<?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%">Daas, C.</style></author><author><style face="normal" font="default" size="100%">Montpied, P.</style></author><author><style face="normal" font="default" size="100%">Hanchi, B.</style></author><author><style face="normal" font="default" size="100%">Dreyer, E.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Responses of photosynthesis to high temperatures in oak saplings assessed by chlorophyll-a fluorescence: inter-specific diversity and temperature-induced plasticity</style></title><secondary-title><style face="normal" font="default" size="100%">Annals of forest science</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">optimal temperature</style></keyword><keyword><style  face="normal" font="default" size="100%">Photochemistry</style></keyword><keyword><style  face="normal" font="default" size="100%">quantum yield</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus canariensis</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus coccifera</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus petraea</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus robur</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus suber</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.afs-journal.org/articles/forest/abs/2008/03/f07131/f07131.html</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">65</style></volume><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">• The sensitivity of photosynthesis to high temperature was investigated in greenhouse-grown saplings of three Mediterranean (Quercus canariensis Willd., Q. coccifera L. and Q. suber L.) and two temperate European oak species (Q. robur L. and Q. petraea Matt. Liebl.). The sensitivity to high temperature was inferred from F0T curves producing the critical temperature (Tc ) at which a rapid rise in ground chlorophyll a ﬂuorescence (F0) occurs. Tc is known to acclimate to moderately increased ambient temperature by displaying signiﬁcant increases. • We ﬁrst checked whether acclimation of Tc was paralleled by an increase in optimal temperature for light driven electron ﬂux (Topt ,), recorded by measuring quantum yield of photochemistry under saturating CO2 and moderate irradiance. Saplings of Q. suber and Q. canariensis were submitted to four, ﬁve days long ambient temperature steps (15, 25, 35 and 15 ◦ C again). Tc was usually largely above 45 ◦ C while Topt was around 30–35 ◦ C. Both increased with ambient temperature in the two species, and decreased again when temperature returned to the initial values. This recovery was nevertheless not complete after a week at 15 ◦ C. • A second experiment tested whether the plasticity of Tc was of the same extent in the ﬁve species. A signiﬁcant increase of Tc followed by a decrease was detected in all species. Only small inter-speciﬁc diﬀerences were detected in Tc , and temperature induced plasticity was similar in the diﬀerent species: Tc increased by about 4–5 ◦ C while ambient temperature was increased from 15 to 35 ◦ C. Mediterranean and European oaks did not diﬀer in this respect. • This result does not support the hypothesis that oak species from warmer regions would display a larger plasticity of Tc in response to increasing temperatures.</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%">Daas, C</style></author><author><style face="normal" font="default" size="100%">Montpied, P</style></author><author><style face="normal" font="default" size="100%">Hanchi, B</style></author><author><style face="normal" font="default" size="100%">Dreyer, E</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Responses of photosynthesis to high temperatures in oak saplings assessed by chlorophyll-a fluorescence: inter-specific diversity and temperature-induced plasticity</style></title><secondary-title><style face="normal" font="default" size="100%">Annals of forest science</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">optimal temperature</style></keyword><keyword><style  face="normal" font="default" size="100%">Photochemistry</style></keyword><keyword><style  face="normal" font="default" size="100%">quantum yield</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus canariensis</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus coccifera</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus petraea</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus robur</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus suber</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2008</style></year></dates><volume><style face="normal" font="default" size="100%">65</style></volume><pages><style face="normal" font="default" size="100%">305</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">• The sensitivity of photosynthesis to high temperature was investigated in greenhouse-grown saplings of three Mediterranean (Quercus canariensis Willd., Q. coccifera L. and Q. suber L.) and two temperate European oak species (Q. robur L. and Q. petraea Matt. Liebl.). The sensitivity to high temperature was inferred from F0T curves producing the critical temperature (Tc ) at which a rapid rise in ground chlorophyll a ﬂuorescence (F0) occurs. Tc is known to acclimate to moderately increased ambient temperature by displaying signiﬁcant increases. • We ﬁrst checked whether acclimation of Tc was paralleled by an increase in optimal temperature for light driven electron ﬂux (Topt ,), recorded by measuring quantum yield of photochemistry under saturating CO2 and moderate irradiance. Saplings of Q. suber and Q. canariensis were submitted to four, ﬁve days long ambient temperature steps (15, 25, 35 and 15 ◦ C again). Tc was usually largely above 45 ◦ C while Topt was around 30–35 ◦ C. Both increased with ambient temperature in the two species, and decreased again when temperature returned to the initial values. This recovery was nevertheless not complete after a week at 15 ◦ C. • A second experiment tested whether the plasticity of Tc was of the same extent in the ﬁve species. A signiﬁcant increase of Tc followed by a decrease was detected in all species. Only small inter-speciﬁc diﬀerences were detected in Tc , and temperature induced plasticity was similar in the diﬀerent species: Tc increased by about 4–5 ◦ C while ambient temperature was increased from 15 to 35 ◦ C. Mediterranean and European oaks did not diﬀer in this respect. • This result does not support the hypothesis that oak species from warmer regions would display a larger plasticity of Tc in response to increasing temperatures.</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%">Di Marco, Giorgio</style></author><author><style face="normal" font="default" size="100%">Manes, Fausto</style></author><author><style face="normal" font="default" size="100%">Tricoli, Domenico</style></author><author><style face="normal" font="default" size="100%">Vitale, Elisabetta</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Fluorescence Parameters Measured Concurrently with Net Photosynthesis to Investigate Chloroplastic CO2 Concentration in Leaves of Quercus ilex L.</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%">carbon assimilation</style></keyword><keyword><style  face="normal" font="default" size="100%">fluorescence</style></keyword><keyword><style  face="normal" font="default" size="100%">fluorescence quenching</style></keyword><keyword><style  face="normal" font="default" size="100%">quantum yield</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus ilex</style></keyword><keyword><style  face="normal" font="default" size="100%">stromal CO2</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1990</style></year></dates><volume><style face="normal" font="default" size="100%">136</style></volume><pages><style face="normal" font="default" size="100%">538-543</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Summary The relationship between net carbon assimilation and non-photochemical quenching (qN) was studied in Q. ilex. In leaf discs, in saturating C02 at various irradiances, qN responded linearly in a 1:1 relationship to 1-A/Ap, which represents the proportion of light energy that is not used in photosynthesis. In calculating Ap, a measured, maximal quantum yield for CO2 fixation of 0.080 for 1-year-oldleaves and 0.085 for young leaveswas used. In attached leaves, under natural conditions, this 1: 1 relation was found when a quantum yield of 0.020 and 0.031 was adopted respectively. According to a model of leaf photosynthesis these quantum yields correspond to stromal CO2 concentrations of 90 and 120μLL L-1, in contrast to an average value of substomatal CO2 concentration of 280μLL L-1 found through gas exchange measurements. Similar results were obtained when the relative increase of fluorescence, observed after a saturating flash given during steady photosynthesis at different irradiances, was plotted against the quantum yield of CO2 fixation. The slope of this relation in attached leaves differed from the slope obtained in saturating CO2 in the leaf discs to such an extent as to indicate stromal CO2 concentrations slightly lower compared with the above values obtained by using qE. The marked difference between stromal and substomatal CO2 concentration could be explained by the highly sclerophyllous character of Q. ilex leaves.</style></abstract></record></records></xml>