Erratum to "Selenium as stressor and antioxidant affects pollen performance in Olea europaea" [FLORA 215 (2015) 16–22]

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Selenium as stressor and antioxidant affects pollen performance in Olea europaea

Abstract Selenium (Se) as an antioxidant is a trace element essential to wellness and the maintenance of human health. Although it has not been confirmed to be an essential micronutrient in higher plants, there is increasing evidence of its benefits in plants in which it inhibits the detrimental effects of environmental stressors, while only few studies refer to its action on pollen germination. Selenium enhances the stress tolerance regulating the production and quenching of reactive oxygen species (ROS); however, the endogenous ROS are essential to the cross-talk between pollen and stigma and promote pollen tube growth. The action of Se has many mechanisms, not all yet fully clarified. In order to deepen the knowledge and fill the gaps in the role of Se as an inhibitor of ROS and, at the same time, a promoter of pollen germination, we attempted this research, enriching olive trees growing in pots and in the field with Se. The plants in pots were kept at a controlled water regime in order to induce drought stress. To test the effect of antioxidant on pollen performance, a single application of Se was supplied to the plants at the beginning of pollen development. Two olive cultivars (Arbequina and Maurino) were used in three different experiments in which Se enrichment was carried out through (i) endo-xylematic drip injection, (ii) foliar spray, (iii) soil application. The pollen performance was assessed at anthesis. The results showed that Se enrichment in non-stressed plants induced a higher rate of pollen viability and germination, but it did not always stimulate their reproductive performance. Different responses were obtained in drought stressed plants, in which Se induced pollen germination, obtaining a performance similar to non-stressed plants. The ROS detection by a quantitative method, applied on hydrated pollen, verified the results just discussed

Current Knowledge on Selenium Biofortification to Improve the Nutraceutical Profile of Food: A Comprehensive Review

Selenium (Se) is an important micronutrient for living organisms, since it is involved in several physiological and metabolic processes. Se intake in humans is often low and very seldom excessive, and its bioavailability depends also on its chemical form, with organic Se as the most available after ingestion. The main dietary source of Se for humans is represented by plants, since many species are able to metabolize and accumulate organic Se in edible parts to be consumed directly (leaves, flowers, fruits, seeds, and sprouts) or after processing (oil, wine, etc.). Countless studies have recently investigated the Se biofortification of plants to produce Se-enriched foods and elicit the production of secondary metabolites, which may benefit human health when incorporated into the diet. Moreover, feeding animals Se-rich diets may provide Se-enriched meat. This work reviews the most recent literature on the nutraceutical profile of Se-enriched foods from plant and animal sources.Fil: D'Amato, Roberto. Università di Perugia; ItaliaFil: Regni, Luca. Università di Perugia; ItaliaFil: Falcinelli, Beatrice. Università di Perugia; ItaliaFil: Mattioli, Simona. Università di Perugia; ItaliaFil: Benincasa, Paolo. Università di Perugia; ItaliaFil: Dal Bosco, Alessandro. Università di Perugia; ItaliaFil: Pacheco, Pablo Hugo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San Luis. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Química de San Luis; ArgentinaFil: Proietti, Primo. Università di Perugia; ItaliaFil: Troni, Elisabetta. Università di Perugia; ItaliaFil: Santi, Claudio. Università di Perugia; ItaliaFil: Businelli, Daniela. Università di Perugia; Itali

Soil selenium (Se) biofortification changes the physiological, biochemical and epigenetic responses to water stress in Zea mays L. by inducing a higher drought tolerance

Requiring water and minerals to grow and to develop its organs, Maize (Zea mays L.) production and distribution is highly rainfall-dependent. Current global climatic changes reveal irregular rainfall patterns and this could represent for maize a stressing condition resulting in yield and productivity loss around the world. It is well known that low water availability leads the plant to adopt a number of metabolic alterations to overcome stress or reduce its effects. In this regard, selenium (Se), a trace element, can help reduce water damage caused by the overproduction of reactive oxygen species (ROS). Here we report the effects of exogenous Se supply on physiological and biochemical processes that may influence yield and quality of maize under drought stress conditions. Plants were grown in soil fertilized by adding 150 mg of Se (sodium selenite). We verified the effects of drought stress and Se treatment. Selenium biofortification proved more beneficial for maize plants when supplied at higher Se concentrations. The increase in proline, K concentrations and nitrogen metabolism in aerial parts of plants grown in Se-rich substrates, seems to prove that Se-biofortification increased plant resistance to water shortage conditions. Moreover, the increase of SeMeSeCys and SeCys2 forms in roots and aerial parts of Se-treated plants suggest resistance strategies to Se similar to those existing in Se-hyperaccumulator species. In addition, epigenetic changes in DNA methylation due to water stress and Se treatment were also investigated using methylation sensitive amplified polymorphism (MSAP). Results suggest that Se may be an activator of particular classes of genes that are involved in tolerance to abiotic stresses. In particular, PSY (phytoene synthase) gene, essential for maintaining leaf carotenoid contents, SDH (sorbitol dehydrogenase), whose activity regulates the level of important osmolytes during drought stress and ADH (alcohol dehydrogenase), whose activity plays a central role in biochemical adaptation to environmental stress. In conclusion, Se-biofortification could help maize plants to cope with drought stress conditions, by inducing a higher drought tolerance

Mechanisms of Pb (II) sorption and desorption at some clays and goethite-water interfaces

The aim of this research is to corroborate the results obtained with Pb (II) sorption and desorption macroscopic equilibrium studies on some soil minerals (montmorillonite, illite, kaolinite and goethite) using microscopic techniques. The sorption isotherms demonstrate that the adsorption capability of the substrates varies in the following sequence: illite $>$ montmorillonite $>$ kaolinite $>$ goethite, and the desorption isotherms demonstrate the irreversibility of the bonds formed. pH adsorption edges on montmorillonite show that at a pH lower than the hydrolysis point the sorption edge is primarily due to ion exchange, while at a pH higher than the hydrolysis point, it is a combination of both ion exchange and precipitation. The EDS semi-quantitative analysis performed by SEM demonstrates that in the clays Pb replaced almost exclusively Ca ions. In the montmorillonite this replacement may also include the Ca ions in the interlayer space, and in the illite also, the replacement of protonated OH groups and the K ions situated at the edge of interlattice sites. Goethite shows an adsorption capability of the same magnitude as kaolinite.Mécanismes d'absorption et de désorption du Pb (II) à l'interface entre solution aqueuse et certaines argiles et la goethite. L'objectif de cette recherche est d'étayer, au moyen de techniques microscopiques, les résultats obtenus par le biais d'études macroscopiques d'équilibre sur l'absorption et la désorption du Pb (II) sur certains composants minéraux du sol (montmorillonite, illite, kaolinite et goethite). Les isothermes d'absorption ont montré que la capacité d'adsorption des substrats variait de la façon suivante : illite $>$ montmorillonite $>$ kaolinite $>$ goethite, et les isothermes de désorption ont démontré l'irréversibilité des liens formés. La variation du pourcentage de Pb adsorbé par la montmorillonite en fonction du pH montrait que, lorsque l'on a une valeur de pH inférieure au point d'hydrolyse, l'absorption est principalement due à une réaction d'échange ionique alors que, lorsque l'on a une valeur de pH supérieure au point d'hydrolyse, l'absorption est due à une combinaison de réactions d'échange ionique et précipitation. Les analyses semi-quantitatives effectuées au microscope électronique à balayage (MEB) couplé à la micro-analyse aux rayons X par dispersion d'énergie (EDS) ont démontré que, dans les argiles, le Pb remplaçait exclusivement les ions Ca. Dans la montmorillonite, cette substitution pourrait intéresser aussi les ions Ca de l'espace interlamellaire et, dans l'illite, il pourrait également y avoir substitution de groupes OH protonés et d'ions K situés au bord des sites interstrates. La goethite a montré une capacité d'adsorption équivalente à celle de la kaolinite

XAS study of lead speciation in a central Italy calcareous soil

""Purpose The Pb absorption processes on a heavy textured calcareous soil, typical of central Italy, were studied using synchrotron X-ray absorption spectroscopy (XAS) in order to probe, at molecular scale, the structure and chemical nature of Pb in contaminated soils and achieve precise description of Pb ions localization into these contaminated soils.. Materials and methods In order to distinguish the role of the different components of soils in Pb retention, samples were prepared from the original soils removing the carbonate fractions, the organic matter, the metal oxides, or selecting the clay fractions. Then these samples were fortified with Pb simulating the natural interactions processes of heavy metal solutions with soils. The quantitative analysis of near edge (XANES) as well extended (EXAFS) regions of Pb LIII edge absorption spectra, in comparison with Pb XAS data of selected reference compounds, allowed the precise determination of local structure and chemical environment of Pb ions in these soil samples.. Results Four components were individuated as the major responsible of Pb retention in calcareous soils: the carbonates, the metal oxide surfaces, the organic matter, and the colloidal inorganic surfaces containing clay components. The structural analysis suggests that, within these experimental conditions, the Pb adsorbed on the soil is generally present as Pb hydroxide with poor crystallization degree. However, the presence of carbonates (CaCO3) induces the co-precipitation of PbCO3-like phases with some degree of crystallinity.. "

Modelling herbicide treatment impact on groundwater quality in a central Italy area

A simulation study, using the MACRO-DB pesticide leaching model, was carried out to determine the impact of different weed control strategies on groundwater quality in a Central Italy area (Umbria) where the drinking water wells for the city of Perugia are located. The simulations considered nine representative soil profiles and two different crop rotations. Weather conditions were those of ten years. Thirty herbicides and twenty-two weed control strategies were tested for their groundwater concentrations. Two maps reporting the risk of groundwater contamination were made from simulations of the two crop rotations applying the strategy with the least groundwater pollution risk for each crop. As even the less polluting strategy in the four-crop rotation exceeds the EU Directive 414/91 limit for drinking water, only the three-crop rotation is recommended. The present findings testify that crop selection is an effective way to minimise groundwater pollution risk.Simulation de l'impact de plusieurs traitements herbicides sur la qualité des eaux souterraines dans une zone de l'Italie centrale. Sur la base du modèle MACRO-DB pour la prévision du lessivage des produits phytosanitaires le long des profils du sol, on a effectué une simulation en vue de déterminer l'impact environnemental provoqué par différentes stratégies de désherbage sur les eaux de nappe dans une zone de l'Italie centrale (Ombrie) où se trouvent les puits pour l'approvisionnement en eau de la ville de Pérouse. Les simulations ont pris en considération neuf profils de sol représentatifs de la zone examinée et deux assolements différents. Les conditions climatiques prises en considération sont celles couvrant dix années. On a calculé au niveau de la nappe les concentrations de trente herbicides et vingt-deux stratégies de désherbage. On a réalisé deux cartes qui reportent le risque de contamination, en simulant deux rotations culturales et en appliquant à chaque culture la stratégie comportant le plus bas risque de pollution de la nappe. Étant donné que la stratégie la moins polluante dans la rotation prévoyant quatre cultures dépasse encore la limite prévue par la Directive EU 414/91 pour les eaux potables, il s'impose de préférer l'assolement à trois cultures, la sélection culturale s'avérant être une méthode valable pour réduire le risque de pollution des eaux de nappe