Terroir 2020 banner
IVES 9 IVES Conference Series 9 Plant nitrogen assimilation and partitioning as a function of crop load

Plant nitrogen assimilation and partitioning as a function of crop load

Abstract

Aims: The optimization of nitrogen use efficiency (NUE, i.e. uptake, assimilation and partitioning) is a solution towards the sustainable production of premium wines, while reducing fertilization and environmental impact. The influence of crop load on the accumulation of N compounds in fruits is still poorly understood. The present study assesses the impacts of bunch thinning on NUE and the consequences on the free amino N (FAN) profile in fruits.

Methods and Results: A large crop load gradient was imposed by bunch thinning (0.5 to 2.5 kg m–2) in a homogeneous plot of 225 vines. Isotope-labelled foliar urea (10 atom % 15N) was applied on the canopy of the fertilized treatment at veraison. The plants were excavated at four phenological stages over the two seasons (bud burst, flowering, veraison and harvest) and were individually split into five plant parts (roots, trunk, canopy, pomace and must). Total nitrogen and its stable isotope composition were determined in each part, with the aim of monitoring NUE as a function of crop load and fertilization.

The N concentration in fruits either at veraison or at harvest was not related to crop load variation. N concentration was maintained in the must to the detriment of N content in the roots. The root dry weight was 15 % lower and the root N quantity 27 % lower under high yielding conditions (HYC, compared to low yielding conditions LYC). The fertilizer N uptake was 41 % higher under HYC than under LYC. Consequently, urea supply had a positive impact on the yeast assimilable N concentration in the must (+55 mg L-1) only under HYC. However, the must FAN profile was significantly affected by the crop load, suggesting a possible modification of the aroma potential, independently from fertilization and grape maturation.

Conclusion: 

Using a 15N-labeling method, we demonstrate that grapevine has a strong ability to regulate nitrogen uptake and reserve mobilization to maintain a constant fruit N concentration despite changes in crop load. Foliar-urea fertilization at veraison was more efficient under HYC and helped to fulfill grape N demand, while limiting the mobilization of N reserves. However, the crop load affected the must FAN profile, inducing a possible modification of the fruit aroma. 

Significance and Impact of the Study: These findings highlight the great capacity of plants to adapt their N metabolism to constraints, e.g. bunch thinning in this case. These results are important to improve perennial fruit crop production through higher fertilization efficiency and lower environmental impact. Without fertilization, plant nutrition can be enhanced through the optimization of agricultural practices. The root activity appears to be key for understanding the mechanisms that balance N nutrition in plants

Download the PDF

DOI:

Publication date: March 25, 2021

Issue: Terroir 2020

Type : Video

Authors

Thibaut Verdenal1, Vivian Zufferey1, Agnes Dienes-Nagy1, Olivier Viret2, Cornelis van Leeuwen3, Jorge Spangenberg4, Jean-Laurent Spring1

1Agroscope Institute, Av. Rochettaz 21, CH-1009 Pully, Switzerland
2Direction générale de l’agriculture, de la viticulture et des affaires vétérinaires (DGAV), Av. de Marcelin 29, CH-1110 Morges, Switzerland
3EGFV, Bordeaux Sciences Agro, INRAE, Univ. Bordeaux, ISVV, F-33882 Villenave d’Ornon, France
4Institute of Earth Surface Dynamics, University of Lausanne, CH-1015 Lausanne, Switzerland

Contact the author

Keywords

Nitrogen partitioning, crop load, isotope labelling, amino acids, vines

Tags

IVES Conference Series | Terroir 2020

Citation

Related articles…

The evolution of the concept of geographical denomination in South America

Vers la fin du XX siècle, la vitiviniculture argentine a subi une profonde transformation qualitative atteignant toute la filière. L’analyse de l’évolution de la superficie des vignobles, l’élaboration des vins, la consommation et les exportations, permet de mettre en évidence ces changements. Dans ce contexte, l’origine apparaît comme un outil de force, d’expansion et de succès sur les marchés.

Read More

GrapeBreed4IPM: developing sustainable solutions for viticulture through multi-actor innovation targeting breeding for integrated pest management

According to the World Economic Forum and the European Union’s Biodiversity Strategy for 2030, the loss of biodiversity and the collapse of ecosystems are major threats facing humanity in the future.

Read More

Foliar application of urea improved the nitrogen composition of Chenin grapes

The nitrogen composition of the grapes directly affects the developments of alcoholic fermentation and influences the final aromatic composition of the wines. The aim of this study was to determine the effect and efficiency of foliar applications of urea on the nitrogen composition of grapes. This study was carried out during 2023 vintage and in the Chenin vineyard located in Estacion Experimental Mendoza (Argentina). Three urea concentrations 3, 6 and 9 Kg N/ha (C1, C2, and C3, respectively) and control (T) were applied in this vineyard at veraison.

Read More

VineyardFACE: Investigation of a moderate (+20%) increase of ambient CO2 level on berry ripening dynamics and fruit composition

Climate change and rising atmospheric carbon dioxide concentration is a concern for agriculture, including viticulture. Studies on elevated carbon dioxide have already been on grapevines, mainly taking place in greenhouses using potted plants or using field grown vines under higher CO2 enrichment, i.e. >650 ppm. The VineyardFACE, located at Hochschule Geisenheim University, is an open field Free Air CO2 Enrichment (FACE) experimental set-up designed to study the effects of elevated carbon dioxide using field grown vines (Vitis vinifera L. cvs. Riesling and Cabernet Sauvignon). As the carbon dioxide fumigation started in 2014, the long term effects of elevated carbon dioxide treatment can be investigated on berry ripening parameters and fruit metabolic composition.
The present study aims to investigate the effect on fruit composition under a moderate increase (+20%; eCO2) of carbon dioxide concentration, as predicted for 2050 on both Riesling and Cabernet Sauvignon. Berry composition was determined for primary (sugars, organic acids, amino acids) and secondary metabolites (anthocyanins). Special focus was given on monitoring of berry diameter and ripening rates throughout three growing seasons. Compared to previous results of the early adaptative phase of the vines [1], our results show little effect of eCO2 treatment on primary metabolites composition in berries. However, total anthocyanins concentration in berry skin was lower for eCO2 treatment in 2020, although the ratio between anthocyanins derivatives did not differ.
[1] Wohlfahrt Y., Tittmann S., Schmidt D., Rauhut D., Honermeier B., Stoll M. (2020) The effect of elevated CO2 on berry development and bunch structure of Vitis vinifera L. cvs. Riesling and Cabernet Sauvignon. Applied Science Basel 10: 2486

Read More

GRAPE SPIRITS FOR PORT WINE PRODUCTION: SCREENING THEIR AROMA PROFILE

Port is a fortified wine, produced from grapes grown in the demarcated Douro region. The fortification process consists in the addition of a grape spirit (77% v/v) to the fermenting juice for fermentation interruption, resulting in remaining residual sugars in the wine and increased alcohol content (19-22%). The approval of grape spirits follows the Appellation (D.O. Port wine) rules1 and it is currently carried out based on analytical control and on sensory evaluation done by the public Institute that upholds the control of the quality of Douro Appellation wines. However, the producers of Port wines would like to have more information about quality markers of grape spirits.

Read More