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11.
Copper tolerance strategies involving the root cell wall pectins in Silene paradoxa L.
Ilaria Colzi, Miluscia Arnetoli, Alessia Gallo, Saer Doumett, Massimo Del Bubba, Sara Pignattelli, Roberto Gabbrielli, Cristina Gonnelli, 2012, original scientific article

Abstract: New insights were provided on the function of root cell wall pectin concentration and methylation degree in copper tolerance studying contrasting ecotypes of Silene paradoxa. A metallicolous copper tolerant population and a non-metallicolous sensitive population were grown in hydroponics and exposed to different CuSO4 treatments to evaluate copper accumulation in relation to pectin concentration and methylation degree of the root cell wall. In short-term exposure experiments the tolerant population decreased root cell wall pectin concentration and increased their methylation degree, while the sensitive population did not respond. Moreover, a positive correlation between root pectin concentration and metal accumulation in root apoplast and symplast was found. In addition, a negative correlation between pectin methylation degree and apoplastic copper concentration were found to be negatively correlated. In longterm exposure experiments, the sensitive population increased the concentration of pectins with the same methylation degree and consequently the ability of its root cell wall to bind the metal. The opposite phenomenon was shown by the tolerant population. Moreover, pectin methylation degree was higher in the tolerant population in respect to the sensitive one, possibly to limit metal binding to the root cell wall. Therefore, in the copper tolerant population of S. paradoxa the generation of metal-excluding root cell walls was suggested to be one of the factors concurring to guarantee a low apoplastic copper accumulation and probably also to limit symplastic copper uptake by the root cells.
Keywords: Copper tolerance Cell wall Pectin Methylation Root
Published in RUNG: 20.04.2020; Views: 2727; Downloads: 0
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12.
A multielement analysis of Cu induced changes in the mineral profilesof Cu sensitive and tolerant populations of Silene paradoxa L.
Sara Pignattelli, Ilaria Colzi, Antonella Buccianti, Ilenia Cattani, Gian Maria Beone, Henk Schat, Cristina Gonnelli, 2013, original scientific article

Abstract: tThis work investigates the Cu induced changes in element profiles in contrasting ecotypes of Silene para-doxa L. A metallicolous copper tolerant population and a non-metallicolous sensitive population weregrown in hydroponics and exposed to different CuSO4treatments. Shoot and root concentrations of Ca,Cu, Fe, K, Mg, Mn, Mo, Na, P, S and Zn were evaluated through ICP-OES.Results indicated that increasing the environmental Cu concentration had a population dependenteffect on element profiles, shoot-to-root ratios and correlations among the elements. Generally, in thetolerant population Cu treatment induced a higher element accumulation in roots and had minimaleffects on the shoot element profile, thus resulting in a progressively decreasing shoot-to-root ratio foreach element. In the sensitive population element concentrations in root and shoot were much moreaffected and without a consistent trend. Copper treatment also affected the correlations between theelements, both in roots and shoots of the two populations, but more so in the sensitive population thanin the tolerant one. Thus, Cu exposure strongly disturbed element homeostasis in the sensitive population,but barely or not in the tolerant one, probably mainly due to a higher capacity to maintain proper rootfunctioning under Cu exposure in the latter. Differences in element profiles were also observed in theabsence of toxic Cu exposure. These differences may reflect divergent population-specific adaptations todifferential nutrient availability levels prevailing in the populations’ natural environments. There is noevidence of inherent side-effects of the Cu tolerance mechanism operating in the tolerant population.
Keywords: Mineral profile, Copper tolerance, Silene paradoxa, Compositional data analysis
Published in RUNG: 20.04.2020; Views: 2778; Downloads: 0
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13.
Linking root traits to copper exclusion mechanisms in Silene paradoxa L. (Caryophyllaceae)
Ilaria Colzi, Sara Pignattelli, Elisabetta Giorni, Alessio Papini, Cristina Gonnelli, 2015, original scientific article

Abstract: Copper is one of the most important pollutants in mine- contaminated soils. This study tests the response in a sensitive population vs a tolerant one of the model species Silene paradoxa in order to understand the general mechanisms of tolerance at the micromorphological and ultrastructural level. Two populations of Silene paradoxa were grown in hydroponics and exposed to different CuSO4 treatments. The roots were investigated with light, fluorescence and transmission electron microscope. Callose and lignin were spectrophotometrically determined. The tolerant population constitutively possessed a higher amount of mucilage and was able to reduce the length of the zone between the apex and the first lignified tracheids. Callose production decreased. It did not show remarkable copper-induced ultrastructural modifications, apart from the presence of precipitates in the tangential walls. The sensitive population showed huge nucleoli with a spongy periphery in the central cylinder together with the presence of electrondense granules in the mitochondria. Plastids were rarely observed and generally very electrondense and elongated. In the copper tolerant population of S. paradoxa some of the root traits concurring to generate metal-excluding roots were suggested to be mucilage and lignin production and the reduction of the subapical root zone.
Keywords: Root, Copper exclusion, Lignin, Callose, Tolerance to copper, Silene paradoxa
Published in RUNG: 20.04.2020; Views: 2650; Downloads: 0
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14.
Under fungal attack on a metalliferous soil: ROS or not ROS? Insights from Silene paradoxa L. growing under copper stress
Cosimo Taiti, Elisabetta Giorni, Ilaria Colzi, Sara Pignattelli, Nadia Bazihizina, Antonella Buccianti, Simone Luti, Luigia Pazzagli, Stefano Mancuso, Cristina Gonnelli, 2016, original scientific article

Abstract: We investigated how the adaptation to metalliferous environments can influence the plant response to biotic stress. In a metallicolous and a non-metallicolous population of Silene paradoxa the induction of oxidative stress and the production of callose and volatiles were evaluated in the presence of copper and of the PAMP fungal protein cerato-platanin, separately and in combination. Our results showed incompatibility between the ordinary ROS-mediated response to fungal attack and the acquired mechanisms of preventing oxidative stress in the tolerant population. A similar situation was also demonstrated by the sensitive population growing in the presence of copper but, in this case, with a lack of certain responses, such as callose production. In addition, in terms of the joint behaviour of emitted volatiles, multivariate statistics showed that not only did the populations respond differently to the presence of copper or biotic stress, but also that the biotic and abiotic stresses interacted in different ways in the two populations. Our results demonstrated that the same incompatibility of hyperaccumulators in ROS-mediated biotic stress signals also seemed to be exhibited by the excluder metallophyte, but without the advantage of being able to rely on the elemental defence for plant protection from natural enemies.
Keywords: Biotic interactions Callose Heavy metals Oxidative stress VOCs
Published in RUNG: 20.04.2020; Views: 3298; Downloads: 0
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15.
Mediterranean Coastal Lagoons: The Importance of Monitoring in Sediments the Biochemical Composition of Organic Matter
Monia Renzi, Francesca Provenza, Sara Pignattelli, Lucrezia Cilenti, Antonietta Specchiulli, Milva Pepi, 2019, original scientific article

Abstract: Transitional water ecosystems are targeted by the European Union (EU) Water Framework Directive (WFD, CE 2000/60) monitoring programs in coastal zones. Concerning sediments, activities performed for the WFD focus on a few variables concerning the biochemical composition of organic matter. Our research reports the effects of oxygen availability on the biochemical composition of organic matter in sediments to highlight levels of targeted variables in time and, according to the depth of sediment layer, both under oxygenated and anoxic conditions in a mesocosm study on sediment cores. Results provide evidence that tested factors of interest (i.e., disturbance type, oxygenic versus anoxic conditions; persistence time of disturbance, 0–14 days; penetration through sedimentary layers, 0–10 cm depth) are able to significantly affect the biochemical composition of organic matter in sediments. Large part of the variables considered in this study (total organic carbon (TOC), total phosphorous (TP), total sulphur (TS), Fe, carbohydrates (CHO), total proteins (PRT), biopolymeric carbon (BPC), chlorophyll-a (Chl-a) are significantly affected and correlated to the oxygenation levels and could be good early indicators of important changes of environmental conditions. Monitoring activities performed under WFD guidelines and management strategies of Mediterranean coastal lagoon ecosystems shall include the biochemical composition of organic matter in sediment to provide an exhaustive picture of such dynamic ecosystems.
Keywords: decomposition, transitional water ecosystems, organic loads, mesocosm, monitoring programs
Published in RUNG: 20.04.2020; Views: 2734; Downloads: 0
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16.
Impact of high or low levels of phosphorus and high sodium in soils on productivity and stress tolerance of Arundo donax plants
Claudia Cocozza, Federico Brilli, Laura Miozzi, Sara Pignattelli, Silvia Rotunno, Cecilia Brunetti, Cristiana Giordano, Susanna Pollastri, Mauro Centritto, Gian Paolo Accotto, Roberto Tognetti, Francesco Loreto, 2019, original scientific article

Abstract: The potential of Arundo donax to grow in degraded soils, characterized by excess of salinity (Na+), and phosphorus deficiency (-P) or excess (+P) also coupled with salinity (+NaP), was investigated by combining in vivo plant phenotyping, quantification of metabolites and ultrastructural imaging of leaves with a transcriptome-wide screening. Photosynthesis and growth were impaired by+Na, -P and+NaP. While+Na caused stomatal closure, enhanced biosynthesis of carotenoids, sucrose and isoprene and impaired anatomy of cell walls, +P negatively affected starch production and isoprene emission, and damaged chloroplasts. Finally, +NaP largely inhibited photosynthesis due to stomatal limitations, increased sugar content, induced/repressed a number of genes 10 time higher with respect to+P and+Na, and caused appearance of numerous and large plastoglobules and starch granules in chloroplasts. Our results show that A. donax is sensitive to unbalances of soil ion content, despite activation of defensive mechanisms that enhance plant resilience, growth and biomass production of A. donax under these conditions.
Keywords: Abiotic stress Giant reed Isoprene emission Phosphorus Salinity Transcriptome
Published in RUNG: 20.04.2020; Views: 2683; Downloads: 0
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17.
The multi-purpose role of hairiness in the lichens of coastal environments: Insights from Seirophora villosa (Ach.) Frödén
Elisabetta Bianchi, Renato Benesperi, Ilaria Colzi, Andrea Coppi, Lorenzo Lazzaro, Luca Paoli, Alessio Papini, Sara Pignattelli, Corrado Tani, Pamela Vignolini, Cristina Gonnelli, 2019, original scientific article

Abstract: The fruticose epiphytic lichen Seirophora villosa, strictly associated with Juniperus shrublands in the Mediterranean basin, was used to investigate the role of hairiness on a lichen thallus, as a characteristic morphological trait. We evaluated the effect of hair removal on the physiological parameters of a set of samples, during desiccation and on exposure to different salt concentrations. Hairy thalli were less affected by salt, suggesting that during dehydration, the presence of hair protects the thallus from light irradiance, oxidative stresses and the lipid peroxidation generated by free radicals, and could offer passive, but selective, water control. Our results showed that hair could not only increase thallus surface and promote water absorption when availability is low, but could also repel the salt dissolved in water by activating a passive resistance mechanism, by preventing salt entering.
Keywords: Antioxidant activity Chlorophyll a fluorescence Juniperus shrublands Hair MDA Salt stress
Published in RUNG: 20.04.2020; Views: 2661; Downloads: 0
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18.
The excess of phosphorus in soil reduces physiological performances over time but enhances prompt recovery of salt-stressed Arundo donax plants
Claudia Cocozza, Federico Brilli, Sara Pignattelli, Susanna Pollastri, Cecilia Brunetti, Cristina Gonnelli, Roberto Tognetti, Mauro Centritto, Francesco Loreto, 2020, original scientific article

Abstract: Arundo donax L. is an invasive grass species with high tolerance to a wide range of environmental stresses. The response of potted A. donax plants to soil stress characterized by prolonged exposure (43 days) to salinity (+Na), to high concentration of phosphorus (+P), and to the combination of high Na and P (+NaP) followed by 14 days of recovery under optimal nutrient solution, was investigated along the entire time-course of the experiment. After an exposure of 43 days, salinity induced a progressive decline in stomatal conductance that hampered A. donax growth through diffusional limitations to photosynthesis and, when combined with high P, reduced the electron transport rate. Isoprene emission from A. donax leaves was stimulated as Na+ concentration raised in leaves. Prolonged growth in P-enriched substrate did not significantly affect A. donax performance, but decreased isoprene emission from leaves. Prolonged exposure of A. donax to + NaP increased the leaf level of H2O2, stimulated the production of carbohydrates, phenylpropanoids, zeaxanthin and increased the de-epoxidation state of the xanthophylls. This might have resulted in a higher stress tolerance that allowed a fast and full recovery following stress relief. Moreover, the high amount of ABA-glucose ester accumulated in leaves of A. donax exposed to + NaP might have favored stomata re-opening further sustaining the observed prompt recovery of photosynthesis. Therefore, prolonged exposure to high P exacerbated the negative effects of salt stress in A. donax plants photosynthetic performances, but enhanced activation of physiological mechanisms that allowed a prompt and full recovery after stress.
Keywords: Arundo donax Phosphorus Salinity Stress tolerance Biomass production
Published in RUNG: 20.04.2020; Views: 2848; Downloads: 0
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