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

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
César Jacobo-Pereira ◽  
Miguel Ángel Muñiz-Castro ◽  
J. Antonio Vázquez-García ◽  
Joel David Flores Rivas ◽  
Alejandro Muñoz-Urias ◽  
...  
Keyword(s):  
Storage Time ◽  
Germination Rate ◽  
Volcanic Belt ◽  
Early Summer ◽  
Ex Situ ◽  
Effect Of Temperature ◽  
Physical Integrity ◽  
X Ray Imaging ◽  
Mexican Volcanic Belt ◽  
Subtropical Species

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.

scholarly journals Experimental seed germination for ex situ conservation of Mexican Podostemaceae

2019 ◽  
Vol 97 (3) ◽  
pp. 413 ◽  
Author(s):  
Valeria Flores-Enríquez ◽  
Guillermo Castillo ◽  
Margarita Collazo-Ortega
Keyword(s):  
Seed Germination ◽  
Storage Time ◽  
Light Quality ◽  
Germplasm Conservation ◽  
Seed Storage ◽  
Germination Percentage ◽  
Seed Banks ◽  
Ex Situ ◽  
Effect Of Temperature ◽  
Collection Site

<p><strong>Background</strong>: Podostemaceae are extremely susceptible to local extinction by habitat loss. Since ~70 % of the river systems in Mexico show some degree of water contamination, it is relevant to generate information about seed storage and germination behavior to design germplasm conservation strategies (<em>e.g</em>., <em>ex situ</em> seed banks) of Mexican podostemads.</p><p><strong>Hypotheses</strong>: Seed germination decreases as seed storage time increases. Further, light quality, temperature and collection site influence similarly the germination response of both species.</p><p><strong>Studied species</strong>: <em>Marathrum foeniculaceum</em> Humb. &amp; Bonpl., <em>Noveloa coulteriana</em> (Tul.)<em> </em>C. Philbrick</p><p><strong>Study site and years of study</strong>: 13 different seeds collections (1996-2013), at four locations in the rivers Horcones and Arroyo del Rincon Jalisco, México. </p><p><strong>Methods</strong>: A germination chamber experiment was performed to evaluate the effect of temperature, light quality and storage time on the germination of both species.</p><p><strong>Results</strong>: Seeds lose viability after nine years of storage. In both species, the time to reach the highest Accumulated Germination Percentage (AGP) was faster in seeds of one-two yr compared to seeds of six-seven yr. <em>N. coulteriana</em> have significant differences in Final Germination Percentage (FGP) between collection rivers. Storage time affects AGP of <em>N. </em>coulteriana more than in <em>M. foeniculaceum.</em></p><p><strong>Conclusions</strong>: Both species can form <em>ex situ</em> seed banks up to 8 yr age in paper bags storage. <em>N. coulteriana</em> is more susceptible to variation in storage conditions compared to <em>M. </em><em>foeniculaceum</em>. Collection site affect seed germination after storing.  Long-term conventional <em>ex situ</em> seed germination storage is not a viable strategy to conserve germplasm of Podostemaceae.</p>

scholarly journals Geochemical Evidence for Slab Melting in the Trans-Mexican Volcanic Belt

2006 ◽  
Vol 48 (3) ◽  
pp. 537-562 ◽  
Author(s):  
A. Gomez-Tuena ◽  
C. H. Langmuir ◽  
S. L. Goldstein ◽  
S. M. Straub ◽  
F. Ortega-Gutierrez
Keyword(s):  
Volcanic Belt ◽  
Slab Melting ◽  
Geochemical Evidence ◽  
Mexican Volcanic Belt ◽  
Trans Mexican Volcanic Belt

scholarly journals Evidence for geomagnetic excursions recorded in Brunhes and Matuyama Chron lavas from the trans-Mexican volcanic belt

2013 ◽  
Vol 118 (6) ◽  
pp. 2648-2669 ◽  
Author(s):  
Daniel M. Michalk ◽  
Harald N. Böhnel ◽  
Norbert R. Nowaczyk ◽  
Gerardo J. Aguírre-Diaz ◽  
Margarita López-Martínez ◽  
...  
Keyword(s):  
Volcanic Belt ◽  
Matuyama Chron ◽  
Mexican Volcanic Belt ◽  
Trans Mexican Volcanic Belt

Tertiary arc-magmatism of the Sierra Madre del Sur, Mexico, and its transition to the volcanic activity of the Trans-Mexican Volcanic Belt

1999 ◽  
Vol 12 (6) ◽  
pp. 513-535 ◽  
Author(s):  
D.J Morán-Zenteno ◽  
G Tolson ◽  
R.G Martı́nez-Serrano ◽  
B Martiny ◽  
P Schaaf ◽  
...  
Keyword(s):  
Volcanic Activity ◽  
Volcanic Belt ◽  
Arc Magmatism ◽  
Mexican Volcanic Belt ◽  
Sierra Madre ◽  
Sierra Madre Del Sur ◽  
Trans Mexican Volcanic Belt

Volcano-sedimentary processes at Las Derrumbadas rhyolitic twin domes, Serdán-Oriental basin, Eastern Trans-Mexican Volcanic Belt

2021 ◽  
pp. SP520-2021-144
Author(s):  
Marie-Noëlle Guilbaud ◽  
Corentin Chédeville ◽  
Ángel Nahir Molina-Guadarrama ◽  
Julio Cesar Pineda-Serrano ◽  
Claus Siebe
Keyword(s):  
Volcanic Belt ◽  
Debris Avalanche ◽  
Density Currents ◽  
Content Type ◽  
Mexican Volcanic Belt ◽  
Wide Range ◽  
Eruptive Episode ◽  
Basin Floor ◽  
Supplementary Material ◽  
Trans Mexican Volcanic Belt

AbstractThe eruption of the ∼10 km3 rhyolitic Las Derrumbadas twin domes about 2000 yrs ago has generated a wide range of volcano-sedimentary deposits in the Serdán-Oriental lacustrine basin, Trans-Mexican Volcanic Belt. Some of these deposits have been quarried, creating excellent exposures. In this paper we describe the domes and related products and interpret their mode of formation, reconstructing the main phases of the eruption as well as syn-and-post eruptive erosional processes. After an initial phreatomagmatic phase that built a tuff ring, the domes grew as an upheaved plug lifting a thick sedimentary pile from the basin floor. During uplift, the domes collapsed repeatedly to form a first-generation of hetero-lithologic hummocky debris avalanche deposits. Subsequent dome growth produced a thick talus and pyroclastic density currents. Later, the hydrothermally-altered over-steepened dome peaks fell to generate 2nd generation, mono-lithologic avalanches. Subsequently, small domes grew in the collapse scars. From the end of the main eruptive episode onwards, heavy rains remobilized parts of the dome carapaces and talus, depositing lahar aprons. Las Derrumbadas domes are still an important source of sediments in the basin, and ongoing mass-wasting processes are associated with hazards that should be assessed, given their potential impact on nearby populations.Supplementary material at https://doi.org/10.6084/m9.figshare.c.5752296

Past and recent biodiversity profiling in ancient Lake Chalco Mexico by a metagenomics analysis

2021 ◽  
Author(s):  
Bárbara Moguel ◽  
Liseth Pérez ◽  
Luis David Alcaraz ◽  
Socorro Lozano-García ◽  
Luis Herrera-Estrella ◽  
...  
Keyword(s):  
Volcanic Belt ◽  
Environmental Dna ◽  
Radiocarbon Dates ◽  
The Past ◽  
Mexican Volcanic Belt ◽  
History Of ◽  
High Throughput Dna Sequencing ◽  
High Altitude Lake ◽  
Taxonomic Groups ◽  
The Relationship

&lt;p&gt;For decades, paleoecological studies in lake sediments have focused on reconstructing the environments of the past and explaining phenomena linked to climatic variations. Recent advances in high-throughput DNA sequencing have allowed access to environmental DNA (eDNA) and ancient sedimentary DNA (sedaDNA) as a new and efficient proxy for past and present biodiversity. The basin of Mexico (BM) is located in the central part of the Trans-Mexican Volcanic Belt at 2,200 m a.s.l.; with the southern portion harboring the Chalco sub-basin. Lake Chalco is one of the last remaining natural aquatic ecosystems within the ever-expanding urban area surrounding Mexico City. The paleoenvironmental history of this lake has been previously characterized using sedimentological and geochemical proxies, as well as preserved microfossils (diatoms, pollen) with a temporal framework based on multiple radiocarbon dates. However, information for the remaining taxonomic groups and metabolic pathways remained unexplored. Here, we present the first metagenomics-based study for the Holocene in a high-altitude lake in Central Mexico &amp;#8211;Lake Chalco. We explored the relationship between the lake&amp;#8217;s paleoenvironmental condition and estimations of taxonomic and metabolic profiles across the sedimentary sequence (2.5 meters long). Multiple biological and abiotic variables revealed three main environmental phases: 1) a cool freshwater lake (FW1: 11,500-11,000 cal years BP), 2) a warm hyposaline lake (HS2: 11,000-6,000 cal years BP), and 3) a temperate, subsaline lake (SS3, &lt;6,000 cal years BP). We describe the structure of the microbiota community and taxonomy richness turnover in the three Holocene paleoenvironmental phases. During the past 12 000 years BP the most abundant domains in Lake Chalco sediments were Bacteria, followed by Archaea, and Eukarya (36,722 genera). The analysis of functional proteins showed high biodiversity with a total of 27,636,243 proteins identified, but it was only possible to annotate 3,227,398 of them. Also, we identified several genes associated with some relevant pathways, such as methanogenesis. Altogether, this study allowed us to reconstruct the natural history of lake Chalco and its surroundings.&lt;/p&gt;

Late Cenozoic tectonics offshore western Mexico and its relation to the structure and volcanic activity in the western Trans-Mexican Volcanic Belt

1993 ◽  
Vol 32 (4) ◽  
pp. 543-559
Author(s):  
Hugo Delgado Granados
Keyword(s):  
Volcanic Activity ◽  
Volcanic Belt ◽  
Late Cenozoic ◽  
Western Mexico ◽  
Mexican Volcanic Belt ◽  
Cenozoic Tectonics ◽  
Trans Mexican Volcanic Belt

La tasa de convergencia calculada indica que la tectónica del occidente de México ha sido tensional durante los últimos 3 Ma. Este estilo de deformación se ve reflejado en la formación de estructuras rift en la parte occidental de la Faja Volcánica Trans-Mexicana [FVTM]. Los valores obtenidos para la tasa de convergencia predicen que, a través del tiempo, se verifica una tectónica menos tensional (con tendencia a la neutralidad) en la parte sureste de la zona de interacción de las placas de Rivera Y Norteamérica, mientras que en la parte noroccidental se vuelve más tensional. Por otra parte, un análisis cualitativo de las tasas de esparcimiento muestra que éstas fueron más rápidas antes de los 6.5 Ma de lo que fueron posteriormente. Después de analizar diferentes parámetros cinemáticos, se concluyó que la tasa de esparcimiento de la cresta del Pacífico Oriental en su sector Pacífico-Rivera, influye fuertemente sobre la tasa de convergencia. De esta manera se puede establecer una correlación positiva entre la evolución de la tasa de esparcimiento de la cresta Pacífico-Rivera y la geología continental. Esta correlación muestra que tasas de esparcimiento relativamente rápidas coinciden con la presencia de volcanismo monogenético calci-alcalino en la parte occidental de la FVTM cuando menos desde hace 10 Ma y que este tipo de volcanismo continúa hasta nuestros días. Sin embargo, cuando la tasa de esparcimiento se ha hecho más lenta (y por tanto la tasa de convergencia se ha hecho menor) durante el periodo comprendido entre 6.5 Ma y 3.5 Ma, se ha verificado en la región una tectónica extensional ampliamente distribuida, volcanismo explosivo y sedimentación lacustre en los sistemas rift de Colima, Tepic-Zacoalco y de Chapala; particularmente entre los 4.6 Ma y 3.9 Ma ha coincidido con volcanismo alcalino en los rifts fr Colima y Tepic-Zacoalco. Un leve incremento en la tasa de esparcimiento después de los 3.5 Ma coinciden con el decremento de actividad volcánica (principalmente alcalina). Durante el periodo entre 1.6 Ma y 0.7 Ma, la tasa de esparcimiento disminuyó de nuevo coincidiendo con un fallamiento normal continuo en las tres estructuras rift mencionadas y en parte, con otra etapa de volcanismo alcalino (entre 1.4 Ma y 0.2 Ma) en los rift de Colima y Tepic-Zacoalco. Después de los 0.7 Ma, la tasa de esparcimiento se ha incrementado levemente. Por otra parte, se observa una relación genética entre el contenido de elementos compatibles en rocas volcánicas de la región con la tasa de convergencia, lo cual implica que tasas de subducción mayores aportan una mayor cantidad de sedimentos acrecionados a la cuña del manto. Esto explica las diferencias geoquímicas entre las rocas volcánicas a lo largo del frente volcánico de la parte occidental de la FVTM.

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