Submitted to: American Society of Enology and Viticulture Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 4/1/2013
Publication Date: 6/24/2013
Publication URL: http://www.asev.org/docs/2013TechnicalAbstracts.pdf
Citation: Shellie, K., King, B.A. 2013. Kaolin-based foliar reflectant alleviates heat stress in deficit-irrigated Malbec. American Society of Enology and Viticulture Annual Meeting Abstracts. 64th ASEV Technical Abstracts/ Pg. 166.
Technical Abstract: We evaluated the interaction effects of a kaolin-based particle film and water deficit on leaf and berry surface temperature, light reflectance, gas exchange characteristics, berry composition and yield of Malbec vines under field conditions over three growing seasons to test the hypothesis that the foliar reflectant would increase anthocyanins and water use efficiency and that response would be less effective under increasing water stress. Own-rooted Malbec grapevines were irrigated with a standard or reduced amount of water and grown under arid field conditions with high solar radiation. Particle film increased the concentration of total monomeric anthocyanins in berries each year and the ratio of anthocyanins to soluble solids in two out of three years. The particle film did not alleviate differences in anthocyanin concentration between east and west-exposed clusters. Under reduced irrigation, particle film decreased the cumulative minutes that surface temperatures exceeded 30°C between mid-July through harvest in east but not west-exposed berries and in east-exposed leaves. Leaves with particle film had lower mid-morning rates of assimilation, lower chlorophyll-a to chlorophyll-b ratio, and a higher ratio of chlorophylls to carotenoids than leaves without particle film. Decreased assimilation was unrelated to the magnitude of leaf reflectance of visible light. Particle film did not affect yield components or fruit maturity, indicating that net primary productivity was sufficient to ripen fruit to maturity. These results demonstrate that foliar particle film can facilitate the accumulation of anthocyanins in deficit-irrigated Malbec under warm, arid conditions with high solar radiation.