Influence of water deficits on grape berry growth

The effects of early and late water deficits on pericarp cell division and enlargement of Syrah berries (Vitis vinifera L.) was determined by DNA extraction and quantification. Different periods and different levels of water deficit were applied between anthesis and maturity to grapevines growing under controlled water supply in two consecutive years. DNA extraction profiles showed that water deficit did not affect cell division. Reduction of berry size and berry weight was caused exclusively by a decrease of pericarp volume, independent of the intensity of the water deficit or the stage of berry development. Decreased cell volume as a result of an early water deficit from flowering to veraison was irreversible. These results support the hypothesis that early water deficits modify the structural properties of the cell components and consequently cell wall extensibility, thereby limiting the subsequent enlargement of pericarp cells.

Research Note: Effect of Light Quality on Fruit Growth, Composition and the Sensory Impact of the Wines

The stage at which grapes are harvested has an influence on the aromatic and phenolic composition of the berries and the resulting wines. The aim of this study was to evaluate wines harvested sequentially as outlined in the berry sugar accumulation model. Two vintages and treatments in which the light qualityand quantity were altered at the fruit zone were compared. In 2010/2011, the grapes were harvested at two ripening stages after the sugar loading plateau was reached, namely the “fresh fruit” stage (20-25 days afterwards) and “pre-mature” stage (at approximately 35 days). In the 2011/2012 season, grapes were harvested 45 days after the sugar loading plateau was reached (the “mature fruit” stage). Vegetative aromas were synonymous with the “fresh fruit” stage in 2010/2011, while the 2011/2012 wines from the “mature fruit” harvest date were characterized by raisin, prune and spicy aromas. In both seasons, the control treatments were rated more intense in ‘satin in the mouth’ in and after expectoration. Wines in which the UV-B radiation was excluded during berry growth were rated the highest in the mouthfeel attribute ‘coarseness’ in both treatment seasons. Wines were analyzed chemically for phenolic content using HPLC, and sensorial using descriptive analysis with a trained panel. In the leaf removal treatments,higher acidity content enhanced the perception of astringency in the wine. Wines were analyzed chemically for phenolic content using HPLC and sensorial using descriptive analysis with a trained panel. Overall, the data showed that grape composition was altered by varying light quality, within a season, but seasonalvariation overrode treatment effects. Flavonol concentration in 2011/2012 wine was higher in the exposed leaf removal treatment compared to the other treatments. High light intensities in 2011/2012 season increased anthocyanin concentration in the wine.. This study emphasizes the importance of the quality and quantity of light on the composition and quality of wines, and presents new findings regarding sensory attributes associated with harvesting at different ripening stages.

Influence of water status on mineral composition of berries in ‘Grenache Noir’ (Vitis vinifera L.)

The influence of vine water status on the seasonal changes of fresh weight, dry matter and the levels of potassium and calcium in grape-berries on field vines of 'Grenache Noir' (Vitis vinifera L.), was studied over a two-year period. Two levels of water status, irrigated and non-irrigated, were investigated using a single level of total leaf surface – each primary shoot was confined to ten leaves, one grape bunch, and the secondary shoots were removed as they appeared. The mineral element contents were determined separately in different fruit compartments, i.e. the skin, flesh and seeds. Potassium and calcium accumulate independently of one another, but their seasonal change in the fruit and their final quantities in the berry depend principally on plant water status. The accumulation of potassium parallels the change in fruit fresh weight; approximately 50 % of the final content was accumulated pre-veraison and loading continued during berry ripening. This report shows that a small quantity of calcium may accumulate throughout fruit ripening phases in situations where water supply is not a limiting factor. These results imply that fruit xylem is functioning partially during ripening. Moreover, in both water status situations, the quantity of calcium in the skin increases during ripening, which suggests apoplastic and/or symplastic migration in the berry.

Salicylic acid treatment of grape berries retards ripening

Research Not

Pathogenesis-related proteins in grapevines induced by salicylic acid and Botrytis cinerea

The grapevine pathogenesis-related proteins (PRs) were studied in order to determine the spatial localization and the temporal production of these inducible proteins. We used leaves of plants obtained from woody cuttings grown in greenhouse. Elicitations were done either with salicylic acid or with strains of Botrytis cinerea. Several PRs extractable at pH 2.8 were found to accumulate in grapevine leaves after salicylic acid treatment or Botrytis infection (SDS-PAGE, coomassie blue). Elicitation with salicylic acid has induced one new protein at about 32 kDa. Botrytis infection has resulted in the accumulation of four major acid-soluble proteins with apparent molecular weights of 27, 32, 34 and 38 kDa. Immunodetections using antisera raised against the tobacco PR-2 family have shown several bands, particularly two bands at 34 and 36 kDa revealed by the anti-2a and present both with salicylic acid and Botrytis

Etude histogénétique du greffage herbacé de combinaisons compatibles du genre Vitis

Des greffes herbacées de deux cultivars compatibles du genre Vitis (Carignan et 99 Richter) ont permis de réaLiser une étude histologique détaillée de la zone de greffage.Différents tissus peuvent contribuer à la formation du cal. En général, les rayons interfasciculaires, le parenchyme cortical, les dérivés récents du cambium et les cellules cambiales elles-mêmes prolifèrent et sont à l'origine des tissus néoformés. Les parenchymes associés au xylème et au phloème participent également à l'élaboration du oal. Toutefois, l'importance relative de ces différents tissus dans le processus de régénération dépend largement de la nature des entailles pratiquées au moment du greffage.L'existence de la soudure greffon/porte-greffe résulte de remaniements pariétaux et se fait préférentiellement par l'intermédiare des tissus néoformés.A l'intérieur du oal un cambium se différencie, qui assure la jonction des cambiums du porte-greffe et du greffon. Le développement d'éléments conducteurs spécialisés (vaisseaux et tubes criblés) permet d'établir des échanges plus importants d'eau, d'éléments minéraux et de métabolites.A histogenetic study of green-grafting between two compatible cultivars of VitisGreen-grafting was performed between Vitis berlandieri x V. rupestris 99 Richter (stock) and V. vinifera Carignan (scion). Various tissues from both partners contribute to the formation of the callus. During the development of the union, newly formed tissues originate preferentially from the cortical parenchyma cells and from the cambial initials (including those of the interfascicular rays). The relative importance of the different tissues in the development of the union varies according to the orientation of the cuts. The union between the two partners occurs preferentially at the level of the neoformed tissues and is accomplished through wall alterations and reorganization. A cambium differentiates within callus tissues, which connects the cambia of stock and scion. Newly formed xylem and phloem ensure efficient transport of water, inorganic and organic nutrients

Berry development of grapevines: Relations between the growth of berries and their DNA content indicate cell multiplication and enlargement

DNA of berries (cv. Shiraz) was extracted and quantified to determine, indirectly, the rate of cell division and enlargement in the grape pericarp. The increase of total DNA in the pericarp begins at anthesis in the ovary of grapevine flowers (day 0, 100 % of flowers at full bloom). This increase in DNA continues during the herbaceous growth period until 35 d after anthesis (day 35, 19 d before the onset of veraison). Total DNA per berry pericarp does not increase linearly during this growth period since 75 % of the DNA has already accumulated before day 20. We determined a cell enlargement index (CEI), to estimate the mean cellular volume. The pericarp cell size increases 16-fold during the whole growth of berries. Volume increase is nearly linear from berry set to the beginning of veraison and thereafter until maturity. The importance of determination of cell division and enlargement of berry pericarp based on the DNA content and its possible application in studies on the influence of environmental factors on berry growth is discussed

Effects of Abiotic Factors on Phenolic Compounds in the Grape Berry – A Review

Grape berry phenolic compounds are widely described in literature. Phenolics can be divided into two main groups: flavonoids and non-flavonoids, of which the flavonoids are the most important. The two bestknown groups of flavonoids are the anthocyanins and condensed tannins (also called proanthocyanidins).  Anthocyanins are responsible for the red colour in grapes. The condensed tannins (proanthocyanidins) are responsible for some major wine sensorial properties (astringency, browning, and turbidity) and areinvolved in the wine ageing processes. This review summarises flavonoid synthesis in the grape berry and the impact of environmental factors on the accumulation rate during ripening of each of the flavonoids.  The impact of the accumulated flavonoids in grapes and the resulting impact on the sensorial aspects of the wine are also discussed

Immunodetection of chitinase-like and beta-1,3-glucanase-like proteins secreted in vitro by embryogenic and non-embryogenic cells of grapevines

Research NoteEmbryogenic and non-embryogenic cell lines were obtained from the rootstock 41B (Vitis vinifera cv. Chasselas x V. berlandieri). A few extracellular proteins from culture media of embryogenic and non-embryogenic grapevine cell lines during multiplication showed a positive reaction with anti-chitinase antibodies (embryogenic cell lines) and anti-β-1,3-glucanase antibodies (non-embryogenic cell lines)

Substitution or dilution? Assessing pre-fermentative water implementation to produce lower alcohol Shiraz wines

Changes to regulations by Food Standards Australia New Zealand have permitted the adjustment of must sugar levels with the addition of water in order to ensure a sound fermentation progress as well as mitigating excessive wine-alcohol levels. This study assessed the implications for Shiraz wine quality following a pre-fermentative must dilution (changing liquid-to-solid ratios), in comparison to juice substitution with water (constant liquid-to-solid ratios) that has previously been deemed a promising way to adjust wine-alcohol levels. While working within the legal limit of water addition to grape must, the effects of both approaches on wine quality parameters and sensory characteristics were rather similar, and of negligible nature. However, different implications between substitution and dilution appeared to be driven by grape maturity, and dilution was found to have a greater impact than substitution on some parameters at higher water implementation rates. In line with previous observations, longer hang-time followed by alcohol adjustments via pre-fermentation water addition were of limited merit compared to simply picking grapes earlier. This work provided further knowledge that supports informed decision making regarding the recently permitted approach of using water during winemaking.Olaf J. Schelezki, Alain Deloire and David W. Jeffer