Oliveira G, Peñuelas (2002) Comparative protective strategies of Cistus albidus and Quercus ilex facing photoinhibitory winter conditions. Environmental and Experimental Botany 47:281-289.
Gimeno I, Vilà M (2002) Recruitment of two Opuntia species invading abandoned olive groves. Acta Oecologica 23:239-246.
Rodrigo A, Avila A (2002) Dry deposition to the forest canopy and surrogate surfaces in two Mediterranean holm oak forests in Montseny (NE Spain). Water, Air and Soil Pollution 136:269-288.
Avila A, Rodrigo A, Rodà F (2002) Nitrogen circulation in a Mediterranean holm oak forest, La Castanya, Montseny, northeastern Spain. Hydrology and Earth System Sciences 6:551-557.
Kramer K, Leinonen I, Bartelink HH, Berbigier P, Borghetti M, Bernhofer Ch, Cienciala E, Dolman AJ, Froer O, Gracia C, Granier A, Grünwald T, Hari P,Jans W, Kellomäki S, Loustau D, Magnani F, Markkanen T, Mohren GMJ, Sabaté S, Sánchez A et al (2002) Evaluation of six process-based forest growth models using eddy-covariance measurements of CO2 and H2O fluxes at six forest sites in Europe. Global Change Biology 8:213-230.
Castells E., Roumet C., Peñuelas J., Roy J. (2002) Intraspecific variability of phenolic concentrations and their responses to elevated CO2 in two mediterranean perennial grasses. Environmental and Experimental Botany. 47: 205-216.EnllaçDoi: 10.1016/S0098-8472(01)00123-X
Intraspecific variability of total phenolic compound concentrations and their responses to elevated CO2 were studied in two wild Mediterranean perennial grasses, Dactylis glomerata and Bromus erectus. Ten and nine genotypes of each species were grown in climate-controlled naturally-lit glasshouses under plant intergenotypic and interspecific competition for water, light and nutrients. Carbon source-sink balance hypotheses of resource allocation were also tested. Elevated CO2 induced changes in dry shoot biomass (DM), leaf total non-structural carbohydrate concentrations [TNC] and leaf nitrogen concentrations [N] found in a previous study (New Phytol. 143 (1999) 73) were related to changes in phenolic compound concentrations. Phenolic compound concentrations increased to 15.2% DM in D. glomerata and 86.9% DM in B. erectus under elevated CO2. These changes were more pronounced when expressed on a structural dry mass basis (DMst). Increases in DMst and [TNCst] and decreases in [Nst] were also found according to current resource allocation hypotheses. However, there were no proportional changes between phenolic responses to elevated CO2 and DMst, [TNCst] and [Nst] responses. Phenolic concentrations were highly determined by genetics in both species, but all studied genotypes responded in a similar way to elevated CO2. Considering the present experimental conditions with plants growing in intraspecific and interspecific competition, the absence of CO2 × genotype interaction would lead to little changes of fitness in terms of antiherbivore chemical defence, and, therefore, to low evolutionary consequences in CBSC under the increasing atmospheric CO2 concentrations of the next decades. © 2002 Elsevier Science B.V. All rights reserved.
Cerdá X., Dahbi A., Retana J. (2002) Spatial patterns, temporal variability, and the role of multi-nest colonies in a monogynous Spanish desert ant. Ecological Entomology. 27: 7-15.EnllaçDoi: 10.1046/j.0307-6946.2001.00386.x
1. The colonies of the Spanish desert ant Cataglyphis iberica are polydomous. This study describes the temporal and spatial patterns of the polydomy in this species at two different sites, and presents analyses of its role in reducing the attacks of the queen over sexual brood, and in allowing better habitat exploitation. 2. The spatial distribution of nests was clumped while colonies were distributed randomly. Mean nearest neighbour distance ranged from 3.4 to 7.0 m for nests and from 12.3 to 14.1 m for colonies. Distance of foragers searching for food varied among nests: mean values were between 6.1 and 12.6 m. 3. At both sites, the maximum number of nests per colony occurred in summer, during the maximum activity period of the species. Colonies regrouped at the end of this period but overwintered in several nests. 4. Nest renewal in C. iberica colonies was high and showed great temporal variability: nests changed (open, close, re-open) continuously through the activity season and/or among years. The lifetime of up to 55% of nests was only 1-3 months. 5. Polydomy in C. iberica might decrease the interactions between the queen and the sexual brood. In all colonies excavated just before the mating period, the nest containing the queen did not contain any virgin female. Females were in the queenless nests of the colony. 6. The results also suggest that polydomous C. iberica colonies may enhance habitat exploitation because foraging activity per colony increases with nest number. The relationship between total prey input and foraging efficiency and number of nests per colony attains a plateau or even decreases after a certain colony size (four to six nests). This value agrees with the observed mean number of nests per colony in C. iberica.
Avila A, Rodà F (2002) Assessing decadal changes in rainwater alkalinity at a rural Mediterranean site in the Montseny Mountains (NE Spain). Atmospheric Environment 36:2881-2890.
Díaz-Delgado R, Lloret F, Pons X, Terradas J (2002) Satellite evidence of decreasing resilience in Mediterranean plant communities after recurrent wildfires. Ecology 83:2293-2303.
Grimmig B., Gonzalez-Perez M.N., Welzl G., Penuelas J., Schubert R., Hain R., Heidenreich B., Betz C., Langebartels C., Ernst D., Sandermann Jr. H. (2002) Ethylene- and ozone-induced regulation of a grapevine resveratrol synthase gene: Different responsive promoter regions. Plant Physiology and Biochemistry. 40: 865-870.EnllaçDoi: 10.1016/S0981-9428(02)01448-1
Stilbene synthases (STSs) are enzymes that play a critical role in the biosynthesis of stilbenes, phytoalexins that are induced by various biotic and abiotic stressors like pathogen attack, UV radiation or ozone exposure. To investigate the molecular basis for ozone- and ethylene-induced plant stress responses, we analysed the full size promoter of the grapevine resveratrol synthase gene (Vst1). Transgenic tobacco plants harbouring a Vst1 promoter::β-glucuronidase (GUS) reporter construct showed an increased GUS activity upon ozone (0.3 μl 1-1, 8 h) or ethylene (10 μl 1-1, 8 h) treatment. Using the fluorimetric GUS assay, deletion analysis of the 5′-flanking sequence identified a minimal ethylene-responsive region between -280 and -40 bp upstream of the translation start codon. This region differs from the ozone-responsive Vstl promoter region, suggesting that ethylene is not directly involved in signalling ozone-induced stilbene biosynthesis. © 2002 Éditions scientifiques et médicales Elsevier SAS. All rights reserved.
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