Expression patterns of antioxidant network in pioneer plants from mine tailings polluted with high levels of heavy metals

[SPA] La intensa actividad minera llevada a cabo en el distrito minero de Cartagena-La Unión durante más de dos mil quinientos años ha generado un gran volumen de residuos, muchos de los cuales se acumulan en balsas de estériles. Aunque la mayoría de estas balsas carecen de vegetación, en determinadas zonas proliferan ciertas especies pioneras que están sometidas a una exposición crónica a altas concentraciones de diversos metales pesados y metaloides. Por su carácter pionero y su tolerancia a metales, estas especies presentan un gran potencial en programas de fitomanejo encaminados a evitar la dispersión de contaminantes mediante el establecimiento de una cubierta vegetal estable y autosostenible a largo plazo. La colonización por especies vegetales de las balsas mineras de la Sierra de Cartagena no sólo está condicionada por la presencia de concentraciones fitotóxicas de metales, bajos niveles de nutrientes esenciales y alta salinidad, sino también por las condiciones de sequía y los altos niveles de radiación solar que son característicos de climas semiáridos. El estudio de las plantas pioneras que colonizan estas estructuras ofrece, por lo tanto, la oportunidad de encontrar mecanismos adaptativos a condiciones de estrés múltiple que permitan dar un salto cualitativo en la aplicación de las técnicas de fitomanejo. La presente Tesis Doctoral se centró, por un lado, en el estudio de sistemas antioxidantes, así como de diversos marcadores de estrés oxidativo y de otros parámetros relacionados con el estrés en tres especies de plantas pioneras crecidas de forma espontánea en balsas de estériles; dos de ellas herbáceas (Zygophyllum fabago y Dittrichia viscosa) y una arbórea (Pinus halepensis). Teniendo en cuenta el marco climático semiárido de este distrito minero, los análisis se realizaron tanto en primavera como en verano en dos años consecutivos (2012 y 2013). Por otro lado, considerando que esta zona minera contiene altos niveles de Pb, se estudió en condiciones controladas de laboratorio el efecto de la exposición, tanto aguda como crónica, a este metal en plantas de Z. fabago, con el fin de determinar los mecanismos de tolerancia que esta especie pone en marcha para contrarrestar la toxicidad del Pb.[ENG] The intense mining activity carried out in the mining district of Cartagena-La Unión for more than two thousand five hundred years has generated a large volume of mine tailings. Although most of these mine tailings remain unvegetated, in certain areas some pioneer species proliferate even though they are chronically exposed to high concentrations of various heavy metals and metalloids. Owing to their pioneer characteristic and their heavy metal tolerance, these species have a great potential in phytoremediation programs aimed at avoiding the dispersion of contaminants through the establishment of a stable and self-sustainable plant cover. The colonization by plant species into mine tailings in semi-arid climates is not only conditioned by the presence of phytotoxic concentrations of metals, low levels of essential nutrients and high salinity, but also by drought conditions and the high sunlight irradiance that are characteristic of these climatic areas. The study of the pioneer plants able to colonize these degraded zones offers the opportunity to find adaptive mechanisms under multi-stress scenarios that allow a qualitative leap in the application of phytomanagement techniques. The present PhD Thesis was focused, on the one hand, on the study of antioxidative response mechanisms, as well as on various oxidative stress markers in different pioneer plants species both herbaceous (Zygophyllum fabago and Dittrichia viscosa) and woody (Pinus halepensis) ones. Taking into account the semiarid climate framework of this mining district, the analyses were conducted both in spring and summer in two consecutive years (2012 and 2013). On the other hand, considering that this mining area contains high levels of Pb, the effect of both acute and chronic exposure to this metal in Z. fabago plants was studied under controlled laboratory conditions in order to determine the tolerance mechanisms that this species used to counteract Pb toxicity.Universidad Politécnica de CartagenaPrograma de doctorado Técnicas Avanzadas en Investigación y Desarrollo Agrario y Alimentario (TAIDA

Seasonal changes in antioxidative/oxidative profile of mining and non-mining populations of Syrian beancaper as determined by soil conditions

Soil pollution by heavy metals/metalloids (HMMs) is a problem worldwide. To prevent dispersion of contaminated particles by erosion, the maintenance of a vegetative cover is needed. Successful plant establishment in multi-polluted soils can be hampered not only by HMM toxicities, but also by soil nutrient deficiencies and the co-occurrence of abiotic stresses. Some plant species are able to thrive under these multi-stress scenarios often linked to marked fluctuations in environmental factors. This study aimed to investigate the metabolic adjustments involved in Zygophyllum fabago acclimative responses to conditions prevailing in HMM-enriched mine-tailings piles, during Mediterranean spring and summer. To this end, fully expanded leaves, and rhizosphere soil, of three contrasting mining and non-mining populations of Z. fabago grown spontaneously in south-eastern Spain were sampled in two consecutive years. Approximately 50 biochemical, physiological and edaphic parameters were examined, including leaf redox components, primary and secondary metabolites, endogenous levels of salicylic acid, and physicochemical properties of soil (fertility parameters and total concentration of HMMs). Multivariate data analysis showed a clear distinction in antioxidative/oxidative profiles between and within the populations studied. Levels of chlorophylls, proteins and proline characterized control plants whereas antioxidant capacity and C- and S-based antioxidant compounds were biomarkers of mining plants. Seasonal variations were characterized by higher levels of alkaloids and PAL and soluble peroxidase activities in summer, and by soluble sugars and hydroxycinnamic acids in spring irrespective of the population considered. Although the antioxidant systems are subjected to seasonal variations, the way and the intensity with which every population changes its antioxidative/oxidative profile seem to be determined by soil conditions. In short, Z. fabago displays a high physiological plasticity that allow it to successfully shift its metabolism to withstand the multiple stresses that plants must cope with in mine tailings piles under Mediterranean climatic conditions.This work was supported by the Ministerio de Ciencia e Innovación [grant number CTM2011-23958]; Ministerio de Ciencia y Tecnología [grant number CGL2006-11569]; and Fundación Séneca [grant number FB/23/FS/02]. AL-O holds a grant from the Ministerio de Educación Cultura y Deporte [grant number AP2012-2559]. Part of this work was carried out at the Instituto de Biotecnología Vegetal, UPCT

Effects of Pb+2 on three populations of Zygophyllum fabago: Genotoxicity study

[SPA] Zygophyllum fabago es un arbusto perenne que es capaz de tolerar las duras condiciones ambientales prevalentes en el sudeste español, donde se localizan las balsas de estériles mineros que se encuentran dispersas por la Sierra de Cartagena. Sin embargo, a pesar de ser una especie pionera en estas balsas y de producir una considerable cantidad de semillas viables, la tasa de cobertura del suelo por esta especie en las balsas de estériles mineros es baja, debido a las condiciones adversas de la zona, sobre todo por los altos contenidos en metales pesados. El objetivo principal de este trabajo es evaluar el nivel de estrés soportado al aplicar plomo a plantas de Z. fabago procedentes de tres poblaciones distintas. El estudio se centra en determinar los daños de ADN debido a la presencia del metal pesado mediante los ensayos cometa y de micronúcleos. Los resultados obtenidos muestran que la toxicidad por plomo se manifiesta de forma diferente dependiendo de la población considerada, lo que sugiere que cada población pone en juego diferentes mecanismos de adaptación para sobrevivir a las condiciones específicas de cada entorno. [ENG] Zygophyllum fabago is a succulent perennial shrub that is able to tolerate harsh environmental conditions prevailing in the southeastern Spain, where mine tailing ponds are scattered throughout the Sierra de Cartagena. However, despite being a pioneer species in the study area and produce a substantial amount of viable seeds, the rate of soil cover by this species in mine tailing ponds is low, probably because of adverse conditions in the area, especially high content of heavy metals. The main objective of this work is to assess the impact of applying a high lead concentration to Z. fabago plants from three different populations in the level of stress endured by the plants. Two genotoxicity assays (the comet assay and the micronucleus test) were carried out in order to evaluate the DNA damage induced by the heavy metal. Our results show that lead toxicity affects differently each population. This may be due to the different adaptation mechanisms developed to survive in any environment.Este trabajo ha sido parcialmente financiado por el MECD (beca FPU AP2012/02559). Parte del trabajo se ha realizado en la Universidad de Aveiro (Portugal) gracias a la concesión de una ayuda para la movilidad del MECD (EST13/00414)

Expression patterns of antioxidant systems in pioneer plants present in mine tailings contaminated with high concentrations of heavy metals

[SPA] Zygophyllum fabago es un arbusto perenne que es capaz de tolerar las duras condiciones ambientales prevalentes en el sudeste español, donde se localizan las balsas de estériles mineros que se encuentran dispersas por la Sierra de Cartagena. Sin embargo, a pesar de ser una especie pionera en estas balsas y de producir una considerable cantidad de semillas viables, la tasa de cobertura del suelo por esta especie en las balsas de estériles mineros es baja, debido a las condiciones adversas de la zona, sobre todo por los altos contenidos en metales pesados. El objetivo principal de este trabajo es evaluar el nivel de estrés soportado al aplicar plomo a plantas de Z. fabago procedentes de tres poblaciones distintas. Los resultados obtenidos muestran que la toxicidad por plomo se manifiesta de forma diferente dependiendo de la población considerada, lo que sugiere que cada población pone en juego diferentes mecanismos de adaptación para sobrevivir a las condiciones específicas de cada entorno. [ENG] Zygophyllum fabago is a succulent perennial shrub that is able to tolerate harsh environmental conditions prevailing in the southeastern Spain, where mine tailing ponds are scattered throughout the Sierra de Cartagena. However, despite being a pioneer species in the study area and produce a substantial amount of viable seeds, the rate of soil cover by this species in mine tailing ponds is low, probably because of adverse conditions in the area, especially high content of heavy metals. The main objective of this work is to assess the impact of applying a high lead concentration to Z. fabago plants from three different populations on the level of stress endured by the plants. Our results show that lead toxicity affects differently each population. This may be due to the different adaptation mechanisms developed to survive in any environment.Este trabajo ha sido parcialmente financiado por el MECD (beca FPU AP2012/02559). Parte del trabajo se ha realizado en la Universidad de Aveiro (Portugal) gracias a la concesión de una ayuda para la movilidad del MECD (EST13/00414)

Antioxidant Capacity as a Marker for Assessing the In Vitro

Cistus heterophyllus subsp. carthaginensis is an endemic and endangered species from the SE Mediterranean coastal region of Spain. Within the framework of the efforts aiming to species conservation, in vitro culture techniques could be of interest. The aim of this study was to evaluate the antioxidant capacity of C. heterophyllus shoot cultures as a possible marker of in vitro performance. The effects of five different basal salt formulations and cytokinin levels on in vitro performance and antioxidant capacity were examined. K+/Na+ and Ca2+/Na+ ratios initially present in culture media greatly affected the antioxidant capacity (the lower the ratios the higher the antioxidant capacity). Increasing concentrations of BA resulted in higher antioxidant capacity. The results obtained point to antioxidant capacity as being a marker of incidence of stress conditions in in vitro cultured C. heterophyllus. A good correlation was found between antioxidant capacity and total soluble phenolics present in Cistus extracts. Catechin was identified in all the extracts and its levels were found to change parallel to the antioxidant capacity, pointing to a prominent role played by this flavonoid in C. heterophyllus defence against oxidative stress, which in turn affects the in vitro performance of this species

Foliar Application of Salicylic Acid Enhances the Endogenous Antioxidant and Hormone Systems and Attenuates the Adverse Effects of Salt Stress on Growth and Yield of French Bean Plants

Salicylic acid (SA) is one of the strongest candidates to be used as a salinity moderator. A hydroponic experiment was conducted to evaluate the effect of foliar application of SA (0.00, 0.75 and 1.50 mM) on growth, productivity, and some physiological and biochemical parameters of French beans (Phaseolus vulgaris L.) continuously exposed to three NaCl levels (0, 50 and 100 mM). NaCl treatment significantly reduced vegetative growth parameters (between 16–50%), membrane stability (10–15%), relative water content (25–31%), chlorophyll content (21–42%), macro- and micronutrient levels (13–52% and 4–49%, respectively), growth promoters (auxins, gibberellins, and cytokinins; 11–28%), and yield of green pods (22–39%), while the phenolic compounds contents (35–55%), total antioxidant capacity (34–51%), proline (60–100%) and malondialdehyde (18–51%) contents, peroxidase activity (35–41%), Na+ (122–152%) and Cl− (170%) ions and abscisic acid (20–30%) contents were significantly increased compared to the non-salt-stressed controls. Foliar application of SA at 0.75 mM was able to overcome the adverse effects of NaCl stress to variable extent, which allowed for close to 90% of the yield of control plants to be reached. In conclusion, this study demonstrated that foliar spraying of SA helped to reduce the harmful effects of NaCl stress on French bean via regulation of some physiological and biochemical processes. This could be the basis of an effective and low-cost strategy to cope with salt stress

SIDA. Guía del educador

Esta guía está elaborada con un objetivo prioritario: ayudar al educador a explicar a los alumnos de Secundaria qué es el Sida, cómo se transmite y cuáles son las medidas de prevención. Se parte de una explicación sobre el uso concreto de la guía, una información básica dividida en diferentes unidades específicas de información y un total de 39 actividades en las que se especifica los objetivos, el material, tiempo y método. Como complemento para la prevención se incluyen apartados referidos a la evaluación y normas higienico-sanitarias. La guía va acompañada de una carpeta con 34 diapositivas y un folleto explicativo que puede utilizarse independientemente en actividades informativas. Se da libertad al educador para su utilización en función del tipo de programa que haya diseñado previamente.MurciaES