Laboratorio Of Fisiologia Vegetal

São Cristóvão, Brazil

Laboratorio Of Fisiologia Vegetal

São Cristóvão, Brazil
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Alet A.I.,IIB INTech | Sanchez D.H.,IIB INTech | Sanchez D.H.,University of California at San Diego | Cuevas J.C.,Laboratorio Of Fisiologia Vegetal | And 10 more authors.
Plant Signaling and Behavior | Year: 2011

Polyamines have been globally associated to plant responses to abiotic stress. Particularly, putrescine has been related to a better response to cold and dehydration stresses. It is known that this polyamine is involved in cold tolerance, since Arabidopsis thaliana plants mutated in the key enzyme responsible for putrescine synthesis (arginine decarboxilase, aDc; ec are more sensitive than the wild type to this stress. Although it is speculated that the overexpression of aDc genes may confer tolerance, this is hampered by pleiotropic effects arising from the constitutive expression of enzymes from the polyamine metabolism. Here, we present our work using A. thaliana transgenic plants harboring the ADC gene from oat under the control of a stress-inducible promoter (pRD29A) instead of a constitutive promoter. The transgenic lines presented in this work were more resistant to both cold and dehydration stresses, associated with a concomitant increment in endogenous putrescine levels under stress. Furthermore, the increment in putrescine upon cold treatment correlates with the induction of known stress-responsive genes, and suggests that putrescine may be directly or indirectly involved in aBa metabolism and gene expression. © 2011 Landes Bioscience.

Bianucci E.,National University of Rio Cuarto | Sobrino-Plata J.,Laboratorio Of Fisiologia Vegetal | Carpena-Ruiz R.O.,Autonomous University of Madrid | Del Carmen Tordable M.,National University of Rio Cuarto | And 3 more authors.
Metallomics | Year: 2012

Cadmium (Cd) is a well known heavy metal considered as one of the most toxic metals on Earth, affecting all viable cells that are exposed even at low concentration. It is introduced to agricultural soils mainly by phosphate fertilizers and causes many toxic symptoms in cells. Phytochelatins (PCs) are non-protein thiols which are involved in oxidative stress protection and are strongly induced by Cd. In this work, we analyzed metal toxicity as well as PCs implication on protection of peanut plants exposed to Cd. Results showed that Cd exposure induced a reduction of peanut growth and produced changes in the histological structure with a deposit of unknown material on the epidermal and endodermal cells. When plants were exposed to 10 μM Cd, no modification of chlorophyll, lipid peroxides, carbonyl groups, or hydrogen peroxide (H 2O2) content was observed. At this concentration, peanut leaves and roots glutathione (GSH) content decreased. However, peanut roots were able to synthesize different types of PCs (PC2, PC3, PC4). In conclusion, PC synthesis could prevent metal disturbance on cellular redox balance, avoiding oxidative damage to macromolecules. This journal is © The Royal Society of Chemistry 2012.

Rubio E.J.,Instituto Nacional de Tecnologia Agropecuaria | Montecchia M.S.,University of Buenos Aires | Tosi M.,University of Buenos Aires | Cassan F.D.,Laboratorio Of Fisiologia Vegetal | And 2 more authors.
The Scientific World Journal | Year: 2013

The genetic diversity among 31 putative Azotobacter isolates obtained from agricultural and non-agricultural soils was assessed using rep-PCR genomic fingerprinting and identified to species level by ARDRA and partial 16S rRNA gene sequence analysis. High diversity was found among the isolates, identified as A. chroococcum, A. salinestris, and A. armeniacus. Selected isolates were characterized on the basis of phytohormone biosynthesis, nitrogenase activity, siderophore production, and phosphate solubilization. Indole-3 acetic-acid (IAA), gibberellin (GA and zeatin (Z) biosynthesis, nitrogenase activity, and siderophore production were found in all evaluated strains, with variation among them, but no phosphate solubilization was detected. Phytohormones excreted to the culture medium ranged in the following concentrations: 2.2-18.2 g IAA mL-1, 0.3-0.7 g GAmL-1, and 0.5-1.2 g Z mL-1. Seed inoculations with further selected Azotobacter strains and treatments with their cell-free cultures increased the number of seminal roots and root hairs in wheat seedlings. This latter effect was mimicked by treatments with IAA-pure solutions, but it was not related to bacterial root colonization. Our survey constitutes a first approach to the knowledge of Azotobacter species inhabiting Argentinean soils in three contrasting geographical regions. Moreover, this phenotypic characterization constitutes an important contribution to the selection of Azotobacter strains for biofertilizer formulations. © 2013 Esteban Julián Rubio et al.

Mendes B.S.S.,Laboratorio Of Fisiologia Vegetal | Willadino L.,Federal Rural University of Pernambuco | da Cunha P.C.,Federal Rural University of Pernambuco | Filho R.A.O.,Federal Rural University of Pernambuco | Camara T.R.,Federal Rural University of Pernambuco
Revista Caatinga | Year: 2011

The bromeliads are hardy plants with exotic beauty, appreciated by consumers worldwide. The species Ananas porteanus Hort ex C. Veitch Koch, in particular, shows great potential for floriculture. These plants acclimate easily to adverse environmental conditions like those found in semi-arid areas. To assess the salinity tolerance of A. porteanus there were two treatments, one without the addition of NaCl (control) and the other with 80 mmol L -1 NaCl. The experiment lasted 90 days and were evaluated in the shoot: shoot dry matter, chloride, sodium and potassium contents, Na + / K + rate, proline content, total soluble carbohydrates, total soluble proteins, total phenols, peroxidase activity, levels of chlorophyll "a" and "b" and membrane damage. Plants of A. porteanus treated with sodium chloride were able to maintain the integrity of the membrane at levels similar to those found in control plants and the maintenance of membrane integrity result in part from increased activity of peroxidase. The increase in proline and protein content also appears to be one of the strategies of this species to cope with damage caused by the excess of NaCl as well as the increase in levels of chlorophyll. Soluble carbohydrates are not used to adjust the osmotic potential in plants subjected to 80 mmol L -1 NaCl. The metabolic changes occurring in plants of A. porteanus treated with sodium chloride led to a new homeostasis that resulted in the plant tolerance to salt stress imposed.

Guerrero-Zuniga L.A.,Mexican Institute of Petroleum | Rodriguez-Dorantes A.,Laboratorio Of Fisiologia Vegetal
International Journal of Oil, Gas and Coal Technology | Year: 2010

Since the initiation of the industrial age with its parallel reliance on the utilisation of the hydrocarbon reserves on earth, the biosphere has been increasingly exposed to an ever expanding chemical variety of anthropogenic origin. Phytoremediation is an environmental technology for the cleaning of polluted soils using plants that needs the knowledge about transport and fate of pollutants for the best clean-up strategy, this knowledge consists in understanding the physiological processes inside plants. Some of these biological processes that can contribute to the containment and/or remediation of contaminants and the mechanisms in phytoremediation are described in this manuscript. Copyright © 2010 Inderscience Enterprises Ltd.

Pineda-Mendoza R.M.,National Polytechnic Institute of Mexico | Olvera-Ramirez R.,Laboratorio Of Fisiologia Vegetal | Martinez-Jeronimo F.,National Polytechnic Institute of Mexico
Hidrobiologica | Year: 2012

Cyanobacterial blooms are of great importance because of the toxic effects that these microorganisms are able to induce, particularly on aquatic organisms. Microcystins (MCs) are the principal toxins biosynthesized by cyanobacteria and are powerful inhibitors of the protein phosphatases 1 and 2A. Zooplankton filter feeders such as cladocerans are directly affected by MCs as a result of ingestion of cyanobacteria or contact with intracellular products when cyanobacterial cells break up during and after blooms. A total of 17 strains of filamentous cyanobacteria isolated from three urban lakes in Mexico City were characterized using the microcystin synthetase region mcyA-Cd. Acute 48-h toxicity was evaluated in different strains using the cladoceran Daphnia magna and total microcystin content was determined by enzyme-linked immunosorbent assay (ELISA). The mcyA-Cd region was amplified in 16 microcystin-producing strains; microcystins were detected in eight strains with values ranging from 0.1422 to 2.772 μg L-1. Nevertheless, all aqueous crude extracts induced acute toxicity in D. magna with LC50 values from 363.91 to 741.8 mg L-1 (dry weight). The toxicity observed in non-microcystin-producing strains may be induced by cyclic peptides other than microcystins (anabaenopeptins, microviridins and cyclamides). The results obtained warn of the toxigenic potential of filamentous cyanobacteria, since though Microcystis spp. is frequently predominant in blooms, other toxins and intracellular metabolites released by filamentous cyanobacteria may induce toxicity on aquatic organisms as well as humans.

Cesar F.R.C.F.,Laboratorio Of Fisiologia Vegetal | Matsumoto S.N.,Laboratorio Of Fisiologia Vegetal | Viana A.E.S.,Laboratorio Of Producao E Melhoramento Vegetal | Santos M.A.F.,Laboratorio Of Fisiologia Vegetal | Bonfim J.A.,Brazilian National Council for Scientific and Technological Development
Coffee Science | Year: 2010

The aim of this study was to evaluate the morphophysiological behavior of coffee leaves (Coffea arabica L.) maintained under different levels of artificial shading in initial vegetative phase. The experiment was carried out from January to June/2007, in agricultural field of Universidade Estadual do Sudoeste da Bahia - UESB, Vitó ria da Conquista, Bahia, Brazil. Four trials were carried out maintaining shading conditions (30, 50 and 70% of sun light radiance) and at a full sunlight, during 90 days after plantlet emergence. For each assay, Catuaí (IAC144), Catucaí 2SL and Acauã varieties were evaluated, following a randomized block design, considering number of leaves, leaf area, leaf relative water content, leaf water potential, number of ordinary epidermis and stomata cell and stomata index. Shading levels affect the water status of coffee plants, resulting in alterations of morphophysiology of leaves. Increase of leaf water content occurs simultaneously with decrease of modulus of water potential and proline content, denoting an interaction between shading and water content to coffee plants. Higher proline content was verified in Catuaí leaves in comparison to Catucaí variety. With light restriction there was a reduction of ordinary epidermis cell and stomata density. Upward of leaf area and leaf number was observed when the light restriction was similar or lower to 42,86 and 25,0%, respectively.

Izquierdo N.G.,Laboratorio Of Fisiologia Vegetal | Izquierdo N.G.,CONICET | Aguirrezabal L.A.N.,Laboratorio Of Fisiologia Vegetal | Aguirrezabal L.A.N.,CONICET | And 6 more authors.
Crop and Pasture Science | Year: 2013

We investigated variability in the response of oil fatty acid composition to temperature among high stearic and high stearic-high oleic sunflower (Helianthus annuus L.) genotypes. Two experiments were conducted with high stearic (including the CAS-3 mutation) and high stearic-high oleic inbred lines (including both the CAS-3 and the high oleic Soldatov mutations). Plants were cultivated in pots with soil, irrigated, and fertilised. Plants were exposed to different day/night temperatures during grain filling: 16/16°C, 26/16°C, 26/26°C, and 32/26°C. Oil fatty acid composition was determined by gas-liquid chromatography in seeds harvested after physiological maturity. Higher temperature during grain filling increased palmitic and oleic acid percentages and reduced stearic and linoleic acid percentages, suggesting some modifications on enzymatic activities. When the high oleic mutation was included, the variation in stearic and oleic acid percentages in response to temperature was reduced but not the variation in palmitic acid concentration. Variations in fatty acid composition in high stearic genotypes were mainly associated with night temperature as reported previously for traditional and high oleic hybrids. Knowing the effect of temperature on oil fatty acid composition in traditional and mutated genotypes is useful for selecting the environment in which to produce grains with the desired oil quality. © 2013 CSIRO.

Olvera-Ramirez R.,Laboratorio Of Fisiologia Vegetal | Centeno-Ramos C.,Laboratorio Of Fisiologia Vegetal | Martinez-Jeronimo F.,Laboratorio Of Hidrobiologia Experimental
Hidrobiologica | Year: 2010

Some cyanobacteria can produce toxins that affect the aquatic biota and represent a human health risk. The cyanobacterium Pseudanabaena tenuis was isolated from the Valle de Bravo dam, and cultured in the laboratory under controlled conditions. We determined the acute toxic effects and performed a chronic (consumption) test in the cladocerans Daphnia magna (a reference test organism) and Ceriodaphnia dubia (a cosmopolitan species). To determine acute toxicity, three exposure ways were assayed: a) cell-free culture medium, b) crude cell extracts of the cyanobacterium after lysing, and c) aqueous extracts of P. tenuis phycobiliproteins. On the other hand, both cladocerans were fed P. tenuis, assessing the effects on survival and reproduction. For comparison, a control culture of both cladocerans was fed the green microalga Pseudokirchneriella subcapitata. Exposure to the cell-free culture medium did not produce any mortality in either cladoceran, but the aqueous and crude extracts generated acute toxicity. D. magna and C. dubia were negatively affected when fed P. tenuis, since their survival, total progeny, average number of neonates per clutch, and the number of clutches decreased. C. dubia was more sensitive than D. magna, both in the acute toxicity tests and to the effects of P. tenuis consumption. Although most of the blooms around the world are dominated by cyanobacteria of the genus Microcystis, attention should be given to other species, such as P. tenuis, because, frequently, it is not recognized that smaller cyanobacteria could exceed the larger species in terms of biomass, and produce noxious biological effects.

Gharbi E.,Tunis el Manar University | Martinez J.-P.,Laboratorio Of Fisiologia Vegetal | Benahmed H.,Tunis el Manar University | Fauconnier M.-L.,University of Liège | And 2 more authors.
Physiologia Plantarum | Year: 2016

This study aimed to determine the effects of exogenous application of salicylic acid (SA) on the toxic effects of salt in relation to ethylene and polyamine synthesis, and to correlate these traits with the expression of genes involved in ethylene and polyamine metabolism in two tomato species differing in their sensitivity to salt stress, Solanum lycopersicum cv Ailsa Craig and its wild salt-resistant relative Solanum chilense. In S. chilense, treatment with 125 mM NaCl improved plant growth, increased production of ethylene, endogenous salicylic acid and spermine. The production was related to a modification of expression of genes involved in ethylene and polyamine metabolism. In contrast, salinity decreased plant growth in S. lycopersicum without affecting endogenous ethylene, salicylic or polyamine concentrations. Exogenous application of salicylic acid at 0.01mM enhanced shoot growth in both species and affected ethylene and polyamine production in S. chilense. Concomitant application of NaCl and salicylic acid improved osmotic adjustment, thus suggesting that salt and SA may act in synergy on osmolyte synthesis. However, the beneficial impact of exogenous application of salicylic acid was mitigated by salt stress since NaCl impaired endogenous SA accumulation in the shoot and salicylic acid did not improve plant growth in salt-treated plants. Our results thus revealed that both species respond differently to salinity and that salicylic acid, ethylene and polyamine metabolisms are involved in salt resistance in S. chilense. © 2016 Scandinavian Plant Physiology Society.

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