Soil Temperature and Climate Change: Implications for Mediterranean Vineyards 

Grapevine (Vitis vinifera) and its derived products, in terms of cultivated area and economic volume, constitute the most relevant fruit crop in the world (7.5 million cultivated hectares). In the current context of climate change, the wine sector faces unprecedented challenges to satisfy a growing demand for wines of greater quality through sustainable viticulture. Global warming threatens quality wine production in Mediterranean wine regions in particular. The increase in heatwaves and drought episodes accelerate the vine phenology and alter the ripening and composition of grapes and wine. Extreme abiotic stress episodes compromise grape production and plant survival, intensifying the pressure on the use of limited resources like water. Abscisic acid (ABA) is an important hormone in the ripening of certain fruits and in plant response to abiotic stress.

This paper follows the one presented by Saayman at the International Symposium on Landscapes of Vines and Wines in the Loire Valley during July 2003. Where Saayman’s paper described the heritage and development of South African vineyard landscapes, this one focuses on how the landscape is used to assist in decision-making concerning the most important long term practices.

To our knowledge all the studies about laccase kinetics and its inhibition have been performed with substrates and conditions very different from those of real grape juice. Moreover, none of these researches really measure enzymatic browning, since they have not taken into account what happens after the oxidation of o-diphenols in o-diquinones and their subsequent polymerization to form melanins1. For that reason, the aim of this research was to develop a new model to measure the kinetics of browning caused by Botrytis cinerea laccase under conditions much closer to those of grape juice and using the substrates naturally present in it.

Saccharomyces cerevisiae, as the workhorse of alcoholic fermentation, is a major actor of winemaking. In this context, this yeast species uses alcoholic fermentation to convert sugars from the grape must into ethanol and CO2 with an outstanding efficiency: it reaches on average 92% of the maximum theoretical yield of conversion. Moreover, S. cerevisiae is also known for its great genetic diversity and plasticity that is directly related to its living environment, natural or technological and therefore to domestication. This leads to a great phenotypic diversity of metabolites production.

Vitis vinifera L. derivatives are susceptible to contamination by biological agents (e.g., bacteria, viruses, fungi), and chemical agents (e.g., heavy metals, persistent organic pollutants).