246 research outputs found
Impact of organic and inorganic fertilizers on tomato vigor, yield and fruit composition under tropical andosol soil conditions
Introduction. Little is known about the impact of organic manure on andosol. Materials and methods. Two varieties of Solanum lycopersicum L. (cvs. âRio grandeâ and âRossol VFNâ) were grown under tropical andosol. The soil was silty, acidic and very poor in Bray P (3 mg·kgâ1) with a strong imbalance in the (Ca:Mg:K) ratio of (74.0:25.0:0.7). Five fertilization treatments were used: (i) control with no fertilizer, (ii) minerals, with a (Ca:Mg:K) ratio of (76:18:6) and 75 mg P·kgâ1 of soil; (iii) poultry manure with a (Ca:Mg:K) ratio of (68:24:7) and 450 mg P·kgâ1 of soil; (iv) a combination of (ii) and (iii), and (v) mineral fertilization as applied by local farmers, with a (Ca:Mg:K) ratio of (73:25:1) and 54 mg P·kgâ1 of soil. Results. All cation-balanced treatments (organic, mineral or a combination of both) significantly improved plant growth, the number of trusses and fruits per plant, the marketable fruit yield and fruit P, K, Ca and Na contents of both tomato varieties considered. The âRio grandeâ variety was the most productive (32â44 t·haâ1) compared with the âRossolâ variety (20â22 t·haâ1). There was no major difference between the organic fertilizer and the cation-balanced mineral fertilizer. There was no effect of mineral fertilizer with an unbalanced cation composition on tomato plant growth and production as compared with unfertilized control. Conclusion. In tropical andosol poor in potassium and phosphorous and with excess of Mg, application of poultry manure in adequate dosage and at the right time is capable of sustaining tomato fruit production, as well as the application of calculated inorganic fertilizer
Le lagon de Mururoa (archipel des Tuamotu) : esquisse des caractéristiques hydrologiques et des échanges avec l'océan
Sampling in horse racing: first and crucial stage
When antidoping control detects a prohibited substance in specimens collected of a horse at the
end of a race, the consequences are serious both for the horse and for its trainer. It is therefore in
everyoneâs interest to collect the samples in strict compliance with the rules of good practice. The
general conditions of sample collection, packaging and shipping are specified.Dans le cadre du contrĂŽle
antidopage, lorsqu'une substance prohibée est mise en évidence dans les prélÚvements d'un
cheval contrÎlé à l'issue d'une course, les conséquences sont importantes, tant pour le
cheval que pour son entraĂźneur. Il convient donc, dans l'intĂ©rĂȘt de tous, que le prĂ©lĂšvement
soit effectué avec la plus grande rigueur, selon des rÚgles de bonne pratique. Les
dispositions générales qui régissent sa réalisation, les modalités d'exécution, de
conditionnement et d'envoi sont précisées
The mitochondrial elongation factor LeEF-Tsmt is regulated during tomato fruit ripening and upon wounding and ethylene treatment
A gene encoding an elongation factor LeEF-Tsmt that participates in the protein synthesis process in mitochondria shows strong expression
in ripening fruit as compared to other organs. It is strongly up-regulated during the first stages of the ripening process in parallel with
the climacteric rise in respiration. LeEF-Tsmt expression is stimulated by ethylene, wounding and high temperature but ethylene-insensitive
mutants exhibit normal expression. Transgenic fruit have been generated in which LeEF-Tsmt has been constitutively up- and down-regulated.
Surprisingly, altering the expression of the gene by genetic transformation with antisense and sense LeEF-Tsmt constructs did not affect the
pattern of respiration and ethylene production during ripening and upon wounding. In addition, expression of the alternative oxidase gene
which is known to play an important role in respiratory climacteric was not affected. Possible reasons for the absence of effect on respiration
of variations of LeEF-Tsmt gene expression are discussed
Involvement of a single periplasmic hydrogenase for both hydrogen uptake and production in some Desulfovibrio species
Au cours de cette étude, nous avons montré que plusieurs bactéries sulfato-réductrices possédant un nombre différent de gÚnes codant pour des hydrogénases, oxydent le lactate en absence de sulfate lorsqu'elles sont en coculture avec #Methanospirillum hungatei. L'efficacité du transfert d'hydrogÚne avec la bactérie méthanogÚne n'est pas corrélée avec le nombre de gÚnes codant pour l'hydrogénase chez ces bactéries sulfato-réductrices. #Desulfovibrio vulgaris Groningen, qui possÚde uniquement le gÚne de l'hydrogénase à nickel-fer (hydrogénase [NiFe]), oxyde l'hydrogÚne en présence de sulfate et produit de l'hydrogÚne au cours de la fermentation du pyruvate. L'hydrogénase de #D. vulgaris Groningen a été purifiée et caractérisée. Son poids moléculaire est de 87 kDA et elle est constituée de deux sous-unités différentes (60 et 28 kDa). L'hydrogénase de cette bactérie contient 10,6 atomes de fer, 0,9 atome de nickel et 12 atomes de soufre par molécule et son spectre d'absorption est caractéristique d'une protéine à centre fer-soufre. Les activités catalytiques de consommation et production d'hydrogÚne sont de 332 et 230 unités/mg de protéine, respectivement. Les cellules de #D. vulgarie Groningen contiennent exclusivement l'hydrogénase [NiFe] quelles que soient les conditions de croissance, ainsi que l'ont montré des études biochimiques et immunologiques. L'immunocytolocalisation de cryosections ultrafines de cellules ayant poussé sur différents milieux indique que l'hydrogénase [NiFe] est localisée dans l'espace périplasmique, le marquage étant plus important sur les cellules cultivées sur H2 et sulfate ou pyruvate seul que sur celles cultivées sur lactate et sulfate. Les résultats nous permettent de conclure que #D. vulgaris Groningen contient une seule hydrogénase de type [NiFe] située dans l'espace périplasmique tel que cela a été décrit chez #D. gigas. (Résumé d'auteur
Contribution à l'étude de la sélectivité de l'absorption des macro-éléments par le sorgho (Sorghum dochna F.)
La sĂ©lectivitĂ© de l'adsorption racinaire du sorgho pour les macro-Ă©lĂ©ments a Ă©tĂ© Ă©tudiĂ©e en substituant chaque macro-Ă©lĂ©ment indispensable (chlore ou sodium) dans les solutions nutritives. L'estimation des phĂ©nomĂšnes de complexation et d'interactions entre espĂšces aqueuses dans une solution nutritive a permis une approche Ă©nergĂ©tique de la disponibilitĂ© des Ă©lĂ©ments nutritifs pour l'absorption. Le risque de prĂ©cipitation minĂ©rale peut ĂȘtre prĂ©vu. La prise en compte des activitĂ©s des ions et un mode de reprĂ©sentation faisant intervenir les proportions dans le milieu nutritif et dans la plante ont permis de caractĂ©riser les aspects suivants de la sĂ©lectivitĂ© : il existe une forte absorption prĂ©fĂ©rentielle des macro-Ă©lĂ©ments indispensables par rapport aux Ă©lĂ©ments non indispensables ; pour de faibles concentrations en Ă©lĂ©ments dans la solution nutritive, lâefficacitĂ© relative de l'absorption privilĂ©gie le potassium par rapport au magnĂ©sium et au calcium pour les cations et les phosphates par rapport aux nitrates et aux sulfates pour les anions ; pour des concentrations plus favorables Ă la nutrition et dans un large domaine de variation, la sĂ©lectivitĂ© se caractĂ©rise par une rĂ©gulation de l'absorption, tendant Ă maintenir constantes les proportions en Ă©lĂ©ments. Il a Ă©tĂ© montrĂ© que le mĂ©canisme de rĂ©gulation est diffĂ©rent pour les cations et pour les anion
Role of ethylene on various ripening pathways and on the development of sensory quality of Charentais cantaloupe melons
Charentais melons (Cucumis melo L., var cantalupensis Naud.) in which ethylene biosynthesis has been suppressed by an antisense ACC oxidase gene have been used to better understand the role of ethylene in the regulation of the ripening process of climacteric fruit and on the development of sensory qualities. We have shown that a number of biochemical and molecular processes associated with the ripening of climacteric fruit are ethylene-independent. In some cases, such as softening of the flesh, the same pathway comprises both ethylene-dependent and -independent components. The various ethylene-dependent events exhibit differential sensitivity to ethylene. The threshold level for degreening of the rind is 1 ppm, while 2.5 ppm are required to trigger the ethylene-dependent component of the softening process. The saturating level of ethylene for all these events is less than 5 ppm, which is by far lower than the internal ethylene concentrations found in the fruit at the climacteric peak (around 100 ppm). Detachment of the fruit influences the development of respiratory climacteric. Fruit remaining attached to the vine, although producing higher levels of ethylene, exhibit a reduced climacteric rise in respiration as compared to detached fruit. The response of antisense ACO fruit to exogenous ethylene in terms of respiration is higher in detached than in attached fruit. Ethylene-suppressed melons show a severe reduction of aroma volatiles production, particularly in ester production. In the biosynthetic pathway of aliphatic esters, the dehydrogenation of fatty acids and aldehydes appears to be ethylene-dependent. In contrast, alcohol acetylation comprises ethylene-dependent and ethylene-independent components, probably corresponding to differentially regulated alcohol acetyl transferases. In terms of sensory quality, these data show that the extension of shelf-life through the inhibition of ethylene production has some beneficial effects on texture and sugar accumulation but is detrimental for the generation of aroma
TdERF1, an ethylene response factor associated with dehydration responses in durum wheat (Triticum turgidum L. subsp. durum)
Water deficit and increasing salinization reduce productivity of wheat, the leading crop for human diet. While the complete genome sequence of this crop has not been deciphered, a BAC library screening allowed the isolation of TdERF1, the first ethylene response factor gene from durum wheat. This gene is putatively involved in mediating salt stress tolerance and its characterization provides clues towards understanding the mechanisms underlyning the adaptation/tolerance of durum wheat to suboptimal growth conditions. TdERF1 expression is differentially induced by high salt treatment in two durum wheat varieties, the salt-tolerant Grecale (GR) and the salt-sensitive Om Rabiaa (OR). To further extend these findings, we show here that the expression of this ERF is correlated with physiological parameters, such as the accumulation of osmo-regulators and membrane integrity, that discriminate between the two contrasted wheat genotypes. The data confirm that GR and OR are two contrasted wheat genotypes with regard to salt-stress and show that TdERF1 is also induced by water stress with an expression pattern clearly discriminating between the twogenotypes. These findings suggest that TdERF1 might be involved in responses to salt and water stress providing a potential genetic marker discriminating between tolerant and sensitive wheat varieties
Ethylene Response Factor Sl-ERF.B.3 Is Responsive to Abiotic Stresses and Mediates Salt and Cold Stress Response Regulation in Tomato
Sl-ERF.B.3 (Solanum lycopersicum ethylene response factor B.3) gene encodes for a tomato transcription factor of the ERF (ethylene responsive factor) family. Our results of real-time RT-PCR showed that Sl-ERF.B.3 is an abiotic stress responsive gene, which is induced by cold, heat, and flooding, but downregulated by salinity and drought. To get more insight into the role of Sl-ERF.B.3 in plant response to separate salinity and cold, a comparative study between wild type and two Sl-ERF.B.3 antisense transgenic tomato lines was achieved. Compared with wild type, Sl-ERF.B.3 antisense transgenic plants exhibited a salt stress dependent growth inhibition. This inhibition was significantly enhanced in shoots but reduced in roots, leading to an increased root to shoot ratio. Furthermore, the cold stress essay clearly revealed that introducing antisense Sl-ERF.B.3 in transgenic tomato plants reduces their cell injury and enhances their tolerance against 14 d of cold stress. All these results suggest that Sl-ERF.B.3 gene is involved in plant response to abiotic stresses and may play a role in the layout of stress symptoms under cold stress and in growth regulation under salinity
Convento franciscano en Orsay
Este es el primer conjunto monåstico completo y totalmente equipado que se construye en Francia desde el siglo XVIII. Desde el punto de vista religioso representa gran interés, ya que significa la posibilidad de adaptarse, tanto en el interior como en el exterior, a las necesidades y exigencias de la Orden, situåndonos siempre en el momento actual constructivo, estético y de comodidades toleradas por la regla
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