<?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%">Fernandes, Ana</style></author><author><style face="normal" font="default" size="100%">Fernandes, Iva</style></author><author><style face="normal" font="default" size="100%">Cruz, Luís Luís</style></author><author><style face="normal" font="default" size="100%">Mateus, Nuno</style></author><author><style face="normal" font="default" size="100%">Cabral, Miguel</style></author><author><style face="normal" font="default" size="100%">de Freitas, Victor</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Antioxidant and Biological Properties of Bioactive Phenolic Compounds from Quercus suber L.</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of Agricultural and Food Chemistry</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">antioxidants</style></keyword><keyword><style  face="normal" font="default" size="100%">Antioxidants: chemistry</style></keyword><keyword><style  face="normal" font="default" size="100%">Antioxidants: isolation &amp; purification</style></keyword><keyword><style  face="normal" font="default" size="100%">Antioxidants: pharmacology</style></keyword><keyword><style  face="normal" font="default" size="100%">Antitumor activity</style></keyword><keyword><style  face="normal" font="default" size="100%">Cell Line</style></keyword><keyword><style  face="normal" font="default" size="100%">Cell Proliferation</style></keyword><keyword><style  face="normal" font="default" size="100%">Cell Proliferation: drug effects</style></keyword><keyword><style  face="normal" font="default" size="100%">Cork</style></keyword><keyword><style  face="normal" font="default" size="100%">Humans</style></keyword><keyword><style  face="normal" font="default" size="100%">Hydrolyzable Tannins</style></keyword><keyword><style  face="normal" font="default" size="100%">Hydrolyzable Tannins: chemistry</style></keyword><keyword><style  face="normal" font="default" size="100%">Hydrolyzable Tannins: isolation &amp; purification</style></keyword><keyword><style  face="normal" font="default" size="100%">Hydrolyzable Tannins: pharmacology</style></keyword><keyword><style  face="normal" font="default" size="100%">phenolic compounds</style></keyword><keyword><style  face="normal" font="default" size="100%">Plant Extracts</style></keyword><keyword><style  face="normal" font="default" size="100%">Plant Extracts: chemistry</style></keyword><keyword><style  face="normal" font="default" size="100%">Plant Extracts: isolation &amp; purification</style></keyword><keyword><style  face="normal" font="default" size="100%">Plant Extracts: pharmacology</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus suber L.</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus: chemistry</style></keyword><keyword><style  face="normal" font="default" size="100%">Tumor</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2009</style></year></dates><publisher><style face="normal" font="default" size="100%">American Chemical Society</style></publisher><volume><style face="normal" font="default" size="100%">57</style></volume><pages><style face="normal" font="default" size="100%">11154-11160</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Phenolic compounds, namely, hydrolyzable tannins and low molecular weight phenolic compounds, were isolated and purified from Portuguese cork from Quercus suber L. Some of these compounds were studied to evaluate their antioxidant activity, including free-radical scavenging capacity (DPPH method) and reducing capacity (FRAP method). All compounds tested showed significant antioxidant activity, namely, antiradical and reducing properties. The antiradical capacity seemed to increase with the presence of galloyl groups. Regarding the reducing capacity, this structure-activity relationship was not so clear. These compounds were also studied to evaluate the growth inhibitory effect on the estrogen responsive human breast cancer cell line (ERþ) MCF-7 and two other colon cancer cell lines (Caco-2 and HT-29). Generally, all the compounds tested exhibited, after a continuous exposure during a 48 h period, a dose-dependent growth inhibitory effect. Relative inhibitory activity was primarily related to the number of phenolic hydroxyl groups (galloyl and HHDP moieties) found in the active structures, with more groups generally conferring increased effects, except for HHDP-di-galloyl-glucose. Mongolicain B showed a greater potential to inhibit the growth of the three cell lines tested, identical to the effect observed with castalagin. Since these compounds are structurally related with each other, this activity might be based within the C-glycosidic ellagitannin moiety.</style></abstract><accession-num><style face="normal" font="default" size="100%">19888728</style></accession-num><notes><style face="normal" font="default" size="100%">From Duplicate 2 (Antioxidant and Biological Properties of Bioactive Phenolic Compounds from Quercus suber L. - Fernandes, Ana; Fernandes, Iva; Cruz, Luís; Mateus, Nuno; Cabral, Miguel; de Freitas, Victor)</style></notes><research-notes><style face="normal" font="default" size="100%">From Duplicate 2 (Antioxidant and Biological Properties of Bioactive Phenolic Compounds from Quercus suber L. - Fernandes, Ana; Fernandes, Iva; Cruz, Luís; Mateus, Nuno; Cabral, Miguel; de Freitas, Victor)</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%">Fernandes, Ana</style></author><author><style face="normal" font="default" size="100%">Fernandes, Iva</style></author><author><style face="normal" font="default" size="100%">Cruz, Luís Luís</style></author><author><style face="normal" font="default" size="100%">Mateus, Nuno</style></author><author><style face="normal" font="default" size="100%">Cabral, Miguel</style></author><author><style face="normal" font="default" size="100%">de Freitas, Victor</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Antioxidant and Biological Properties of Bioactive Phenolic Compounds from Quercus suber L.</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of Agricultural and Food Chemistry</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">antioxidants</style></keyword><keyword><style  face="normal" font="default" size="100%">Antioxidants: chemistry</style></keyword><keyword><style  face="normal" font="default" size="100%">Antioxidants: isolation &amp; purification</style></keyword><keyword><style  face="normal" font="default" size="100%">Antioxidants: pharmacology</style></keyword><keyword><style  face="normal" font="default" size="100%">Antitumor activity</style></keyword><keyword><style  face="normal" font="default" size="100%">Cell Line</style></keyword><keyword><style  face="normal" font="default" size="100%">Cell Proliferation</style></keyword><keyword><style  face="normal" font="default" size="100%">Cell Proliferation: drug effects</style></keyword><keyword><style  face="normal" font="default" size="100%">Cork</style></keyword><keyword><style  face="normal" font="default" size="100%">Humans</style></keyword><keyword><style  face="normal" font="default" size="100%">Hydrolyzable Tannins</style></keyword><keyword><style  face="normal" font="default" size="100%">Hydrolyzable Tannins: chemistry</style></keyword><keyword><style  face="normal" font="default" size="100%">Hydrolyzable Tannins: isolation &amp; purification</style></keyword><keyword><style  face="normal" font="default" size="100%">Hydrolyzable Tannins: pharmacology</style></keyword><keyword><style  face="normal" font="default" size="100%">phenolic compounds</style></keyword><keyword><style  face="normal" font="default" size="100%">Plant Extracts</style></keyword><keyword><style  face="normal" font="default" size="100%">Plant Extracts: chemistry</style></keyword><keyword><style  face="normal" font="default" size="100%">Plant Extracts: isolation &amp; purification</style></keyword><keyword><style  face="normal" font="default" size="100%">Plant Extracts: pharmacology</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus suber L.</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus: chemistry</style></keyword><keyword><style  face="normal" font="default" size="100%">Tumor</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2009</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2009///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/19888728http://dx.doi.org/10.1021/jf902093m</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">57</style></volume><pages><style face="normal" font="default" size="100%">11154 - 11160</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Phenolic compounds, namely, hydrolyzable tannins and low molecular weight phenolic compounds, were isolated and purified from Portuguese cork from Quercus suber L. Some of these compounds were studied to evaluate their antioxidant activity, including free-radical scavenging capacity (DPPH method) and reducing capacity (FRAP method). All compounds tested showed significant antioxidant activity, namely, antiradical and reducing properties. The antiradical capacity seemed to increase with the presence of galloyl groups. Regarding the reducing capacity, this structure-activity relationship was not so clear. These compounds were also studied to evaluate the growth inhibitory effect on the estrogen responsive human breast cancer cell line (ERþ) MCF-7 and two other colon cancer cell lines (Caco-2 and HT-29). Generally, all the compounds tested exhibited, after a continuous exposure during a 48 h period, a dose-dependent growth inhibitory effect. Relative inhibitory activity was primarily related to the number of phenolic hydroxyl groups (galloyl and HHDP moieties) found in the active structures, with more groups generally conferring increased effects, except for HHDP-di-galloyl-glucose. Mongolicain B showed a greater potential to inhibit the growth of the three cell lines tested, identical to the effect observed with castalagin. Since these compounds are structurally related with each other, this activity might be based within the C-glycosidic ellagitannin moiety.</style></abstract><issue><style face="normal" font="default" size="100%">23</style></issue><notes><style face="normal" font="default" size="100%">From Duplicate 2 (Antioxidant and Biological Properties of Bioactive Phenolic Compounds from Quercus suber L. - Fernandes, Ana; Fernandes, Iva; Cruz, Luís; Mateus, Nuno; Cabral, Miguel; de Freitas, Victor)From Duplicate 2 (Antioxidant and Biological Properties of Bioactive Phenolic Compounds from Quercus suber L. - Fernandes, Ana; Fernandes, Iva; Cruz, Luís; Mateus, Nuno; Cabral, Miguel; de Freitas, Victor)The following values have no corresponding Zotero field:&lt;br/&gt;publisher: American Chemical Society&lt;br/&gt;accession-num: 19888728</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%">García-Plazaola, José Ignacio</style></author><author><style face="normal" font="default" size="100%">Esteban, Raquel</style></author><author><style face="normal" font="default" size="100%">Hormaetxe, Koldobika</style></author><author><style face="normal" font="default" size="100%">Fernández-Marín, Beatriz</style></author><author><style face="normal" font="default" size="100%">Becerril, José Maria</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Photoprotective responses of Mediterranean and Atlantic trees to the extreme heat-wave of summer 2003 in Southwestern Europe</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 summer 2003</style></keyword><keyword><style  face="normal" font="default" size="100%">antioxidants</style></keyword><keyword><style  face="normal" font="default" size="100%">antioxidants á heat-wave á</style></keyword><keyword><style  face="normal" font="default" size="100%">heat-wave</style></keyword><keyword><style  face="normal" font="default" size="100%">mediterranean species</style></keyword><keyword><style  face="normal" font="default" size="100%">mediterranean species á photoprotection</style></keyword><keyword><style  face="normal" font="default" size="100%">photoprotection</style></keyword><keyword><style  face="normal" font="default" size="100%">summer 2003</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://link.springer.com/10.1007/s00468-007-0199-yhttp://www.springerlink.com/index/10.1007/s00468-007-0199-y</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">22</style></volume><pages><style face="normal" font="default" size="100%">385 - 392</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Summer 2003 was extremely hot in Europe. High light in combination with heat and drought exacerbates the generation of photo-oxidative stress. Under these conditions photoprotective responses can be critical for plant survival. Photoprotection was analysed in 2003 in several Mediterranean and Atlantic woody species. These data were compared with previous summers (1998, 1999 and 2001) to evaluate the potential acclimation for each species. A pattern of changes consisting on a decrease in chlorophyll, ascorbate and Fv/Fm and an increase in tocopherol, xanthophyll cycle pigments (VAZ) and deepoxidation index was regularly observed. Acclimation potential was measured by the use of the plasticity index for each parameter. Mediterranean species were more plastic than Atlantic ones. The latter were unable to increase antioxidant pools to the same extent or to downregulate the efﬁciency of light energy conversion. These results indicate that most Mediterranean species are able to perform an efﬁcient acclimation to heat stress, whilst Atlantic species will be more affected by climate warming.</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%">García-Plazaola, José Ignacio</style></author><author><style face="normal" font="default" size="100%">Esteban, Raquel</style></author><author><style face="normal" font="default" size="100%">Hormaetxe, Koldobika</style></author><author><style face="normal" font="default" size="100%">Fernández-Marín, Beatriz</style></author><author><style face="normal" font="default" size="100%">Becerril, José Maria</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Photoprotective responses of Mediterranean and Atlantic trees to the extreme heat-wave of summer 2003 in Southwestern Europe</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 summer 2003</style></keyword><keyword><style  face="normal" font="default" size="100%">antioxidants</style></keyword><keyword><style  face="normal" font="default" size="100%">antioxidants á heat-wave á</style></keyword><keyword><style  face="normal" font="default" size="100%">heat-wave</style></keyword><keyword><style  face="normal" font="default" size="100%">mediterranean species</style></keyword><keyword><style  face="normal" font="default" size="100%">mediterranean species á photoprotection</style></keyword><keyword><style  face="normal" font="default" size="100%">photoprotection</style></keyword><keyword><style  face="normal" font="default" size="100%">summer 2003</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2008</style></year></dates><volume><style face="normal" font="default" size="100%">22</style></volume><pages><style face="normal" font="default" size="100%">385-392</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Summer 2003 was extremely hot in Europe. High light in combination with heat and drought exacerbates the generation of photo-oxidative stress. Under these conditions photoprotective responses can be critical for plant survival. Photoprotection was analysed in 2003 in several Mediterranean and Atlantic woody species. These data were compared with previous summers (1998, 1999 and 2001) to evaluate the potential acclimation for each species. A pattern of changes consisting on a decrease in chlorophyll, ascorbate and Fv/Fm and an increase in tocopherol, xanthophyll cycle pigments (VAZ) and deepoxidation index was regularly observed. Acclimation potential was measured by the use of the plasticity index for each parameter. Mediterranean species were more plastic than Atlantic ones. The latter were unable to increase antioxidant pools to the same extent or to downregulate the efﬁciency of light energy conversion. These results indicate that most Mediterranean species are able to perform an efﬁcient acclimation to heat stress, whilst Atlantic species will be more affected by climate warming.</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%">Penuelas, J</style></author><author><style face="normal" font="default" size="100%">Llusia, J</style></author><author><style face="normal" font="default" size="100%">Asensio, D</style></author><author><style face="normal" font="default" size="100%">MUNNÉ-BOSCH, S</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Linking isoprene with plant thermotolerance, antioxidants and monoterpene emissions</style></title><secondary-title><style face="normal" font="default" size="100%">Plant, Cell &amp; Environment</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">antioxidants</style></keyword><keyword><style  face="normal" font="default" size="100%">ascorbic acid</style></keyword><keyword><style  face="normal" font="default" size="100%">fumigation</style></keyword><keyword><style  face="normal" font="default" size="100%">Fv/Fm</style></keyword><keyword><style  face="normal" font="default" size="100%">high temperatures</style></keyword><keyword><style  face="normal" font="default" size="100%">isoprene</style></keyword><keyword><style  face="normal" font="default" size="100%">Monoterpenes</style></keyword><keyword><style  face="normal" font="default" size="100%">photosynthetic rates</style></keyword><keyword><style  face="normal" font="default" size="100%">thermotolerance</style></keyword><keyword><style  face="normal" font="default" size="100%">zeaxanthin</style></keyword><keyword><style  face="normal" font="default" size="100%">α-tocopherol</style></keyword><keyword><style  face="normal" font="default" size="100%">β-carotene</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2005</style></year></dates><publisher><style face="normal" font="default" size="100%">Blackwell Science Ltd</style></publisher><volume><style face="normal" font="default" size="100%">28</style></volume><pages><style face="normal" font="default" size="100%">278-286</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The purpose of the present study was to test the possible plant thermotolerance role of isoprene and to study its relationship with non-enzymatic antioxidants and terpene emissions. The gas exchange, chlorophyll fluorescence, extent of photo- and oxidative stress, leaf damage, mechanisms of photo- and antioxidant protection, and terpene emission were measured in leaves of Quercus ilex seedlings exposed to a ramp of temperatures of 5 °C steps from 25 to 50 °C growing with and without isoprene (10 µL L−1) fumigation. The results showed that isoprene actually conferred thermotolerance (shifted the decrease of net photosynthetic rates from 35 to 45 °C, increased Fv/Fm at 50 °C from 0.38 to 0.65, and decreased the leaf area damaged from 27 to 15%), that it precluded or delayed the enhancement of the antioxidant non-enzymatic defence conferred by α-tocopherol, ascorbic acid or β-carotene consumption in response to increasing temperatures, and that it decreased by approximately 70% the emissions of monoterpenes at the highest temperatures. This suggests that there are inducible mechanisms triggered by the initial stages of thermal damage that up-regulate these antioxidant compounds at high temperatures and that these mechanisms are somehow suppressed in the presence of exogenous isoprene, which seems to already exert an antioxidant-like behaviour.</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%">Penuelas, J.</style></author><author><style face="normal" font="default" size="100%">Llusia, J.</style></author><author><style face="normal" font="default" size="100%">ASENSIO, D.</style></author><author><style face="normal" font="default" size="100%">MUNNÉ-BOSCH, S.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Linking isoprene with plant thermotolerance, antioxidants and monoterpene emissions</style></title><secondary-title><style face="normal" font="default" size="100%">Plant, Cell &amp; Environment</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">antioxidants</style></keyword><keyword><style  face="normal" font="default" size="100%">ascorbic acid</style></keyword><keyword><style  face="normal" font="default" size="100%">fumigation</style></keyword><keyword><style  face="normal" font="default" size="100%">Fv/Fm</style></keyword><keyword><style  face="normal" font="default" size="100%">high temperatures</style></keyword><keyword><style  face="normal" font="default" size="100%">isoprene</style></keyword><keyword><style  face="normal" font="default" size="100%">Monoterpenes</style></keyword><keyword><style  face="normal" font="default" size="100%">photosynthetic rates</style></keyword><keyword><style  face="normal" font="default" size="100%">thermotolerance</style></keyword><keyword><style  face="normal" font="default" size="100%">zeaxanthin</style></keyword><keyword><style  face="normal" font="default" size="100%">α-tocopherol</style></keyword><keyword><style  face="normal" font="default" size="100%">β-carotene</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2005</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2005///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://dx.doi.org/10.1111/j.1365-3040.2004.01250.x</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">28</style></volume><pages><style face="normal" font="default" size="100%">278 - 286</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The purpose of the present study was to test the possible plant thermotolerance role of isoprene and to study its relationship with non-enzymatic antioxidants and terpene emissions. The gas exchange, chlorophyll fluorescence, extent of photo- and oxidative stress, leaf damage, mechanisms of photo- and antioxidant protection, and terpene emission were measured in leaves of Quercus ilex seedlings exposed to a ramp of temperatures of 5 °C steps from 25 to 50 °C growing with and without isoprene (10 µL L−1) fumigation. The results showed that isoprene actually conferred thermotolerance (shifted the decrease of net photosynthetic rates from 35 to 45 °C, increased Fv/Fm at 50 °C from 0.38 to 0.65, and decreased the leaf area damaged from 27 to 15%), that it precluded or delayed the enhancement of the antioxidant non-enzymatic defence conferred by α-tocopherol, ascorbic acid or β-carotene consumption in response to increasing temperatures, and that it decreased by approximately 70% the emissions of monoterpenes at the highest temperatures. This suggests that there are inducible mechanisms triggered by the initial stages of thermal damage that up-regulate these antioxidant compounds at high temperatures and that these mechanisms are somehow suppressed in the presence of exogenous isoprene, which seems to already exert an antioxidant-like behaviour.</style></abstract><issue><style face="normal" font="default" size="100%">3</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%">García-Plazaola, J. I.</style></author><author><style face="normal" font="default" size="100%">Olano, J. M.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Photoprotection in evergreen Mediterranean plants during sudden periods of intense cold weather</style></title><secondary-title><style face="normal" font="default" size="100%">Trees-Structure and …</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">a-tocopherol</style></keyword><keyword><style  face="normal" font="default" size="100%">antioxidants</style></keyword><keyword><style  face="normal" font="default" size="100%">photooxidative stress</style></keyword><keyword><style  face="normal" font="default" size="100%">xanthophyll cycle</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://www.springerlink.com/index/GXVQKX8N55WL2X09.pdf</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">17</style></volume><pages><style face="normal" font="default" size="100%">285 - 291</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The photoprotective responses to an abrupt period of exceptional cold weather were studied in several Mediterranean evergreen species with different ecological requirements. The same pattern of response was observed in most of the species with little change in hydrophilic antioxidants (ascorbate and glutathione) and the carotenoid pool, an increase in the content of a -tocopherol, and a night retention of de-epoxidised xanthophylls (antheraxanthin and zeaxanthin). The accumulation of these xanthophylls correlated with a sustained decrease in maximal photochemical efficiency (Fv/Fm). This reduction in the rate of electron transport would reduce the production of superoxide in photosystem I, as well as the subsequent hydrogen peroxide and hydroxyl radical. Thereby if any transitory photooxidative stress is produced under these conditions it should be due mainly to the formation of singlet oxygen by triplet excited chlorophyll within the antenna. Since a-tocopherol is the main scavenger of singlet oxygen and lipid peroxy radicals, the large increase of this antioxidant within the species could be enough to compensate for the higher degree of photooxidative stress, playing an essential role in the survival of vegetation during the incidence of exceptional cold fronts 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%">Garcia-Plazaola, J I</style></author><author><style face="normal" font="default" size="100%">OLANO, J M</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Photoprotection in evergreen Mediterranean plants during sudden periods of intense cold weather</style></title><secondary-title><style face="normal" font="default" size="100%">Trees-Structure and …</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">a-tocopherol</style></keyword><keyword><style  face="normal" font="default" size="100%">antioxidants</style></keyword><keyword><style  face="normal" font="default" size="100%">photooxidative stress</style></keyword><keyword><style  face="normal" font="default" size="100%">xanthophyll cycle</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2003</style></year></dates><volume><style face="normal" font="default" size="100%">17</style></volume><pages><style face="normal" font="default" size="100%">285-291</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The photoprotective responses to an abrupt period of exceptional cold weather were studied in several Mediterranean evergreen species with different ecological requirements. The same pattern of response was observed in most of the species with little change in hydrophilic antioxidants (ascorbate and glutathione) and the carotenoid pool, an increase in the content of a -tocopherol, and a night retention of de-epoxidised xanthophylls (antheraxanthin and zeaxanthin). The accumulation of these xanthophylls correlated with a sustained decrease in maximal photochemical efficiency (Fv/Fm). This reduction in the rate of electron transport would reduce the production of superoxide in photosystem I, as well as the subsequent hydrogen peroxide and hydroxyl radical. Thereby if any transitory photooxidative stress is produced under these conditions it should be due mainly to the formation of singlet oxygen by triplet excited chlorophyll within the antenna. Since a-tocopherol is the main scavenger of singlet oxygen and lipid peroxy radicals, the large increase of this antioxidant within the species could be enough to compensate for the higher degree of photooxidative stress, playing an essential role in the survival of vegetation during the incidence of exceptional cold fronts 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%">García-Plazaola, Josá I.</style></author><author><style face="normal" font="default" size="100%">Artetxe, Unai</style></author><author><style face="normal" font="default" size="100%">Duñabeitia, Miren K.</style></author><author><style face="normal" font="default" size="100%">Becerril, Josá M.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Role of Photoprotective Systems of Holm-Oak (Quercus ilex) in the Adaptation to Winter Conditions</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of Plant Physiology</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">antioxidants</style></keyword><keyword><style  face="normal" font="default" size="100%">chilling</style></keyword><keyword><style  face="normal" font="default" size="100%">Mediterranean evergreens</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus ilex</style></keyword><keyword><style  face="normal" font="default" size="100%">sun/shade</style></keyword><keyword><style  face="normal" font="default" size="100%">xanthophylls</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://linkinghub.elsevier.com/retrieve/pii/S0176161799800649</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">155</style></volume><pages><style face="normal" font="default" size="100%">625 - 630</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Holm-oak (Quercus ilex L.) is a Mediterranean evergreen sclerophyllous species adapted to a wide range of environmental conditions and consequently its leaves must be able to withstand variable stresses. Changes in pigment and antioxidant composition were assessed in relation to chilling stress, light environment and leaf aging. Photosynthetic capacity during winter was rwo-fold higher than in spring. However, the photochemical efficiency of PSI! was reduced in sun leaves probably because of an increased rate of thermal energy dissipation related to the superior zeaxanthin concentration. Lutein, neoxanthin, ~-carotene and the xanthophyll cycle pool increased during winter especially in sun leaves, while lutein epoxide and a-carotene decreased markedly. The main antioxidant accumulated during winter was ascorbate, while glutathione and a-tocopherol were not seasonally affected. Catalase increased in spring as a consequence of higher photorespiration rates, while GR and MOHAR activities were higher in sun leaves during winter. The high MOHAR activity indicates an important role for this enzyme in the adaptation to environmental factors associated to winter. The present study demonstrates that holm-oak is able to acclimate to a variety of environmental stress factors by inducing dramatic changes in their photosynthetic characteristics, pigment composition and antioxidant defences.</style></abstract><issue><style face="normal" font="default" size="100%">4-5</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%">García-Plazaola, Josá I</style></author><author><style face="normal" font="default" size="100%">Artetxe, Unai</style></author><author><style face="normal" font="default" size="100%">Duñabeitia, Miren K</style></author><author><style face="normal" font="default" size="100%">Becerril, Josá M</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Role of Photoprotective Systems of Holm-Oak (Quercus ilex) in the Adaptation to Winter Conditions</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of Plant Physiology</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">antioxidants</style></keyword><keyword><style  face="normal" font="default" size="100%">chilling</style></keyword><keyword><style  face="normal" font="default" size="100%">Mediterranean evergreens</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus ilex</style></keyword><keyword><style  face="normal" font="default" size="100%">sun/shade</style></keyword><keyword><style  face="normal" font="default" size="100%">xanthophylls</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1999</style></year></dates><volume><style face="normal" font="default" size="100%">155</style></volume><pages><style face="normal" font="default" size="100%">625-630</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Holm-oak (Quercus ilex L.) is a Mediterranean evergreen sclerophyllous species adapted to a wide range of environmental conditions and consequently its leaves must be able to withstand variable stresses. Changes in pigment and antioxidant composition were assessed in relation to chilling stress, light environment and leaf aging. Photosynthetic capacity during winter was rwo-fold higher than in spring. However, the photochemical efficiency of PSI! was reduced in sun leaves probably because of an increased rate of thermal energy dissipation related to the superior zeaxanthin concentration. Lutein, neoxanthin, ~-carotene and the xanthophyll cycle pool increased during winter especially in sun leaves, while lutein epoxide and a-carotene decreased markedly. The main antioxidant accumulated during winter was ascorbate, while glutathione and a-tocopherol were not seasonally affected. Catalase increased in spring as a consequence of higher photorespiration rates, while GR and MOHAR activities were higher in sun leaves during winter. The high MOHAR activity indicates an important role for this enzyme in the adaptation to environmental factors associated to winter. The present study demonstrates that holm-oak is able to acclimate to a variety of environmental stress factors by inducing dramatic changes in their photosynthetic characteristics, pigment composition and antioxidant defences.</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%">Schwanz, P</style></author><author><style face="normal" font="default" size="100%">Polle, A</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Antioxidative systems, pigment and protein contents in leaves of adult mediterranean oak species (Quercus pubescens and Q. ilex) with lifetime exposure to elevated CO2</style></title><secondary-title><style face="normal" font="default" size="100%">New Phytologist</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">antioxidants</style></keyword><keyword><style  face="normal" font="default" size="100%">carbon dioxide enrichment</style></keyword><keyword><style  face="normal" font="default" size="100%">Drought</style></keyword><keyword><style  face="normal" font="default" size="100%">Oxidative stress</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus spp. (holm oak - white oak)</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1998</style></year></dates><publisher><style face="normal" font="default" size="100%">Cambridge University Press</style></publisher><volume><style face="normal" font="default" size="100%">140</style></volume><pages><style face="normal" font="default" size="100%">411-423</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The aim of the present study was to investigate the effects of elevated CO2 on the antioxidative systems and the contents of pigments, soluble protein and lipid peroxidation in leaves of adult oaks, Quercus pubescens and Quercus ilex, grown at naturally enriched CO2 concentrations. For this purpose, a field study was conducted at two CO2 springs in Central Italy. Measurements of the pre-dawn water potentials indicated less drought stress in trees close to CO2 springs than in those grown at ambient CO2 concentrations. Most leaf constituents investigated showed significant variability between sampling dates, species and sites. The foliar contents of protein and chlorophylls were not affected in trees grown close to the CO2 vents compared with those in ambient conditions. Increases in glutathione and other soluble thiols were observed, but these responses might have been caused by a low pollution of the vents with sulphurous gases. At CO2 vents, glutathione reductase was unaffected, and superoxide dismutase activity was significantly diminished, in both species. Generally, the activities of catalase, guaiacol peroxidase and ascorbate peroxidase as well as the sum of dehydroascorbate and ascorbate were decreased in leaves from trees grown in naturally CO2-enriched environments compared with those grown at ambient CO2 concentrations. The reduction in protective enzymes did not result in increased lipid peroxidation, but increased monodehydroascorbate radical reductase and dehydroascorbate reductase activities found in leaves of Q. pubescens suggest that the smaller pool of ascorbate was subjected to higher turnover rates. These data show that changes in leaf physiology persist, even after lifetime exposure to enhanced atmospheric CO2. The results suggest that the down-regulation of protective systems, which has also previously been found in young trees or seedlings under controlled exposure to elevated CO2 concentrations, might reflect a realistic response of antioxidative defences in mature trees in a future high-CO2 world.</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%">Faria, T</style></author><author><style face="normal" font="default" size="100%">Garcia-Plazaola, J I</style></author><author><style face="normal" font="default" size="100%">Abadía, A</style></author><author><style face="normal" font="default" size="100%">Cerasoli, S</style></author><author><style face="normal" font="default" size="100%">Pereira, J S</style></author><author><style face="normal" font="default" size="100%">Chaves, M M</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Diurnal changes in photoprotective mechanisms in leaves of cork oak (Quercus suber) during summer</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%">antioxidants</style></keyword><keyword><style  face="normal" font="default" size="100%">photoinhibition</style></keyword><keyword><style  face="normal" font="default" size="100%">photosynthesis</style></keyword><keyword><style  face="normal" font="default" size="100%">Stomatal conductance</style></keyword><keyword><style  face="normal" font="default" size="100%">xanthophylls</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1996</style></year></dates><volume><style face="normal" font="default" size="100%">16</style></volume><pages><style face="normal" font="default" size="100%">115-123</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Daily variations in photoprotective mechanisms were studied in sun and shade leaves of 40-year-old cork oak (Quercus suber L.) trees during early summer in Portugal. Although trees were not severely water stressed because predawn leaf water potentials remained high, photosynthesis and stomatal conductance decreased at midday. The midday depression in gas exchange was not reversed by short-term exposure to “optimal” conditions of temperature, light and vapor pressure deficit. Chlorophyll a fluorescence, maximum photochemical yield of photosystem II and the quantum yield of noncyclic electron transport showed midday depressions, but recovered by the evening. Both short-term changes in the components of the xanthophyll cycle (reversible de-epoxidation of violaxanthin during the day) as well as long-term changes (higher xanthophyll content in sun compared with shade leaves) were detected and may play a role in the dissipation of excess energy at midday. Because the activities of enzymes of the antioxidant system, superoxide dismutase and ascorbate peroxidase, were high enough to cope with the increase in oxygen reactive species likely to arise under the stressful conditions of midday, we conclude that these enzymes may provide an additional mechanism for energy dissipation.</style></abstract><notes><style face="normal" font="default" size="100%">10.1093/treephys/16.1-2.115</style></notes><research-notes><style face="normal" font="default" size="100%">10.1093/treephys/16.1-2.115</style></research-notes></record></records></xml>