<?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%">Corcuera, L</style></author><author><style face="normal" font="default" size="100%">Morales, F</style></author><author><style face="normal" font="default" size="100%">Abadía, A</style></author><author><style face="normal" font="default" size="100%">Gil-Pelegrín, E</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Seasonal changes in photosynthesis and photoprotection in a Quercus ilex subsp. ballota woodland located in its upper altitudinal extreme in the Iberian Peninsula</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%">antioxidant enzymatic activity</style></keyword><keyword><style  face="normal" font="default" size="100%">chlorophyll fluorescence</style></keyword><keyword><style  face="normal" font="default" size="100%">photosynthetic pigments</style></keyword><keyword><style  face="normal" font="default" size="100%">summer stress</style></keyword><keyword><style  face="normal" font="default" size="100%">winter stress</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2005</style></year></dates><volume><style face="normal" font="default" size="100%">25</style></volume><pages><style face="normal" font="default" size="100%">599-608</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Quercus ilex L. subsp. ballota (Desf.) Samp., a Mediterranean evergreen species growing in a continental Mediterranean climate, did not experience water stress and showed greater sensitivity to winter stress than to summer stress over a 12-month period. Net CO2 assimilation rates and photosystem II (PSII) efficiency decreased markedly during the cold months and recovered completely in spring. Lutein, neoxanthin and β-carotene to chlorophyll (Chl) molar ratios all showed the same trend throughout the year, increasing from September to March. This increase was a result of increases in carotenoid concentrations, because Chl concentration per unit leaf area remained stable, and was higher at the end than at the beginning of the first growing season. Lutein-epoxide was a minor component of the total lutein pool. Thermal energy dissipation and non-photochemical quenching (NPQ) were associated with the de-epoxidated forms of the xanthophyll cycle pigments in the warm months. Photosynthetic rates decreased slightly at midday in summer. These changes were accompanied by decreases in maximum potential PSII efficiency (which recovered during the night), actual and intrinsic PSII efficiencies, photochemical quenching and increases in NPQ. Overall, our data indicate down-regulation of photosynthesis during the summer. The diurnal de-epoxidation of violaxanthin to antheraxanthin and zeaxanthin occurred throughout the year, except in January. Antioxidant enzymatic activity increased in the winter months, especially during the coldest months, highlighting its key role in photoprotection against photo-oxidation. Structural and functional modifications protected PSII from permanent damage and allowed 1-year-old leaves to photosynthesize at high rates when temperatures increased in spring.</style></abstract><notes><style face="normal" font="default" size="100%">10.1093/treephys/25.5.599</style></notes><research-notes><style face="normal" font="default" size="100%">10.1093/treephys/25.5.599</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%">Corcuera, L</style></author><author><style face="normal" font="default" size="100%">Morales, F</style></author><author><style face="normal" font="default" size="100%">Abadía, A</style></author><author><style face="normal" font="default" size="100%">Gil-Pelegrín, E</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">The effect of low temperatures on the photosynthetic apparatus of Quercus ilex subsp. ballota at its lower and upper altitudinal limits in the Iberian peninsula and during a single freezing-thawing cycle</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%">chlorophyll fluorescence</style></keyword><keyword><style  face="normal" font="default" size="100%">Holm oak</style></keyword><keyword><style  face="normal" font="default" size="100%">photochemical and non-photochemical quenching</style></keyword><keyword><style  face="normal" font="default" size="100%">photoprotection</style></keyword><keyword><style  face="normal" font="default" size="100%">photosystem ii efficiency</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2004</style></year></dates><volume><style face="normal" font="default" size="100%">19</style></volume><pages><style face="normal" font="default" size="100%">99-108</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">We investigated the response of the photosynthetic apparatus during an episode of extreme low winter temperature in Quercus ilex subsp. ballota (Desf.) Samp., a typical Mediterranean evergreen species in the Iberian peninsula. Both plants in a woodland located at high altitude (1,177 m. a.s.l.) and potted plants obtained from acorns of the same populations grown at low altitude (225 m. a.s.l.) were analyzed. Net CO2 assimilation rate was negative and there was a marked decrease in photosystem II (PSII) efficiency during winter in leaves of the woodland population (high altitude individuals). These processes were accompanied by increases in nonphotochemical quenching (NPQ) and in the de-epoxidated carotenoids within the xanthophyll cycle, mechanisms aimed to dissipate excess energy. In addition, these deepoxidated carotenoids were largely preserved during the night. There was no chlorophyll bleaching during the winter, which suggests that leaves were not experiencing photoinhibitory damage. In fact, the net photosynthetic rate and the PSII efficiency recovered in spring. These changes were not observed, or were much more reduced, in individuals located at lower altitude after a few frosts. When the response to rapid temperature changes (from 20°C to −5°C and from −5°C to 20°C) was studied, it was found that the maximum potential PSII efficiency was fairly stable, ranging from 0.70 to 0.75. The rest of the photosynthetic parameters measured, actual and intrinsic PSII efficiency, photochemical and NPQ, responded immediately to the changes in temperature and, also, the recovery after cold events was practically immediate.</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%">Gulías, J</style></author><author><style face="normal" font="default" size="100%">Flexas, J</style></author><author><style face="normal" font="default" size="100%">Abadía, A</style></author><author><style face="normal" font="default" size="100%">Madrano, H</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Photosynthetic responses to water deficit in six Mediterranean sclerophyll species: possible factors explaining the declining distribution of Rhamnus ludovici-salvatoris, an endemic Balearic species.</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%">chlorophyll fluorescence</style></keyword><keyword><style  face="normal" font="default" size="100%">deciduous</style></keyword><keyword><style  face="normal" font="default" size="100%">Drought</style></keyword><keyword><style  face="normal" font="default" size="100%">evergreen</style></keyword><keyword><style  face="normal" font="default" size="100%">Gas exchange</style></keyword><keyword><style  face="normal" font="default" size="100%">leaf mass area</style></keyword><keyword><style  face="normal" font="default" size="100%">nitrogen</style></keyword><keyword><style  face="normal" font="default" size="100%">Pistacia</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus</style></keyword><keyword><style  face="normal" font="default" size="100%">Rhamnus</style></keyword><keyword><style  face="normal" font="default" size="100%">xanthophyll cycle</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2002</style></year></dates><publisher><style face="normal" font="default" size="100%">Oxford University Press / USA</style></publisher><volume><style face="normal" font="default" size="100%">22</style></volume><pages><style face="normal" font="default" size="100%">687-697</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">We sought to explain the declining distribution in the Balearic Islands of the endemic shrub Rhamnus ludovici-salvatoris R. Chodat, by comparing its photosynthetic response to drought with that of several widely distributed, competing Mediterranean species (R. alaternus L., Quercus ilex L., Pistacia lentiscus L., Q. humilis Mill. and P. terebinthus L.). [ABSTRACT FROM PUBLISHER]</style></abstract><notes><style face="normal" font="default" size="100%">Accession Number: 51808417; Gulías, J. 1 Flexas, J. 1 Abadía, A. 2; Email Address: dbajfs4@ps.uib.es Madrano, H. 1; Affiliation: 1: Laboratori de Fisiologia Vegetal, Departament de Biologia, Universitat de les Illes Balears Carretera de Valldemossa, Km. 7.5, 07071 Palma de Mallorca, Balears, Spain 2: Departamento de Nutriciön Vegetal, Estaciön Experimental de Aula Dei (Consejo Superior de Investigaciones Científicas) Apartado 202, 50080 Zaragoza, Aragön, Spain; Source Info: Jul2002, Vol. 22 Issue 10, p687; Subject Term: BUCKTHORNS; Subject Term: PLANT-water relationships; Subject Term: PHOTOSYNTHESIS; Subject Term: PLANT physiology; Subject Term: BALEARIC Islands (Spain); Subject Term: SPAIN; Author-Supplied Keyword: chlorophyll fluorescence; Author-Supplied Keyword: deciduous; Author-Supplied Keyword: drought; Author-Supplied Keyword: evergreen; Author-Supplied Keyword: gas exchange; Author-Supplied Keyword: leaf mass area; Author-Supplied Keyword: nitrogen; Author-Supplied Keyword: Pistacia; Author-Supplied Keyword: Pistacia Quercus; Author-Supplied Keyword: Quercus; Author-Supplied Keyword: Rhamnus; Author-Supplied Keyword: xanthophyll cycle; Number of Pages: 11p; Illustrations: 2 Charts, 2 Graphs; Document Type: Article</style></notes><research-notes><style face="normal" font="default" size="100%">Accession Number: 51808417; Gulías, J. 1 Flexas, J. 1 Abadía, A. 2; Email Address: dbajfs4@ps.uib.es Madrano, H. 1; Affiliation: 1: Laboratori de Fisiologia Vegetal, Departament de Biologia, Universitat de les Illes Balears Carretera de Valldemossa, Km. 7.5, 07071 Palma de Mallorca, Balears, Spain 2: Departamento de Nutriciön Vegetal, Estaciön Experimental de Aula Dei (Consejo Superior de Investigaciones Científicas) Apartado 202, 50080 Zaragoza, Aragön, Spain; Source Info: Jul2002, Vol. 22 Issue 10, p687; Subject Term: BUCKTHORNS; Subject Term: PLANT-water relationships; Subject Term: PHOTOSYNTHESIS; Subject Term: PLANT physiology; Subject Term: BALEARIC Islands (Spain); Subject Term: SPAIN; Author-Supplied Keyword: chlorophyll fluorescence; Author-Supplied Keyword: deciduous; Author-Supplied Keyword: drought; Author-Supplied Keyword: evergreen; Author-Supplied Keyword: gas exchange; Author-Supplied Keyword: leaf mass area; Author-Supplied Keyword: nitrogen; Author-Supplied Keyword: Pistacia; Author-Supplied Keyword: Pistacia Quercus; Author-Supplied Keyword: Quercus; Author-Supplied Keyword: Rhamnus; Author-Supplied Keyword: xanthophyll cycle; Number of Pages: 11p; Illustrations: 2 Charts, 2 Graphs; Document Type: Article</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%">Fleck, I</style></author><author><style face="normal" font="default" size="100%">Hogan, K P</style></author><author><style face="normal" font="default" size="100%">Llorens, L</style></author><author><style face="normal" font="default" size="100%">Abadía, A</style></author><author><style face="normal" font="default" size="100%">Aranda, X</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Photosynthesis and photoprotection in Quercus ilex resprouts after fire</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%">chlorophyll fluorescence</style></keyword><keyword><style  face="normal" font="default" size="100%">Gas exchange</style></keyword><keyword><style  face="normal" font="default" size="100%">Holm oak</style></keyword><keyword><style  face="normal" font="default" size="100%">photoinhibition</style></keyword><keyword><style  face="normal" font="default" size="100%">Photosystem II</style></keyword><keyword><style  face="normal" font="default" size="100%">zeaxanthin</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1998</style></year></dates><volume><style face="normal" font="default" size="100%">18</style></volume><pages><style face="normal" font="default" size="100%">607-614</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Plants that resprout after fires often have higher rates of photosynthesis than before a fire. To elucidate the mechanism of this response, we studied gas exchange and chlorophyll fluorescence in Quercus ilex L. plants growing on control (unburned) sites and on sites that had been burned the preceding summer. In early July, photosynthetic rates and stomatal conductance were similar in plants on unburned and burned plots, and in young and old foliage within unburned plots. At this time, photochemical efficiency of photosystem II (PSII), nonphotochemical quenching of chlorophyll fluorescence (NPQ), and the de-epoxidation of violaxanthin to zeaxanthin were also similar among leaves of different ages and treatments. In late July, photosynthetic rates and stomatal conductances were much greater in resprouts on the burned areas than in unburned plants. From early to late July, unburned plants showed an increase in NPQ and the de-epoxidation of violaxanthin to zeaxanthin, indicating increased photoprotection as a result of enhanced nonradiative dissipation of excess light energy. Plants on the burned plots did not show these changes. Leaves of all ages and treatments showed no substantial reduction in potential quantum yield of PSII (Fv/Fm) at midday or predawn, indicating that there was little or no photoinhibition. Leaf nitrogen and soluble protein contents varied with leaf age during July, but did not vary between treatments. We conclude that the primary effect of burning is an increase in water availability to resprouting plants that eliminates the need for photoprotection, at least in the short term. The decrease in photosynthetic rates of unburned leaves in late July was the result of reduced stomatal conductance. We suggest that lowered stomatal conductance is the primary limiting factor in Q. ilex leaves, governing the regulation of carboxylation activity and energy dissipation processes.</style></abstract><notes><style face="normal" font="default" size="100%">10.1093/treephys/18.8-9.607</style></notes><research-notes><style face="normal" font="default" size="100%">10.1093/treephys/18.8-9.607</style></research-notes></record></records></xml>