<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Escudero, Alfonso</style></author><author><style face="normal" font="default" size="100%">Fernández, José</style></author><author><style face="normal" font="default" size="100%">Cordero, Angel</style></author><author><style face="normal" font="default" size="100%">Mediavilla, Sonia</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Distribution of leaf characteristics in relation to orientation within the canopy of woody species</style></title><secondary-title><style face="normal" font="default" size="100%">Acta Oecologica</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Canopy orientation</style></keyword><keyword><style  face="normal" font="default" size="100%">leaf morphology</style></keyword><keyword><style  face="normal" font="default" size="100%">Leaf temperature</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus</style></keyword><keyword><style  face="normal" font="default" size="100%">water potential</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2013</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2013///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.sciencedirect.com/science/article/pii/S1146609X13000155</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">48</style></volume><pages><style face="normal" font="default" size="100%">13 - 20</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Over the last few decades considerable effort has been devoted to research of leaf adaptations to environmental conditions. Many studies have reported strong differences in leaf mass per unit area (LMA) within a single tree depending on the photosynthetic photon flux density (PPFD) incident on different locations in the crown. There are fewer studies, however, of the effects of differences in the timing of light incidence during the day on different crown orientations. Leaves from isolated trees of Quercus suber and Quercus ilex in a cold Mediterranean climate were sampled to analyze differences in LMA and other leaf traits among different crown orientations. Gas-exchange rates, leaf water potentials, leaf temperatures and PPFD incident on leaf surfaces in different crown orientations were also measured throughout one entire summer day for each species. Mean daily PPFD values were similar for the leaves from the eastern and western sides of the canopy. On the western side, PPFD reached maximum values during the afternoon. Maximum leaf temperatures were approximately 10–20% higher on the west side, whereas minimum leaf water potentials were between 10 and 24% higher on the east side. Maximum transpiration rates were approximately 22% greater on the west, because of the greater leaf-to-air vapor pressure deficits (LAVPD). Mean individual leaf area was around 10% larger on the east than on the west side of the trees. In contrast, there were no significant differences in LMA between east and west sides of the crown. Contrary to our expectations, more severe water stress on the west side did not result in increases in LMA, although it was associated with lower individual leaf area. We conclude that increases in LMA measured by other authors along gradients of water stress would be due to differences in light intensity between dry and humid sites.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Mediavilla, Sonia</style></author><author><style face="normal" font="default" size="100%">Gallardo-López, Victoria</style></author><author><style face="normal" font="default" size="100%">González-Zurdo, Patricia</style></author><author><style face="normal" font="default" size="100%">Escudero, Alfonso</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Patterns of leaf morphology and leaf N content in relation to winter temperatures in three evergreen tree species.</style></title><secondary-title><style face="normal" font="default" size="100%">International journal of biometeorology</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">leaf density</style></keyword><keyword><style  face="normal" font="default" size="100%">leaf mass per unit area</style></keyword><keyword><style  face="normal" font="default" size="100%">leaf n content</style></keyword><keyword><style  face="normal" font="default" size="100%">leaf thickness</style></keyword><keyword><style  face="normal" font="default" size="100%">winter temperature gradient</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2012</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2012///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/21969112</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">56</style></volume><pages><style face="normal" font="default" size="100%">915 - 926</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The competitive equilibrium between deciduous and perennial species in a new scenario of climate change may depend closely on the productivity of leaves along the different seasons of the year and on the morphological and chemical adaptations required for leaf survival during the different seasons. The aim of the present work was to analyze such adaptations in the leaves of three evergreen species (Quercus ilex, Q. suber and Pinus pinaster) and their responses to between-site differences in the intensity of winter harshness. We explore the hypothesis that the harshness of winter would contribute to enhancing the leaf traits that allow them to persist under conditions of stress. The results revealed that as winter harshness increases a decrease in leaf size occurs in all three species, together with an increase in the content of nitrogen per unit leaf area and a greater leaf mass per unit area, which seems to be achieved only through increased thickness, with no associated changes in density. P. pinaster was the species with the most intense response to the harshening of winter conditions, undergoing a more marked thickening of its needles than the two Quercus species. Our findings thus suggest that lower winter temperatures involve an increase in the cost of leaf production of evergreen species, which must be taken into account in the estimation of the final cost and benefit balance of evergreens. Such cost increases would be more pronounced for those species that, like P. pinaster, show a stronger response to the winter cold.</style></abstract><issue><style face="normal" font="default" size="100%">5</style></issue><notes><style face="normal" font="default" size="100%">The following values have no corresponding Zotero field:&lt;br/&gt;accession-num: 21969112</style></notes></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Mediavilla, Sonia</style></author><author><style face="normal" font="default" size="100%">Escudero, Alfonso</style></author><author><style face="normal" font="default" size="100%">González-Zurdo, Patricia</style></author><author><style face="normal" font="default" size="100%">García-Ciudad, Antonia</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Morphological and chemical leaf composition of Mediterranean evergreen tree species according to leaf age</style></title><secondary-title><style face="normal" font="default" size="100%">Trees</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Fibre concentration</style></keyword><keyword><style  face="normal" font="default" size="100%">Leaf age class</style></keyword><keyword><style  face="normal" font="default" size="100%">Leaf mass per area</style></keyword><keyword><style  face="normal" font="default" size="100%">leaf thickness</style></keyword><keyword><style  face="normal" font="default" size="100%">Leaf tissue density</style></keyword><keyword><style  face="normal" font="default" size="100%">Mineral content</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2011</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2011///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://dx.doi.org/10.1007/s00468-011-0544-z</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">25</style></volume><pages><style face="normal" font="default" size="100%">669 - 677</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Changes in morphology [leaf dry mass per unit area (LMA), thickness and density] and chemical composition (macronutrients and ﬁbres content) in different age leaves of eight evergreen Mediterranean woody species were investigated. LMA and leaf thickness increased with leaf age increasing. Young tissues possessed higher concentrations of N, P, K, and Mg and lower Ca concentrations on a dry mass basis. However, mineral content was independent of age on leaf area basis (except for Ca content) suggesting that the changes in mineral concentration with leaf ageing are due to dilution in the larger dry mass accumulated in the oldest leaves. Leaf tissue density (LTD) increased during the ﬁrst year of the leaf life. Lignin and hemicellulose concentrations did not vary along leaf life and the cellulose concentration increased with leaf age in most species between the current-year and the one-year old leaves. Our results suggested that physical leaf reinforcement with a higher cellulose concentration and density might be a leaf response to the unfavourable climatic conditions during the ﬁrst winter.</style></abstract><issue><style face="normal" font="default" size="100%">4</style></issue><notes><style face="normal" font="default" size="100%">The following values have no corresponding Zotero field:&lt;br/&gt;publisher: Springer-Verlag</style></notes></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Juárez-López, Francisco José</style></author><author><style face="normal" font="default" size="100%">Escudero, Alfonso</style></author><author><style face="normal" font="default" size="100%">Mediavilla, Sonia</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Ontogenetic changes in stomatal and biochemical limitations to photosynthesis of two co-occurring Mediterranean oaks differing in leaf life span</style></title><secondary-title><style face="normal" font="default" size="100%">Tree Physiology</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">A–ci response curves</style></keyword><keyword><style  face="normal" font="default" size="100%">biochemical capacity</style></keyword><keyword><style  face="normal" font="default" size="100%">leaf morphology</style></keyword><keyword><style  face="normal" font="default" size="100%">leaf N allocation</style></keyword><keyword><style  face="normal" font="default" size="100%">mature trees</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus faginea</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus ilex</style></keyword><keyword><style  face="normal" font="default" size="100%">seedlings</style></keyword><keyword><style  face="normal" font="default" size="100%">Stomatal conductance</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2008</style></year></dates><volume><style face="normal" font="default" size="100%">28</style></volume><pages><style face="normal" font="default" size="100%">367-374</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">A quantitative analysis was applied to the stomatal and biochemical limitations to light-saturated net photosynthesis under optimal field conditions in mature trees and seedlings of the co-occurring evergreen oak, Quercus ilex L., and the deciduous oak, Q. faginea Lam. Stomatal limitation to photosynthesis, maximal Rubisco activity and electron transport rate were determined from assimilation versus intercellular leaf carbon dioxide concentration response curves of leaves that were subsequently analyzed for nitrogen (N) concentration, mass per unit area, thickness and percent internal air space. In both species, seedlings had a lower leaf mass per unit area, thickness and leaf N concentration than mature trees. The root system of seedlings during their third year after planting was dominated by a taproot. A lower leaf N concentration of seedlings was associated with lower maximal Rubisco activity and electron transport rate and with assimilation rates similar to or lower than those of mature trees, despite the higher stomatal conductances and potential photosynthetic nitrogen-use efficiencies of seedlings. Consequently, stomatal limitation to photosynthesis increased with tree age in both species. In both seedlings and mature trees, a lower assimilation rate in Q. ilex than in Q. faginea was associated with lower stomatal conductance, N allocation to photosynthetic functions, maximal Rubisco activity and electron transport rate, and potential photosynthetic nitrogen-use efficiency but greater leaf thickness and leaf mass per unit area. Tree-age-related changes differed quantitatively between species, and the characteristics of the two species were more similar in seedlings than in mature trees. Despite higher stomatal conductances, seedlings are more N limited than adult trees, which contributes to lower biochemical efficiency.</style></abstract><notes><style face="normal" font="default" size="100%">10.1093/treephys/28.3.367</style></notes><research-notes><style face="normal" font="default" size="100%">10.1093/treephys/28.3.367</style></research-notes></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Mediavilla, Sonia</style></author><author><style face="normal" font="default" size="100%">Escudero, Alfonso</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Stomatal responses to drought of mature trees and seedlings of two co-occurring Mediterranean oaks</style></title><secondary-title><style face="normal" font="default" size="100%">Forest Ecology and Management</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Drought</style></keyword><keyword><style  face="normal" font="default" size="100%">growth stages</style></keyword><keyword><style  face="normal" font="default" size="100%">leaf water potential</style></keyword><keyword><style  face="normal" font="default" size="100%">mediterranean quercus species</style></keyword><keyword><style  face="normal" font="default" size="100%">Stomatal conductance</style></keyword><keyword><style  face="normal" font="default" size="100%">vapour pressure deficit</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2004</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2004///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://linkinghub.elsevier.com/retrieve/pii/S0378112703003827</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">187</style></volume><pages><style face="normal" font="default" size="100%">281 - 294</style></pages><isbn><style face="normal" font="default" size="100%">3423294515</style></isbn><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">We studied stomatal responses to decreasing predawn water potential (Cpd ) and increasing leaf-to-air water vapour pressure deﬁcit (VPD) of seedlings and mature trees of two co-occurring Mediterranean oaks with contrasting leaf habits: the evergreen Quercus rotundifolia and the deciduous Quercus faginea. Our objective was to deﬁne and to compare the stomatal strategies of both speciesfordroughtresistanceandtoidentifythepossibledifferencesbetweengrowthstagesinselecteddroughtadaptationattributes. Among the mature trees, Q. rotundifolia exhibited a water-use behaviour that was more conservative than that of Q. faginea: lower maximum stomatal conductances and greater sensitivity to VPD than the deciduous species. As a result, the leaf water potential of the evergreen species never decreased along the day and along the growth season as much as in the deciduous species; this may help to guarantee longer leaf longevity by avoiding irreversible damage during the summer drought. The seedlings of the two species showed a less conservative water-use strategy in comparison with adult trees: a relatively high stomatal conductance and lower stomatal sensitivity to soil and atmospheric drought. As a consequence, leaf water potential decreased more in the seedlings along the day than in the adults. Q. rotundifolia was the species for which the most pronounced differences between growth stages were obtained. Thus, interspeciﬁc differences in response to drought disappeared in the ﬁrst stages of the life of the trees, and the seedlings of the two species showed a common strategy, probably as a response to the competition from the herbaceous layer. A low stomatal sensitivity in beneﬁt of an increase in growth would probably be a more successful strategy under the competitive conditions that seedlings experience during their establishment.</style></abstract><issue><style face="normal" font="default" size="100%">2-3</style></issue></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Mediavilla, Sonia</style></author><author><style face="normal" font="default" size="100%">Escudero, Alfonso</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Stomatal responses to drought of mature trees and seedlings of two co-occurring Mediterranean oaks</style></title><secondary-title><style face="normal" font="default" size="100%">Forest Ecology and Management</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Drought</style></keyword><keyword><style  face="normal" font="default" size="100%">growth stages</style></keyword><keyword><style  face="normal" font="default" size="100%">leaf water potential</style></keyword><keyword><style  face="normal" font="default" size="100%">mediterranean quercus species</style></keyword><keyword><style  face="normal" font="default" size="100%">Stomatal conductance</style></keyword><keyword><style  face="normal" font="default" size="100%">vapour pressure deficit</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2004</style></year></dates><volume><style face="normal" font="default" size="100%">187</style></volume><pages><style face="normal" font="default" size="100%">281-294</style></pages><isbn><style face="normal" font="default" size="100%">3423294515</style></isbn><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">We studied stomatal responses to decreasing predawn water potential (Cpd ) and increasing leaf-to-air water vapour pressure deﬁcit (VPD) of seedlings and mature trees of two co-occurring Mediterranean oaks with contrasting leaf habits: the evergreen Quercus rotundifolia and the deciduous Quercus faginea. Our objective was to deﬁne and to compare the stomatal strategies of both speciesfordroughtresistanceandtoidentifythepossibledifferencesbetweengrowthstagesinselecteddroughtadaptationattributes. Among the mature trees, Q. rotundifolia exhibited a water-use behaviour that was more conservative than that of Q. faginea: lower maximum stomatal conductances and greater sensitivity to VPD than the deciduous species. As a result, the leaf water potential of the evergreen species never decreased along the day and along the growth season as much as in the deciduous species; this may help to guarantee longer leaf longevity by avoiding irreversible damage during the summer drought. The seedlings of the two species showed a less conservative water-use strategy in comparison with adult trees: a relatively high stomatal conductance and lower stomatal sensitivity to soil and atmospheric drought. As a consequence, leaf water potential decreased more in the seedlings along the day than in the adults. Q. rotundifolia was the species for which the most pronounced differences between growth stages were obtained. Thus, interspeciﬁc differences in response to drought disappeared in the ﬁrst stages of the life of the trees, and the seedlings of the two species showed a common strategy, probably as a response to the competition from the herbaceous layer. A low stomatal sensitivity in beneﬁt of an increase in growth would probably be a more successful strategy under the competitive conditions that seedlings experience during their establishment.</style></abstract></record></records></xml>