Eduardo Luiz Voigt

Universidade Federal do Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil

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Publications (10)12.64 Total impact

  • [show abstract] [hide abstract]
    ABSTRACT: This study assessed the relationships between external K+ supply and K+ : Na+ ratios associated with Na+ toxicity in Jatropha curcas. Plants were exposed to increasing external K+ concentrations (6.25, 12.5, 25, 37.5, and 50 mM), combined with 50 mM NaCl in a nutrient solution. Photosynthesis progressively increased as the external K+ : Na+ ratios increased up to 0.75. The increase of photosynthesis and plant dry matter correlated positively with K+ : Na+ in xylem and leaves. The transport rates of K+ and Na+ from roots to xylem and leaves were inversely correlated. These ions presented an antagonistic pattern of accumulation in all organs. Maximum rates of photosynthesis and plant growth occurred with leaf K+ : Na+ ratios that ranged from 1.0 to 2.0, indicating that this parameter in leaves might be a good indicator for a favorable K+ homeostasis under salinity conditions. The higher K+ affinity and selectivity compared with Na+ in all organs associated with higher xylem flux and transport to shoots are essential for maintaining adequate K+ : Na+ ratios at the whole-plant level. These characteristics, combined with adequate K+ concentrations, allow J. curcas to sustain high rates of photosynthesis and growth even under toxic NaCl levels.
    Journal of Plant Nutrition and Soil Science 04/2013; 176(2). · 1.38 Impact Factor
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    ABSTRACT: This work evaluated the oxidative protection mechanisms triggered by high temperatures in salt-stressed cashew (Anacardium occidentale) plants. In the first experiment, cashew plants in a greenhouse were subjected to a wide range of NaCl concentrations under natural conditions involving high temperatures. In the second experiment, the plants were exposed to 100mM NaCl alone, heat alone (42°C) or a combination of both heat and NaCl. Data analysis from the two experiments revealed that salt-stressed plants were favored by high temperatures in terms of oxidative protection, as indicated by a decrease in lipid peroxidation and H2O2 concentration. The H2O2 concentration and lipid peroxidation results were corroborated in long-term salt exposure in a greenhouse; however, greenhouse plants that were subjected to high salinity exhibited mild protein oxidation. High temperature positively modulated protein content and the activities of catalase (CAT), superoxide dismutase (SOD) and ascorbate peroxidase (APX) in salt-stressed plants, but salinity exerted a negative effect on APX activity. The changes in ascorbate redox state were favorable for cashew protection under high salinity combined with heat. The data demonstrate that high temperature is essential for the oxidative protection of salt-stressed cashew plants, which display an efficient protection mechanism represented by the activities of CAT, SOD and APX as well as favorable changes in the ascorbate redox state under acute salt stress.
    Environmental and Experimental Botany - ENVIRON EXP BOT. 01/2011; 74:162-170.
  • Pesquisa Agropecuaria Brasileira - PAB. 01/2009; 44(4).
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    ABSTRACT: Seedling establishment is a critical process to crop productivity, especially under saline conditions. This work was carried out to investigate the hypothesis that reserve mobilization is coordinated with salt-induced inhibition of seedling growth due to changes in source-sink relations. To test this hypothesis, cashew nuts (Anacardium occidentale) were sown in vermiculite irrigated daily with distilled water (control) or 50mM NaCl and they were evaluated at discrete developmental stages from the seed germination until the whole seedling establishment. The salt treatment coordinately delayed the seedling growth and the cotyledonary reserve mobilization. However, these effects were more pronounced at late seedling establishment than in earlier stages. The storage protein mobilization was affected by salt stress before the lipid and starch breakdown. The globulin fraction represented the most important storage proteins of cashew cotyledons, and its mobilization was markedly delayed by NaCl along the seedling establishment. Free amino acids were mostly retained in the cotyledons of salt-treated seedlings when the mobilization of storage proteins, lipids and starch was strongly delayed. Proline was not considerably accumulated in the cotyledons of cashew seedlings as a response to NaCl salinity. According to these results it is noteworthy that the salt-induced inhibition of seedling growth is narrowly coordinated with the delay of reserve mobilization and the accumulation of hydrolysis products in cotyledons. Also, it was evidenced that free amino acids, especially those related to nitrogen transport, are potential signals involved in the regulation of storage protein hydrolysis during cashew seedling establishment under NaCl salinity.
    Journal of plant physiology 05/2008; 166(1):80-9. · 2.50 Impact Factor
  • Brazilian Journal of Plant Physiology 01/2008; 20(1).
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    ABSTRACT: The work evaluated the role of enzymatic and non-enzymatic antioxidants in cashew (Anacardium occidentale) leaves under 0, 50, 100, 150 and 200 mM NaCl. Salt stress increased protein oxidation and decreased the lipid peroxidation, indicating that lipids are less susceptible to oxidative damage. The superoxide dismutase (SOD) activity was not changed, ascorbate peroxidase (APX) activity steadily decreased while the catalase (CAT) activity strongly increased with the increasing NaCl concentration. High salinity also induced alterations in the ascorbate (AsA) and glutathione (GSH) redox state. The salt resistance in cashew may be associated with maintaining of SOD activity and upregulation of CAT activity in concert with the AsA and GSH antioxidants.
    Biologia Plantarum 56(1). · 1.69 Impact Factor
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    ABSTRACT: Na+ accumulation was investigated in the roots of 11-d-old cowpea [Vigna unguiculata (L.) Walp.] plants. The relative contribution of different membrane transporters on Na+ uptake was estimated by applying Ca2+, K+, NH4 +, and pharmacological inhibitors. Na+ accumulation into the root symplast was decreased by half in the presence of 1 mM Ca2+ and it was almost abolished by 100 mM K+. The inhibitory effect of external NH4+ on Na+ accumulation was more pronounced in the roots of NH4 +-free growing plants. Na+ accumulation was reduced about 73 % by 0.1 mM flufenamate and it was almost blocked by 2 mM quinine. In addition, 20 mM tetraethylammonium and 1.0 mM Cs+ decreased Na+ accumulation by 28 and 30 %, respectively. These results evidenced that low-affinity Na+ uptake by cowpea roots depends on Ca2+-sensitive and Ca2+-insensitive pathways. The Ca2+-sensitive pathway is probably mediated by nonselective cation channels and the Ca2+-insensitive one may involve K+ channels and to a lesser extent NH4 +-sensitive K+ transporters.
    Biologia Plantarum 53(4):764-768. · 1.69 Impact Factor
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    ABSTRACT: The aim of this work was to investigate the balance between the activities of ascorbate peroxidase (APX) and phenol peroxidases (POD) and cowpea root growth in response to dehydration and salt stress. Root growth and indicators of oxidative response were markedly changed in response to salinity and dehydration. Salt treatment strongly inhibited root elongation, which was associated with an increase in lignin content and a significant decrease in the concentrations of apoplastic hydrogen peroxide (H2O2) and ascorbate. In conditions of extreme salinity, cytosol–APX activity was significantly decreased. In contrast, cell-wall POD activity was greatly increased, whereas lipid peroxidation was unchanged. These results indicate that POD could be involved in both H2O2 scavenging and the inhibition of root elongation under high salinity. In contrast, dehydration stimulated primary root elongation and increased lipid peroxidation and apoplastic ascorbate content, but it did not change APX and POD activities or H2O2 concentration. When cowpea roots were subjected to salinity followed by dehydration, the water and pressure potentials were decreased, and lipid peroxidation was markedly increased, highlighting the additive nature of the inhibitory effects caused by salt and dehydration. The proline concentration was markedly increased by dehydration alone, as well as by salt followed by dehydration, suggesting a possible role for proline in osmotic adjustment. Salinity and dehydration induce contrasting responses in the growth and morphology of cowpea roots. These effects are associated with different types of oxidative modulation involving cytosolic-APX and cell-wall POD activities and apoplast H2O2 and ascorbate levels.
    Journal of Plant Growth Regulation 32(2). · 1.99 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: The aim of this work was to investigate the role of the antioxidant enzymes in salt tolerance comparing the salt-sensitive (Pérola) and a salt-tolerant (Pitiúba) cultivar of cowpea [Vigna unguiculata (L.) Walp.]. Salt stress (100 mM NaCl for 8 d) reduced the leaf growth rate more in the sensitive cultivar. The salt-induced decrease in the relative water content, Na+ accumulation and increase in leaf electrolyte leakage was similar in both cultivars. Salt stress induced a higher increase in the activities of superoxide dismutase (SOD), ascorbate peroxidase (APX) and phenol peroxidase (POX) in the tolerant cultivar than in sensitive one.
    Biologia Plantarum 54(1):159-163. · 1.69 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: The work evaluated the role of enzymatic and non-enzymatic antioxidants in cashew (Anacardium occidentale) leaves under 0, 50, 100, 150 and 200 mM NaCl. Salt stress increased protein oxidation and decreased the lipid peroxidation, indicating that lipids are less susceptible to oxidative damage. The superoxide dismutase (SOD) activity was not changed, ascorbate peroxidase (APX) activity steadily decreased while the catalase (CAT) activity strongly increased with the increasing NaCl concentration. High salinity also induced alterations in the ascorbate (AsA) and glutathione (GSH) redox state. The salt resistance in cashew may be associated with maintaining of SOD activity and upregulation of CAT activity in concert with the AsA and GSH antioxidants.
    Biologia Plantarum · 1.69 Impact Factor