Impact of cadmium and zinc on growth and water status of Zygophyllum fabago in two contrasting metallicolous populations from SE Spain: comparison at whole plant and tissue level.

Cadmium and zinc accumulation and toxicity were assessed in whole plants and callus culture of two Zygophyllum fabago populations originating from two metallicolous sites in Murcia (southeast Spain), La Peña and Mazarrón, the first containing 2.8-times more Cd and five-times more Zn than the second. Seedlings from both ecotypes were exposed for 3 weeks to 1 or 10 µm Cd, and to 10 or 100 µm Zn in nutrient solution in a controlled environment. Calli from both ecotypes were exposed to 0.01, 0.1 or 1 mm Cd, and to 0.1, 1 or 5 mm Zn. Plants from both populations exhibited similar tolerance to Zn, while tolerance to Cd appeared more important in plants from La Peña than those from Mazarrón. Only minor differences were recorded in final Cd accumulation, with higher Cd retention in roots and stems of plants from La Peña. In both populations, transient decreases in the rate of Zn intake and translocation from root to shoot were recorded. This reduction in ion uptake was not more efficient for the population from the most contaminated area compared to the less contaminated area. Similar concentrations of Cd were found in cotyledon-derived calli from the two populations, but absorbed Cd induced conspicuous water stress in calli issues from Mazarrón but not in those from La Peña. It is concluded that, beside comparable levels of heavy metal concentration in tissues, the physiological strategy of tolerance may differ according to the metal and according to the considered population.

Genetic structure of Atriplex halimus populations in the Mediterranean Basin.

BACKGROUND AND AIMS: The saltbush Atriplex halimus is a chenopodiaceous plant well adapted to dry saline habitats and widely distributed in the Mediterranean Basin. A study was carried out to analyse the genetic diversity of A. halimus at the level of the Mediterranean Basin. METHODS: To assess the intra- and interpopulational variation of A. halimus a total of 51 populations and six plants per populations was analysed with the RAPD-PCR technique. For the study of the phylogeny of the populations, 21 samples of A. halimus and seven samples of other species of Atriplex were analysed by the sequencing of the ITS (internal transcribed spacer) region of the ribosomal DNA. KEY RESULTS: The AMOVA analysis of the RAPD results showed that populations were divided into two discrete genetic groups, as the variation among groups accounted for 54.36 % of the total variance of the collection. At the same time, the intrapopulational diversity was high, as 301 out of 306 plants analysed constituted an individual RAPD haplotype. The sequencing of the ITS region also showed a significant separation of the two genetic groups, with a genetic distance of 0.023 nucleotide substitutions per site. Using A. breweri, A. canescens, A. glauca and A. prostrata as outgroups in the phylogenetic analysis, A. breweri and A. canescens are the species closest to A. halimus from this group, while A. prostrata is the most distant. CONCLUSIONS: The present work indicates that two genetic groups of A. halimus can be distinguished after analysing the genetic diversity of 51 populations from ten countries in the Mediterranean Basin.

Análisis económico de las explotaciones de ganado ovino y caprino en la región de Murcia / Economic analysis of sheep and goat farms of the Region of Murcia

Se realiza el análisis económico en explotaciones tipo de ovino y caprino de diferentes zonas de la Regiónde Murcia, para comprobar su rentabilidad y como paso previo y herramienta imprescindible para la toma dedecisiones en materia de Política Sectorial, reordenación sectorial y criterio a la hora de seleccionar las ayudas,porque independientemente de su rentabilidad siguen siendo dos sectores estratégicos en el aprovechamientode recursos de zonas marginales, empleo agrario y fi jación de población.Se observa como ambos sectores son dependientes de las subvenciones en su rentabilidad, a pesar de que elsector caprino ha evolucionado con mucho más dinamismo

An economical analisys is made for sheep and goat farms in different areas of Region de Murcia, in order toasses their profi tability. This is a needed tool for decission makers in the fi elds of Sectorial Policy and sectorialre-ordination. It is a criterion to select economical support as well, because independently of the profi tability,they still are two strategic sectors in the exploitation of marginal area resources, farm employment, and populationestabilization.It is observed that both sectors profi tability depend on the subsidies, in spite of the fact that goat farms haveevolved with a higher dynamism