<?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%">Mediavilla, Sonia</style></author><author><style face="normal" font="default" size="100%">Gallardo-López, Victoria</style></author><author><style face="normal" font="default" size="100%">González-Zurdo, Patricia</style></author><author><style face="normal" font="default" size="100%">Escudero, Alfonso</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Patterns of leaf morphology and leaf N content in relation to winter temperatures in three evergreen tree species.</style></title><secondary-title><style face="normal" font="default" size="100%">International journal of biometeorology</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">leaf density</style></keyword><keyword><style  face="normal" font="default" size="100%">leaf mass per unit area</style></keyword><keyword><style  face="normal" font="default" size="100%">leaf n content</style></keyword><keyword><style  face="normal" font="default" size="100%">leaf thickness</style></keyword><keyword><style  face="normal" font="default" size="100%">winter temperature gradient</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2012</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2012///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/21969112</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">56</style></volume><pages><style face="normal" font="default" size="100%">915 - 926</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The competitive equilibrium between deciduous and perennial species in a new scenario of climate change may depend closely on the productivity of leaves along the different seasons of the year and on the morphological and chemical adaptations required for leaf survival during the different seasons. The aim of the present work was to analyze such adaptations in the leaves of three evergreen species (Quercus ilex, Q. suber and Pinus pinaster) and their responses to between-site differences in the intensity of winter harshness. We explore the hypothesis that the harshness of winter would contribute to enhancing the leaf traits that allow them to persist under conditions of stress. The results revealed that as winter harshness increases a decrease in leaf size occurs in all three species, together with an increase in the content of nitrogen per unit leaf area and a greater leaf mass per unit area, which seems to be achieved only through increased thickness, with no associated changes in density. P. pinaster was the species with the most intense response to the harshening of winter conditions, undergoing a more marked thickening of its needles than the two Quercus species. Our findings thus suggest that lower winter temperatures involve an increase in the cost of leaf production of evergreen species, which must be taken into account in the estimation of the final cost and benefit balance of evergreens. Such cost increases would be more pronounced for those species that, like P. pinaster, show a stronger response to the winter cold.</style></abstract><issue><style face="normal" font="default" size="100%">5</style></issue><notes><style face="normal" font="default" size="100%">The following values have no corresponding Zotero field:&lt;br/&gt;accession-num: 21969112</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%">Mediavilla, Sonia</style></author><author><style face="normal" font="default" size="100%">Escudero, Alfonso</style></author><author><style face="normal" font="default" size="100%">González-Zurdo, Patricia</style></author><author><style face="normal" font="default" size="100%">García-Ciudad, Antonia</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Morphological and chemical leaf composition of Mediterranean evergreen tree species according to leaf age</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%">Fibre concentration</style></keyword><keyword><style  face="normal" font="default" size="100%">Leaf age class</style></keyword><keyword><style  face="normal" font="default" size="100%">Leaf mass per area</style></keyword><keyword><style  face="normal" font="default" size="100%">leaf thickness</style></keyword><keyword><style  face="normal" font="default" size="100%">Leaf tissue density</style></keyword><keyword><style  face="normal" font="default" size="100%">Mineral content</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2011</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2011///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://dx.doi.org/10.1007/s00468-011-0544-z</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">25</style></volume><pages><style face="normal" font="default" size="100%">669 - 677</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Changes in morphology [leaf dry mass per unit area (LMA), thickness and density] and chemical composition (macronutrients and ﬁbres content) in different age leaves of eight evergreen Mediterranean woody species were investigated. LMA and leaf thickness increased with leaf age increasing. Young tissues possessed higher concentrations of N, P, K, and Mg and lower Ca concentrations on a dry mass basis. However, mineral content was independent of age on leaf area basis (except for Ca content) suggesting that the changes in mineral concentration with leaf ageing are due to dilution in the larger dry mass accumulated in the oldest leaves. Leaf tissue density (LTD) increased during the ﬁrst year of the leaf life. Lignin and hemicellulose concentrations did not vary along leaf life and the cellulose concentration increased with leaf age in most species between the current-year and the one-year old leaves. Our results suggested that physical leaf reinforcement with a higher cellulose concentration and density might be a leaf response to the unfavourable climatic conditions during the ﬁrst winter.</style></abstract><issue><style face="normal" font="default" size="100%">4</style></issue><notes><style face="normal" font="default" size="100%">The following values have no corresponding Zotero field:&lt;br/&gt;publisher: Springer-Verlag</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%">Gratani, L</style></author><author><style face="normal" font="default" size="100%">Crescente, M F</style></author><author><style face="normal" font="default" size="100%">Petruzzi, M</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Relationship between leaf life-span and photosynthetic activity of Quercus ilex in polluted urban areas (Rome).</style></title><secondary-title><style face="normal" font="default" size="100%">Environmental pollution (Barking, Essex : 1987)</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">chlorophyll content</style></keyword><keyword><style  face="normal" font="default" size="100%">leaf life-span</style></keyword><keyword><style  face="normal" font="default" size="100%">leaf thickness</style></keyword><keyword><style  face="normal" font="default" size="100%">Net photosynthesis</style></keyword><keyword><style  face="normal" font="default" size="100%">shoot production</style></keyword><keyword><style  face="normal" font="default" size="100%">traffic level</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2000</style></year></dates><volume><style face="normal" font="default" size="100%">110</style></volume><pages><style face="normal" font="default" size="100%">19-28</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Anatomical, morphological and physiological leaf traits of Quercus ilex in response to different traffic levels (high traffic level, type A sites; average traffic level, type B sites; control sites, type C sites) were analysed in Rome. Superficial leaf deposits were analysed comparing unwashed and washed leaf samples. Washing lowered Pb 61% in A, 54% in B and 27% in C. Sr, Fe, Cu, Zn and Al showed the same trend as Pb. The higher photosynthetic activity of 1-year-old leaves (Pn=7.0+/-2.9 micromol m(-2 )s(-1), average value) in A sites with respect to B sites (6.7+/-2.4 micromol m(-2 )s(-1)) and C sites (6.7+/-1.8 micromol m(-2 )s(-1)) seems to be related to higher stomatal conductance (g(s)=0.13+/-0.06 mol m(-2 )s(-1)), higher total chlorophyll content (Chl=1.57 mg g(-1)) and higher leaf thickness (L(T)=218.9 microm), particularly palisade parenchyma thickness (109.4 microm). Q. ilex showed, on average, 95% of 1-year-old leaves and rarely 2-year-old leaves in A and B sites; 77% 1-year leaves, 20% previous-year leaves and sporadic 3-year leaves in C sites. The enhanced leaf senescence in A sites is compensated by a stimulated shoot production (18% higher with respect to C sites); 25% increased specific leaf area seems to be compensatory growth occurring in order to increase the size of the assimilatory area. The inverse trend of leaf life-span and Pn seems to be Q. ilex' adaptive strategy in polluted areas.</style></abstract><accession-num><style face="normal" font="default" size="100%">15092853</style></accession-num></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%">Gratani, L</style></author><author><style face="normal" font="default" size="100%">Bombelli, A</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Leaf anatomy, inclination, and gas exchange relationships in evergreen sclerophyllous and drought semideciduous shrub species</style></title><secondary-title><style face="normal" font="default" size="100%">PHOTOSYNTHETICA</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">cistus incanus</style></keyword><keyword><style  face="normal" font="default" size="100%">leaf inclination</style></keyword><keyword><style  face="normal" font="default" size="100%">leaf life-span</style></keyword><keyword><style  face="normal" font="default" size="100%">leaf mass/area ratio</style></keyword><keyword><style  face="normal" font="default" size="100%">leaf thickness</style></keyword><keyword><style  face="normal" font="default" size="100%">net photosynthetic rate</style></keyword><keyword><style  face="normal" font="default" size="100%">phillyrea latifolia</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus ilex</style></keyword><keyword><style  face="normal" font="default" size="100%">transpiration rate</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1999</style></year></dates><publisher><style face="normal" font="default" size="100%">INST EXPERIMENTAL BOTANY, ACAD SCI CZECH REPUBLIC</style></publisher><pub-location><style face="normal" font="default" size="100%">NA KARLOVCE 1A, PRAGUE 6 CS-160 00, CZECH REPUBLIC</style></pub-location><volume><style face="normal" font="default" size="100%">37</style></volume><pages><style face="normal" font="default" size="100%">573-585</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">There are significant differences in leaf life-span among evergreen sclerophyllous species and drought semideciduous species growing in the Mediterranean maquis. Cistus incanus, which has a leaf life-span of four-eight months, was characterised by the highest net photosynthetic rates (PN). while Quercus ilex and Phillyrea latifolia, which maintain their leaves two-three and two-four years, respectively, had a lower PN- The longer leaf life-span of the two evergreen sclerophyllous species may be justified to cover the high production costs of leaf protective structures such as cuticle, hairs, and sclereids: cuticle and hairs screen radiation penetrating into the more sensitive tissues, and sclereids have a light-guiding function. Q. ilex and P. latifolia have the highest leaf mass/area ratio (LMA = 209 g m(-2)) and a mesophyll leaf density (2065 cells per mm(2) of leaf cross section area) about two times higher than C. incanus. In the typical evergreen sclerophyllous species the steepest leaf inclination (alpha = 56 degrees) reduces 42% of radiation absorption, resulting in a reduced physiological stress at leaf level, particularly in summer. C. incanus, because of its low leaf life-span, requires a lower leaf investment in leaf protective structures. It exhibits a drastic reduction of winter leaves just before summer drought, replacing them with smaller folded leaves. The lower leaf inclination (alpha = 44 degrees) and the lower LMA (119 g m(-2)) of C. incanus complement photosynthetic performance. Water use efficiency (WUE) showed the same trend in Q. ilex, P. latifolia, and C. incanus, decreasing 60% from spring to summer, due to the combined effects of decreased CO2 uptake and increased transpirational water loss.</style></abstract></record></records></xml>