Nutrients and heavy metals in a vineyard soil under organic, biodynamic and conventional management

The analysis of the distribution of natural plant populations allows an ecological characterization of cultivated environments in thermal, water and trophic terms; it guides the choice or selection of plants (or grape varieties) to cultivate (Astruc et al ., 1984, 1987; Delpoux, 1971; Jacquinet and Astruc, 1979). This approach has given good results in areas where the topography is the determining factor in the ecological differentiation of the terroirs.

Grape skin has a barrier and protective function in grapes. Cell wall of grape skins is mainly composed of polysaccharides such as pectins, celulloses and hemicelluloses and structural proteins. Terroir, variety and changes during ripening can affect the content of polysaccharides in grapes. The aim of this study was to evaluate the content of polysaccharides (PS) in grapes along the ripening process. Three red grape varieties were studied: Garnacha (G), Tempranillo (T) and Prieto Picudo (PP).

The gustatory balance of wines relies on sweetness, bitterness and sourness. In dry wines, sweetness does not result from the presence of residual sugar as in sweet wines, but is due to other non-volatile compounds. Such taste-active compounds are released during winemaking, by grapes, yeasts or oak wood and belong numerous chemical families [1]. Beyond this diversity, stereochemistry of molecules can also influence their sensory properties [2]. However, the molecular determinants associated with this taste have only been partially elucidated. Astilbin (2R, 3R) was recently reported to contribute to wine sweetness [3]. As its aglycon contains two stereogenic centers, three other stereoisomers may be present: neoisoastilbin (2S, 3R), isoastilbin (2R, 3S), and neoastilbin (2S, 3S). These compounds have already been observed in natural products, but never in wine. This work aimed at assaying their presence for the first time in wines as well as their taste properties.The isomers were synthesized from astilbin and purified by semi-preparative HPLC.

The crossings of three wild Vitis species are commonly used as rootstocks in wine production worldwide. Factors such as disease resistance and vigor are most important for their selection.
With climate change extending drought conditions and water limitations, the selection of rootstocks conferring increased tolerance to drought takes on greater importance. Therefore, identifying Vitis species with improved drought tolerance and incorporating them into breeding programs could contribute to more resilient rootstocks under water limiting conditions. Furthermore, those species serve as a valuable resource to increase genetic variability of rootstocks. We hypothesize that species native to drier habitats will exhibit superior physiological performance under drought stress.

One cultivar could produce distinct wines with typical properties and qualities different depending on its cultivated and its mesoclimatic conditions.