<?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%">Ogaya, Romà</style></author><author><style face="normal" font="default" size="100%">Llusia, Joan</style></author><author><style face="normal" font="default" size="100%">Barbeta, Adrià</style></author><author><style face="normal" font="default" size="100%">Asensio, Dolores</style></author><author><style face="normal" font="default" size="100%">Liu, Daijun</style></author><author><style face="normal" font="default" size="100%">Alessio, Giorgio Arturo</style></author><author><style face="normal" font="default" size="100%">Penuelas, Josep</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Foliar CO2 in a holm oak forest subjected to 15 years of climate change simulation</style></title><secondary-title><style face="normal" font="default" size="100%">Plant Science</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">climate change</style></keyword><keyword><style  face="normal" font="default" size="100%">Drought</style></keyword><keyword><style  face="normal" font="default" size="100%">mediterranean forest</style></keyword><keyword><style  face="normal" font="default" size="100%">phillyrea latifolia</style></keyword><keyword><style  face="normal" font="default" size="100%">photosynthetic rates</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus ilex</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2014</style></year></dates><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">A long-term experimental drought to simulate future expected climatic conditions for Mediterranean forests, a 15% decrease in soil moisture for the following decades, was conducted in a holm oak forest since 1999. Net photosynthetic rate, stomatal conductance and leaf water potential were measured from 1999 to 2013 in Quercus ilex and Phillyrea latifolia, two co-dominant species of this forest. These measurements were performed in four plots, two of them received the drought treatment and the two other plots were control plots. The three studied variables decreased with increases in VPD and decreases in soil moisture in both species, but the decrease of leaf water potential during summer drought was larger in P. latifolia, whereas Q. ilex reached higher net photosynthetic rates and stomatal conductance values during rainy periods than P. latifolia. The drought treatment decreased ca. 8% the net photosynthetic rates during the overall studied period in both Q. ilex and P. latifolia, whereas there were just non-significant trends toward a decrease in leaf water potential and stomatal conductance induced by drought treatment. Future drier climate may lead to a decrease in the carbon balance of Mediterranean species, and some shrub species well resistant to drought could gain competitive advantage relative to Q. ilex, currently the dominant species of this forest.</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%">Barbeta, Adrià</style></author><author><style face="normal" font="default" size="100%">Ogaya, Romà</style></author><author><style face="normal" font="default" size="100%">Penuelas, Josep</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Dampening effects of long-term experimental drought on growth and mortality rates of a Holm oak forest</style></title><secondary-title><style face="normal" font="default" size="100%">GLOBAL CHANGE BIOLOGY</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">acclimation</style></keyword><keyword><style  face="normal" font="default" size="100%">Arbutus unedo</style></keyword><keyword><style  face="normal" font="default" size="100%">experimental drought</style></keyword><keyword><style  face="normal" font="default" size="100%">global-change-type drought</style></keyword><keyword><style  face="normal" font="default" size="100%">Holm oak</style></keyword><keyword><style  face="normal" font="default" size="100%">mediterranean forest</style></keyword><keyword><style  face="normal" font="default" size="100%">phillyrea latifolia</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus ilex</style></keyword><keyword><style  face="normal" font="default" size="100%">tree growth</style></keyword><keyword><style  face="normal" font="default" size="100%">tree mortality</style></keyword><keyword><style  face="normal" font="default" size="100%">vegetation stabilizing processes</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2013</style></year></dates><publisher><style face="normal" font="default" size="100%">WILEY-BLACKWELL</style></publisher><pub-location><style face="normal" font="default" size="100%">111 RIVER ST, HOBOKEN 07030-5774, NJ USA</style></pub-location><volume><style face="normal" font="default" size="100%">19</style></volume><pages><style face="normal" font="default" size="100%">3133-3144</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Forests respond to increasing intensities and frequencies of drought by reducing growth and with higher tree mortality rates. Little is known, however, about the long-term consequences of generally drier conditions and more frequent extreme droughts. A Holm oak forest was exposed to experimental rainfall manipulation for 13years to study the effect of increasing drought on growth and mortality of the dominant species Quercus ilex, Phillyrea latifolia, and Arbutus unedo. The drought treatment reduced stem growth of A. unedo (-66.5%) and Q. ilex (-17.5%), whereas P. latifolia remained unaffected. Higher stem mortality rates were noticeable in Q. ilex (+42.3%), but not in the other two species. Stem growth was a function of the drought index of early spring in the three species. Stem mortality rates depended on the drought index of winter and spring for Q. ilex and in spring and summer for P. latifolia, but showed no relation to climate in A. unedo. Following a long and intense drought (2005-2006), stem growth of Q. ilex and P. latifolia increased, whereas it decreased in A. unedo. Q. ilex also enhanced its survival after this period. Furthermore, the effect of drought treatment on stem growth in Q. ilex and A. unedo was attenuated as the study progressed. These results highlight the different vulnerabilities of Mediterranean species to more frequent and intense droughts, which may lead to partial species substitution and changes in forest structure and thus in carbon uptake. The response to drought, however, changed over time. Decreased intra- and interspecific competition after extreme events with high mortality, together with probable morphological and physiological acclimation to drought during the study period, may, at least in the short term, buffer forests against drier conditions. The long-term effects of drought consequently deserve more attention, because the ecosystemic responses are unlikely to be stable over time.Nontechnical summaryIn this study, we evaluate the effect of long-term (13years) experimental drought on growth and mortality rates of three forest Mediterranean species, and their response to the different intensities and durations of natural drought. We provide evidence for species-specific responses to drought, what may eventually lead to a partial community shift favoring the more drought-resistant species. However, we also report a dampening of the treatment effect on the two drought-sensitive species, which may indicate a potential adaptation to drier conditions at the ecosystem or population level. These results are thus relevant to account for the stabilizing processes that would alter the initial response of ecosystem to drought through changes in plant physiology, morphology, and demography compensation.</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%">Barbeta, Adrià</style></author><author><style face="normal" font="default" size="100%">Ogaya, Romà</style></author><author><style face="normal" font="default" size="100%">Penuelas, Josep</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Comparative study of diurnal and nocturnal sap flow of Quercus ilex and Phillyrea latifolia in a Mediterranean holm oak forest in Prades (Catalonia, NE Spain)</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%">á</style></keyword><keyword><style  face="normal" font="default" size="100%">Drought</style></keyword><keyword><style  face="normal" font="default" size="100%">ilex á sap flow</style></keyword><keyword><style  face="normal" font="default" size="100%">nocturnal sap flow</style></keyword><keyword><style  face="normal" font="default" size="100%">nocturnal sap flow á</style></keyword><keyword><style  face="normal" font="default" size="100%">phillyrea latifolia</style></keyword><keyword><style  face="normal" font="default" size="100%">phillyrea latifolia á quercus</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus ilex</style></keyword><keyword><style  face="normal" font="default" size="100%">sap flow</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.springerlink.com/index/10.1007/s00468-012-0741-4http://link.springer.com/10.1007/s00468-012-0741-4</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">26</style></volume><pages><style face="normal" font="default" size="100%">1651 - 1659</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Droughts are a cyclical disturbance in Mediterranean ecosystems and climate change models forecast an increase of their frequency and severity. Some experimental and observational studies have shown that cooccurring species may cope with drier conditions with different strategies and present different responses. Here, we investigate sap ﬂow response to drought in order to explain the observed differential growth and mortality of Quercus ilex and Phillyrea latifolia at Prades Holm oak forest (NE Spain). We measured sap ﬂow of these species and compared their diurnal, nocturnal and seasonal patterns and their relationship with environmental variables. Both species described qualitatively similar daily patterns, either during daylight or night. Sap ﬂow rates were signiﬁcantly higher in P. latifolia except in autumn and spring. P. latifolia was more sensitive to soil moisture. Nocturnal sap ﬂow was detected in both species with no signiﬁcant differences and hourly rates suffered a progressive increase from 3 a.m. to dawn in most sampled nights. Our results indicate a better adaptation of P. latifolia to this site as it can take better advantage of wet periods while maintaining higher sap ﬂow rates during dry periods. Along with previous ecophysiological studies at the same location it may be inferred that at its drier distributional limit Q. ilex would be at disadvantage with respect to other species like P. latifolia, as the latter would cope better with increasing xeric conditions already occurring and further predicted for Mediterranean ecosystems. Our results also show nocturnal sap ﬂow to be relevant in individual water losses in these two species as they can be up to 35–40 % of daily sap ﬂow. Further research on the underlying mechanisms of this nocturnal sap ﬂow is required since it may also enhance early morning CO2 ﬁxation or nutrient supply to leaves.</style></abstract><issue><style face="normal" font="default" size="100%">5</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%">Llusia, Joan</style></author><author><style face="normal" font="default" size="100%">Penuelas, Josep</style></author><author><style face="normal" font="default" size="100%">Seco, Roger</style></author><author><style face="normal" font="default" size="100%">Filella, Iolanda</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Seasonal changes in the daily emission rates of terpenes by Quercus ilex and the atmospheric concentrations of terpenes in the natural park of Montseny, NE Spain</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of Atmospheric Chemistry</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">montseny</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus ilex</style></keyword><keyword><style  face="normal" font="default" size="100%">Seasonality</style></keyword><keyword><style  face="normal" font="default" size="100%">Terpene air concentrations</style></keyword><keyword><style  face="normal" font="default" size="100%">Terpene emission rates</style></keyword><keyword><style  face="normal" font="default" size="100%">VOC</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2012</style></year></dates><volume><style face="normal" font="default" size="100%">69</style></volume><pages><style face="normal" font="default" size="100%">215-230</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">We studied the daily patterns in the rates of terpene emissions by the montane holm oak, Quercus ilex, in three typical days of winter and three typical days of summer in Montseny, a natural park near Barcelona, and related them to the air concentrations of terpenes, ozone and NO2 . Terpene emission rates were about 10 times higher in summer than in winter. Emissions virtually stopped in the dark. In both seasons, rates of terpene emissions were well correlated with light, air temperature and relative humidity. Rates of emissions were also correlated with stomatal conductance and the rates of transpiration and photosynthesis. Almost all the individual terpenes identified followed the same pattern as total terpenes. The most abundant terpene was α-pinene, followed by sabinene + β-pinene, limonene, myrcene, camphene and α- phellandrene. Atmospheric terpene concentrations were also about 10 times higher in summer than in winter. A significant diurnal pattern with maxima at midday was observed, especially in summer. The increase by one order of magnitude in the concentrations of these volatile isoprenoids highlights the importance of local biogenic summer emissions in these Mediterranean forested areas which also receive polluted air masses from nearby or distant anthropic sources. Atmospheric concentrations of O3 and NO2 were also significantly higher in summer and at midday hours. In both seasons, concentrations of O3 were significantly correlated with concentrations of terpenes and NO2 in the air and with rates of terpene emission.</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%">Llusia, Joan</style></author><author><style face="normal" font="default" size="100%">Penuelas, Josep</style></author><author><style face="normal" font="default" size="100%">Seco, Roger</style></author><author><style face="normal" font="default" size="100%">Filella, Iolanda</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Seasonal changes in the daily emission rates of terpenes by Quercus ilex and the atmospheric concentrations of terpenes in the natural park of Montseny, NE Spain</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of Atmospheric Chemistry</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">montseny</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus ilex</style></keyword><keyword><style  face="normal" font="default" size="100%">Seasonality</style></keyword><keyword><style  face="normal" font="default" size="100%">Terpene air concentrations</style></keyword><keyword><style  face="normal" font="default" size="100%">Terpene emission rates</style></keyword><keyword><style  face="normal" font="default" size="100%">VOC</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.springerlink.com/index/10.1007/s10874-012-9238-1</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">69</style></volume><pages><style face="normal" font="default" size="100%">215 - 230</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">We studied the daily patterns in the rates of terpene emissions by the montane holm oak, Quercus ilex, in three typical days of winter and three typical days of summer in Montseny, a natural park near Barcelona, and related them to the air concentrations of terpenes, ozone and NO2 . Terpene emission rates were about 10 times higher in summer than in winter. Emissions virtually stopped in the dark. In both seasons, rates of terpene emissions were well correlated with light, air temperature and relative humidity. Rates of emissions were also correlated with stomatal conductance and the rates of transpiration and photosynthesis. Almost all the individual terpenes identified followed the same pattern as total terpenes. The most abundant terpene was α-pinene, followed by sabinene + β-pinene, limonene, myrcene, camphene and α- phellandrene. Atmospheric terpene concentrations were also about 10 times higher in summer than in winter. A significant diurnal pattern with maxima at midday was observed, especially in summer. The increase by one order of magnitude in the concentrations of these volatile isoprenoids highlights the importance of local biogenic summer emissions in these Mediterranean forested areas which also receive polluted air masses from nearby or distant anthropic sources. Atmospheric concentrations of O3 and NO2 were also significantly higher in summer and at midday hours. In both seasons, concentrations of O3 were significantly correlated with concentrations of terpenes and NO2 in the air and with rates of terpene emission.</style></abstract><issue><style face="normal" font="default" size="100%">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%">Ogaya, Romà</style></author><author><style face="normal" font="default" size="100%">Penuelas, Josep</style></author><author><style face="normal" font="default" size="100%">Asensio, Dolores</style></author><author><style face="normal" font="default" size="100%">Llusia, Joan</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Chlorophyll fluorescence responses to temperature and water availability in two co-dominant Mediterranean shrub and tree species in a long-term field experiment simulating climate change</style></title><secondary-title><style face="normal" font="default" size="100%">Environmental and Experimental Botany</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Chlorophyll ﬂuorescence</style></keyword><keyword><style  face="normal" font="default" size="100%">climate change</style></keyword><keyword><style  face="normal" font="default" size="100%">Cold</style></keyword><keyword><style  face="normal" font="default" size="100%">Drought</style></keyword><keyword><style  face="normal" font="default" size="100%">evergreen leaves</style></keyword><keyword><style  face="normal" font="default" size="100%">Fv/Fm</style></keyword><keyword><style  face="normal" font="default" size="100%">Heat</style></keyword><keyword><style  face="normal" font="default" size="100%">mediterranean forest</style></keyword><keyword><style  face="normal" font="default" size="100%">phillyrea latifolia</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus ilex</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://linkinghub.elsevier.com/retrieve/pii/S009884721100178X</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">73</style></volume><pages><style face="normal" font="default" size="100%">89 - 93</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">A rain exclusion experiment simulating drought conditions expected in Mediterranean areas for the following decades (15% decrease in soil moisture) is being conducted since 1999 in a Mediterranean holm oak forest to study its response to the forecasted climatic changes for the coming decades. The maximum PSII quantum yield of primary photochemistry (Fv/Fm) was measured in Quercus ilex, and Phillyrea latifolia, the co-dominant species of the studied forest, from 1999 to 2009 in four plots: two of them were control plots and the other two plots received the rain exclusion treatment. In both species, the Fv/Fm values were highly dependent on air temperatures, and in a second term, in water availability. P. latifolia was the species with the larger decrease in Fv/Fm values induced by low air temperatures, while in hot seasons, the Fv/Fm values in P. latifolia were even higher than in Q. ilex. Rainfall exclusion decrease Fv/Fm values signiﬁcantly only in few monitoring dates. The most drought resistant species P. latifolia was more affected by the experimental rainfall exclusion than Q. ilex that instead lost number of leaves per tree. There was a synergic effect of drought stress and winter cold in P. latifolia not observed in Q. ilex, but a more conservative strategy in P. latifolia maintaining leaves with a down-regulation of the linear photosynthetic electron transport. These results indicate that, although other physiological and reproductive strategies at whole plant level must be also taken into account, the warmer and drier environment expected for the following decades could favour the species more sensitive to cold and more resistant to drought, the shrub P. latifolia, in detriment of the tree Q. ilex as already observed in the ﬁeld after severe heat-drought episodes.</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%">Blanch, Josep-salvador</style></author><author><style face="normal" font="default" size="100%">Llusia, Joan</style></author><author><style face="normal" font="default" size="100%">Niinemets, Ülo</style></author><author><style face="normal" font="default" size="100%">Noe, Steffen M.</style></author><author><style face="normal" font="default" size="100%">Penuelas, Josep</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Instantaneous and historical temperature effects on α -pinene emissions in Pinus halepensis and Quercus ilex</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of Environmental Biology</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">acclimation</style></keyword><keyword><style  face="normal" font="default" size="100%">emission model</style></keyword><keyword><style  face="normal" font="default" size="100%">Pinus halepensis</style></keyword><keyword><style  face="normal" font="default" size="100%">previous climate effects</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus ilex</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><volume><style face="normal" font="default" size="100%">332</style></volume><pages><style face="normal" font="default" size="100%">1 - 6</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">We compared the role of instantaneous temperature and temperature history in the determination of α-pinene emissions in Mediterranean conifer Pinus halepensis that stores monoterpenes in resin ducts, and in Mediterranean broad-leaved evergreen Quercus ilex that lacks such specialized storage structures. In both species, α-pinene emission rates (E) exhibited a significant exponential correlation with leaf temperature and the rates of photosynthetic electron transport (JCO 2 +O 2 ) started to decrease after an optimum at approximately 35 o C. However, there was a higher dependence of E on mean temperature of previous days than on mean temperature of current day for P. halepensis but not for Q. ilex. JCO 2 +O 2 showed a maximum relationship to mean temperature of previous 3 and 5 days for P. halepensis and Q. ilex respectively. We conclude that although the best correlation of emission rates were found for instantaneous foliar temperatures, the effect of accumulated previous temperature conditions should also be considered in models of monoterpene emission, especially for terpene storing species.</style></abstract><issue><style face="normal" font="default" size="100%">January</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%">Blanch, Josep-salvador</style></author><author><style face="normal" font="default" size="100%">Penuelas, Josep</style></author><author><style face="normal" font="default" size="100%">Sardans, Jordi</style></author><author><style face="normal" font="default" size="100%">Llusia, Joan</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Drought, warming and soil fertilization effects on leaf volatile terpene concentrations in Pinus halepensis and Quercus ilex</style></title><secondary-title><style face="normal" font="default" size="100%">Acta Physiologiae Plantarum</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">fertilization</style></keyword><keyword><style  face="normal" font="default" size="100%">Pinus halepensis</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus ilex</style></keyword><keyword><style  face="normal" font="default" size="100%">Temperature</style></keyword><keyword><style  face="normal" font="default" size="100%">terpene concentration</style></keyword><keyword><style  face="normal" font="default" size="100%">water stress</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2008</style></year></dates><volume><style face="normal" font="default" size="100%">31</style></volume><pages><style face="normal" font="default" size="100%">207-218</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The changes in foliar concentrations of volatile terpenes in response to water stress, fertilization and temperature were analyzed in Pinus halepensis and Quercus ilex. The most abundant terpenes found in both species were a-pinene and D 3 -carene. b-Pinene and myrcene were also abundant in both species. P. halepensis concentrations were much greater than those of Q. ilex in agreement with the lack of storage in the latter species (15205.60 ± 1140.04 vs. 0.54 ± 0.08 lg g -1 [d.m.]). The drought treatment (reduction to 1/3 of full watering) signiﬁcantly increased the total terpene concentrations in both species (54% in P. halepensis and 119% in Q. ilex). The fertilization treatment (addition of either 250 kg N ha -1 or 250 kg P ha -1 or both) had no signiﬁcant effects on terpene foliar concentrations. The terpene concentrations increased from 0.25 lg g -1 [d.m.] at 30C to 0.70 lg g -1 [d.m.] at 40C in Q. ilex (the non-storing species) and from 2,240 lg g -1 [d.m.] at 30C to 15,621 lg g -1 [d.m.] at 40C in P. halepensis (the storing species). Both species presented negative relationship between terpene concentrations and relative water contents (RWC). The results of this study show that higher terpene concentrations can be expected in the warmer and drier conditions predicted for the next decades in the Mediterranean region.</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%">Blanch, Josep-salvador</style></author><author><style face="normal" font="default" size="100%">Penuelas, Josep</style></author><author><style face="normal" font="default" size="100%">Sardans, Jordi</style></author><author><style face="normal" font="default" size="100%">Llusia, Joan</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Drought, warming and soil fertilization effects on leaf volatile terpene concentrations in Pinus halepensis and Quercus ilex</style></title><secondary-title><style face="normal" font="default" size="100%">Acta Physiologiae Plantarum</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">fertilization</style></keyword><keyword><style  face="normal" font="default" size="100%">Pinus halepensis</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus ilex</style></keyword><keyword><style  face="normal" font="default" size="100%">Temperature</style></keyword><keyword><style  face="normal" font="default" size="100%">terpene concentration</style></keyword><keyword><style  face="normal" font="default" size="100%">water stress</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2008</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2008///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.springerlink.com/index/10.1007/s11738-008-0221-z</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">31</style></volume><pages><style face="normal" font="default" size="100%">207 - 218</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The changes in foliar concentrations of volatile terpenes in response to water stress, fertilization and temperature were analyzed in Pinus halepensis and Quercus ilex. The most abundant terpenes found in both species were a-pinene and D 3 -carene. b-Pinene and myrcene were also abundant in both species. P. halepensis concentrations were much greater than those of Q. ilex in agreement with the lack of storage in the latter species (15205.60 ± 1140.04 vs. 0.54 ± 0.08 lg g -1 [d.m.]). The drought treatment (reduction to 1/3 of full watering) signiﬁcantly increased the total terpene concentrations in both species (54% in P. halepensis and 119% in Q. ilex). The fertilization treatment (addition of either 250 kg N ha -1 or 250 kg P ha -1 or both) had no signiﬁcant effects on terpene foliar concentrations. The terpene concentrations increased from 0.25 lg g -1 [d.m.] at 30C to 0.70 lg g -1 [d.m.] at 40C in Q. ilex (the non-storing species) and from 2,240 lg g -1 [d.m.] at 30C to 15,621 lg g -1 [d.m.] at 40C in P. halepensis (the storing species). Both species presented negative relationship between terpene concentrations and relative water contents (RWC). The results of this study show that higher terpene concentrations can be expected in the warmer and drier conditions predicted for the next decades in the Mediterranean region.</style></abstract><issue><style face="normal" font="default" size="100%">1</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%">Blanch, Josep-salvador</style></author><author><style face="normal" font="default" size="100%">Penuelas, Josep</style></author><author><style face="normal" font="default" size="100%">Llusia, Joan</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Sensitivity of terpene emissions to drought and fertilization in terpene-storing Pinus halepensis and non-storing Quercus ilex</style></title><secondary-title><style face="normal" font="default" size="100%">Physiologia Plantarum</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Drought</style></keyword><keyword><style  face="normal" font="default" size="100%">Emission rates</style></keyword><keyword><style  face="normal" font="default" size="100%">Fertlization</style></keyword><keyword><style  face="normal" font="default" size="100%">mediterranean ecosystems (voyant)</style></keyword><keyword><style  face="normal" font="default" size="100%">Pinus halepensis</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus ilex</style></keyword><keyword><style  face="normal" font="default" size="100%">storing and non-storing species</style></keyword><keyword><style  face="normal" font="default" size="100%">terpene</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2007</style></year></dates><publisher><style face="normal" font="default" size="100%">Blackwell Publishing Ltd</style></publisher><volume><style face="normal" font="default" size="100%">131</style></volume><pages><style face="normal" font="default" size="100%">211-225</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">We studied the effects of water stress, fertilization and time course on foliar volatile terpene emission rates by Quercus ilex and Pinus halepensis in a garden experiment. The terpenes mostly emitted by both species were α-pinene, β-pinene, β-myrcene and Δ3-carene. P. halepensis emission rates (average 31.45 μg g−1 DM h−1) were similar to those of Q. ilex (average 31.71 μg g−1 DM h−1). The effects of drought (reduction to one-third of full watering) and fertilization (250 kg N ha−1, 250 kg P ha−1, or both) were different depending on the species: the drought treatment significantly increased the terpene emissions from Q. ilex by 33%, and the fertilization treatments reduced the terpene emissions from P. halepensis by 38%. Terpene emission rates increased with time course in parallel to raising summer temperatures in P. halepensis and Q. ilex, whose emission rates were temperature related (r = 0.42 and r = 0.68, respectively) and light related (r = 0.32 and r = 0.57, respectively). There was a positive relationship for P. halepensis, and a negative relationship for Q. ilex, between emission rates and relative water contents. No relationship was found between emission rates and N or P foliar concentrations. The results of this study show complex species-specific responses with stronger and faster short-term responses in terpene-non-storing than in storing species and indicate that terpene emissions may significantly change in the warmer, drier and more fertilized conditions predicted for the next decades in the Mediterranean region.</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%">Blanch, Josep-salvador</style></author><author><style face="normal" font="default" size="100%">Penuelas, Josep</style></author><author><style face="normal" font="default" size="100%">Llusia, Joan</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Sensitivity of terpene emissions to drought and fertilization in terpene-storing Pinus halepensis and non-storing Quercus ilex</style></title><secondary-title><style face="normal" font="default" size="100%">Physiologia Plantarum</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Drought</style></keyword><keyword><style  face="normal" font="default" size="100%">Emission rates</style></keyword><keyword><style  face="normal" font="default" size="100%">Fertlization</style></keyword><keyword><style  face="normal" font="default" size="100%">mediterranean ecosystems (voyant)</style></keyword><keyword><style  face="normal" font="default" size="100%">Pinus halepensis</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus ilex</style></keyword><keyword><style  face="normal" font="default" size="100%">storing and non-storing species</style></keyword><keyword><style  face="normal" font="default" size="100%">terpene</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2007</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2007///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://dx.doi.org/10.1111/j.1399-3054.2007.00944.x</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">131</style></volume><pages><style face="normal" font="default" size="100%">211 - 225</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">We studied the effects of water stress, fertilization and time course on foliar volatile terpene emission rates by Quercus ilex and Pinus halepensis in a garden experiment. The terpenes mostly emitted by both species were α-pinene, β-pinene, β-myrcene and Δ3-carene. P. halepensis emission rates (average 31.45 μg g−1 DM h−1) were similar to those of Q. ilex (average 31.71 μg g−1 DM h−1). The effects of drought (reduction to one-third of full watering) and fertilization (250 kg N ha−1, 250 kg P ha−1, or both) were different depending on the species: the drought treatment significantly increased the terpene emissions from Q. ilex by 33%, and the fertilization treatments reduced the terpene emissions from P. halepensis by 38%. Terpene emission rates increased with time course in parallel to raising summer temperatures in P. halepensis and Q. ilex, whose emission rates were temperature related (r = 0.42 and r = 0.68, respectively) and light related (r = 0.32 and r = 0.57, respectively). There was a positive relationship for P. halepensis, and a negative relationship for Q. ilex, between emission rates and relative water contents. No relationship was found between emission rates and N or P foliar concentrations. The results of this study show complex species-specific responses with stronger and faster short-term responses in terpene-non-storing than in storing species and indicate that terpene emissions may significantly change in the warmer, drier and more fertilized conditions predicted for the next decades in the Mediterranean region.</style></abstract><issue><style face="normal" font="default" size="100%">2</style></issue><notes><style face="normal" font="default" size="100%">The following values have no corresponding Zotero field:&lt;br/&gt;publisher: Blackwell Publishing Ltd</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%">Lloret, Francisco</style></author><author><style face="normal" font="default" size="100%">Penuelas, Josep</style></author><author><style face="normal" font="default" size="100%">Ogaya, Romà</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Establishment of co-existing Mediterranean tree species under a varying soil moisture regime</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of Vegetation Science</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">climate change</style></keyword><keyword><style  face="normal" font="default" size="100%">Drought</style></keyword><keyword><style  face="normal" font="default" size="100%">mediterranean forest</style></keyword><keyword><style  face="normal" font="default" size="100%">Nitrogen use</style></keyword><keyword><style  face="normal" font="default" size="100%">phillyrea latifolia</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus ilex</style></keyword><keyword><style  face="normal" font="default" size="100%">Recruitment</style></keyword><keyword><style  face="normal" font="default" size="100%">Regeneration</style></keyword><keyword><style  face="normal" font="default" size="100%">Seedling</style></keyword><keyword><style  face="normal" font="default" size="100%">sprouting</style></keyword><keyword><style  face="normal" font="default" size="100%">water use efficiency</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://dx.doi.org/10.1111/j.1654-1103.2004.tb02258.x</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">15</style></volume><pages><style face="normal" font="default" size="100%">237 - 244</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">We investigated the responses of two co-existing Mediterranean trees with different regeneration strategies (Phillyrea latifolia seedlings and Quercus ilex sprouts) to experimental drought below the forest canopy. We considered different recruitment stages and used leaf isotopic discrimination to estimate water use efficiency (WUE) and nitrogen availability and use. Drought decreased the emergence and survival of seedlings and sprouts. Survival and growth of older saplings were not influenced by drought. Seedling emergence of P. latifolia was higher than Q. ilex sprout production, but Q. ilex sprouts had higher survival and growth rates. These differences disappeared in the sapling stage. Carbon isotopic discrimination suggested that Q. ilex sprouts had higher WUE than P. latifolia seedlings. Drought increased WUE of recruits, particularly in Q. ilex. Water use regulation increased with ageing, particularly in P. latifolia. Q. ilex had higher δ15N values than P. latifolia; these were also higher under drier soil conditions. Current year seedlings had higher δ15N than saplings, particularly in P. latifolia, suggesting they exploit superficial soil layers. These results suggest that sprouts obtain benefit from resources stored in parent plants. At earlier stages, they perform better than seedlings. This response is not coupled to adult vulnerability to drought for these species, revealing the difficulty of predicting species dynamics during climate change.</style></abstract><issue><style face="normal" font="default" size="100%">2</style></issue><notes><style face="normal" font="default" size="100%">The following values have no corresponding Zotero field:&lt;br/&gt;publisher: Blackwell Publishing Ltd</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%">Sardans, Jordi</style></author><author><style face="normal" font="default" size="100%">Penuelas, Josep</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Increasing drought decreases phosphorus availability in an evergreen Mediterranean forest</style></title><secondary-title><style face="normal" font="default" size="100%">Plant and Soil</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">climate change</style></keyword><keyword><style  face="normal" font="default" size="100%">Drought</style></keyword><keyword><style  face="normal" font="default" size="100%">Mediterranean ecosystems</style></keyword><keyword><style  face="normal" font="default" size="100%">mineralomasses</style></keyword><keyword><style  face="normal" font="default" size="100%">nutrient concentrations</style></keyword><keyword><style  face="normal" font="default" size="100%">nutrient cycles</style></keyword><keyword><style  face="normal" font="default" size="100%">phosphorus</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus ilex</style></keyword><keyword><style  face="normal" font="default" size="100%">Soil</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2004</style></year></dates><volume><style face="normal" font="default" size="100%">267</style></volume><pages><style face="normal" font="default" size="100%">367-377</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Mediterranean ecosystems are water-limited and frequently also nutrient-limited. We aimed to investigate the effects of increasing drought, as predicted by GCM and eco-physiological models for the next decades, on the P cycle and P plant availability in a Mediterranean forest. We conducted a ﬁeld experiment in a mature evergreen oak forest, establishing four drought-treatment plots and four control plots (150 m2 each). After three years, the runoff and rainfall exclusion reduced an overall 22% the soil moisture, and the runoff exclusion alone reduced it 10%. The reduction of 22% in soil moisture produced a decrease of 40% of the accumulated aboveground plant P content, above all because there was a smaller increase in aerial biomass. The plant leaf P content increased by 100 ± 40 mg m−2 in the control plots, whereas it decreased by 40 ± 40 mg m−2 in the drought plots. The soil Po-NaHCO3 (organic labile-P fraction) increased by 25% in consonance with the increase in litterfall, while the inorganic labile-P fraction decreased in relation to the organic labile-P fraction up to 48%, indicating a decrease in microbial activity. Thus, after just three years of slight drought, a clear trend towards an accumulation of P in the soil and towards a decrease of P in the stand biomass was observed. The P accumulation in the soil in the drought plots was mainly in forms that were not directly available to plants. These indirect effects of drought including the decrease in plant P availability, may</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%">Sardans, Jordi</style></author><author><style face="normal" font="default" size="100%">Penuelas, Josep</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Increasing drought decreases phosphorus availability in an evergreen Mediterranean forest</style></title><secondary-title><style face="normal" font="default" size="100%">Plant and Soil</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">climate change</style></keyword><keyword><style  face="normal" font="default" size="100%">Drought</style></keyword><keyword><style  face="normal" font="default" size="100%">Mediterranean ecosystems</style></keyword><keyword><style  face="normal" font="default" size="100%">mineralomasses</style></keyword><keyword><style  face="normal" font="default" size="100%">nutrient concentrations</style></keyword><keyword><style  face="normal" font="default" size="100%">nutrient cycles</style></keyword><keyword><style  face="normal" font="default" size="100%">phosphorus</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus ilex</style></keyword><keyword><style  face="normal" font="default" size="100%">Soil</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://www.springerlink.com/index/10.1007/s11104-005-0172-8</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">267</style></volume><pages><style face="normal" font="default" size="100%">367 - 377</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Mediterranean ecosystems are water-limited and frequently also nutrient-limited. We aimed to investigate the effects of increasing drought, as predicted by GCM and eco-physiological models for the next decades, on the P cycle and P plant availability in a Mediterranean forest. We conducted a ﬁeld experiment in a mature evergreen oak forest, establishing four drought-treatment plots and four control plots (150 m2 each). After three years, the runoff and rainfall exclusion reduced an overall 22% the soil moisture, and the runoff exclusion alone reduced it 10%. The reduction of 22% in soil moisture produced a decrease of 40% of the accumulated aboveground plant P content, above all because there was a smaller increase in aerial biomass. The plant leaf P content increased by 100 ± 40 mg m−2 in the control plots, whereas it decreased by 40 ± 40 mg m−2 in the drought plots. The soil Po-NaHCO3 (organic labile-P fraction) increased by 25% in consonance with the increase in litterfall, while the inorganic labile-P fraction decreased in relation to the organic labile-P fraction up to 48%, indicating a decrease in microbial activity. Thus, after just three years of slight drought, a clear trend towards an accumulation of P in the soil and towards a decrease of P in the stand biomass was observed. The P accumulation in the soil in the drought plots was mainly in forms that were not directly available to plants. These indirect effects of drought including the decrease in plant P availability, may</style></abstract><issue><style face="normal" font="default" size="100%">1-2</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%">Penuelas, Josep</style></author><author><style face="normal" font="default" size="100%">Boada, Martí</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">A global change-induced biome shift in the Montseny mountains (NE Spain)</style></title><secondary-title><style face="normal" font="default" size="100%">Global Change Biology</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">altitudinal shift</style></keyword><keyword><style  face="normal" font="default" size="100%">biome replacement</style></keyword><keyword><style  face="normal" font="default" size="100%">Calluna heathland</style></keyword><keyword><style  face="normal" font="default" size="100%">climate change</style></keyword><keyword><style  face="normal" font="default" size="100%">defoliation status</style></keyword><keyword><style  face="normal" font="default" size="100%">Fagus sylvatica</style></keyword><keyword><style  face="normal" font="default" size="100%">Land use change</style></keyword><keyword><style  face="normal" font="default" size="100%">mediterranean forest</style></keyword><keyword><style  face="normal" font="default" size="100%">Montseny mountains</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus ilex</style></keyword><keyword><style  face="normal" font="default" size="100%">Recruitment</style></keyword><keyword><style  face="normal" font="default" size="100%">temperate forest</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2003</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2003///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://dx.doi.org/10.1046/j.1365-2486.2003.00566.x</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">9</style></volume><pages><style face="normal" font="default" size="100%">131 - 140</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Shifts in plant species and biome distribution in response to warming have been described in past climate changes. However, reported evidence of such shifts under current climate change is still scarce. By comparing current and 1945 vegetation distribution in the Montseny mountains (Catalonia, NE Spain), we report here a progressive replacement of cold-temperate ecosystems by Mediterranean ecosystems. Beech (Fagus sylvatica) forest has shifted altitudinally upwards by ca. 70 m at the highest altitudes (1600–1700 m). Both the beech forests and the heather (Calluna vulgaris) heathlands are being replaced by holm oak (Quercus ilex) forest at medium altitudes (800–1400 m). This beech replacement has been observed to occur through a progressive isolation and degradation of beech stands. In ‘isolated’ (small and surrounded by holm oaks) beech stands, beech trees are 30% more defoliated, beech recruitment is 41% lower, and holm oak recruitment is three times higher than in ‘continental’ (large and continuous) beech stands. The progressively warmer conditions, complemented by the land use changes (mainly the cessation of traditional land management) are the apparent causes, providing a paradigmatic example of global change affecting distributions of plant species and biomes.</style></abstract><issue><style face="normal" font="default" size="100%">2</style></issue><notes><style face="normal" font="default" size="100%">The following values have no corresponding Zotero field:&lt;br/&gt;publisher: Blackwell Science, Ltd</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%">Filella, Iolanda</style></author><author><style face="normal" font="default" size="100%">Penuelas, Josep</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Altitudinal differences in UV absorbance, UV reflectance and related morphological traits of Quercus ilex and Rhododendron ferrugineum in the Mediterranean region</style></title><secondary-title><style face="normal" font="default" size="100%">Plant Ecology</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Altitude</style></keyword><keyword><style  face="normal" font="default" size="100%">carotenoids/chlorophyll a ratio</style></keyword><keyword><style  face="normal" font="default" size="100%">leaf hair density</style></keyword><keyword><style  face="normal" font="default" size="100%">Mediterranean Region</style></keyword><keyword><style  face="normal" font="default" size="100%">ndpi</style></keyword><keyword><style  face="normal" font="default" size="100%">pri</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus ilex</style></keyword><keyword><style  face="normal" font="default" size="100%">rhododendron ferrugineum</style></keyword><keyword><style  face="normal" font="default" size="100%">slw</style></keyword><keyword><style  face="normal" font="default" size="100%">Thickness</style></keyword><keyword><style  face="normal" font="default" size="100%">uv absorbing compounds</style></keyword><keyword><style  face="normal" font="default" size="100%">uv reflectance</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1999</style></year></dates><volume><style face="normal" font="default" size="100%">145</style></volume><pages><style face="normal" font="default" size="100%">157-165</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">We studied the variations in different physiological parameters associated with UV-B radiation defense: UV-B radiation absorbance, UV-visible spectral reﬂectance, carotenoids concentration, leaf thickness, SLW (speciﬁc leaf weigth) and trichome density in Quercus ilex growing at 200 and 1200 m and Rhododendron ferrugineum growing at 2200 m. We examined the role of these parameters as protection mechanisms in an altitudinal gradient of increasing UV radiation in northern Catalonia and in sun and shade leaves. The concentration of UV-B radiation absorbing pigments was 15% higher in sun leaves of Q. ilex at 1200 m than in those from 200 m altitude. Sun leaves of R. ferrugineum presented concentrations three times higher than those of Q. ilex. Reﬂectance ranged between 5% (in the region 300–400 nm) and 12% (in the region 280–300 nm). The variation of reﬂectance with altitude followed an inverse trend respect to absorbance in the 280–300 nm region, with higher values the lower the altitude, but in the 300–400 nm region, reﬂectance of the lower site was the lowest. In both species and altitudes sun leaves presented higher concentrations of UV-B radiation absorbing pigments and UV reﬂectance than shade leaves. Quercus ilex trees of the higher location presented higher NDPI (Normalized Difference Pigment Reﬂectance Index) values, indicating higher carotenoids/chlorophylla ratio. Actual measurements of carotenoid/chlorophyll a ratio conﬁrmed this pattern. The photochemical reﬂectance index (PRI) presented higher values the higher the location indicating lower photosynthetic radiation-use efﬁciency. Speciﬁc leaf weight (SLW) and leaf thickness were larger in Q. ilex trees of higher location than in those of lower location. In both sites, sun leaves also presented larger SLW values than shade leaves. Adaxial leaf hair density in sun leaves was signiﬁcantlly higher in the lower location. UV absorption and linked morphological traits (SLW, leaf thickness measured in Q. ilex) presented the larger differences among studied plants at different altitudes and seem to be the dominant UV protecting mechanisms.</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%">Filella, Iolanda</style></author><author><style face="normal" font="default" size="100%">Penuelas, Josep</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Altitudinal differences in UV absorbance, UV reflectance and related morphological traits of Quercus ilex and Rhododendron ferrugineum in the Mediterranean region</style></title><secondary-title><style face="normal" font="default" size="100%">Plant Ecology</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Altitude</style></keyword><keyword><style  face="normal" font="default" size="100%">carotenoids/chlorophyll a ratio</style></keyword><keyword><style  face="normal" font="default" size="100%">leaf hair density</style></keyword><keyword><style  face="normal" font="default" size="100%">Mediterranean Region</style></keyword><keyword><style  face="normal" font="default" size="100%">ndpi</style></keyword><keyword><style  face="normal" font="default" size="100%">pri</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus ilex</style></keyword><keyword><style  face="normal" font="default" size="100%">rhododendron ferrugineum</style></keyword><keyword><style  face="normal" font="default" size="100%">slw</style></keyword><keyword><style  face="normal" font="default" size="100%">Thickness</style></keyword><keyword><style  face="normal" font="default" size="100%">uv absorbing compounds</style></keyword><keyword><style  face="normal" font="default" size="100%">uv reflectance</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1999</style></year><pub-dates><date><style  face="normal" font="default" size="100%">1999///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.springerlink.com/index/m8hl41013mvtx776.pdf</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">145</style></volume><pages><style face="normal" font="default" size="100%">157 - 165</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">We studied the variations in different physiological parameters associated with UV-B radiation defense: UV-B radiation absorbance, UV-visible spectral reﬂectance, carotenoids concentration, leaf thickness, SLW (speciﬁc leaf weigth) and trichome density in Quercus ilex growing at 200 and 1200 m and Rhododendron ferrugineum growing at 2200 m. We examined the role of these parameters as protection mechanisms in an altitudinal gradient of increasing UV radiation in northern Catalonia and in sun and shade leaves. The concentration of UV-B radiation absorbing pigments was 15% higher in sun leaves of Q. ilex at 1200 m than in those from 200 m altitude. Sun leaves of R. ferrugineum presented concentrations three times higher than those of Q. ilex. Reﬂectance ranged between 5% (in the region 300–400 nm) and 12% (in the region 280–300 nm). The variation of reﬂectance with altitude followed an inverse trend respect to absorbance in the 280–300 nm region, with higher values the lower the altitude, but in the 300–400 nm region, reﬂectance of the lower site was the lowest. In both species and altitudes sun leaves presented higher concentrations of UV-B radiation absorbing pigments and UV reﬂectance than shade leaves. Quercus ilex trees of the higher location presented higher NDPI (Normalized Difference Pigment Reﬂectance Index) values, indicating higher carotenoids/chlorophylla ratio. Actual measurements of carotenoid/chlorophyll a ratio conﬁrmed this pattern. The photochemical reﬂectance index (PRI) presented higher values the higher the location indicating lower photosynthetic radiation-use efﬁciency. Speciﬁc leaf weight (SLW) and leaf thickness were larger in Q. ilex trees of higher location than in those of lower location. In both sites, sun leaves also presented larger SLW values than shade leaves. Adaxial leaf hair density in sun leaves was signiﬁcantlly higher in the lower location. UV absorption and linked morphological traits (SLW, leaf thickness measured in Q. ilex) presented the larger differences among studied plants at different altitudes and seem to be the dominant UV protecting mechanisms.</style></abstract></record></records></xml>