Mariela Gómez-Romero’s research while affiliated with Universidad Michoacana de San Nicolás de Hidalgo and other places

Soil salinity is one of the main challenges that modern agriculture faces. Avocado, which is classified as a glycophyte, is very sensitive to salt stress. There are botanical varieties of avocado that differ in their salt tolerance. This study investigated how salt stress affects the in vitro germination of two avocado botanical varieties americana (West Indian breed) and drymifolia (Mexican native) with different salt tolerances. This study also assessed the potential role of the avocado PaHAK2 high-affinity K+ transporter HAK/KUP/KT in response to saline stress during germination. Salinity (60 mM NaCl) delayed the germination speed of the drymifolia variety relative to the americana variety. A computational 3D inference protein model of the PaHAK2 protein showed 10 highly conserved transmembrane domains. During the imbibition period, there was a differential increase in the expression of the PaHAK2 gene at 60 mM NaCl in both varieties, which suggests the presence of osmotic adjustment and regulation. The enhanced expression of PaHAK2 in the americana variety suggests an adaptive advantage to salinity. We conclude that PaHAK2 participates in the response of avocado to salt stress during seed germination.

Background: Many landscapes, both natural and anthropogenic, are dominated by degraded soils that have low phosphorus availability due to low overall phosphorus concentration or to phosphorus sequestration by iron-rich minerals. Questions and / or Hypotheses: Does the application of low molecular weight organic acids improve phosphorus availability and plant growth in phosphorus-poor soils, and is this effect modulated by ectomycorrhizal fungi? Studied species / data description /Mathematical model: Pinus pseudostrobus and its ectomycorrhiza Pisolithus arhizus, in addition to six sodium salts of organic acids. Study site and dates: The experiment was carried out in a shade house (35 % shade) in Morelia, Michoacán in 2015. Methods: We conducted experiments with Pinus pseudostrobus and its ectomycorrhiza Pisolithus arhizus in addition to six sodium salts of organic acids. Sodium salts of citrate, oxalate, acetate, tartrate, succinate and malate were added to the soil at 0, 4, 8, 16, 32 and 64 micromolar concentrations. Results: The salts of the organic acids-particularly tartrate and malate-solubilized phosphorus and improved plant growth after 12 months in the absence of P. arhizus. When plants were inoculated with P. arhizus, the effect of most organic acids was either detrimental or non-significant. However, citrate, tartrate and succinate improved biomass and morphological parameters. Conclusions: These results suggest that adding appropriate organic acids to heavily degraded soils can aid P. pseudostrobus establishment and its benefits are higher than the association with mycorrhiza for young plants during the initial stages of fungal colonization.

Aim of study: We assessed potential carbon (C) sequestration in gullies formed in Acrisols and Andosols, on the basis of long-term field restoration trials and GIS analysis. Area of study: Two field trials in Michocán, Mexico, restored with Pinus pseudostrobus, Pinus greggii and Pinus devoniana in 2005 and 2009. Material and methods: Soil C content was analyzed from field samples, and C content of aerial tree biomass of the three Pinus species was estimated by means of allometric equations. The potential restoration area was calculated with a GIS using available layers from the INEGI (Mexican National Institute for Geography and Statistics). Main results: The spatial analysis showed that 1.83% of the Mexican territory are Acrisols and 1.18% are Andosols. From which, 40.87% of Acrisols and 42% of Andosols are eroded. The area with gullies was 2810 km² for both groups of soils within the elevational range of conifer forests in Mexico. C content at the two restored sites was on average of 1.27 t/ha. Soil C content in a 30-cm depth profile was 4.25 t/ha. The potential C sequestration for an average period of 13 years for an area of 2810 km² was 3.947 megatons of C (MtC). A total of four states ‒ Michoacán, Chiapas, Oaxaca, and Puebla ‒ concentrate 89% of the possible capture. Research highlights: Severely degraded sites where gullying is dominant have a high potential for C sequestration once erosion has been controlled and plant cover has been restored.

In pioneering research, it has been documented that the CNT influences the development of plants through the balance of phytoregulators. Therefore, in this work the objective is to evaluate the effects of the CNT functionalized by non-covalent method with kinetin that have in Avena sativa. CNT was characterized by FTIR and Raman to confirm functionality. The results showed that the application of CNT with phytoregulators modified plant development.

Bark beetle infestations have historically been primary drivers of stand thinning in Mexican pine forests. However, bark beetle impacts have become increasingly extensive and intense, apparently associated with climate change. Our objective was to describe the possible association between abundance of bark beetle flying populations and the occurrence of given value intervals of temperature, precipitation and their balance, in order to have a better comprehension of the climatic space that might trigger larger insect abundances, an issue relevant in the context of the ongoing climatic change. Here, we monitored the abundance of two of the most important bark beetle species in Mexico, Dendroctonus frontalis and D. mexicanus. We sampled 147 sites using pheromone-baited funnel traps along 24 altitudinal transects in 11 Mexican states, from northwestern Chihuahua to southeastern Chiapas, from 2015 to 2017. Through mixed model analysis, we found that the optimum Mean Annual Temperatures were 17°C–20°C for D. frontalis in low-elevation pine-oak forest, while D. mexicanus had two optimal intervals: 11–13°C and 15–18°C. Higher atmospheric Vapor Pressure Deficit (≥ 1.0) was correlated with higher D. frontalis abundances, indicating that warming-amplified drought stress intensifies trees’ vulnerability to beetle attack. As temperatures and drought stress increase further with projected future climatic changes, it is likely that these Dendroctonus species will increase tree damage at higher elevations. Pine forests in Mexico are an important source of livelihood for communities inhabiting those areas, so providing tools to tackle obstacles to forest growth and health posed by changing climate is imperative.

Antecedentes y Objetivos: Los disturbios antropogénicos o naturales pueden ser tan fuertes que para recuperar sitios degradados se requiere de intervención. Una forma de facilitar el proceso de recuperación es mediante el uso de especies nativas adaptadas al ambiente local, pero aún existe desconocimiento sobre su desempeño. Asimismo, el establecimiento de interacciones con hongos micorrícicos puede contribuir a tener un mayor éxito en supervivencia y crecimiento de especies empleadas en la restauración. El arbusto Tecoma stans es una especie nativa con potencial para restauración, ya que se considera que tiene resistencia al estrés. Por lo tanto, en el presente estudio se exploró si establece interacciones con hongos micorrícicos y una bacteria, y si esto tiene efectos sobre su crecimiento. Métodos: Se estableció un experimento en condiciones semicontroladas, para lo cual se germinaron sus semillas y las plántulas se inocularon con hongos micorrícicos (Rhizophagus intraradices, Pisolithus arhizus y Scleroderma verrucosum) y con una bacteria (Azospirillum brasilense). Después de seis meses de crecimiento en los tratamientos de inoculo se cuantificó la tasa relativa de crecimiento, se estimaron rasgos morfofuncionales de la raíz y la parte aérea, y se midió el grado infección en las raíces. Resultados clave: Detectamos que todos los hongos infectaron las plántulas y cada uno afectó de forma distinta el crecimiento y los rasgos morfofuncionales. En la inoculación con S. verrucosum las plántulas crecieron más, tuvieron más hojas, una mayor copa y un sistema radicular de mayor volumen y con raíces de mayor diámetro. Conclusiones: Los resultados indican que el uso de hongos micorrícicos contribuiría al éxito del establecimiento de T. stans en la restauración, ya que promueve su crecimiento y características que potencialmente permitirían a la especie una mayor capacidad de ganancia de recursos.

Lichens are symbiotic organisms that comprise a fungus and a photosynthetic partner wich are recognized as a good indicator of climate change. However, our understanding of how aridity affects the diversity of saxicolous lichens in drylands is still limited. To evaluate the relationship between saxicolous lichen diversity and aridity in a central México dryland, a geographical transect was established of 100 km to build an aridity gradient in the semiarid zone of the State of Querétaro, Mexico, comprising ten sampling sites with a 10 km separation. Species richness, abundance and diversity of soil lichen species were recorded using two sampling methods: the quadrat-intercept and the line-intercept method, to compare their performance in assessing soil lichen diversity in drylands. The number of species and Shannon diversity of saxicolous lichens were higher at intermediate values of the aridity index (AI = 0.10–0.34). Quadrat intercept and point intercept methods gave quite similar results, which means that the selected method does not influence the results in a significant way. This study confirms the role of saxicolous lichens as climate change indicators and reveals the importance of the sampling method selection in the evaluation of different parameters of soil lichen diversity in drylands.

The authors wish to make the following corrections to their paper [...]