GiESCO 2019 banner
IVES 9 IVES Conference Series 9 GiESCO 9 GiESCO 2019 9 Optical visualization of embolism spread in drought‐induced leaves: revealing differences across three grapevine genotypes

Optical visualization of embolism spread in drought‐induced leaves: revealing differences across three grapevine genotypes

Abstract

Context and purpose of the study ‐Evaluation of xylem embolism is an important challenge in identifying drought tolerant genotypes within the context of climate change. Visualization methods such as the optical vulnerability technique (Brodribb et al. 2016) has been shown to be a reliable and accessible approach to observe the spread of embolism in dehydrating leaves (Hochberg et al. 2017; Lamarque et al. 2018). In this study we use the optical technique to examine the development of leaf embolism in three grapevine cultivars as a method to characterize their drought‐tolerance strategy.

Material and methods ‐Potted plants of Grenache, Semillon and Syrah were grown outdoors in 2018 under well‐watered conditions. Leaf embolism formation and spread was evaluated in four individuals per genotype by monitoring changes in light transmission through the xylem after the irrigation was cutted‐off. For each plant, a mature leaf was placed on a scanner and imaged every 5 minutes until complete desiccation. Simultaneous measurements of stem water potential (Ystem) were registered using psychrometers properly installed on the main stem. The accuracy of the psychrometers was evaluated by measuring the leaf water potential in adjacent leaves previously bagged with aluminum foil using a Scholander pressure bomb. The stack of images obtained were analyzed using the ImageJ software as described in Lamarque et al. (2018). The percentage of embolism (%emb) was calculated as the cumulative number of embolised pixels normalized to the total number of embolised pixels throughout the dehydration. Finally, the %emb was represented as a function of Ystem and different events were colored using a continuous scale respective to their time of appearance.

Results ‐Embolism formation and spread in the leaves were detected at different times for each cultivar since the beginning of drought. While Grenache showed the first embolism event at around 48 h of desiccation (‐0.48 MPa), Semillon showed its first event after 72 h (‐1.5 MPa). Syrah plants were placed in between the other two genotypes showing the first embolisms at ‐0.68 MPa. The vulnerability curves (%emb vs Ystem) constructed from the data obtained followed a sigmoidal function for all genotypes and showed a great variability between individuals. In spite of this, the time and water potentials at which the main embolisms occurred was significantly different between cultivars where Grenache showed an early cavitation (P50 at ‐1.43 MPa), followed by Syrah (P50 at ‐1.65 MPa) and Semillon (P50 at ‐2.08 Mpa). The optical technique tested in this study revealed genotype differences in the temporal appearance of leaf embolism suggesting a different strategy to tolerate dehydration. 

DOI:

Publication date: June 19, 2020

Issue: GiESCO 2019

Type: Article

Authors

Silvina DAYER (1), Régis BURLETT (2), Laurent LAMARQUE2, Sylvain DELZON2, Gregory GAMBETTA1*

(1) Institut des Sciences de la Vigne et du Vin, Écophysiologie et Génomique Fonctionnelle de la Vigne, UMR 1287, 210 Chemin de Leysotte, F-33140 Villenave-d’Ornon, France
(2) Biodiversité Gènes et Communautés, Institut National de la Recherche Agronomique (INRA), Université Bordeaux, 33610 Cestas, France

Contact the author

Keywords

 Embolism, drought, xylem cavitation, vessels, grapevine

Tags

GiESCO 2019 | IVES Conference Series

Citation

Related articles…

Combining effect of leaf removal and natural shading on grape ripening under two irrigation strategies in Manto negro (Vitis vinifera L.)

The increasingly frequent heat waves during grape ripening pose challenges for high quality wine grape production. Defoliation is a common practice that can improve the control of diseases in bunches, but also it increases the exposure to sunlight. Grapes exposed to solar radiation reach temperatures over the optimum for berry development and maturation. This makes the development of irrigation and canopy management techniques of great importance to maximize yield and grape quality. A field experiment was carried out during 2021 using Manto negro wine grapes to study the effect of applied irrigation and different light exposure levels on grape quality. Two irrigation treatments were imposed based on the frequency and amount of water doses in a four-block experimental vineyard at Bodega Ribas (Mallorca). Three light exposure treatments were randomly applied in each irrigation plot. The light treatments included exposed clusters from pea size, non-exposed clusters, and shaded clusters after softening. Leaf area index and canopy porosity was estimated every 2 weeks. Midday leaf water potential was measured weekly. Additionally, apparent electrical conductivity was measured between rows to estimate the soil water content variability. Light and temperature sensors were installed at the bunch level to quantify the differences in bunch temperature and light intensity among treatments. The effect of irrigation and cluster light exposure on berry weight, TSS, TA, malic acid, tartaric acid, K+, and pH were analysed at 5 moments along grape ripening. During different heat waves, the natural shading technique decreased the maximum bunch temperature around 10 °C respect to the exposed bunches in both irrigation strategies. The combination of defoliation and shading techniques after softening decreased TSS at harvest and affected most of the quality parameters during the last stages of ripening, showing an interesting technique to delay ripening in warm viticulture areas.

Potential use of the yeast Starmerella bacillaris as a sustainable biocontrol agent against gray mold disease in viticulture

Pest biocontrol strategies are gaining attention as eco-friendly alternatives to the use of synthetic pesticides, including in viticulture.

Aromatic profile of Savatiano Greek Grape Variety as affected by various terroirs in the PGI zone of Attica.

Regionality, frequently called terroir, is often used to market wines from different locations. Savatiano (Vitis Vinifera L.), is the dominant indigenous variety of the Mesogeia – Attiki region, reaching a percentage of 70% of the total vine cultivation, and being the most widely planted variety in Greece. In this context, this research focuses on the evaluation of the impact of different terroirs within the PGI Attiki zone on the aromatic profile of Savatiano.

First characterization of thiol precursors in colombard and gros manseng: comparison of two cultivation practices

AIM: Organic production of wine in the past years has known an important augmentation. This type of cultivation practice switches synthetic phytosanitary product for copper-based protection as fungicide.

Spatio-temporal analysis of grapevine water behaviour in hillslope vineyards. the example of corton hill, Burgundy

Hillslope vineyards show various and complex water dynamics between soil and plants, and in order to gain further insight into this phenomenon, 8 grapevine plots were monitored during three vintages, from 2010 to 2013, on Corton Hill, Burgundy, France.