Particle Film Mechanisms of Action That Reduce the Effect of Environmental Stress in ‘Empire’ Apple

摘要: ADDITIONAL INDEX WORDS. kaolin, Surround, whole canopy gas exchange, vapor pressure deficit, fruit, photosynthetically active radiation, Malus ·domestica ABSTRACT. Heat stress is a limiting factor of plant productivity throughout the world and kaolin-based particle films (PF) have demonstrated that reflective nature resulting surface can increase primarily by reducing temperature in leaf, canopy. The purpose this study was to evaluate environmental mechanisms related physiological responses 'Empire' apple (Malus ·domestica) exchange at level PF treatments identify those parameters key response increased productivity. Trees received either no treatment or season-long applications each supplemental irrigation full replacement evapotranspiration. Studies were begun 1998 continued 2007. Fruit number fruit weight measured all years. Whole carbon dioxide assimilation rates (A) for 4-year period determine relationship with incoming light deficit (VPD) levels. photosynthetic varied between years as result variation VPD radiation (PAR) There unique PAR levels greater than 1600 mmolm -2 s -1 which combination maintained midday A maximum compared other although reduced increasing VPD. This indicated limited A, adequate water could maintain sun during minimize depression commonly observed reduces daily accumulation. accumulation likely partitioned fruit. Increased from treatment, control, positively correlated growing season air indicating environment becomes hotter and/or drier, magnitude leaf subsequent effect. heat load on exposed leaves enabling them better regulate improved distribution inside gain scale. hue angle red color 5 10 use may be an effective substitute evaporative cooling reduce solar injury improve quality through weight. results indicate benefits would occur agroecosystems large VPDs high temperatures further enhance