Studies with antitranspirants on grapevines (Vitis vinifera Var. Sultana)

Abstract

A range of antitranspirants has been tested under glasshouse conditions for their effectiveness In reducing the water consumption of grapevines (Vitis vinifera cv. Sultana). The substances tested included three that form plastic films, Polycote J (Tag), Polycote S720, and Acropol (S789, a silicone type compound), and the inhibitor phenyl mercurrc acetate which 1s known to be effective at suppressing transpiration In cotton. The only substance found to be an effective transpiration suppressant was Acropol, which reduced water consumption by an average of 50% when applied as a leaf spray. Repeated applications at 12-day intervals were necessary and the substance had a morphogenetic effect, bringing about a significant increase In the leaf area but a decrease in dry matter production, especially evident In the lower root weight of treated plants. (Similar morphogenetic effects were shown with Polycote S720, where the increased leaf area was shown to be a result of increased leaf number despite a slightly lower mean leaf area ) In short-term experiments both Acropol and Polycote S720 reduced carbon dioxide uptake in the light and carbon dioxide output in the dark. When Acropol was applied to plants in the field it did not affect the rate of sugar accumulation In grapes.