 IVES 9 IVES Conference Series 9 Macrowine 9 Macrowine 2021 9 Grapevine diversity and viticultural practices for sustainable grape growing 9 Measurement of trans-membrane and trans-tissue voltages in the Shiraz berry mesocarp

Measurement of trans-membrane and trans-tissue voltages in the Shiraz berry mesocarp

Abstract

AIM: In mid to late ripening, sugar and potassium (K+) accumulation into the berry slows and is eventually completed1. K+ is the most abundant cation in the berry, undertaking important physiological roles. During late ripening, Shiraz mesocarp cells die within the central region of the berry. The cessation of K+ import may be a contributing factor to this loss in cell vitality. Many K+ trans-membrane transporters and channels are regulated by the membrane voltage (Vm). We thus measured trans-membrane voltage (Vm) and trans-tissue voltages (Vt) in the mesocarp during Shiraz berry development.

METHODS: Vm measurement Shiraz berries, grown in Coombe vineyard at the University of Adelaide, were sampled weekly from the completion of véraison to the late-ripening stage. To assess Vm, the microelectrode was inserted through the berry skin and into mesocarp. During injection, voltage signals and the corresponding depths of the micropipette tip were recorded. Vt measurement The Vt was measured by a similar method described above without micropipette injection. A small piece of skin was removed, allowing the measurement of Vt from the pedicel to the mesocarp surface. Living berries and dead berries from véraison and late-ripening stage were used. Dead berries were measured after freezing overnight followed by thawing.

RESULTS: Vm The voltages became less negative with increasing tissue depth. This may be attributed to the more severe hypoxia within deeper regions of the berry2. Voltage responses were detected in both living berries and dead berries in the late-ripening stage, with similar profiles. This indicates that other structures or factors contributed to the voltage detected by this method. Vt In living berries, the Vt values were more negative in véraison berries than those in late-ripening berries. This trend was not observed in dead berries. There was no significant difference between the Vt values measured from living berries and dead berries in late-ripening stage.

CONCLUSIONS

The uneven distribution of the Vm between berry compartments may be correlated with oxygen concentration, which could impact on K+ transport within berries. The declined Vm and Vt in the late ripening berries could be associated with the cessation of K+ import into berries.

DOI:

Publication date: September 2, 2021

Issue: Macrowine 2021

Type: Article

Authors

Yin Liu

National Wine and Grape Industry Centre, Charles Sturt University, Wagga Wagga, NSW 2678, Australia,Suzy ROGIERS (New South Wales Department of Primary Industries, Wagga Wagga, NSW 2678, Australia) Leigh SCHMIDTKE (National Wine and Grape Industry Centre, Charles Sturt University, Wagga Wagga, NSW 2678, Australia) Stephen TYERMAN (School of Agriculture, Food and Wine, The University of Adelaide, PMB1, Glen Osmond, SA 5064, Australia)

Contact the author

Keywords

grape berry ripening, microelectrode, voltage, mesocarp

Citation

Terroir analysis and its complexity

Terroir is not only a geographical site, but it is a more complex concept able to express the “collective knowledge of the interactions” between the environment and the vines mediated through human action and “providing distinctive characteristics” to the final product (OIV 2010). It is often treated and accepted as a “black box”, in which the relationships between wine and its origin have not been clearly explained. Nevertheless, it is well known that terroir expression is strongly dependent on the physical environment, and in particular on the interaction between soil-plant and atmosphere system, which influences the grapevine responses, grapes composition and wine quality. The Terroir studying and mapping are based on viticultural zoning procedures, obtained with different levels of know-how, at different spatial and temporal scales, empiricism and complexity in the description of involved bio-physical processes, and integrating or not the multidisciplinary nature of the terroir. The scientific understanding of the mechanisms ruling both the vineyard variability and the quality of grapes is one of the most important scientific focuses of terroir research. In fact, this know-how is crucial for supporting the analysis of climate change impacts on terroir resilience, identifying new promised lands for viticulture, and driving vineyard management toward a target oenological goal. In this contribution, an overview of the last findings in terroir studies and approaches will be shown with special attention to the terroir resilience analysis to climate change, facing the use and abuse of terroir concept and new technology able to support it and identifying the terroir zones.

Application of a low-cost device VIS-NIRs-based for polyphenol monitoring during the vinification process

In red wine production, phenolic maturity is becoming increasingly important. Anthocyanins, flavonoids and total polyphenols content and availability significantly influence the harvest time of wine grapes while, during vinification process, their extraction strongly affects wine body, color and texture

Caractérisation des productions vitivinicoles des terroirs du Barolo (Piemonte, Italie)

Le projet “Caractérisation des productions vitivinicoles du Barolo” est né par la volonté de la Région Piémont de créer une équipe multidisciplinaire de recherche pour l’individuation des différences

Nitrogen requirements of table grape cultivars grown in the san Joaquin valley of California

Ground water in the interior valleys of California is contaminated with nitrates derived from agricultural activities, primarily the over-fertilization of crops.

AROMA AND SENSORY CHARACTERIZATION OF XINOMAVRO RED WINES FROM DIFFERENT GREEK PROTECTED DESIGNATIONS OF ORIGIN, EFFECT OF TERROIR CHARACTERISTICS

The quality of wines has often been associated with their geographical area of production. The aim of this work was to characterize Protected Designation of Origin (PDO) Xinomavro red wines from different geographical areas of Amyndeon and Naoussa in Northern Greece, elaborated with variables that contribute to their differentiation, such as soil characteristics, altitude, monthly average temperature and rainfall.
Xinomavro fruit parcels from different vineyards within the two PDO zones (5 PDO Naoussa and 6 PDO Amyndeon) were vinified following a standard winemaking process. A total of 25 aroma compounds were quantified using gas chromatography-mass spectrometry (GC-MS) with simultaneous full scan and selected ion monitoring for data recording, and odor activity values (OAVs) were determined.