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Xylem Sap Bleeding as a Physiological Indicator in Grapevine: Genotype and Climate Influence.
Eleonora Nistor1, Alin Dobrei1, Andreea Dragoescu-Petrica2
1Department of Horticulture, Faculty of Engineering and Applied Technologies, University of Life Sciences "King Mihai I" from Timisoara, 119 Calea Aradului, 300645 Timisoara, Romania.
Grapevine xylem sap analysis reveals significant differences in bleeding patterns and chemical composition among cultivars and growing seasons. Monitoring sap traits offers early insights for vineyard management and cultivar selection in changing climates.
Area of Science:
- Viticulture and Oenology
- Plant Physiology
- Agricultural Science
Background:
- Early-season grapevine xylem sap characteristics are crucial for optimizing vineyard management.
- Fluctuating environmental conditions necessitate a deeper understanding of grapevine responses.
- Sap flow and composition can indicate grapevine health and metabolic activity.
Purpose of the Study:
- To investigate xylem sap parameters (onset, duration, intensity, chemical composition) in four grapevine cultivars.
- To assess the influence of cultivar and climate on sap traits over three growing seasons.
- To evaluate xylem sap analysis as an early diagnostic tool for vineyard management.
Main Methods:
- Field study over three growing seasons (2022-2024) in western Romania.
- Monitoring xylem sap onset, bleeding duration, and intensity in 'Cabernet Sauvignon', 'Merlot', 'Muscat Ottonel', and 'Pinot Noir'.
- Chemical profiling of sap components (solubles, nutrients, proteins, acids, phenolics) and statistical analysis (PCA).
Main Results:
- Significant differences in sap onset and duration were observed among cultivars and years, influenced by spring temperatures.
- 'Pinot Noir' showed the highest and earliest sap flow; 'Muscat Ottonel' and 'Pinot Noir' had higher phenolic content.
- Warmer years correlated with richer sap profiles, while higher precipitation reduced phenolic acid and resveratrol levels. PCA confirmed cultivar and season impacts.
Conclusions:
- Xylem sap bleeding is a sensitive indicator of grapevine reactivation, influenced by genotype and climate.
- Sap trait monitoring at dormancy release can guide vineyard practices like pruning, irrigation, and fertilization.
- Findings support selecting climate-resilient cultivars and rootstock-scion combinations for sustainable viticulture.
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