Identification of the trans isomers of abscisic acid and of abscisyl-β-D-glucopyranoside in latent buds of the grapevine and their evolution during the post-dormancy phase

The trans isomers(t-ABA and t-ABA-GE) of abscisic acid (ABA) and of abscisyl-β-D-glucopyranoside (ABA-GE) have been identified in the latent buds of Vitis vinifera L.. cv. Merlot, during the post-dormancy phase. During this phase, the amounts of the four forms of ABA in the buds became minimal. The quantities of ABA-GE and of t-ABA-GE, normally present in much greater quantities than free ABA, decreased strongly. This diminution appeared to be directly linked to the increase of water content of the buds. Although potential bud burst can be related to these phenomena, the role of the trans isomers remains obscure

Developmental processes, polyamine composition and content of fruiting cuttings of Vitis vinifera L.: Responses to nitrogen deficiency

Fruiting cuttings of cv. Cabernet Sauvignon exposed to nitrogen (N) deficiency showed alterations of the N and phosphorus content, the number of berries per plant and berry characteristics at maturity. Conjugated and bound polyamines changed in various tissues at different and critical stages of development and responded strongly to N deficiency. At anthesis the conjugated and bound spermidine content in flowers and the N supply were closely and inversely correlated, while conjugated and bound forms of putrescine responded in the opposite way. However, in these organs N deficiency led to a high content of bound spermidine and a marked decrease of conjugated putrescine. At fruit set, N deficiency was associated with a high content of bound diaminopropane in berries. In ripe berries free putrescine and the N supply were inversely correlated.

L'abscissate de β-D-glucopyranose peut-il être une source d'acide abscissique libre in vivo?

Can abscisyl-β-D-glucopyranoside be a source of free abscisic acid in vivo?In grape seeds, the evolution of abscisic acid (ABA) and of its glucose ester abscisyl-ß-D-glucopyranoside (ABA-GE) during treatments for breaking dormancy was investigated. It could be shown that complete disappearance of ABA-GE content from the seeds must essentially be due to the conversion of ABA-GE into free ABA. This phenomenon seems only to take place under the influence of stratification treatments andin the presence of vital embryos. The amounts of free ABA accumulated decrease mainly by diffusion and degradation, thus becoming minimal. The rate of germination appears closely linked with the amount of free ABA in the seeds. When germination takes place, there is no langer any free ABA present in the seeds. Afterwards, from the first developmental stages of the plantlet, free ABA and ABA-GE reappear, particularly in the cotyledons, where both forms are probably synthesized from a precursor located in these organs

Utilisation de la dialyse et de la chromatographie ultra-rapide pour le dosage de l'acide abscissique: Application à la vigne

Use of dialysis and high pressure liquid chromatography for determination of abscisic acid:Application to grapevineA method for ABA extraction using dialysis together with high pressure liquid chromatography (with a short reverse phase column, C18 - 3 μm) obviously improves the conditions of ABA and ABA-GE analysis in different organs of vine. The most obvious improvement is the reduction of chromatographic run time to 3 min without any loss of efficiency. Besides saving time, reproducibility of results shows that the proposed method is really suitable for routine analysis

An Efficient OpenMP Loop Scheduler for Irregular Applications on Large-Scale NUMA Machines

International audienceNowadays shared memory HPC platforms expose a large number of cores organized in a hierarchical way. Parallel application programmers strug- gle to express more and more fine-grain parallelism and to ensure locality on such NUMA platforms. Independent loops stand as a natural source of paral- lelism. Parallel environments like OpenMP provide ways of parallelizing them efficiently, but the achieved performance is closely related to the choice of pa- rameters like the granularity of work or the loop scheduler. Considering that both can depend on the target computer, the input data and the loop workload, the application programmer most of the time fails at designing both portable and ef- ficient implementations. We propose in this paper a new OpenMP loop scheduler, called adaptive, that dynamically adapts the granularity of work considering the underlying system state. Our scheduler is able to perform dynamic load balancing while taking memory affinity into account on NUMA architectures. Results show that adaptive outperforms state-of-the-art OpenMP loop schedulers on memory- bound irregular applications, while obtaining performance comparable to static on parallel loops with a regular workload

Activities of polyamine oxidases and diaminopropane contents during flowering of Vinis vinifera L.

Research Not

Erratum

Evolution des teneurs en polyamines dans les boutons floraux, les fleurs et les jeunes baies de Vitis villifera L. (cv. Cabernet Sauvignon) atteints d'eutypioseVitis 43 (3), 139-144 (2004

Comparaison de la teneur en amidon, en glucides solubles et en acide abscissique des bourgeons latents et des entre-noeuds au cours du cycle végétatif de la vigne

Au cours du cycle annuel, l'évolution des teneurs des différents sucres solubles et de l'amidon des bourgeons et des entre-noeuds du Merlot noir est comparable. Les teneurs en glucides solubles totaux (GST), généralement plus faibles dans les bourgeons, diminuent de juillet à la mi-octobre avant de s'accumuler intensément jusqu'au mois de décembre pour chuter jusqu'au débourrement. Selon les périodes du cycle, les teneurs en hexoses des bourgeons sont soit plus élevées, soit pratiquement identiques à celles des entrenoeuds. Un phénomène inverse est observé pour le saccharose, sucre soluble le plus abondant pendant presque tout le cycle. L' accumulation du raffinose, comme celle du saccharose, dès le mois d'octobre semble en relation avec la diminution des températures journalières moyennes, ce qui paraît confirmer leur rôte cryoprotecteur face au froid hivernal. Les teneurs en raffinose des bourgeons, moins élevées que celles des entre-noeuds, diminuent ensuite à partir de la mi-novembre alors que celles des entre-noeuds ne diminuent qu'à l'approche du débourrement.Les teneurs en amidon, généralement moins élevées dans les bourgeons, évoluent la plupart du temps à l'inverse des GST. En présence des feuilles, l'ABA (acide abscissique) des bourgeons semble contrôler cette évolution en agissant comme inhibiteur de son accumulation. Peu avant la chute des feuilles et jusqu'a la mi-février, a diminution des teneurs en amidon des bourgeons paraît être favorisée par la diminution des teneurs en ABA certainement par la levée de l'inhibition de la synthese de l'α-amylase. L'ABA semble agir aussi, de juillet au début février, comme inhibiteur de l'accumulation du saccharose. Enfin, à l'approche du débourrement, la diminution des teneurs en ABA laisse apparaître une évolution inverse à celle de l'amidon mais parallèle à celle du saccharose.Comparison of the contents of starch, soluble carbohydrates and abscisic acid of latent buds and internodes during the vegetative cycle of grapevineIn the course of the annual cycle the contents of various soluble sugars and of starch were determined in buds and internodes of cv. Merlot. In general, the total soluble carbohydrate content was lower in buds compared to internodes; it decreased from July to mid-October, increased intensely until December and decreased again until bud burst. The content of hexoses corresponded to this cycle; in buds they were either higher or equal to those of the internodes. Sucrose behaved inversely. Starting in October, the accumulation of raffinose and sucrose was obviously related to the decrease of the daily average temperatures which possibly confirms their role as cryoprotectors in winter. The contents of raffinose in buds which were lower compared to those of internodes decreased after mid-November while in internodes they decreased only at the onset of bud burst. Generally, the starch content was lower in buds compared to internodes, its alterations were inversely related to the total soluble carbohydrates. In the presence of leaves the abscisic acid (ABA) content of buds appeared to affect this development by inhibiting the accumulation of starch. The decrease of the starch content of buds appears to be associated with the decrease of the ABA content; a decreasing ABA content is assumed to suspend the inhibition of the a-amylase synthesis. From July to the onset of February ABA is suggested to inhibit the accumulation of sucrose. Before bud burst decreasing amounts of ABA indicate a development which is inversely related to starch but runs parallel to the development of sucrose

Analyse des polyamines conjuguées aux acides hydroxycinnamiques dans les fleurs de vigne et les baies de raisin

La comparaison des deux cépages Merlot et Cabernet-Sauvignon en plein champ montre que les polyamines conjuguées aux acides hydroxycinnamiques peuvent être considérées comme des marqueurs du début de la floraison et de la croissance du fruit. Des polyamines conjuguées aux acides hydroxycinnamiques sont présentes en grande quantité dans les organes reproducteurs des boutons floraux et des fleurs. Les ovaires renferment essentiellement des polyamines conjuguées insolubles dans l'eau alors que dans les anthères s'accumulent des composés basiques solubles dans l'eau comme principalement le para-coumaryldiaminopropane. Après la floraison, les teneurs en polyamines conjuguées chutent considérablement pour s'accumuler à nouveau dans les jeunes baies, uniquement sous leur forme soluble dans l'eau et liée à l'acide férulique. L'intervention de ces substances dans les mécanismes liés au contrôle de la reproduction chez la vigne est discutée.Hydroxycinnamic acid amines in flowers and berries of Vitis viniferaThe determination of phenolamines in flowers and berries of field-grown Vitis vinifera (cv. Cabernet-Sauvignon and Merlot) shows that these compounds can be considered as valuable markers of the onset of flowering and growth of berries. Hydroxycinnamic acid amines are found in large amounts in the reproductive organs. The ovaries contain neutral phenolamines and the anthers the basic compound para-coumaryldiaminopropane. After flowering, hydroxycinnamic acid amines rapidly and dramatically decreased. In young berries, levels of polyamines increased; they were found to be soluble in water and conjugated with ferulic acid. The possible role of these molecules in processes controlling reproduction of grape is discussed

Evolution de la composition en polyamines des baies de raisin au cours du processus d'infection par Botrytis cinerea

Evolution of polyamine composition in grape berries during infection with Botrytis cinereaPolyamines are growth regulators occurring naturally in grapevine(Vitis vinifera L.) and pathogenic fungi, e.g. Botrytis cinerea. Investigation of polyamines of in vitro-grown Botrytis cinerea mycelium and infected berries has shown modifications in the metabolism of the berries which are directly related to the development of the fungi in the berries. The abnormal polyamine concentrations in infected berries appear to be of fungal origin for free polyamines and of plant origin for conjugated polyamines. The specific role of each type of polyamine is discussed with regard to the host-parasite relation.