Macrowine 2021
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


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.


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.


Publication date: September 2, 2021

Issue: Macrowine 2021

Type: Article


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


grape berry ripening, microelectrode, voltage, mesocarp


Related articles…

Physiological and growth reaction of Shiraz/101-14 Mgt to row orientation and soil water status

Advanced knowledge on grapevine row orientation is required to improve establishment, management and outcomes of vineyards on terroirs with different environmental conditions (climate, soil, topography) and in view of a future change to more extreme climatic conditions. The purpose of this study was to determine the combined effect of row orientation, plant water status and ripeness level on the physiological and viticultural reaction of Shiraz/101-14 Mgt.

Effects of mechanical leafing and deficit irrigation on Cabernet Sauvignon grown in warm climate of California

San Joaquin Valley accounts for 40% of wine grape acreage and produces 70% of wine grape in California. Fruit quality is one of most important factors which impact the economical sustainability of farming wine grapes in this region. Due to the recent drought and expected labor cost increase, the wine industry is thrilled to understand how to improve fruit quality while maintaining the yield with less water and labor input. The present study aims to study the interactive effects of mechanical leafing and deficit irrigation on yield and berry compositions of Cabernet Sauvignon grown in warm climate of California.

The effects of cane girdling on berry texture properties and the concentration of some aroma compounds in three table grape cultivars

The marketability of the table grapes is highly influenced by the consumer demand; therefore the market value of the table grapes is mainly characterized by its berry size, colour, taste and texture. Girdling could cause accumulation of several components in plants above the ringing of the phloem including clusters and resulting improved maturity. The aim of the experiments was to examine the effect of girdling on berry texture characteristics and aroma concentration.

Application of a fluorescence-based method to evaluate the ripening process and quality of Pinot Blanc grape

The chemical composition of grape berries at harvest is one of the most important factors that should be considered to produce high quality wines. Among the different chemical classes which characterize the grape juice, the polyphenolic compound, such as flavonoids, contribute to the final taste and color of wines. Recently, an innovative non-destructive method, based on chlorophyll fluorescence, was developed to estimate the phenolic maturity of red grape varieties through the evaluation of anthocyanins accumulated in the berry skin. To date, only few data are available about the application of this method on white grape varieties.

Different yield regulation strategies in semi-minimal-pruned hedge (SMPH) and impact on bunch architecture

Yields in the novel viticulture training system Semi-Minimal-Pruned Hedge (SMPH) are generally higher compared to the traditional Vertical Shoot Positioning (VSP). Excessive yields have a negative impact on the vine and wine quality, which can result in substantial losses in yield in subsequent vintages (alternate bearing) or penalties in fruit quality. Therefore yield regulation is essential. The bunch architecture in SMPH differs from VSP. Generally there is a higher amount but smaller bunches with lower single berry weights in SMPH compared to VSP.