Enhanced Productivity and Water-Use Efficiency in Grapevines Using Calcium Oxide Particle Films

Abstract This study aimed to evaluate the effects of calcium oxide (7% CaO) particle film application, under two water regimes, on the photosynthetic system and productivity of Vitis labrusca cv. ‘Isabel Precoce’ during the warm season in the Brazilian Northeast. The experiment was conducted in a randomised block design with four treatments: (i) 65% of crop evapotranspiration (ETc) with particle film; (ii) 65% of ETc without particle film; (iii) 100% of ETc with particle film; and (iv) 100% of ETc without particle film (control). We monitored particle film deposition on leaves, Falker chlorophyll indices, chlorophyll a fluorescence transient, proline content, leaf water potential, and productivity. The results indicated that the calcium-based particle film provided artificial leaf shading and photoprotection, leading to an increase in the chlorophyll a index. Furthermore, chlorophyll a fluorescence performance indices were higher in plants treated with the particle film, reflecting improved physiological function. Proline content was lower under water deficit when the film was applied. Leaf water potential and productivity were also improved by the particle film. Therefore, the use of calcium oxide particle film, combined with reduced irrigation (65% of ETc), represents a promising strategy to mitigate the adverse effects of dry conditions on grapevine physiology and yield.