<?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%">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%">Kleikamp, Bernd</style></author><author><style face="normal" font="default" size="100%">Joergensen, Rainer Georg</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Evaluation of arbuscular mycorrhiza with symbiotic and nonsymbiotic pea isolines at three sites in the Alentejo, Portugal</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of Plant Nutrition and Soil Science</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">amf</style></keyword><keyword><style  face="normal" font="default" size="100%">arbuscular mycorrhiza</style></keyword><keyword><style  face="normal" font="default" size="100%">growth response</style></keyword><keyword><style  face="normal" font="default" size="100%">mediterranean dryland farming</style></keyword><keyword><style  face="normal" font="default" size="100%">myc-mutant</style></keyword><keyword><style  face="normal" font="default" size="100%">p and n nutrition</style></keyword><keyword><style  face="normal" font="default" size="100%">pea</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2006</style></year></dates><volume><style face="normal" font="default" size="100%">169</style></volume><pages><style face="normal" font="default" size="100%">661-669</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Providing an appropriate negative control for the experimental factor arbuscular mycorrhiza (AM) is a fundamental methodological problem. Therefore, the nonmycorrhizal (myc – ) and nonnodulating (nod – ) pea (Pisum sativum L.) mutant P2 was studied together with the parental symbiotic isogenetic variety FRISSON in three experiments: (1) growth response to water supply in a climate chamber under nonsymbiotic growth conditions, (2) field evaluation at three sites in the Alentejo, South Portugal, and (3) growth response to P supply in a soil low in available P in a greenhouse-chamber experiment. In the climate chamber at high NPK levels, mutant P2 achieved the same biomass as FRISSON at 80% and 40% water-holding capacity, respectively. For the field evaluation, three sites were chosen with normal arable use (Évora), extensive use as Montado (Portel), and intensive horticultural use (Mitra). The colonization of pea roots with AM fungi ranged from 4% (Mitra) to more than 90% (Portel), probably caused by differences in P availability. The plant density of mutant P2 was generally 25% lower than that of FRISSON. Yield indices were all lowest at Portel, despite the same NPK fertilization. Grain and shoot yield of mutant P2 did not reach the level of FRISSON at any site. Differences in N and P concentrations between the two isolines were insignificant in most cases. Differences in the amount of shoot P per plant consistently mirrored the mycorrhizal status of the three sites. Roughly 50% of the yield depression per m2 could be attributed to the lower plant density of mutant P2, the remaining 50% must be caused by AM-fungal colonization or other factors. In the final pot experiment using the soil with low P availability from Portel, the main benefit of AM for peas was enhanced P uptake. Central questions could not be answered using a nonmycorrhizal control. However, mutants remain one interesting tool, best be used in combination with other approaches to estimate the effects of mycorrhization.</style></abstract></record></records></xml>