The effect of extreme water stress on leaf drying limits and possibilities of recovering in three grapevine (Vitis vinifera L.) cultivars

Abstract

This study was conducted in three grapevine cultivars (cv. Chardonnay, Merlot and Cabernet
Sauvignon) vines during the 2009 growing season in the ECOTRON of the campus of Montpellier 
SupAgro/France. The aim of this research was to analyze the effect of sudden and extreme water stress 
(EWS) to determine the limit of the leaf drying (depend on leaf), possibilities of recovering, and its 
relationship with grapes composition. A randomized block design was used. There were three blocks 
with three replicates. In the experiment all plots consisted of totally 36 grapevines. During the entire 
experiment in ESW vines both pd and md values were close to each other by decreasing to about -2.1 
MPa in all three varieties. After this level ( -2.1 MPa) they both get close to each other until their equality 
in -3.7 MPa. This value was determined as the threshold of all leaf dryings in the vines. In EWS vines the 
lowest read pd and md was -4.6 MPa. In the next measurement pd and md were forced to -5.0 MPa, and 
water exit from leaf petiole was not observed in the same vines. After EWS treatment, berries became 
smaller and these lead to increase of Anthocyanin concentration, Folin-Ciocalteu index (FCI) and PTI 
values at harvest time. However as a result of EWS applications pH values increased to a level which 
had a negative effect on wine quality. There was a reduction in the values of 100 berry weight, berry 
volume, total soluble solids (TSS), sugar concentration, sugar content per berry, K and tartaric acid. 
The conclusion is that as a result of sudden EWS although all the leaves dried, vines did not die even 
they recovered by rewatering. However EWS had a negative effect on the berry quality.