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Nicotiana langsdorffiiwild type and genetically modified exposed to chemical and physical stress: changes in element content
No full textThe concentrations of 19 elements in wild and genetically modified Nicotiana langsdorffii
(N. langsdorffii) exposed to Chromium (VI) and to water deficit were determined and
compared to provide new information about their response to abiotic stress.
Genetic modifications by GR and RolC genes (encoding for the rat glucocorticoid receptor
and for Agrobacterium rhizogenes RolC, respectively) were investigated because they induce
significant, but only partially known changes in the plant response to stress.
Simultaneous determination of Al, As, Ba, Ca, Cd, Co, Cr, Cs, Cu, Fe, K, Mg, Mn, Na, Pb,
Rb, Sr, V and Zn was carried out by ICP-MS equipped with a collision/reaction cell (ICPORS-
MS). The methodology was optimised by testing the grinding, homogenisation, digestion
and analysis procedures, to reduce the uncertainty of the experimental results and to
identify statistically significant differences between nine sample pools, for a total of 75
samples. The quality control procedure was carried out by blank control and by evaluating
the detection limits and repeatability. Trueness was assessed by analysing certified reference
material, NIST 1573a.
Significant differences were observed in the uptake and accumulation of several elements
in the wild-type N. langsdorffii samples, either with respect to the plants submitted to water
deficit and exposure to Cr(VI) or with respect to the genetically modified plants. The
differences were highlighted by principal component analysis (PCA). The analysis of the
element content of the whole plant, combined with the data found in the literature, allows us
to hypothesise effects on the metabolic mechanism controlling the uptake and translocation of
elements inside the vegetal organism. Because genetic and chemical stress decreases the
nutrient concentration in the whole plant, we can say that the uptake at root level is affected.
The increase in concentration of elements such as As, Sr and Al indicates a decreased
selectivity in the uptake of potentially toxic elements and, consequently, highlights the effects
on the plant’s metabolic processes
Distribuzione e speciazione di metalli in traccia nell'acqua di mare superficiale del bacino delle isole Eolie
No full textSummary - The distribution and speciation of cadmium, lead and copper in the Eolian Basin (South Tyrrhenian Sea) was studied by analysis of surface sea water samples using anodic stripping voltammetry (DPASV). Samples were analyzed to determine the total metal content (after acid digestion), the metal distribution between free fraction (or ASVlabile, mainly ionic and inorganically complexed metal) and bound fraction (organically complexed metal). The complexing capacity of the water was also evaluated by determination of the content of strong organic ligands complexing metals and the related conditional stability constants
Statistical analysis of the physical properties and durability of water-repellent mortars made with limestone cement, natural hydraulic lime and pozzolana-lime
Full text linkMultivariate statistical methods are proposed for the analysis of the physical properties of limestone cement, natural hydraulic lime and pozzolana-lime mortars admixed with water-repellents. The relation- ship between the physical properties and the durability of the mortars is evaluated by principal compo- nent analysis (PCA) and linear regression models. PCA allows to visualize (i) three groups of mortars according to the binder used and the structural/mechanical properties; (ii) the durability in relation to the mortar properties in simulated conditions. Linear regression models allow to identify and quantify associations between properties, composition and durability
METHOD VALIDATION OF THE ELEMENTAL CHARACTERIZATION OF NICOTIANA LANGSDORFII BY ICP-LRMS AND ORS‐ICP-LRMS
No full textHPLC-HRMS simultaneous determination of salicylic, shikimicand jasmonicacids in wild and transgenic NicotianaLangsdorffiiplants exposed to abioticstresses
Full text linkWhen dealing with adverse or limiting growth conditions, plants respond by specific-stress mechanisms which are regulated by the phytohormonal network. Salicylic acid (SA) and Jasmonic acid (JA) are hormones involved in plant growth and development, which also take part in plant response towards different kind of stresses. Shikimic acid (SHA) is an important plant intermediate and a key molecule in the biosynthesis of many secondary metabolites implicated in the stress response mechanisms. The Nicotiana genus includes small, well characterized plants, traditionally used as biological models for genetic and physiological studies; the insertion of the rolC gene from Agrobacterium rhizogenes and the rat glucocorticoid receptor (GR) gene in Nicotiana plants have been previously investigated, demonstrating interesting results for the production of resistant plants. In this study, a new HPLC-ESI-LTQ Orbitrap method for the simultaneous quantification of SA, JA and SHA in N. Langsdorffii is presented. The method was developed and validated by estimating matrix effect, accuracy, precision and the detection limits. The method, which, to our known, is the first which permit the simultaneous quantification of these three compounds, was then applied to 82 wild and transgenic plants, exposed to chemical, water and heat stresses. The results showed a differential regulation of the phytohormones’ levels in the wild and genetically modified plants, as a clear indication of the activation of stress response processes. A differential induction of the shikimic acid pathway in stressed plants was moreover observed, highlighting the mechanisms the plant behavior against different abiotic stresses
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