<?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%">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%">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%">Faria, T</style></author><author><style face="normal" font="default" size="100%">Silvério, D</style></author><author><style face="normal" font="default" size="100%">Breia, E</style></author><author><style face="normal" font="default" size="100%">Cabral, R</style></author><author><style face="normal" font="default" size="100%">Abadía, A</style></author><author><style face="normal" font="default" size="100%">Abadia, J</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%">Differences in the response of carbon assimilation to summer stress (water deficits, high light and temperature) in four Mediterranean tree species</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%">Energy dissipation</style></keyword><keyword><style  face="normal" font="default" size="100%">Eucalyptus globulus</style></keyword><keyword><style  face="normal" font="default" size="100%">Olea europaea</style></keyword><keyword><style  face="normal" font="default" size="100%">photosynthesis</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus ilex</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus suber</style></keyword><keyword><style  face="normal" font="default" size="100%">xanthophyll cycle</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><publisher><style face="normal" font="default" size="100%">Munksgaard International Publishers</style></publisher><volume><style face="normal" font="default" size="100%">102</style></volume><pages><style face="normal" font="default" size="100%">419-428</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Daily changes in photoprotective mechanisms were studied in sun leaves of Quercus suber L., Quercus ilex L., Olea europaea L. and Eucalyptus globulus Labill. trees during the summer in Portugal. Even though stomatal closure explained most of the diurnal variation in carbon assimilation along the summer, a decline in the photochemical yield of photosystem II (F′v/F′m) also occurred, as a result of an excess of intercepted solar radiation when carbon assimilation is limited by stomatal closure due to high vapour pressure deficits and/or soil water deficits. These changes were accompanied by the conversion of violaxanthin to antheraxanthin and zeaxanthin which were correlated with thermal dissipation of excess photon energy. In spite of a common general response, differences between species were observed -Olea europaea, which is a slow-growing tree, had the lowest net photosynthetic rates, the highest proportion of carotenoids in relation to chlorophyll and the highest rates of de-epoxidation of violaxanthin. This enabled a large thermal dissipation of the excess intercepted radiation but led to rather small values of light utilisation for photochemistry (ca 20%). In contrast, in E. globulus, a fast-growing tree, photosynthetic rates were the highest, thermal dissipation of absorbed radiation the lowest and maximal values of light utilisation for photochemistry reached ca 50%. The two Quercus species exhibited an intermediate response. A high degree of co-ordination is apparent between stomatal behaviour, photosynthetic capacity and photoprotection 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%">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>