Macrowine 2021
IVES 9 IVES Conference Series 9 An excessive leaf-fruit ratio reduces the yeast assimilable nitrogen in the must

An excessive leaf-fruit ratio reduces the yeast assimilable nitrogen in the must

Abstract

Yeast assimilable nitrogen (YAN) in the grape must is a key variable for wine quality as a source of aroma precursors. In a situation of YAN deficiency, a foliar urea application upon the vine at veraison enhances YAN concentration and facilitates must fermentation. In 2013, Agroscope investigated the impact of leaf-fruit ratio on the nitrogen (N) assimilation and partitioning in grapevine Vitis vinifera cv. Chasselas following foliar-urea application with the aim of improving its efficiency on the YAN concentration. Two factors, canopy height with two levels (90 and 140 cm), and crop load with two levels (§§5 and 10 clusters per vine), were combined in a split plot trial (5 vines per treatment). All treatments received 20 kg/ha of 15N-labelled foliar urea (10 atom% 15N) at veraison. An extra 5-vine control treatment (150-cm canopy and 5 bunches per vine) received no foliar urea. As a result, the leaf-fruit ratio had a strong impact on the grape maturity at harvest and on the labelled-N partitioning after urea application. The YAN varied from 143 ± 17 mg/L when the leaf-fruit ratio was 1.6 m2/kg (light-exposed leaf area / fruit quantity), up to 230 ± 25 mg/L when the leaf-fruit ratio was 0.4 m2/kg. The grapes were the strongest sink of all the vine organs, with more than 20 % of their total organic N originating from the urea treatment. Whereas a too small leaf-fruit ratio affected the grape maturity and the accumulation of labelled N in the reserve organs, a large canopy induced a diminution of the total N concentration (% dry weight) in all organs comparable to a “dilution” in the plant. Thus a balanced leaf-fruit ratio – between 1 and 1.5 m2/kg – should be maintained in order to guarantee the grape maturity, the accumulation of YAN in the must and the storage of N in the reserve organs. This study fosters further research at the isotopic molecular level to unravel other mechanisms controlling the source-sink relationship and the specific N partitioning between grapevine organs.

Publication date: April 4, 2024

Issue: Macrowine 2016

Type: Poster

Authors

Thibaut Verdenal* 

*Agroscope

Contact the author

Tags

IVES Conference Series | Macrowine | Macrowine 2016

Citation

Related articles…

Reduction of herbaceous aromas by wine lactic acid bacteria mediated degradation of volatile aldehydes

Consumers typically prefer wines with floral and fruity aromas over those presenting green-pepper, vegetal or herbaceous notes. Pyrazines have been identified as causatives for herbaceous notes in wines, especially Bordeaux reds. However, pyrazines are not universally responsible for herbaceousness, and several other wine volatile compounds are known to produce distinct vegetal/herbaceous aromas in wines. Specifically, volatile aldehydes elicit sensations of herbaceousness or grassiness and have been described in wines well above their perception thresholds.
Read More

The impact of different yeasts and harvest time on the wine quality of Beihong and Beimei (<I>V. vinifera x V. amurensis</I>)

Beihong and Beimei are two wine cultivars from ‘Muscat Hamberg’ (V. vinifera L.) and wild V. amurensis Rupr., which were released in China in 2008. Here，two enology practices were reported. Firstly, the impact of different yeasts including D254, GRE, K1, D21 and BDX on dry wine quality of Beihong and Beimei was investigated. For Beihong, among wines fermented by all yeasts, residual sugar content was the lowest, total anthocyanin and resveratrol contents were the highest in the wine by D254. However, the wine by D254 had lower titrable acid than those by the other yeasts except BDX.

Read More

Characterization of non-Saccharomyces yeast and its interaction with Saccharomyces cerevisiae with investigation of fermentation kinetics and aromatic composition

[lwp_divi_breadcrumbs home_text="IVES" use_before_icon="on" before_icon="||divi||400" module_id="publication-ariane" _builder_version="4.20.4" _module_preset="default" module_text_align="center" module_font_size="16px" text_orientation="center"...
Read More

Moscatel vine-shoot extracts as grapevine biostimulant to increase the varietal aroma of Airén wines

There is a growing interest in the exploitation of vine-shoots waste, since they are often left or burned. Sánchez-Gómez et al. [1] have shown that vines-shoots aqueous extracts have significant contents of bioactive compounds, among which several polyphenols and volatiles are highlighted. Recent studied had demonstrated that the chemical composition of vine-shoots is enhanced when vine-shoots are toasted
[2,3]. The application of vegetable products in the vineyards has led to significant changes towards a more “Sustainable Viticulture”. An innovative foliar application for Airén vine-shoot extracts have been carried out to the vineyard. It has been shown that they act as grape biostimulants, improving certain wine quality characteristics [4].

Read More

Influence of methyl jasmonate foliar application to vineyard on grape volatile composition over three consecutive vintages

An alternative to improve grape quality is the application to the vineyard of elicitors. Although these compounds were first used to increase resistance of plants against pathogens, it has been found that they are also able to induce mechanisms involved in the synthesis of phenolic compounds and some amino acids. However, researches about the influence of elicitors on grape volatile composition are scarcely. Therefore, the aim of this work was to study the influence of methyl jasmonate (MeJ) foliar application on grape aroma composition over three consecutive vintages. MeJ was applied to Tempranillo grapevines at a concentration of 10 mM in 2013, 2014, and 2015 years. Control plants were sprayed with water.

Read More