Physiological and histological approaches to study berry shrivel in grapes

Vivian Zufferey,Katia Gindro,Olivier Viret,Jean-Laurent Spring,Francine Voinesco

doi:10.20870/oeno-one.2015.49.2.89

Abstract

Aims: The current work aims to study berry shrivel in grapes (a grape-ripening disorder) in relation to vine water status and climatic conditions using physiological and histological approaches.Methods and results: Measurements of rachis hydraulic conductance on grapevine clusters (Vitis vinifera L.) and observations of the vascular tissues (xylem and phloem) using transmission electron microscopy were conducted on rachises from healthy clusters and clusters having berry shrivel (BS) symptoms during the season. BS intensity was largely dependent on the vine water status: BS was greater in vines without water stress than in vines with moderate to high water stress around veraison time. Preliminary results showed that rachis hydraulic conductance declined sharply after veraison but remained slightly higher in healthy clusters in comparison with clusters presenting BS symptoms. An important degradation of the primary phloem was observed in the rachises of BS clusters, with the appearance of hard, non-functional liber (secondary phloem) and a disorganization of the cell content in the phloem tissue. An alteration of the primary xylem was also observed in the middle of the rachis and in the secondary rachis ramifications.Conclusion: These results suggest that the decrease in sugar and water accumulation in BS berries would primarily be associated with a decline in rachis phloem functionality.Significance and impact of the study: The management of the vine water status plays a key role in berry shrivel development.

Highlights

Berry shrivel (BS) is a grape-ripening disorder that has been increasing for more than a decade in the vineyards of the Northern Hemisphere, in Europe
Measurements of rachis hydraulic conductance on grapevine clusters (Vitis vinifera L.) and observations of the vascular tissues using transmission electron microscopy were conducted on rachises from healthy clusters and clusters having berry shrivel (BS) symptoms during the season
Preliminary results showed that rachis hydraulic conductance declined sharply after veraison but remained slightly higher in healthy clusters in comparison with clusters presenting BS symptoms

Summary

Introduction

Berry shrivel (BS) is a grape-ripening disorder that has been increasing for more than a decade in the vineyards of the Northern Hemisphere, in Europe. It was previously mentioned by Jensen (1970), this disorder was named « Zweigelt disease » in Austria (Reisenzein and Berger, 1997) in reference to the susceptibility of this variety. Berries remain generally pink, especially when the phenomenon occurs early during the ripening phase. BS is often associated with a loss of turgor and visible shriveling or shrinking of grape berries. In some varieties, such as Sauvignon, berries can retain their firmness and not shrivel at all. The rachises of BSaffected clusters do not present the same imbalances between potassium, magnesium, and calcium as do BSN-affected clusters (Bachteler et al, 2013)

Methods

Results

Discussion

Conclusion