 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

Development of a standardized method for metabolite analysis by NMR to assess wine authenticity

The wine sector generates a considerable amount of wealth but is facing a growing problem of fraud. Wine counterfeiting is one of the oldest and most common cases of food fraud worldwide. Therefore, the authenticity and traceability of wine are major concerns for both the industry and consumers. To address these issues, robust and reliable analysis and control methods are necessary. Several methods have been developed, ranging from simple organoleptic tests to more advanced methodologies such as isotopic techniques or residual radioactivity measurements.

NEUROPROTECTIVE AND ANTI-INFLAMMATORY PROPERTIES OF HYDROXYTYROSOL: A PROMISING BIOACTIVE COMPONENT OF WINE

Hydroxytyrosol (HT) is a phenolic compound present in olives, virgin olive oil and wine. HT has attracted great scientific interest due to its biological activities which have been related with the ortho-dihydroxy conformation in the aromatic ring. In white and red wines, HT has been detected at concentrations ranging from 0.28 to 9.6 mg/L and its occurrence has been closely related with yeast metabolism of aromatic amino acids by Ehrlich pathway during alcoholic fermentation. One of the most promising properties of this compound is the neuroprotective activity against pathological mechanisms related with neurode-generative disorders including Alzheimer’s and Parkinson’s disease.

Natural variability and vine-growers behaviour

Le vigneron est confronté à une variabilité naturelle omniprésente, liée au millésime et aux facteurs pédoclimatiques. Depuis 10 ans, en Champagne, la relation qu’entretient le vigneron avec l’espace a évolué. Les exemples d’entreprises collectives à vocation territoriale se sont multipliés : gestion de l’hydraulique viticole, maillages de groupements de conseil viticole (Magister), sites en confusion sexuelle, réseau maturation, analyses de sols par secteur, …

Induction of polyphenols in seedlings of Vitis vinifera cv. Monastrell by the application of elicitors

Contamination problems arising from the use of pesticides in viticulture have raised concerns. One of the alternatives to reduce contamination is the use of elicitors, molecules capable of stimulating the natural defences of plants, promoting the production of phenolic compounds (PC) that offer protection against biotic and abiotic stress. Previous studies on Cabernet-Sauvignon seedlings demonstrated that foliar application of elicitors methyl jasmonate (MeJ) and benzothiadiazole (BTH) increased proteins and PC involved in grapevine defence mechanisms. However, no trials had been conducted on Monastrell seedlings, a major winegrape variety in Spain.

Monferace a new “old style” for Grignolino wine, an autochthonous Italian variety: unity in diversity

Monferace project is born from an idea of 12 winegrowers willing to create a new “old style” Grignolino wine and inspired byancient winemaking techniques of this variety (1). Monferace wine is produced with 100% Grignolino grapes after 40 months of ageing, of which 24 in wooden barrels of different volumes. Grignolino is an autochthonous Italian variety cultivated in Piedmont (north-west Italy), recently indicated as a “nephew” of the famous Nebbiolo (2) and is used to produce three different DOC wines. The Monferace Grignolino is cultivated in the geographical area identified in the Aleramic Monferrato, defined by the Po and Tanaro rivers, in the heart of Piedmont and the produced wine is characterized by a high content of tannins, marked when young, that evolve over the years. Its color is generally slight ruby red and garnet red with orange highlights with ageing.