Leaf necrosis induced by the insecticide carbaryl in Vitis rupestris ‘B38’

Alteration of sap pH is one of the first chemical changes that occurs within the xylem vessels of plants exposed to drought. Xylem sap acidification accompanied by the accumulation of soluble sugars has been recently documented in several species (Sharp and Davis, 2009; Secchi and Zwieniecki, 2016). Here, Vitis vinifera plants of the anysohydric cultivar Barbera were exposed to either short (no irrigation; SD) or to prolonged drought (continual reduction of 10% water; PD). When comparable severe stress was reached, the potted grapes were re-watered. SD was characterized by fast (2–3 days) stomatal closure and high abscisic acid (ABA) accumulation in xylem sap (>400 μg L−1) and in leaf. In PD plants, the rise in ABA levels was considerably diminished.

The objective this work has been study the possibility of partially or completely replacing sulphur in the winemaking of white wines through the use of the prefermentative saturation of musts with CO2.

Le manque de connaissances concernant la physiologie de la maturation du raisin a longtemps interdit d’interpréter l’effet du terroir ou du millésime sur la qualité des vendanges en termes moléculaires. L’hypothèse selon laquelle c’est la perméabilité membranaire qui contrôlerait le sens comme l’intensité du stockage des acides est pourtant déjà ancienne (1). L’étude du transport des acides organiques et de son coût énergétique permet d’avancer certaines hypothèses concemant les sites potentiels de la régulation du contenu en sucres et acides du raisin sous l’effet de paramètres environnementaux.

Grapevine physiology and production are challenged by forecasted increases in temperature and water deficits. Within this scenario, photoselective overhead shade films are promising tools in warm viticulture areas to overcome climate change related factors. The aim of this study was to evaluate the vulnerability of ‘Cabernet Sauvignon’ grape berry to solar radiation overexposure and optimize shade film use for berry integrity. A randomized complete block design field study was conducted across two years (2020-2021) in Oakville, Napa Valley, CA, with four shade films (D1, D3, D4, D5) differing in the percent of radiation spectra transmitted and compared to an uncovered control (C0). Integrals for gas exchange parameters and mid-day stem water potential were unaffected by the shade films in 2020 and 2021. By harvest, berries from uncovered and shaded vines did not differ in their size or primary metabolism in either year. Despite precipitation exclusion during the dormant season in the shaded treatments, yield did not differ between them and the control in either season. In 2020, total skin anthocyanins (mg/g fresh mass) in the shaded treatments was greater than C0 during berry ripening and at harvest. Conversely, flavonol concentrations in 2020 were reduced in shaded vines compared to C0. The 2020 growing season highlighted the impact of heat degradation on flavonoids. Flavonoid concentrations in 2021 increased until harvest while flavonoid degradation was apparent from veraison to harvest in 2020 across shaded and control vines. Wine analyses highlighted the importance of light spectra to modify wine composition. Wine color intensity, tonality and anthocyanin values were enhanced in D4 whereas antioxidant properties were enhanced in C0 and D5 wines. Altogether, our results highlighted the need of new approaches in warm viticulture areas given the impact that composition of light has on berry and wine quality.

No other agricultural product has a stronger relationship with the soil than wine. This study aimed to characterize the sensory profile of red wines from the Douro Demarcated Region (RDD) certified as DOC Douro, through the application of Quantitative Descriptive Analysis (QDA®) and Temporal Dominance of Sensations (TDS) sensory methods. QDA® provides a complete word description for all a product’s sensory properties. The TDS, which is relatively recent in the sensory field [1], allows to evaluation and description of the evolution of the dominant sensory perceptions during the tasting of a food product.Eighteen commercial wines from different producers were evaluated, six different samples representing each of the three sub-regions of the RDD.