532 research outputs found
Seed Dormancy and Seedling Ecophysiology Reveal the Ecological Amplitude of the Threatened Endemism Picris willkommii (Schultz Bip.) Nyman (Asteraceae)
Plant communities can undergo drastic changes in their composition if the ecosystem is
severely altered by human actions or climate change. These changes endanger any vulnerable species, mainly if it lives in a small area, as is the case of Picris willkommii (Schultz Bip.) Nyman. Therefore, it is essential to know how an ecosystem alteration could affect the seasonal pattern of the life
cycle, seed production, germination time, as well as both plant emergence and development. During
three consecutive years, the growth phenology and seed morpho-physiological traits of Picris
willkommii were assessed, as well as the environmental factors that affect them (light, temperature,
substrate). Under natural conditions, germination is in early autumn (15–25 °C air temperature),
flowering is in spring, and seed maturation in late spring. The species produces two types of seeds
differentiated in the degree of dormancy and other morpho–physiological traits, which contributes
to the dispersal and spreading capacity; it prefers fine-textured limestone substrates with high N
and P availability; it does not tolerate frosts below −5 °C; and it is able to acclimatize to changing
environmental conditions, but there is a risk of being replaced by other more aggressive species. All
of this is useful for species conservation programsThe authors want to thank the support of the Andalusian Government for
providing some batches of seeds and allowing the study of this species; and the support of Ricardo Arribas, the company Dintel Domus S.A. and the Ayamonte´s city council for the acquisition of
materials for experimentation and for their help in field trip
Adaptación a la sequía y necesidades hídricas de Eucalyptus globulus Labill. en Huelva
Eucalyptus globulus Labill. es una especie
ampliamente utilizada en plantaciones para
producción de madera. Está adaptada a vivir sobre
suelos pobres y bajo clima mediterráneo pero suave
y con influencia oceánica. Soporta cierto grado de
estrés hídrico pero le van mal temperaturas extremas
que sobrepasen 40 ºC ó -5 ºC. Su cultivo en la
provincia de Huelva está seriamente limitado por la
frugalidad de los suelos y la sequía estival, así como
por el ataque de plagas, especialmente virulentas en
situaciones de estrés hídrico como en el caso de
Phoracantha spp. En este trabajo se muestra una
recopilación de varias experiencias, llevadas a cabo
en vivero y en parcelas de campo, sobre la reacción
de los clones al estrés hídrico y sus necesidades de
consumo de agua. Al igual que para otros tipos de
estreses biótico o abióticos, la especie manifestó
variabilidad genética (a nivel clonal) en su grado de
resistencia al estrés hídrico, lo que ofrece la
posibilidad de seguir desarrollando programas de
selección y mejora de la especie destinada a
plantaciones forestales. Dicha resistencia se
implementaba al ser expuestos a situaciones de
estrés hídrico, poniendo en juego mecanismos de
evitación (morfología foliar, cierre estomático,
vulnerabilidad a la cavitación del xilema, etc.) y de
tolerancia (ajuste osmótico y elástico). No obstante
el grado de variación de cada uno de los parámetros
medidos difirió entre los clones, manifestando
distintas estrategias entre clones, lo que puede ser
utilizado a la hora de establecer el criterio de
selección en función del objetivo perseguido en cada
línea de mejora (resistencia al ataque por
Phoracantha spp., producción y eficiencia en el uso
del agua, resistencia a valores críticos de estrés
hídrico, etc.).___________________________________________Eucalyptus glubulus is a widely used species in
forest plantations for wood production. It is adapted
to live on poor soils under Mediterranean climate
with oceanic influence. It supports some degree of
water stress but not extreme temperatures exceeding
40 ºC or -5 ºC. Its cultivation in the province of
Huelva is seriously limited by the frugality of the
soils and the summer drought, and it is attacked by
pests such as Phoracantha spp., particularly virulent
under water stress conditions. In this work, we
analyzed the results of several experiments, carried
out in nurseries and in field plots, regarding to the
response of E. globulus clones to water stress and its
water consumption needs. As for other biotic or
abiotic stresses, the species showed genetic
variability (at clonal level) in their resistance to
water stress, which offers the possibility to further
develop and improve breeding programs. Under
water stress conditions, it reacts by coming into play
avoidance mechanisms (leaf morphology, stomatal
closure, vulnerability to xylem cavitation, etc..) and
tolerance mechanisms (osmotic and elastic
adjustment). However, the degree of variation of
each of the above cited parameters differed between
clones, showing different strategies among them.
This can be used when establishing the selection
criteria in relation to the purpose of each breeding
program (resistance to be attacked by Phoracantha
spp., production and water use efficiency, resistance
to threshold values of water stress, etc.
Characterization of abiotic coaditions affecting vegetation distribution in the river plate coastal plain, Argentina
The river Plate coastal plain is located in northeastern Buenos Aires province, where geological events such as sea transgressions and regressions in the Holocene have produced a stratigraphic column with marine-estuarine, fluviatile and continental sediments, as well as a variety of landforms and soils. The aim of this paper is to describe these different coastal settings and their influence in the distribution of plant communities.Facultad de Ciencias Naturales y Muse
Characterization of abiotic coaditions affecting vegetation distribution in the river plate coastal plain, Argentina
The river Plate coastal plain is located in northeastern Buenos Aires province, where geological events such as sea transgressions and regressions in the Holocene have produced a stratigraphic column with marine-estuarine, fluviatile and continental sediments, as well as a variety of landforms and soils. The aim of this paper is to describe these different coastal settings and their influence in the distribution of plant communities.Facultad de Ciencias Naturales y Muse
Biomass Yield and Economic, Energy and Carbon Balances of Ulmus pumila L., Robinia pseudoacacia L. and Populus × euroamericana (Dode) Guinier Short-Rotation Coppices on Degraded Lands under Mediterranean Climate
The steadily increasing demand for energy and concerns about climate change have
prompted countries to promote the use of renewable energy sources, including lignocellulosic
biomass. In this context, this work aims to assess the biomass production for energy purposes in
crops with short rotation, as well as its effect on soil properties. Deciduous tree species were used,
mainly Siberian elm (Ulmus pumila L.), black locust (Robinia pseudoacacia L.) and a hybrid poplar clone
(Populus × euroamericana (Dode) Guinier, clone ‘AF2’). Four field trials were implemented, under two
different types of Mediterranean climate, where highly productive taxa were tested, in addition to the
mixed planting of a nitrogen-fixing species with a non-fixing one. Short-rotation coppices (SRCs) of
these taxa yield about 12–14 t ha−1 year−1 of high-quality dry woody biomass, when fertilizers and
irrigation water are supplied; generate 205–237 GJ ha−1 year−1 net and earnings of about EUR 1.5 per
EUR 1 invested; and sequester into the soil 0.36–0.83 t ha−1 year−1 of C and 57 kg ha−1 year−1 of N.
Therefore, these species raised as SRCs could improve degraded soils if the crop is properly managed,
resulting in favorable economic, energy and CO2 emission balances. The use of mixed plantations
can bring economic and environmental gains, and the biomass transformation into high-quality chips
or pellets gives it added valueThis research was funded by the Science and Innovation Ministry (ref. AGL2010-16575)
and the Economy and Competitiveness Ministry of Spain (ref. CTQ2013-46804-C2-1-R and CTQ2017-
85251-C2-2-R), by FEDER funds of the EU, and by the company ENCE, energía y celulosa S.A. (8%, 6%,
6%, 70%, 10%, respectively).
The authors want to thank the Diputación de Granada (Spain) for the donation
of farmland for the establishment of the experimental plots in Los Morales, and for the help in the
cultivation works; the company Tubocás S.L. for its contribution to the sampling and transport of
biomass, as well as to the harvest at the end of each crop rotation; and Biopoplar Ibérica S.L. for the
provision of some plant tax
Quality of the Pellets Obtained with Wood and Cutting Residues of Stone Pine (Pinus pinea L.)
The use of wood and residual biomass from forestry works is a CO2 emission-neutral
source of energy that also contributes to reducing the risk of spreading forest fires, especially under
Mediterranean climate. The forest stands of stone pine (Pinus pinea L.) occupies about 0.7 million
hectares in the Mediterranean basin. In this study, the commercial quality of the pellets manufactured
from different types of cutting residues (needles and thin branches, medium branches and bark), as
well as wood from trunks and thick branches, was assessed. It was concluded that with the exclusive
use of residual biomass it is not possible to obtain pellets of high commercial quality, useful for
residential or industrial use. However, the highest quality pellets could be obtained by combining
them with stone pine debarked wood, but in a certain proportion that differs depending on the type
of residue (around 15% for bark, 30% for medium branches and less than 15% for needles and thin
branches). It is recommended to take advantage of both the thick wood (trunk + thick branches) and a
proportion of medium branches and bark, while in the case of needles and thinnest branches it would
be more convenient to leave them in the forest for their incorporation into the soil, given their high
nutrients concentration and their low quality for energetic use. The results found support a greater
valorization of the biomass obtained in the stone pine fellings. In the future it will be necessary to
study which is the most appropriate logistics of the silvicultural works to be able to conveniently
apply the results of this study.This study was financed by Projects: “Iberian Center for Research and Forest Firefighting”,
CILIFO (0753_CILIFO_5_E) and “Strengthening of cross-border systems for the prevention and
extinction of forest fires and improvement of resources for rural employment generation post COVID-
19”, FIREPOCTEP (0756_FIREPOCTEP_6_E). Both are Projects co-financed by the European Regional
Development Fund (ERDF), within the framework of the Interreg V A Spain—Portugal Program
(POCTEP) 2014–2020
Aclimatación al frío en diferentes clones de Eucalyptus globulus Labill durante el régimen natural de endurecimiento
En la región mediterránea la principal limitación de la expansión del las plantaciones de Eucalyptus es la ocurrencia periódica de temperaturas bajas durante los meses de invierno (-5 a -10 oC). Por esta razón es crucial implementar un programa para mejorar la resistencia al frío en las especies utilizadas de este género. E. globulus, la especie más extendida en la península ibérica es considerada una especie moderadamente susceptible al frío. Se testaron 16 clones a los cuales se les realizó un seguimiento durante el régimen natural de endurecimiento y la salida del mismo para el periodo 2005-2006. La tolerancia al frío fue evaluada en tejido foliar desarrollado, tanto en hojas pecioladas maduras como en hojas sentadas juveniles, simulando condiciones de helada en ambiente controlado. De esta forma se demostró que existe un proceso de aclimatación de las plantas a las bajas temperaturas a medida que se acumulan las horas de frío y una desaclimatación de las mismas a medida que acaba el invierno. En todos los clones se determinó un máximo de tolerancia para la segunda quincena de enero, lo que corresponde con un total acumulado de 415 horas de frío por debajo de los 7 oC (HF7). Por otra parte se observó un cambio significativo en el umbral de temperaturas que causan un daño al 50% de la superficie del tejido foliar (TL50), siendo el valor medio de éstas -4,5 ºC antes de comenzar la temporada de frío y de – 6,5 ºC una vez alcanzado el máximo de endurecimiento.______________________________The greatest constraint on the expansion of Eucalyptus plantations in the Mediterranean region is the periodic occurrence of low temperatures (–5 to –10 oC) during winter. This has raised the need to launch a programme aimed at increasing the tolerance to cold weather of Eucalyptus species in the region. Eucalyptus globulus, which is the most widespread Eucalyptus species in the Iberian peninsula, is moderately vulnerable to cold. In this work, a total of 16 clones of this species were monitored during their natural hardening regime and at its end over the period 2005–06. Tolerance to cold was evaluated in well-developed tissue of both mature petiolate leaves and seated young leaves by mimicking freezing conditions in a controlled environment. The plants were found to gradually acclimate to low temperatures as the number of cold hours increased and to de-acclimate as the winter neared its end. Tolerance in all clones peaked in the second half of January, after an overall 415 could hours at temperatures below 7 oC (HF7). Also, the temperature threshold below which at least 50% of leaf surface tissue was damaged (TL50) varied markedly, from an average –4.5 oC at the beginning of the cold season to an average –6.5 oC at the point of maximum hardening
Un trío olvidado : Consideraciones en torno al estudio de la música de juglares, ministriles y goliardos
Dentro de la historia de la música, uno de los aspectos que recibe menor tratamiento en la profusa bibliografía que circula en las instituciones especializadas, es el que se refiere a la música de juglares, ministriles y goliardos. Uno de los argumentos por los cuales pareciera justificarse la omisión de dichas prácticas en la bibliografía es el de la falta de documentación escrita, esto es, música conservada a partir de una notación musical decodificable. Pero tal vez subyazca otra razón, ya que no es casual que las músicas producidas por estos grupos están estrechamente vinculadas a la cultura popular medieval. Por ello, y para entender plenamente esta ausencia, es necesario reflexionar en torno al concepto de música imperante y enraizado en los ámbitos académicos occidentales, que ha llevado a la musicología histórica a desarrollar un determinado camino metodológico con una consecuente delimitación de su objeto de estudio.
(Párrafo extraído del texto a modo de resumen) Mesa: El arte en mirada: abordajes, discusiones y aperturasFacultad de Bellas Arte
Un trío olvidado : Consideraciones en torno al estudio de la música de juglares, ministriles y goliardos
Dentro de la historia de la música, uno de los aspectos que recibe menor tratamiento en la profusa bibliografía que circula en las instituciones especializadas, es el que se refiere a la música de juglares, ministriles y goliardos. Uno de los argumentos por los cuales pareciera justificarse la omisión de dichas prácticas en la bibliografía es el de la falta de documentación escrita, esto es, música conservada a partir de una notación musical decodificable. Pero tal vez subyazca otra razón, ya que no es casual que las músicas producidas por estos grupos están estrechamente vinculadas a la cultura popular medieval. Por ello, y para entender plenamente esta ausencia, es necesario reflexionar en torno al concepto de música imperante y enraizado en los ámbitos académicos occidentales, que ha llevado a la musicología histórica a desarrollar un determinado camino metodológico con una consecuente delimitación de su objeto de estudio.
(Párrafo extraído del texto a modo de resumen) Mesa: El arte en mirada: abordajes, discusiones y aperturasFacultad de Bellas Arte
Un trío olvidado : Consideraciones en torno al estudio de la música de juglares, ministriles y goliardos
Dentro de la historia de la música, uno de los aspectos que recibe menor tratamiento en la profusa bibliografía que circula en las instituciones especializadas, es el que se refiere a la música de juglares, ministriles y goliardos. Uno de los argumentos por los cuales pareciera justificarse la omisión de dichas prácticas en la bibliografía es el de la falta de documentación escrita, esto es, música conservada a partir de una notación musical decodificable. Pero tal vez subyazca otra razón, ya que no es casual que las músicas producidas por estos grupos están estrechamente vinculadas a la cultura popular medieval. Por ello, y para entender plenamente esta ausencia, es necesario reflexionar en torno al concepto de música imperante y enraizado en los ámbitos académicos occidentales, que ha llevado a la musicología histórica a desarrollar un determinado camino metodológico con una consecuente delimitación de su objeto de estudio.
(Párrafo extraído del texto a modo de resumen) Mesa: El arte en mirada: abordajes, discusiones y aperturasFacultad de Bellas Arte
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