11. The excess of phosphorus in soil reduces physiological performances over time but enhances prompt recovery of salt-stressed Arundo donax plantsClaudia 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: 2995; Downloads: 0
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12. Scanning Photoelectron Spectro‐Microscopy: A Modern Tool for the Study of Materials at the NanoscalePatrick Zeller, Matteo Amati, Hikmet Sezen, Mattia Scardamaglia, Claudia Struzzi, Carla Bittencourt, Gabriel Lantz, Mahdi Hajlaoui, Evangelos Papalazarou, Marino Marsi, Mattia Fanetti, Stefano Ambrosini, Silvia Rubini, Luca Gregoratti, 2018, review article Keywords: Scanning photoemission microscopy, graphene, GaAs, nanowires, Fermi Level, Mott-Hubbard transition
Published in RUNG: 07.12.2018; Views: 3645; Downloads: 0
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13. Pursuing the stabilisation of crystalline nanostructured magnetic manganites through a green low temperature hydrothermal synthesisArianna Minelli, Paolo Dolcet, Stefano Diodati, Sandra Gardonio, Claudia Innocenti, Denis Badocco, Stefano Gialanella, Paolo Pastore, Luciano Pandolfo, Andrea Caneschi, Angela Trapanati, Silvia Gross, 2017, original scientific article Abstract: A quick, easy and green water-based synthesis protocol involving coprecipitation of oxalates combined with hydrothermal treatment resulted in the crystallisation of nanostructured manganites at a relatively low temperature (180 °C). The subcritical hydrothermal approach was shown to play a key role in stabilising phases which are generally achieved at much higher temperatures and under harsher conditions, thus disclosing an exciting alternative for their synthesis. Through this mild wet chemistry approach, the compounds CuMnO2, ZnMn2O4 and ZnMnO3 were synthesised as nanocrystalline powders. Noticeably, the optimised route proved to be effective in stabilising the exotic polymorph cubic spinel ZnMnO3 in pure form. This is particularly notable, as very few records concerning this compound are available in the literature. The compounds were fully characterised from compositional, structural, morphological and magnetic points of view.
Keywords: nanostructured manganites, low temperature wet chemistry synthesis
Published in RUNG: 28.03.2017; Views: 4394; Downloads: 0
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14. An extracellular polymeric substance quickly chelates mercury(II) with N-heterocyclic groupsFranco Baldi, Michele Gallo, Salvatore Daniale, Dario Battistel, Claudia Faleri, Alojz Kodre, Iztok Arčon, 2017, original scientific article Abstract: A strain of Klebsiella oxytoca DSM 29614 is grown on sodium citrate in the presence of 50 mg l−1 of Hg as Hg(NO3)2. During growth, the strain produces an extracellular polymeric substance (EPS), constituted by a mixture of proteins and a specific exopolysaccharide. The protein components, derived from the outer membrane of cells, are co-extracted with the extracellular exopolysaccharide using ethanol. The extracted EPS contains 7.5% of Hg (total amount). This indicates that EPS is an excellent material for the biosorption of Hg2+, through chemical complexation with the EPS components. The binding capacity of these species towards Hg2+ is studied by cyclic voltammetry, and Hg L3-edge XANES and EXAFS spectroscopy. The results found indicate that Hg2+ is mainly bound to the nitrogen of the imidazole ring or other N-heterocycle compounds. The hydroxyl moities of sugars and/or the carboxyl groups of two glucuronic acids in the polysaccharide can also play an important role in sequestring Hg2+ ions. However, N-heterocyclic groups of proteins bind Hg2+ faster than hydroxyl and carboxyl groups of the polysaccharide.
Keywords: Klebsiella oxytoca, Biosorption, Proteins, Polysaccharide, Cyclic voltammetry, EXAFS analysis
Published in RUNG: 03.03.2017; Views: 4718; Downloads: 0
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