Apoplastic pH influences Vitis vinifera Barbera recovery responses to short and prolonged drought 

Merlot grapevine is the second wine cultivar most planted in the world and especially in the Bordeaux wine region. This cultivar has many advantages in producing high quality wine; however, in the last decade, climate change has increased the sugar concentration in berries at harvest and shortened the maturation cycle. If this has been up to now a great opportunity to improve wine quality profile, we are touching the tipping point. High sugar concentration at harvest induces high alcool content in wine which can negatively impact wine quality. There are many viticultural and oenological practices possible to limit this effect. In this study we focus on plant material through intra-varietal diversity of Merlot cultivar.

The mechanization of vineyard work originally led to a reduction in planting densities due to the lack of machinery adapted to the vineyard. The current availability of specific machinery makes it possible to establish higher planting densities. In this work, three planting densities (1.40×0.80 m, 1.80×1 m and 2.20×1.20 m, corresponding to 8928, 5555 and 3787 plants/ha respectively) were studied with four varieties autochthonous of Galicia (northwestern Spain): Albariño and Treixadura (white), Sousón and Mencía (red). The vines were trained in a vertical shoot positioning system using a single Royat cordon, and pruned to spurs with two buds each. Agronomic data (yield, pruning wood weight, Ravaz index) and oenological data in must were collected. The higher planting density (1.40×0.80 m) had no significant effect on grape yield per vine in white varieties, although production per hectare was much higher due to the greater number of plants. In red varieties, this planting density resulted in a significantly lower production per vine, compensated by the greater number of plants. In addition, it significantly reduced the Brix degree in the must of the Albariño, Treixadura and Sousón varieties, and increased the total acidity in the latter two and Mencía. It also caused an increase in extractable and total anthocyanins and IPT in red grapes. The effects of high planting density on grapes are of great interest for the adaptation of varieties in the context of climate change. In the future, it could be advisable to modify the limits imposed by the appellations of origin on the planting density of these varieties in order to obtain more balanced wines.

Un projet multidisciplinaire sur l’effet du sol et du climat sur la qualité du vin a débuté en Afrique du Sud il y a 5 ans. Des mesures sont effectuées sous culture sèche dans des vignes de Sauvignon Blanc dans six localités différentes, cinq dans le district de Stellenbosch et une à Durbanville.

Adapting viticulture to climate change is crucial, as it presents significant challenges for future grape production.

Astringency has been defined by the American Society for Testing Materials as “the complex of sensations due to shrinking, drawing or puckering of the epithelium as a result of exposure to substances such as alums or tannins”. Regarding the importance of astringency in wine consumer acceptance, elucidating the molecular mechanisms underpinning this complex sensation represents an important goal for scientists. Although different mechanisms have been described (Gibbins & Carpenter, 2013), the salivary protein precipitation is still the most accepted theory. According to this, wine astringency perceived in the oral cavity is originally attributed to the interaction and subsequence precipitation of salivary proteins by wine tannins –mainly flavanols–.