Seed integrity, effect of temperature and storage time on germination of Populus luziarum and P. primaveralepensis, endangered subtropical species from Mexico

César Jacobo Pereira MIGUEL ANGEL MUÑIZ CASTRO JOSE ANTONIO VAZQUEZ GARCIA Joel David Flores Rivas ALEJANDRO MUÑOZ URIAS FRANCISCO MARTIN HUERTA MARTINEZ (2022, [Artículo])

"Background: Populus luziarum and P. primaveralepensis are endemic species of western Mexico; growing in riparian forests they are critically endangered. The best way to conserve their seeds is unknown, which could be limiting for their conservation.

Hypothesis: The germinability of both subtropical species is like that of boreal and template Salicaceae species that disperse seeds in spring and early summer, as they germinate quickly with high percentages, and rapidly lose their viability when stored at ambient temperature.

Studied species: Populus luziarum and P. primaveralepensis. Study site and dates: Western Trans-Mexican Volcanic Belt. Jalisco, Mexico. October 2019.

Methods: The physical integrity of the seeds was assessed by X-ray imaging and compared with germinability. In addition, the effect of storage time (nine weeks) under two temperatures (4 and 21 °C) on the percentage and mean germination rate was evaluated.

Results: No significant differences were found between physical integrity and germination in freshly collected seeds for both species. Germination in the first 24 hrs was 91 and 95 % for Populus luziarum and P. primaveralepensis, respectively (week 0). Germination percentages were lower when stored at 21 °C, but P. primaveralepensis was decreased more slowly.

Conclusions: Seeds of subtropical Populus respond similarly to those of species from temperate and boreal climates with early seed dispersal, a crucial condition for establishing ex situ reforestation and conservation programs."

Salicaceae Seed physical integrity Seed storage conditions Subtropical endemic species White poplars BIOLOGÍA Y QUÍMICA CIENCIAS DE LA VIDA BIOLOGÍA VEGETAL (BOTÁNICA) BIOLOGÍA VEGETAL (BOTÁNICA)

Effect of Nitrogen, Phosphorus and Potassium on regional organic substrates in Agave salmiana production in Huichapan, Hidalgo, Mexico

EMILIO RAYMUNDO MORALES MALDONADO MONICA GUTIERREZ ROJAS RAMON JAIME HOLGUIN PEÑA Daniel Ruiz-Juárez Jorge Luis Vega Chávez Ana Cristina Reyes Godoy (2022, [Artículo])

"Mexico has 159 species of Agave spp. In the agri-food industry stand out are Agave tequilana, A. angustifolia, and A. salmiana. A limitation to producing maguey seedlings is the low availability of organic substrates that favor plant adaptation in the field. The objective was to evaluate the effect of nitrogen (N), phosphorus (P) and potassium (K) found in substrates in response to vegetative and root growth of A. salmiana in agricultural areas of Huichapan, Hidalgo, Mexico. The treatment consisted of earthworm humus (EH) and leaf compost (LC) substrates with materials from the region with different percentages of EH (100, 75, 50%), LC (5, 10%), and sand (20, 40%). The treatments were applied with 14 random replications in two phases in seeds and 40-day-seedlings. The variables evaluated were NPK amount and pH in substrates. The physiological variables measured were plant height, leaf number, stem diameter, root length, and volume. Significant differences (P≤0.05) were observed in seedling physiology due to the effect of the treatment. The best agronomic responses (plant growth and root length/weight) of Agave seedlings were T5 (75% earthworm humus + 20% sand + 5% leaf-soil) and T6 (50% earthworm humus + 40% sand + 10% leaf-soil); in both treatments, the NPK percentages were different from the control (Haplic Phaeozem soil) group. The final concentration of NPK in T6 was N = 0.04%, P = 398.13 mg Kg-1 and K = 11.88 meq 100g-1 . The results infer that NPK availability in soil and progressive acidification (initial pH = 8.6, final pH = 7.4) of the substrate can favorably influence the plant response. The interactions between NPK availability in the substrate and their use for a better response in maguey seedling adaptability open up new lines of research on the productive systems in the región of Huichapan, Hidalgo, Mexico."

maguey, nutritional quality, plant physiology, productive soils, seedling BIOLOGÍA Y QUÍMICA CIENCIAS DE LA VIDA BIOLOGÍA VEGETAL (BOTÁNICA) FERTILIDAD DEL SUELO FERTILIDAD DEL SUELO

Isolation and characterization of endophytic bacteria associated with roots of jojoba (Simmondsia chinensis (Link) Schneid)

RICARDO VAZQUEZ JUAREZ TANIA ZENTENO SAVIN ENRIQUE MORALES BOJORQUEZ Elvia Pérez Rosales Lilia Alcaráz Meléndez María Esther Puente Eduardo Quiroz Guzmán (2017, [Artículo])

"In this communication, the diversity and beneficial characteristics of endophytic bacteria have been studied in Simmondsia chinensis that has industrial importance because of the quality of its seed oil. Endophytes were isolated (N = 101) from roots of the jojoba plants collected, of which eight were identified by partial sequencing of the 16S rDNA gene. The isolated bacteria were Bacillus sp., Methylobacterium aminovorans, Oceanobacillus kimchi, Rhodococcus pyridinivorans and Streptomyces sp. All isolates had at least one positive feature, characterizing them as potential plant growth promoting bacteria. In this study, R. pyridinivorans and O. kimchi are reported as plant growth promoters."

Endophytic bacteria, plant growth promoters, Simmondsia chinensis, seed oil BIOLOGÍA Y QUÍMICA CIENCIAS DE LA VIDA MICROBIOLOGÍA BACTERIOLOGÍA BACTERIOLOGÍA

Phylogenetic relationships of Pseudo-nitzschia subpacifica (Bacillariophyceae) from the Mexican Pacific, and its production of domoic acid in culture

Sonia Quijano (2020, [Artículo])

Pseudo-nitzschia is a cosmopolitan genus, some species of which can produce domoic acid (DA), a neurotoxin responsible for the Amnesic Shellfish Poisoning (ASP). In this study, we identified P. subpacifica for the first time in Todos Santos Bay and Manzanillo Bay, in the Mexican Pacific using SEM and molecular methods. Isolates from Todos Santos Bay were cultivated under conditions of phosphate sufficiency and deficiency at 16°C and 22°C to evaluate the production of DA. This toxin was detected in the particulate (DAp) and dissolved (DAd) fractions of the cultures during the exponential and stationary phases of growth of the cultures. The highest DA concentration was detected during the exponential phase grown in cells maintained in P-deficient medium at 16°C (1.14 ± 0.08 ng mL-1 DAd and 4.71 ± 1.11 × 10−5 ng cell-1 of DAp). In P-sufficient cultures DA was higher in cells maintained at 16°C (0.25 ± 0.05 ng mL-1 DAd and 9.41 ± 1.23 × 10−7 ng cell-1 of DAp) than in cells cultured at 22°C. Therefore, we confirm that P. subpacifica can produce DA, especially under P-limited conditions that could be associated with extraordinary oceanographic events such as the 2013–2016 "Blob" in the northeastern Pacific Ocean. This event altered local oceanographic conditions and possibly generated the presence of potential harmful species in areas with economic importance on the Mexican Pacific coast. © 2020 Quijano-Scheggia et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

domoic acid, domoic acid, kainic acid, Article, cell growth, controlled study, diatom, Mexico, morphology, nonhuman, Pacific Ocean, phylogeny, plant cell, plant growth, Pseudo nitzschia, toxin analysis, cell culture technique, classification, diatom, CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA CIENCIAS DE LA TIERRA Y DEL ESPACIO OCEANOGRAFÍA OCEANOGRAFÍA