<?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%">Tretiach, M</style></author><author><style face="normal" font="default" size="100%">Bolognini, G</style></author><author><style face="normal" font="default" size="100%">Rondi, A</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Photosynthetic activity of Quercus ilex at the extremes of a transect between Mediterranean and submediterranean vegetation (Trieste NE Italy)</style></title><secondary-title><style face="normal" font="default" size="100%">FLORA</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">CO2</style></keyword><keyword><style  face="normal" font="default" size="100%">competition</style></keyword><keyword><style  face="normal" font="default" size="100%">Drought stress</style></keyword><keyword><style  face="normal" font="default" size="100%">Gradient</style></keyword><keyword><style  face="normal" font="default" size="100%">photos</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1997</style></year></dates><publisher><style face="normal" font="default" size="100%">GUSTAV FISCHER VERLAG</style></publisher><pub-location><style face="normal" font="default" size="100%">VILLENGANG 2, D-07745 JENA, GERMANY</style></pub-location><volume><style face="normal" font="default" size="100%">192</style></volume><pages><style face="normal" font="default" size="100%">369-378</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Microclimatic data and CO2 gas exchange rates were measured in the&lt;br/&gt;coastal area near Trieste (NE Italy) in two groups of plants rowing at&lt;br/&gt;the extremes of a floristic-vegetational gradient between an evergreen&lt;br/&gt;Mediterranean maquis on the coast and a winter deciduous&lt;br/&gt;submediterranean woodland on the Karst plateau, where Q. ilex persists&lt;br/&gt;only sporadically but is still a co-dominant tree.&lt;br/&gt;Field data were recorded from sunrise to sunset during the periods of&lt;br/&gt;highest productivity and of maximum physiological stress. i.e. high&lt;br/&gt;temperatures and water deficit in summer, and low temperatures and&lt;br/&gt;strong, dry winds in winter. Photosynthesis was measured with a portable&lt;br/&gt;Infrared Gas Analyzer.&lt;br/&gt;Microclimatic data showed that summer and winter stress were more&lt;br/&gt;intense on the Karst plateau. Assimilation of the coastal population was&lt;br/&gt;higher because a positive CO2 balance was maintained during both stress&lt;br/&gt;periods. During summer drought stress diurnal assimilation of the inland&lt;br/&gt;population was just in balance with nocturnal leaf respiration. In&lt;br/&gt;winter, on the contrary, photosynthetic activity ceased almost&lt;br/&gt;completely for almost a week, due to the lower temperature regime and to&lt;br/&gt;strong, dry winter winds that caused severe mechanical damages and, more&lt;br/&gt;generally, a drastic shortening of the leaf life span.&lt;br/&gt;The competition ability of Q. ilex in ecotonal areas is briefly&lt;br/&gt;discussed on the basis of these results. Winter stress seems to be the&lt;br/&gt;main factor limiting the distribution of Q. ilex northwards.</style></abstract></record></records></xml>