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San Miguel de Tucumán, Argentina

Podazza G.,Institute Ecologia | Arias M.,Catedra de Anatomia Vegetal | Prado F.E.,Catedra de Fisiologia Vegetal
Journal of Hazardous Materials | Year: 2012

In order to assess implications of Cd-induced oxidative stress in roots of the citrus rootstock Citrumelo, seedlings were hydroponically exposed to two relatively realistic Cd concentrations during 7 days. Our results showed that increasing Cd concentrations in external solution were associated with higher Cd accumulations in roots. At 5μM Cd the accumulation of Cd in roots was over 70-f higher than in aerial part (stem+leaves). Malondialdehyde (MDA), superoxide radical (O 2 -), hydrogen peroxide (H 2O 2) and lipoxygenase activity (LOX) increased in Cd-exposed roots, suggesting a metal-induced oxidative stress. The Cd treatment enhanced the activity of antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and guaiacol-type peroxidase (G-POD), as well as the content of secondary metabolites i.e. soluble phenolics (SPs) and lignin. Histochemical analyses of roots showed that Cd, H 2O 2, (O 2 -), lignin and G-POD displayed a similar location pattern. Almost all analyzed parameters showed a similar dynamic tendency with increases under 5μM Cd followed by decreases under 10μM Cd, suggesting that a complex coordinated Cd-defensive mechanism is operating in Citrumelo roots exposed to environmental realistic Cd concentrations. © 2012 Elsevier B.V.

Cerioni L.,CONICET | Volentini S.I.,CONICET | Prado F.E.,Catedra de Fisiologia Vegetal | Rapisarda V.A.,CONICET | Rodriguez-Montelongo L.,CONICET
Journal of Applied Microbiology | Year: 2010

Aim: To investigate the cellular damage on Penicillium digitatum produced by a sequential oxidative treatment (SOT), previously standardized in our laboratory, to prevent the conidia growth. Lethal SOT consists of 2-min preincubation with 10 ppm NaClO followed by 2-min incubation with 6 mmol l -1 CuSO 4 and 100 mmol l -1 H 2O 2 at 25°C. Methods and Results: After the application of lethal SOT or sublethal SOT (decreasing only the H 2O 2 concentration), we analysed several conidia features such as germination, oxygen consumption, ultrastructure and integrity of the cellular wall and membrane. Also, we measured the production of reactive oxygen species (ROS) and the content of thiobarbituric acid-reactive species (TBARS). With the increase of H 2O 2 concentration in the SOT, germination and oxygen consumption of conidia became inhibited, while the membrane permeability, ROS production and TBARS content of conidia increased. Several studies revealed ultrastructural disorganization in P. digitatum conidia after lethal SOT, showing severe cellular damage without apparent damage to the cell wall. In addition, mycelium of P. digitatum was more sensitive than conidia to the oxidative treatment, because growth ceased and permeability of the membranes increased after exposure of the mycelium to a SOT with only 50 mmol l -1 H 2O 2 compared to a SOT of 100 mmol l -1 for these effects to occur on conidia. Conclusion: Our insights into cellular changes produced by the lethal SOT are consistent with the mode of action of the oxidant compounds, by producing both alteration of membrane integrity and intracellular damage. Significance and Impact of the Study: Our results allow the understanding of SOT effects on P. digitatum, which will be useful to develop a reliable treatment to control postharvest diseases in view of its future application in packing houses. © 2010 The Society for Applied Microbiology.

Cerioni L.,CONICET | Rodriguez-Montelongo L.,CONICET | Ramallo J.,SA San Miguel | Prado F.E.,Catedra de Fisiologia Vegetal | And 2 more authors.
Postharvest Biology and Technology | Year: 2012

A sequential oxidative treatment (SOT), using sodium hypochlorite (NaClO) and hydrogen peroxide (H2O2) in the presence of a cupric salt inhibited in vitro growth and germination of Penicillium digitatum conidia, causal agent of citrus green mold. Here, modifications of this SOT were evaluated in vivo to control this disease in inoculated lemons. The treatment that consisted of two sequential 2-min baths: one with 200mgL-1 NaClO followed by a second with 600mmolL-1 H2O2 in the presence of 6mmolL-1 CuSO4, resulted in 50% of disease control. When this treatment was combined with a third 2-min bath containing 30gL-1 NaHCO3 at 37°C (SOT-NaHCO3) and applied at 24h post-inoculation, green mold incidence was reduced to ∼5%. In non-inoculated lemons stored at 5°C for 45 d, this treatment did not modify the appearance or weight compared to untreated lemons. Furthermore, phenolic content and the oxygen consumption rate in flavedo and albedo tissues were not affected by the SOT-NaHCO3. The malondialdehyde content in flavedo tissues increased immediately after treatment, but decreased to levels similar to control fruit 2 d later. The SOT-NaHCO3 combines compounds that are safe to the environment and human health, thus it represent a potential alternative to synthetic fungicides for the integrated control of postharvest diseases. © 2011 Elsevier B.V..

Ruiz V.E.,CONICET | Interdonato R.,Catedra de Fisiologia Vegetal | Cerioni L.,CONICET | Albornoz P.,Institute Morfologia Vegetal | And 4 more authors.
Journal of Photochemistry and Photobiology B: Biology | Year: 2016

UV-B radiation (UVBR) is a small fraction of the solar spectrum from 280 to 315 nm. UVBR produces photomorphogenic acclimation responses in plants, modulating their cellular structure and physiology. Here, changes in the peel of harvested lemons after short time exposure to UVBR were analyzed and its potential effects against fungal infection were studied. In the flavedo, UVBR treatment induced variations in the respiratory profiles and increased the phenolic compound contents. Final products of the flavonoid pathway (flavones, flavonols and anthocyanins) increased more markedly than their precursors (flavanones and dihydroflavonols). The increased accumulation of soluble phenolics in the flavedo of treated lemons is associated with the high antioxidant activity found in the flavedo of these samples. Supporting the biochemical determinations, anatomical observations showed abundant intravacuolar deposits of phenolic compounds and an increase in the cell wall thickness in UVBR-treated samples. Metabolic and anatomical modifications associated to UVBR improved natural defenses against Penicillium digitatum, the causal agent of green mold disease. Our results suggest that mature postharvest lemons exposed to the artificial radiation showed phenotypic plasticity, allowing an acclimation response to UVBR which confers fruit resistance to pathogens. Thus, combination of UVBR with other treatments could represent an important improvement to control postharvest diseases on citrus. © 2016 Elsevier B.V. All rights reserved.

Ruffino A.M.C.,Catedra de Fisiologia Vegetal | Rosa M.,Catedra de Fisiologia Vegetal | Hilal M.,Catedra de Fisiologia Vegetal | Gonzalez J.A.,Institute Ecologia | Prado F.E.,Catedra de Fisiologia Vegetal
Plant and Soil | Year: 2010

A growth chamber experiment was conducted to assess the effect of salinity on emergence, growth, water status, photosynthetic pigments, osmolyte accumulation, and ionic content of quinoa seedlings (Chenopodium quinoa). The aim was to test the hypothesis that quinoa seedlings are well adapted to grow under salinity due to their ability to adjust the metabolic functionality of their cotyledons. Seedlings were grown for 21 days at 250 mM NaCl from the start of the germination. Germination percentage and cotyledon area were not affected by salt whereas seedling height decreased 15%. FW increased in both control and salt-treated cotyledons, but the increase was higher under salinity. DW only increased in salt-treated cotyledons. The DW/FW ratio did not show significant differences between treatments. Relative water content, chlorophyll, carotenoids, lipids, and proteins were significantly lower under salinity. Total soluble sugars, sucrose and glucose concentrations were higher in salt-treated than in control cotyledons. Ion concentration showed a different distribution pattern. Na + and Cl - concentrations were higher under salinity, while an inverse result was observed for K + concentration. Proline and glycinebetaine concentrations increased under salinity, but the increase was higher in the former than the latter. The osmoprotective role of proline, glycinebetaine, and soluble sugars is discussed. © Springer Science + Business Media B.V. 2009.

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