Terroir 2004 banner
IVES 9 IVES Conference Series 9 Canopy photosynthetic activity and water relations of Syrah/R99 as affected by row orientation on a particular terroir

Canopy photosynthetic activity and water relations of Syrah/R99 as affected by row orientation on a particular terroir

Abstract

[English version below]

L’activité photosynthétique et les relations hydriques de plantes de Syrah sur R99 un mois après la véraison ont été étudiées dans un vignoble de la région de Stellenbosch. Le vignoble, planté à 2,75 entre rangs et 1,5 m sur le rang, sur un sol de type Glenrosa, était en pente et exposé a l’ouest: pour les rangs on avait adopté une orientation nord –sud. Les plantes, conduites selon un système de type en cordon de Royat, avaient donc un port ascendant de la végétation, palissée dans un plan vertical à l’aide de trois paires de fils. Une irrigation à micro-jets était appliquée dans la phase comprise entre la nouaison et la fermeture de la grappe et à la véraison. Le tronc était ébourgeonné et la végétation rognée à 1,4 m de hauteur. On a mesuré la photosynthèse et le potentiel hydrique de feuilles en position basale, médiane et apicale soit des bourgeons principaux, soit des entre-cœurs. On a considéré des entre-cœurs en position apicale, médiane et basale le long du bourgeon principal. Soit le matin, soit l’après-midi on a examiné le coté est et le coté ouest du rang.. On a comparé la photosynthèse et le potentiel hydrique de feuilles situées à l’extérieur ou à l’intérieur de la végétation: on a considéré séparément les feuilles apicales, médianes et basales des bourgeons principaux et les feuilles médianes des bourgeons anticipés, situés en position apicale, médiane et basale.
Le nombre de couches du feuillage augmente typiquement du sommet à la base de la végétation et la pénétration de la lumière baisse en proportion. Sur les bourgeons principaux l’activité photosynthétique de toutes les feuilles était plus élevée le matin que l’après midi, soit pour la face au soleil soit pour celle à l’ombre. La photosynthèse des feuilles exposées directement au soleil diminuait du sommet vers la zone basale. Sur le côté à l’ombre la photosynthèse des feuilles médianes était plus limitée en comparaison aux feuilles apicales et basales. L’activité photosynthétique de la plante entière était donc plus importante le matin que pendant l’après-midi. Le potentiel hydrique des feuilles exposées au soleil était beaucoup plus bas que celui des feuilles ombragées. Même si on s’attendait un potentiel hydrique inférieur pour le côté ensoleillé, les différences n’ont pas été en ligne avec les différences importantes trouvées pour l’activité photosynthétique. Le côté ensoleillé du rang avait un potentiel hydrique légèrement plus bas le matin que l’après midi. Les bourgeons secondaires de la zone basale sur le coté exposé au soleil avaient une activité phothosynthétique plus élevée le matin par rapport à l’après midi, tandis que pour les bourgeons secondaires en position apicale et médiane l’activité était à peu prés la même pendant toute la journée. Dans le cas des bourgeons secondaires l’activité photosynthétique des feuilles exposées par rapport aux feuilles ombragées et leur potentiel hydrique suivaient un comportement (matin contre après midi et côté soleil contre côté ombragé) analogues à celui des feuilles des bourgeons principaux.
Si l’on compare l’activité photosynthétique et le potentiel hydrique des feuilles externes et internes du couvert en position différente on trouve le même modèle de comportement pour les deux types de bourgeons que l’on avait observé pour le côté exposé ou non exposé du couvert. Pendant la matinée des grandes différences se produisaient entre les feuilles internes et externes de la végétation sur la face ensoleillée du rang, tandis que, si l’on prend ces mesures du côté ombragé, les valeurs de toutes les feuilles sont pareilles à celles des feuilles internes du côté ensoleillé.
Ces résultats fournissent des indications sur les performances photosynthétiques et sur les relations hydriques que l’on peut s’attendre, en rapport à un terroir particulier, si l’on choisit une orientation donnée des rangs.

The photosynthetic activity and water relations of a Syrah/R99 vineyard, situated in the Stellenbosch region, were investigated approximately one month after véraison. Vines were vertically trained, spur pruned, and spaced 2.75 x 1.5 m in North-South orientated rows on a terroir with Glenrosa soil and a West-facing slope. Microsprinkler-irrigation was applied at pea berry size and at véraison stages. The 1.4 m high canopies were suckered, shoot-positioned and topped and accommodated by means of three sets of double wires. Photosynthetic activity and water potential were measured on leaves in apical, middle and basal positions on both primary and secondary shoots. Lateral shoots in apical, middle and basal positions were measured. Both East and West sides of the canopy were measured in the morning and in the afternoon. In addition, photosynthesis and water potential of interior and exterior leaves on primary (apical, middle and basal leaves) and secondary (middle leaves in apical, middle and basal positions) shoots were compared.
The canopy typically increased in number of leaf layers from top to bottom. Light penetration decreased in tandem. On primary shoots, photosynthetic activity of leaves on sunny and shaded sides of the canopy was higher in the morning than in the afternoon. Photosynthesis of sun-exposed leaves decreased from the apical to basal position. On the shaded part of the canopy, photosynthesis of middle leaves was reduced compared to apical and basal leaves. The photosynthetic activity of the canopy was therefore higher in the morning than in the afternoon. Water potential of leaves on the sunny side of the canopy was also consistently lower than that of leaves on the shaded side. Although the sunny side is expected to display lower water potential, the differences were, however, not in line with the large differences found for photosynthetic activity. The sun-exposed side of the canopy had slightly lower water potential in the morning than in the afternoon.
Basally positioned secondary shoots on the sunny side of the canopy had higher photosynthetic activity in the morning than in the afternoon; that of secondary shoots in apical and middle positions was, however, similar in the morning than in the afternoon. Photosynthetic patterns of leaves on the sunny side of the canopy versus the shaded side of the canopy were similar to those on the primary shoot. Water potential patterns of leaves on secondary shoots (morning versus afternoon and sunny side versus shaded side) were similar to those of leaves on primary shoots.
Comparing the photosynthetic activity and water potential of exterior and interior leaves in different positions on either primary or secondary shoots, similar patterns than those found for sunny and shaded sides of the canopy occurred. In the morning, large differences between the exterior and interior leaves occurred when measured from the sunny side. However, when measured from the shaded side, values were similar to those of interior leaves measured from the sunny side and no marked differences between exterior and interior leaves were found.
The results are useful for application to terroirs forcing different row orientations. It provides an indication of the photosynthetic performance and water relations that can be expected with a particular row orientation.

Download the PDF

DOI:

Publication date: January 12, 2022

Issue: Terroir 2004

Type: Article

Authors

V. Novello (1) and J.J. Hunter (2)

(1) Dipartimento di Colture Arboree, University of Turin, Via Leonardo da Vinci 44, I-10095 Grugliasco (TO), Italy
(2) ARC Infruitec-Nietvoorbij, Private Bag X5026, 7599 Stellenbosch, South Africa

Contact the author

;

Keywords

Terroir, row orientation, vegetative growth, reproductive growth, water relations, photosynthesis

Tags

IVES Conference Series | Terroir 2004

Citation

Related articles…

Climate, Viticulture, and Wine … my how things have changed!

The planet is warmer than at any time in our recorded past and increasing greenhouse emissions and persistence in the climate system means that continued warming is highly likely. Climate change has already altered the basic framework of growing grapes for wine production worldwide and will likely continue to do so for years to come. The wine sector can continue to play an important role in leading the agricultural sector in addressing climate change. From developing on…

Read More

Adaptability of grapevines to climate change: characterization of phenology and sugar accumulation of 50 varieties, under hot climate conditions

Climate is the major factor influencing the dynamics of the vegetative cycle and can determine the timing of phenological periods. Knowledge of the phenology of varieties, their chronological duration, and thermal requirements, allows not only for the better management of interventions in the vineyard, but also to predict the varieties’ behaviour in a scenario of climate change, giving the wine producer the possibility of selecting the grape varieties that are best adapted to the climatic conditions of a certain terroir. In 2014, Symington Family Estates, Vinhos, established two grape variety libraries in two different places with distinctive climate conditions (Douro Superior, and Cima Corgo), with the commitment of contributing to a deeper agronomic and oenological understanding of some grape varieties, in hot climate conditions. In these research vineyards are represented local varieties that are important in the regional and national viticulture, but also others that have over time been forgotten — as well as five international reference cultivars. From 2017 to 2021, phenological observations have been made three times a week, following a defined protocol, to determine the average dates of budbreak, flowering and veraison. With the climate data of each location, the thermal requirements of each variety and the chronological duration of each phase have been calculated. During maturation, berry samples have been gathered weekly to study the dynamics of sugar accumulation, between other parameters. The data was analysed applying phenological and sugar accumulation models available in literature. The results obtained show significant differences between the varieties over several parameters, from the chronological duration and thermal requirements to complete the various stages of development, to the differences between the two locations, confirming the influence of the climate on phenology and the stages of maturation, in these specific conditions.

Read More

Variations of soil attributes in vineyards influence their reflectance spectra

Knowledge on the reflectance spectrum of soil is potentially useful since it carries information on soil chemical composition that can be used to the planning of agricultural practices. If compared with analytical methods such as conventional chemical analysis, reflectance measurement provides non-destructive, economic, near real-time data. This paper reports results from reflectance measurements performed by spectroradiometry on soils from two vineyards in south Brazil. The vineyards are close to each other, are on different geological formations, but were subjected to the same management. The objective was to detect spectral differences between the two areas, correlating these differences to variations in their chemical composition, to assess the technique’s potential to predict soil attributes from reflectance data.To that end, soil samples were collected from ten selected vine parcels. Chemical analysis yield data on concentration of twenty-one soil attributes, and spectroradiometry was performed on samples. Chemical differences significant to a 95% confidence level between the two studied areas were found for six soil attributes, and the average reflectance spectra were separated by this same level along most of the observed spectral domain. Correlations between soil reflectance and concentrations of soil attributes were looked for, and for ten soil traits it was possible to define wavelength domains were reflectance and concentrations are correlated to confidence levels from 95% to 99%. Partial Least Squares Regression (PLSR) analyses were performed comparing measured and predicted concentrations, and for fifteen out of 21 soil traits we found Pearson correlation coefficients r > 0.8. These preliminary results, which have to be validated, suggest that variations of concentration in the investigated soil attributes induce differences in reflectance that can be detected by spectroradiometry. Applications of these observations include the assessment of the chemical content of soils by spectroradiometry as a fast, low-cost alternative to chemical analytical methods.

Read More

Assessing the climate change vulnerability of European winegrowing regions by combining exposure, sensitivity and adaptive capacity indicators

Winegrowing regions recognized as protected designations of origin (PDOs) are closely tied to well defined geographic locations with a specific set of pedoclimatic attributes and strictly regulated by legal specifications. However, climate change is increasingly threatening these regions by changing local conditions and altering winegrowing processes. The vulnerability to these changes is largely heterogenous across different winegrowing regions because it is determined by individual characteristics of each region, including the capacity to adapt to new climatic conditions and the sensitivity to climate change, which depend not only on natural, but also socioeconomic and legal factors. Accurate vulnerability assessments therefore need to combine information about adaptive capacity and climate change sensitivity with projected exposure to new climatic conditions. However, most existing studies focus on specific impacts neglecting important interactions between the different factors that determine climate change vulnerability. Here, we present the first comprehensive vulnerability assessment of European wine PDOs that spatially combines multiple indicators of adaptive capacity and climate change sensitivity with high-resolution climate projections. We found that the climate change vulnerability of PDO areas largely depends on the complex interactions between physical and socioeconomic factors. Homogenous topographic conditions and a narrow varietal spectrum increase climate change vulnerability, while the skills and education of farmers, together with a good economic situation, decrease their vulnerability. Assessments of climate change consequences therefore need to consider multiple variables as well as their interrelations to provide a comprehensive understanding of the expected impacts of climate change on European PDOs. Our results provide the first vulnerability assessment for European winegrowing regions at high spatiotemporal resolution that includes multiple factors related to climate exposure, sensitivity, and adaptive capacity on the level of single winegrowing regions. They will therefore help to identify hot spots of climate change vulnerability among European PDOs and efficiently direct adaptation strategies.

Read More

δ13C : A still underused indicator in precision viticulture  

The first demonstration of the interest of carbon isotope composition of sugars in grapevine, as an integrated indicator of vineyard water status, dates back to 2000 (Gaudillère et al., 1999; Van Leeuwen et al., 2001). Thanks to the isotopic discrimination of Carbon that takes place during plant photosynthesis, under hydric stress conditions, it is possible to accurately estimate the photosynthetic activity. Ever since, δ13C has been widely applied with success to zonation, terroir studies and vine physiology research, but is still not widely used by viticulturists. This is quite astonishing by considering the impact of global warming on viticulture and the need to improve water management, that would justify a widespread use of δ13C.
The lack of private laboratories proposing the analysis, the cost of the technology, as well as the long analytical delays, have been detrimental to its development. Some laboratories tried to overcome the analytical difficulties of isotopic analysis by using fourier transformed infrared spectroscopy, as a fast and cheap alternative to the official OIV method (IRMS). These claimed FTIR models have never been published or peer reviewed and cannot be considered robust. In this work, thanks to the recent acquisition of IRMS technology, new modern and robust applications of δ13C for viticulture are proposed. This includes the use of the analysis to make parcel separations at harvesting, the possibility to increase the precision of hydric stress cartography and the potential cost reduction when compared with Scholander pressure bomb analysis.

Read More