High survival rate of newly planted grapevines is important to prevent re-planting and ensure full production as soon as possible. There is a direct link between young vine growth and sustainable vineyard performance. It is expected that future climatic conditions will put additional strain on vineyard establishment. In this glasshouse study, the combined effects of increased temperature, increased CO2 and water deficit on physiology and growth of grafted vines were investigated. Four glass house compartments were set up with different levels and combinations of temperature and CO2. Within each compartment, water supply was applied as additional treatment factor. Grafted vines obtained from commercial nurseries were established in pots in a randomized block design and monitored during the first 12 weeks of growth. One rootstock (101-14 Mgt) was used throughout the study with Shiraz (SH 470) and Merlot noir (MO 348) as scion cultivars. Physiological activity and vegetative growth parameters were measured during the growth period with main sampling times at 4, 8 and 12 weeks after planting. The water and CO2 treatments played a more important role than the temperature treatment. Photosynthetic activity and the efficiency of water and nitrogen use were enhanced under high CO2 levels, provided that water deficit was not too severe. Under moderate water stress conditions, possible negative effects were mitigated by elevated CO2. Inherent phenology-linked patterns in the grapevine pertaining to shoot and root growth and physiological activity were similar for the various treatment combinations. Root and shoot growth depended strongly on water availability, while it was further enhanced by higher CO2 levels. Scion cultivars differed in their sensitivity and reaction to treatments. The strong interactions found between growth stage, available water, ambient temperature and CO2 levels stress the necessity of a multi-variable research approach to climate-related effects on the grapevine.
Authors: Hanlé Theron1 and Kobus Hunter2
1Cape Peninsula University of Technology (CPUT), Wellington, South Africa
2ARC Infruitec-Nietvoorbij, Stellenbosch, South Africa
Keywords: CO2, grapevine growth, grapevine physiology, temperature, water deficit