Séminaire IBIP organisé dans le cadre des mobilités du Master Européen Vinifera (consortium EMaVE) de l’Institut des Hautes Etudes de la Vigne et du Vin de (IHEV) de Montpellier SupAgro
Les séminaires ont lieu sur le Campus Montpellier SupAgro/INRA de La Gaillarde (2, place P. Viala Montpellier)

Jeudi 14 mars 2013
Amphi 208 (Cœur d’Ecole) à 14h

Grapevine reserve dynamics and the post-harvest period

Bruno Hopzalfel
Research Theme Leader ‐ National Wine & Grape Industry Centre ‐ New South Wales‐ Australia

The carbohydrate reserve pool of the perennial structure of grapevines is determined by internal requirements for growth and the production of assimilates, through translocation, accumulation and mobilisation of carbohydrates. The processes of depletion and replenishment of reserves during the growing season are also influenced by the vineyard environment and by viticultural practices; therefore carbohydrates in the roots and the wood vary between vineyards and seasons. In addition, the stored carbohydrates of the perennial structure provide a buffer against contingencies such as frost events, insect pests or disease that reduce the assimilatory capacity of the canopy. The focus of the research is on the understanding of the carbohydrate reserve dynamics within and between seasons and the influence of cultural practises on reserves in relation to vine development, grape production and fruit composition. The total non-structural carbohydrates (TNC) of the perennial tissues consist of starch and soluble sugars, which are dominated by glucose, fructose and sucrose. The roots have relatively lower soluble sugar concentrations in comparison to the aerial parts of grapevine, while starch concentrations in the roots can be much higher. The starch reserves are most evident in the ray storage tissues (parenchyma), during the spring growth flush these reserves appear to disappear faster from phloem ray than from the xylem ray tissues of roots and canes. Prior to bud-burst the roots can contain up to 75% of the TNC in own rooted Shiraz, although lower starch concentrations have been observed in rootstocks, suggesting differences in partitioning. The seasonal changes in concentrations are most pronounced in the roots, with a depletion commonly occurring in early spring for canopy establishment and during maturation, depending on crop load. The replenishment of the carbohydrate reserves generally occurs during early berry development and after harvest. The length and effectiveness of the post-harvest period can alter winter carbohydrate reserves of the perennial structure and consequentially the vegetative and reproductive development in the next season. The removal of leaves at harvest results in lower wood and root carbohydrate levels at leaf fall, and smaller canopies and yields in the following growing season. In contrast, an extension of the post-harvest period by early crop removal increases shoot growth, bunch numbers and size. Recent work has shown that carbohydrate reserve storage through cultural practice does not substantially alter the seasonal pattern of reserve dynamics. This suggests that developmental stage or seasonal climatic factors have a stronger influence on carbohydrate mobilisation and storage, with cultural practise being more suitable for long-term adjustments. The rapid determination of winter carbohydrate reserves using ATR-FT-IR spectrometry will provide a monitoring tool to determine changes in viticultural intervention requirements and vineyard performance for the coming season. The mobilisation and storage of reserves can also be influenced by the soil environment, with warmer root temperatures in spring increasing the mobilisation of root reserves and the shoot biomass. Fruit set can be affected by altered soil temperature and there are indications that berry maturation and composition is influenced as well. Elevated ambient temperatures are likely to result in an increased winter reserve accumulation due to increased assimilate production after harvest, with consequences for the development of grapevines in the following season. Further research will continue to focus on carbohydrate reserve dynamics of the perennial structure in relation to vine development and grape composition, but also considering the issues of vine balance and the challenges of seasonal variations and climate change.

Contact : Anne Pellegrino

Contacts IBIP :
Sabine Zimmermann
Philippe Nacry
Christine Granier
Chantal Baracco