Terroir 2004 banner
IVES 9 IVES Conference Series 9 Sugar loading and phenolic accumulation as affected by ripeness level of Syrah/R99 grapes

Sugar loading and phenolic accumulation as affected by ripeness level of Syrah/R99 grapes

Abstract

[English version below]

Le chargement et l’accumulation des sucres ainsi que la biosynthèse des phénols ont été étudiés sur la Syrah, dans le cadre d’un programme de recherche de paramètres qui permettraient de déterminer une ou plusieurs qualités de raisin en relation avec des styles de vins pour un terroir donné. La relation entre la dynamique d’accumulation des sucres et, en parallèle, la biosynthèse des phénols a été étudiée sur Syrah/99R plantée dans un vignoble situé sur la station expérimentale de ARC Infruitec-Nietvoorbij, Stellenbosch (Afrique du Sud). La cinétique des analyses a été réalisée depuis le stade post floraison (nouaison) jusqu’au stade sur-maturation. Les vignes sont conduites en Espalier (2,75m x 1,5m), les rangs sont orientés nord – sud, le vignoble est en pente orientée est. Une irrigation par micro aspersion est appliquée de la nouaison à la véraison. La hauteur de végétation est de 1,4 m, avec 3 hauteurs de fils de palissage. Les vignes sont ébourgeonnées, palissées et écimées. La dynamique d’accumulation des sucres par baie a été étudiée à l’aide d’un protocole développé par Deloire et al., 2004 (sous presse). La biosynthèse des phénols (tanins totaux et leur degré de polymérisation, proanthocyanidols et anthocyanes) a été étudiée par spectrophotométrie et HPLC pour les anthocyanes. Le sucre est utilisé comme indicateur des relations vigne – baie (relations source – puits).
Les tanins totaux (TT) de la baie sont synthétisés depuis l’anthèse jusqu’à la véraison. Leur concentration augmente durant la croissance herbacée des baies. Elle diminue en concentration de véraison à maturation, alors que durant cette période, la quantité de TT par baie est stable. Quand les sucres sont utilisés comme indicateur physiologique, il ressort clairement que la biosynthèse des anthocyanes évolue, par baie, jusqu’à ce que ces dernières atteignent un contenu en sucre de 20 – 21 °Brix. Après ce point, l’évolution des anthocyanes par baie est indépendante de l’évolution du contenu en sucre par baie, qui se fait alors essentiellement par concentration (perte d’eau de la baie). Le chargement actif des baies en sucre est dépendant de la photosynthèse des feuilles et la régulation du déchargement phloémien du sucre dans les baies semble en partie dépendante du microclimat des grappes et des baies elles mêmes. Le chargement actif en sucre de la baie n’est pas directement corrélé à son volume.

Sugar loading and phenolic accumulation in Syrah grapes were investigated as part of an elaborate study to determine parameters that would indicate high grape quality and different grape and wine styles on a particular terroir. The relationship between the dynamics of sugar loading and phenolic accumulation in the berries of a Syrah/R99 vineyard, situated at the ARC Infruitec-Nietvoorbij , in the Stellenbosch region (South Africa), was investigated from pea size stage (green berry) to late maturity. Vines were vertically trained and spaced 2.75 x 1.5 m in north-south orientated rows on a terroir with Glenrosa soil and a west-facing slope. Microsprinkler-irrigation was applied at pea berry size and at véraison stages. The 1.4 m high canopies were suckered, shoot-positioned and topped and accommodated by means of three sets of double wires. The dynamics of berry sugar loading were studied by a method from Deloire et al, 2004 (under publication), the berry phenolic composition (total tannins and polymerisation, proanthocyanidins, anthocyanins) was analysed by spectrophotometry and anthocyanins by HPLC. Sugar was used as physiological indicator of the plant-berry (source-sink) relationship and as bunch microclimatic indicator.
The total tannin (TT) component in the berry was synthesised from anthesis to véraison. The TT concentration increased during the green berry growth stages and decreased during ripening as the berry increased in volume. The TT per berry also increased during the green berry growth stages, but kept stable during ripening. When sugar content per berry is used as physiological indicator, it is clear that anthocyanin biosynthesis occurred until a specific berry sugar content, i.e. 20 – 21 0Brix, is reached. After this point, anthocyanin evolution per berry seemed independent of berry sugar evolution, which is at that time mainly due to concentration (berry water loss) than to loading. Thus, although berry sugar loading is dependent on photosynthetic activity of the leaves, the regulation of sugar phloem unloading in the berry sink seemed to be, in part, affected by the microclimate that the berry experienced. Berry sugar loading was not directly correlated with berry volume.

DOI:

Publication date: January 10, 2022

Issue: Terroir 2004

Type: Article

Authors

A. Deloire (1), E. Kraeva (1), M. Martin (2) et J.J. Hunter (3)

(1) Agro Montpellier, UMR 1083 « sciences pour l’œnologie et la viticulture », 2 place Viala, 34060 Montpellier cedex 1, France
(2) INRA, Unité expérimentale de Pech Rouge, 11430 Gruissan, France
(3) ARC Infruitec-Nietvoorbij, Private Bag X5026, 7599 Stellenbosch, South Africa

Contact the author

Keywords

Vitis vinifera, bunch, sugar, microclimate, indicator, vine functioning

Tags

IVES Conference Series | Terroir 2004

Citation

Related articles…

Bioclimatic shifts and land use options for Viticulture in Portugal

Land use, plays a relevant role in the climatic system. It endows means for agriculture practices thus contributing to the food supply. Since climate and land are closely intertwined through multiple interface processes, climate change may lead to significant impacts in land use. In this study, 1-km observational gridded datasets are used to assess changes in the Köppen–Geiger and Worldwide Bioclimatic (WBCS)

VINIoT: Precision viticulture service for SMEs based on IoT sensors network

The main innovation in the VINIoT service is the joint use of two technologies that are currently used separately: vineyard monitoring using multispectral imaging and deployed terrain sensors. One part of the system is based on the development of artificial intelligence algorithms that are feed on the images of the multispectral camera and IoT sensors, high-level information on water stress, grape ripening status and the presence of diseases. In order to obtain algorithms to determine the state of ripening of the grapes and avoid losing information due to the diversity of the grape berries, it was decided to work along the first year 2020 at berry scale in the laboratory, during the second year at the cluster scale and on the last year at plot scale. Different varieties of white and red grapes were used; in the case of Galicia we worked with the white grape variety Treixadura and the red variety Mencía. During the 2020 and 2021 campaigns, multispectral images were taken in the visible and infrared range of: 1) sets of 100 grapes classifying them by means of densimetric baths, 2) individual bunches. The images taken with the laboratory analysis of the ripening stage were correlated. Technological maturity, pH, probable degree, malic acid content, tartaric acid content and parameters for assessing phenolic maturity, IPT, anthocyanin content were determined. It has been calculated for each single image the mean value of each spectral band (only taking into account the pixels of interest) and a correlation study of these values with laboratory data has been carried out. These studies are still provisional and it will be necessary to continue with them, jointly with the training of the machine learning algorithms. Processed data will allow to determine the sensitivity of the multispectral images and select bands of interest in maturation.

Anthocyanin profile is differentially affected by high temperature, elevated CO2 and water deficit in Tempranillo (Vitis vinifera L.) clones

Anthocyanin potential of grape berries is an important quality factor in wine production. Anthocyanin concentration and profile differ among varieties but it also depends on the environmental conditions, which are expected to be greatly modified by climate change in the future. These modifications may significantly modify the biochemical composition of berries at harvest, and thus wine typicity. Among the diverse approaches proposed to reduce the potential negative effects that climate change may have on grape quality, genetic diversity among clones can represent a source of potential candidates to select better adapted plant material for future climatic conditions. The effects of individual and combined factors associated to climate change (increase of temperature, rise of air CO2 concentration and water deficit) on the anthocyanin profile of different clones of Tempranillo that differ in the length of their reproductive cycle were studied. The aim was to highlight those clones more adapted to maintain specific Tempranillo typicity in the future. Fruit-bearing cuttings were grown in controlled conditions under two temperatures (ambient temperature versus ambient temperature + 4ºC), two CO2 levels (400 ppm versus 700 ppm) and two water regimes (well-watered versus water deficit), both in combination or independently, in order to simulate future climate change scenarios. Elevated temperature increased anthocyanin acylation, whereas elevated CO2 and water deficit favoured the accumulation of malvidin derivatives, as well as the acylation and tri-hydroxylation level of anthocyanins. Although the changes in anthocyanin profile observed followed a common pattern among clones, such impact of environmental conditions was especially noticeable in one of the most widely distributed Tempranillo clones, the accession RJ43.

Towards adaptation to climate change in Rioja: Quality evaluation of wines obtained from Grenache x Tempranillo selections

The wine sector is of great relevance and tradition in Mediterranean countries, however, it may be most susceptible to climate change. In recent years, wine production is facing changes worldwide, both at environmental as well as commercial levels, due to global warming and the shift in consumers’ preferences. Wine growers and wine makers are in search of solutions that allow to face these new challenges. One of the most promising initiatives in the long term is the introduction of new plant materials, specifically intraspecific hybridizations between premium varieties that may improve traditional germplasm in its adaptation to climate change. These inter-varietal crosses have the potential to generate quality wines, whilst maintaining the regional typicity, and constitute an attractive alternative for the consumer due to their sensory attributes. In this study, we have evaluated wines from 29 intraspecific Garnacha x Tempranillo hybrids in two different locations, with the aim to assess their oenological potential and sensory attributes. Thirteen of the selections were white and 16 were red. Microvinifications were conducted with two or three replications depending on grape availability. Conventional oenological parameters were determined for all wines. The sensory evaluation and hedonic scores were given by five experts. Red selections obtained higher quality scores than white ones. Among the white selections with higher quality scores, GT-41 Varea and GT-159 Varea outstand, due to their high total acidity and high malic acid content. Regarding red selections, GT-57 Varea and GT-57 UR were perceived as higher in quality, highlighted for their moderate alcoholic and high anthocyanin content. Our results indicate that intraspecific hybridization may be a powerful tool for adapting traditional cultivars to climate change in Rioja.

Legacy of land-cover changes on soil erosion and microbiology in Burgundian vineyards

Soils in vineyards are recognized as complex agrosystems whose characteristics reflect complex interactions between natural factors (lithology, climate, slope, biodiversity) and human activities. To date, most of the unknown lies in an incomplete understanding of soil ecosystems, and specifically in the microbial biodiversity even though soil microbiota is involved in many key functions, such as nutrient cycling and carbon sequestration. Soil biological properties are indicative of soil quality. Therefore, understanding how soil communities are related to soil ecosystem functioning is becoming an essential issue for soil strategy conservation. Here, we propose to assess the importance of land-cover history on the present-day microbiological and physico-chemical properties. The studied area was selected in the Burgundian vineyards (Pernand-Vergelesses, Burgundy, France) where land occupation has been reconstructed over the last 40 years. Soil samples were collected in five areas reflecting various land cover history (forest, vineyards, shifting from forest to vineyards). For each area, physico-chemical parameters (pH, C, N, P, grain size) were measured and DNA was extracted to characterize the abundance and diversity of microbial communities. The obtained results show significant differences in the five areas suggesting that present-day microbial molecular biomass and bacterial taxonomic is partly inherited from past land occupation. Over longer period of time, such study of land-uses legacies may help to better assess ecosystem recovery and the impact of management practices for a better soil quality and vineyards sustainability.