<?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%">Tsonev, Tsonko</style></author><author><style face="normal" font="default" size="100%">Wahbi, Said</style></author><author><style face="normal" font="default" size="100%">Sun, Pengsen</style></author><author><style face="normal" font="default" size="100%">Sorrentino, Giuseppe</style></author><author><style face="normal" font="default" size="100%">Centritto, Mauro</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Gas Exchange, Water Relations and their Relationships with Photochemical Reflectance Index in Quercus ilex Plants during Water Stress and Recovery</style></title><secondary-title><style face="normal" font="default" size="100%">INTERNATIONAL JOURNAL OF AGRICULTURE AND BIOLOGY</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">CO2 transport conductance</style></keyword><keyword><style  face="normal" font="default" size="100%">Drought</style></keyword><keyword><style  face="normal" font="default" size="100%">leaf gas exchange</style></keyword><keyword><style  face="normal" font="default" size="100%">photorespiration</style></keyword><keyword><style  face="normal" font="default" size="100%">Relative water content</style></keyword><keyword><style  face="normal" font="default" size="100%">Spectral reflectance index</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2014</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2014///</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">16</style></volume><pages><style face="normal" font="default" size="100%">335 - 341</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Diffusional limitations to photosynthesis (A), relative water content (RWC) and their association with photochemical reflectance index (PRI) were studied in holm oak (Quercus ilex L.) saplings subjected to water stress and subsequent water stress relief. RWC decreased sharply as drought progressed. Following rewatering, RWC gradually increased to pre-stress values. A, stomatal conductance (g(s)), mesophyll conductance (g(m)), total conductance (g(t)), and PRI changed in parallel with RWC. A decrease in A resulted from coordinated suppression in leaf conductance. As water stress progressed, A measured in non-photorespiratory conditions (A(1%O2)) became more than 3 times higher compared to that recorded at 21% \{[\}O-2], indicating that photorespiration likely increased in response to water stress. A(1%O2) was significantly correlated with all leaf conductances. A(1%O2) was limited more by g(s) than by g(m), indicating that higher g(m) favors photosynthesis over photorespiration. There was a significant linear correlation between RWC and PRI. Significant non-linear relationships were also found both between PRI and A and PRI and g(t). These data imply that PRI may clearly detect normal and stressed status of holm oak, but it is not very informative when plants are severely stressed. Overall, our data indicate that: a) PRI is an important indicator of leaf water status as evident from RWC; b) because leaf conductance did not limit photosynthesis when photorespiration was suppressed, holm oak, and in general sclerophyllous species, will respond to future elevated \{[\}CO2] significantly more than mesophyllous plants; c) PRI can be used to predict changes in the performance of holm oak subjected to physiological water stress, whereas caution is needed under severe drought. (C) 2014 Friends Science Publishers</style></abstract><issue><style face="normal" font="default" size="100%">2</style></issue><notes><style face="normal" font="default" size="100%">The following values have no corresponding Zotero field:&lt;br/&gt;pub-location: 399-B, PEOPLES COLONY NO 1, FAISALABAD, 38090, PAKISTAN&lt;br/&gt;publisher: FRIENDS SCIENCE PUBL</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%">Disante, Karen B</style></author><author><style face="normal" font="default" size="100%">Fuentes, David</style></author><author><style face="normal" font="default" size="100%">Cortina, Jordi</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Response to drought of Zn-stressed Quercus suber L. seedlings</style></title><secondary-title><style face="normal" font="default" size="100%">Environmental and Experimental Botany</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">growth response</style></keyword><keyword><style  face="normal" font="default" size="100%">Heavy metal</style></keyword><keyword><style  face="normal" font="default" size="100%">Relative water content</style></keyword><keyword><style  face="normal" font="default" size="100%">water use efﬁciency</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2011</style></year></dates><publisher><style face="normal" font="default" size="100%">Elsevier B.V.</style></publisher><volume><style face="normal" font="default" size="100%">70</style></volume><pages><style face="normal" font="default" size="100%">96-103</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Zinc is an essential nutrient for higher plants but it becomes toxic as its availability increases. In nature, different stress factors commonly occur concurrently, challenging our ability to predict their impacts. Information on zinc (Zn) effect on plant ability to withstand other sources of stress is scarce. This study examines the effect of zinc supply rate on the response of Quercus suber L. seedlings to water stress. Seedlings were treated with four levels of zinc from 3 to 150 M, and then exposed to a short severe drought. Zinc concentration in leaves and roots increased with zinc availability. Maximum photosynthetic rate, photochemical efﬁciency, root length and speciﬁc root length decreased as Zn availability increased. The decrease was particularly intense between 50 and 150 M Zn. The relative effects of drought were less intense in seedlings receiving higher doses of Zn than in those receiving 3 M. Thus, at severe drought, relative water content of detached leaves decreased to 52% in seedlings receiving the lowest level of Zn. In contrast, relative water content remained above 70% in seedlings exposed to high concentrations of this metal. The pattern was similar for photosynthetic rate and stomatal conductance, as the decrease in these variables resulting from severe drought was 100% and 90% in seedlings receiving 3 M and 65% and 56% in seedlings receiving the highest Zn dose. Our results suggest that morpho-physiological responses to zinc may foster water conservation strategies and alleviate the effects of drought in the short term, but they may impair seedling ability to root and grow in a longer term</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%">Lansac, A R</style></author><author><style face="normal" font="default" size="100%">ZABALLOS, J P</style></author><author><style face="normal" font="default" size="100%">Martin, A</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Seasonal water potential changes and proline accumulation in Mediterranean shrubland species</style></title><secondary-title><style face="normal" font="default" size="100%">Plant Ecology</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Cistus ladanifer</style></keyword><keyword><style  face="normal" font="default" size="100%">Genista hirsuta</style></keyword><keyword><style  face="normal" font="default" size="100%">Halimium viscosum</style></keyword><keyword><style  face="normal" font="default" size="100%">Juniperus oxycedrus</style></keyword><keyword><style  face="normal" font="default" size="100%">Lavandula pedunculata</style></keyword><keyword><style  face="normal" font="default" size="100%">Leaf mass per area</style></keyword><keyword><style  face="normal" font="default" size="100%">nitrogen</style></keyword><keyword><style  face="normal" font="default" size="100%">Proline</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus faginea</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus rotundifolia</style></keyword><keyword><style  face="normal" font="default" size="100%">Relative water content</style></keyword><keyword><style  face="normal" font="default" size="100%">retama sphaerocarpa</style></keyword><keyword><style  face="normal" font="default" size="100%">Thymus zygis</style></keyword><keyword><style  face="normal" font="default" size="100%">water potential</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1994</style></year></dates><volume><style face="normal" font="default" size="100%">113</style></volume><pages><style face="normal" font="default" size="100%">141-154</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">We studied the water relations of 6 shrub and 3 tree species typical of the mediterranean climate region of central Spain to identify differential responses to water stress between and within species, and to determine if free proline concentration in leaves could be used as a water stress indicator. Predawn and midday water potentials (ffdw) on a seasonal basis, relative water content (RWC), leaf mass per area, foliar nitrogen and free proline concentrations were measured. The lowest water potentials were observed at the end of the summer, with recovery to higher water potentials in the fall and winter seasons. Species differed regarding the annual qdw fluctuation. Thymus zygis, Halimium viscosum, Genista hirsuta and Juniperus oxycedrus exhibited the most negative midday and predawn ~ w (both less than -6 MPa) with a large magnitude of response to changing conditions in soil moisture of the upper horizon of the soil. Lavandula pedunculata and Cistus ladanifer showed a moderate response. Quercus rotundifolia, Quercus faginea and Retama sphaerocarpa showed a modest response. The ~ w of different size individuals of Quercus rotundifolia and Cistus ladanifer were compared. The annual fflw fluctuation was greater in small individuals as compared to large individuals. In every species, there was an increase in proline concentration of bulk leaf tissues when predawn kVw dropped below -5 MPa. Small plants of Cistus ladanifer reached lower water potentials and also higher concentration of proline than bigger plants. Proline could possibly be used as a drought stress indicator in every species except Q. rotundifolia. It is suggested that in addition to water stress avoidance due to deep root systems, some mechanisms of water stress tolerance may operate among shrub and tree species of central Spain.</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%">Salleo, S</style></author><author><style face="normal" font="default" size="100%">GULLO, M A L O</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Sclerophylly and Plant Water Relations in Three Mediterranean Quercus Species</style></title><secondary-title><style face="normal" font="default" size="100%">Annals of Botany</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Drought resistance</style></keyword><keyword><style  face="normal" font="default" size="100%">leaf conductance</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus ilex</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus pubescens (PG)</style></keyword><keyword><style  face="normal" font="default" size="100%">Quercus suber L.</style></keyword><keyword><style  face="normal" font="default" size="100%">Relative water content</style></keyword><keyword><style  face="normal" font="default" size="100%">sclerophylly</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1990</style></year></dates><volume><style face="normal" font="default" size="100%">65</style></volume><pages><style face="normal" font="default" size="100%">259-270</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The possible role in drought resistance played by sclerophylly was studied in the Mediterranean oaks Quercus ilex, Q. suber and Q. pubescens. Studies were conducted on leaves at 30, 50 and 80% of their final surface area, as well as on mature leaves of the current year's growth in June and September and on 1-year-old leaves.Leaves of different ages of the three species showed quite different degrees of sclerophylly (DS). Q. ilex leaves reached the definitive DS of 1.75 g dm−2 during leaf expansion; Q. pubescens leaves hardened at the end of their expansion, with a final DS of 0.93 g dm−2; Q. suber showed the lowest DS of 0.76 g dm−2.Leaf conductance to water vapour (g1) of 1-year-old leaves of Q. ilex, measured in the field, showed a duration of the g1 peak values about twice that of the other two species. The minimum leaf relative water content (RWC), however, was near the same in the three species, indicating that water loss was recovered partly by Q. ilex leaves. This was apparently due to the higher bulk modulus of elasticity (max) as resulting from leaf water potential isotherms.High correlation coefficients were noted between DS and max but large changes in DS were needed to display minor changes in max. When both DS and max were correlated to the minimum RWC, an increase in DS of 133 % (corresponding to an increase in max of only 12 %) was needed to cause an increase in RWC of 2%. Therefore, sclerophylly cannot be considered as significantly related to a drought-avoiding strategy.</style></abstract></record></records></xml>