Resumen de Grapevine canopy response to a high‐temperature event during deficit irrigation

E.J. Edwards, L. Smithson, D.C. Graham, Peter R. Clingeleffer

• Background and Aims: Despite much anecdotal evidence, there has been little scientific investigation of the potential effects of a high‐temperature event on grapevines during deficit irrigation. This study examined the interaction between temperature and water status on leaf physiology.

  Methods and Results: Two experiments used Cabernet Sauvignon cuttings grown in a glasshouse at approximately 27–30°C before deficit irrigation treatments were imposed. When water stress was apparent, a 2‐day high‐temperature event with maximum daytime temperatures of approximately 40–45°C was generated. Leaf damage, stomatal conductance and water potential of deficit‐irrigated vines were all affected to a greater extent than in the well‐watered vines.

  Conclusions: The negative effects of a high‐temperature event on vine physiology were more severe in vines experiencing water stress than in well‐watered vines, but recovery was rapid even without re‐watering.

  Significance of the Study: An increase in the use of deficit irrigation will lead to a greater likelihood of vines being water stressed on hot days, and the observed responses indicate that this will result in greater damage to the vine.