for seeds of Calotropis procera do not change neither in its native regions nor in lands where it is exotic. Calotropis procera show germination traits that may increase their probability of colonization. Studied species: Calotropis procera is a perennial plant native to some desertic areas in Asia and Africa and now naturalized in America. Study site and dates: Mature fruits were collected in Oaxaca in September 2019 to test germination parameters. The last experiment was conducted in September 2021. Methods: We determined the effect of different temperatures, photoblastic response, and loss of viability of seeds kept at laboratory conditions for two years. We performed several sowings under controlled conditions and achieved germinability, t50 and the time to germinate. Results: Seeds were non-dormant, neutral photoblastic and did not lose viability after two years of dry storage. Temperature affected germinability and t50. Optimum germination temperature was 30 °C with no germination above 40 °C. Conclusions: Germination requirements of seeds of Calotropis procera studied were similar to those reported worldwide. Though seed germination was affected by maximum mean temperatures, seeds germinated fast and at high percentages under a wide range of temperatures, which together with other attributes, may confer C. procera great chances for successful colonization.

Background: Mesoamerica is one of the most important biodiversity hotspots on the planet. Despite significant efforts made over two centuries to contribute to the floristic knowledge of this region, our understanding of its flora is still scattered and uneven. Questions: What is the magnitude of the vascular plant species richness in the Usumacinta River Basin? Study site and dates: Usumacinta River Basin (Guatemala and Mexico), 1838-2018. Methods: We compiled the checklist by systematizing the floristic information acquired from various sources derived from numerous floristic and ecological studies. Results: We recorded 6,977 species, 1,892 genera and 274 families. The largest numbers of species (5,746) and records (58,859) correspond to the Mexican portion of the Usumacinta River Basin, compared to its Guatemalan counterpart (4,445 species and 19,952 records). The most species-rich families were Orchidaceae (598 species), Fabaceae (512), and Asteraceae (476). The prevalence of these and all other families with significant contributions to the flora varied among three elevation-defined sectors into which the Usumacinta River Basin was subdivided (lower, middle, and upper basin). Conclusions: The Usumacinta River Basin is a strategic region for plant biodiversity conservation as it hosts almost one third of all vascular plant species known for Mesoamerica and ca. 6 % of the entire flora in the Americas. Further botanical exploration should focus on those areas of the basin for which little or no information is available in order to gain a better appreciation of its flora.

Background: Populations of Capsicum annuum var. glabriusculum are found in a wide portion of the Mexican territory, and it is ancestor of many cultivated forms relevant for the Mexican diet. Questions: What are the proportions of phenotypic and genetic variation distributed among its sampled regions, populations and within populations. How does the climate correlates to the population’s phenotypic variation. Species: Capsicum annuum var. glabriusculum. Study sites and years: 24 populations form three regions were sampled: Northwest, states of Sonora and Sinaloa; South: Oaxaca and Southeast Tabasco and Yucatán, in Mexico. The experiment was performed between years 2016 to 2018. Methods: Fruits from single plants were collected in wild populations. Plants were grown in a greenhouse. Nested ANOVAS were performed to estimate phenotypic and genetic variance components for different spatial scales. Climate correlation was estimated through univariate and multivariate methods. Results: 49.8 % of phenotypic variation was detected within families, 11.1 % among families (within populations), 21.3 % among populations and 17.6 % among regions. The genetic basis of phenotypic variation was 50.1% on average, for this genetic variation 34.2 % was found among regions, 39.4% among populations and 26.3 % within populations. Climate factors generated different patterns of correlations for vegetative, foliar and reproductive traits. Conclusions: Northwest plants were shorth, with small leaves and large fruits, Southeast plants were tall, with large leaves and small fruits, South plants developed intermediate phenotypic traits. Climate explained a large proportion of phenotypic differentiation.

Background: Agave potatorum is an endemic species of ecological, cultural and economic importance. Despite its importance and its overexploited status, it is barely cultivated and its natural populations have been disappearing, so an alternative is propagation by plant tissue culture. Questions: Is it possible to regenerate new individuals from somatic structures? From which explant do more seedlings regenerate? What combination of plant growth regulators stimulates more bud formation? Species studied: Agave potatorum, seeds from Oaxaca, Mexico Study site and dates: Botanical Garden, Institute of Biology, UNAM, Mexico City, Mexico. Since 2020 Methods: The explant culture of cotyledons, stems and leaves sections in modified MS medium was explored, one month with BAP (0-2 mg/L) combined with 2,4-D (0-0.5 mg/L). Subsequently in MS without plant growth regulators. The obtained plants with 3 or more roots underwent an acclimatization process. Results: The seeds' germination was achieved and at two months, the in vitro (56.04 %) and ex vitro (31.87 %) germination were obtained. At 10 months after the induction period, the total number of shoots and plantlets of all treatments was 228, most of them (206) were with BAP 1.5-2 mg/L with 2,4-D 0.5 mg/L promoted the regeneration of 8.1-12.5 shoots/explant of stem and leaf. More than 70 % of the plants survived in greenhouse after two months of culture. Conclusions: This investigation can contribute to the conservation of Agave potatorum, address climate change, conserve ecosystemic services, and strengthen the economy by using this and other endangered species sustainably.

Background: Chthamalia is a genus of Gonolobinae distinctive by its climbing or creeping habit, its flowers up to two centimeters in diameter and its cyathiform gynostegial corona with generally linear appendages. Eight species have been reported in Mexico, but none of them correspond to the taxon studied in this article. Questions and/or hypotheses: What are the characteristics that differentiate the individuals of this taxon with respect to other species of Chthamalia? What is its distribution and conservation status? Studied species: Chthamalia tehuacana and morphologically similar species. Study site and dates: Tehuacán Valley, Puebla, Mexico, 2021-2022. Methods: An intensive search for information related to the genus was carried out and eight herbaria and databases were consulted. A comparative analysis between morphologically similar species was performed. The conservation status of the new species was evaluated following the guidelines of the IUCN. Populations were observed for floral visitors and semi-structured surveys were carried out to know the common names and uses of the taxon. Results: The new species Chthamalia tehuacana is described and compared with C. ojadapantha, C. schaffneri, and Matelea pueblensis. Detailed images of the species as well as floral visitors of C. tehuacana are provided. A distribution map is presented and a conservation status of Vulnerable is suggested. Conclusions: This contribution enriches the knowledge of Chthamalia in Mexico, which now has nine registered species and increases its level of endemism to 78 %. Likewise, it highlights the high diversity of Apocynaceae in the Tehuacán-Cuicatlán Valley.