Inhibition of Oenococcus oeni during alcoholic fermentation by a selected Lactiplantibacillus plantarum strain

Dans les Charentes, en réponse à une crise de production du vignoble destiné à la production de Cognac, un plan de diversification viticole pour des vins de pays de qualité est mis en place. Il nécessite une connaissance des sols et de leurs caractéristiques viticoles pour orienter le choix des types de vins et adapter l’itinéraire technique de production.

Une étude de la physiologie de la vigne (cv. Merlot) et de la qualité des vins a été réalisée au Tessin de 2006 à 2008. La méthodologie utilisée pour cette étude intégrait tous les paramètres qui définissent les terroirs: facteurs naturels (géologie, pédologie et climat), facteurs physiologiques de la vigne et qualité des vins qui sont les révélateurs de la valeur d’un terroir.

Aims: This work aimed i) to calibrate the accuracy of estimating vineyard water status by crop water stress index (CWSI) compared to stem water potential; ii) to determine the time interval during the day that best correlates to stem water potential and iii) to understand the its usefulness.

Aljarafe Alto est une petite zone naturelle dans le département de Séville (Espagne), où le cépage autochtone cultivé est le Palomino Garrido Fino.

In wine growing regions around the world, climate change has the potential to affect vine transpiration and overall vineyard water use due to related changes in atmospheric demand and soil water deficits. Grapevines control their transpiration in response to a changing environment by regulating conductance of water through the soil-plant-atmosphere continuum. Most vineyard water use models currently estimate vine transpiration by applying generic crop coefficients to estimates of reference evapotranspiration, but this does not account for changes in vine conductance associated with water stress, nor differences thought to exist between varieties. The response of bulk stomatal conductance to daily weather variability and seasonal drought stress was studied on Cabernet-Sauvignon, Merlot, Tempranillo, Ugni blanc, and Semillon vines in a non-irrigated vineyard in Bordeaux France. Whole vine sap flow, temperature and humidity in the vine canopy, and net radiation absorbed by the vine canopy were measured on 15-minute intervals from early July through mid-September 2020, together with periodic measurement of leaf area, canopy porosity, and predawn leaf water potential. From this data, bulk stomatal conductance was calculated on 15-minute intervals, and multiple regression analysis was performed to identify key variables and their relative effect on conductance. Attention was focused on addressing multicollinearity and time-dependency in the explanatory variables and developing regression models that were readily interpretable. Variability of vapor pressure deficit over the day, and predawn water potential over the season explained much of the variability in conductance, with relative differences in response coefficients observed across the five varieties. By characterizing this conductance response, the dynamics of vine transpiration can be better parameterized in vineyard water use modeling of current and future climate scenarios.