Foliar application of ABA enhances the water productivity of wheat in near-field conditions. Foliar application of ABA enhances the water productivity of wheat in near-field conditions. A to B, Changes of leaf temperature in response to ABA application. A, Wheat plants are shown 24 h after ABA application (left panel) and in a thermogram (right panel). Half of the plants grown for 30 d in single pots (n = 3) were exposed to 100 µM ABA solution or mock-treated with aqueous solution containing 1% (v/v) dimethyl sulfoxide. The inner center of the treated plants as indicated by the box in the thermogram was used to determine the leaf surface temperature, and temperature differences were expressed in comparison to the mock-treated plants of the same pot. Scale bar = 2 cm. B, Leaf temperature increase in response to different ABA concentrations was assessed 24 h after treatment. C to H, Wheat plants were grown under near-field conditions and treated with ABA or exposed to drought. The well-watered plants (33 d old) were treated with either mock or ABA solutions (30 and 100 µM) at time points indicated by red arrows. Eight to nine plants were cultivated in cylinders (n = 4 per treatment), with a diameter of 0.15 m, length of 1.1 m, and soil volume of 19 L. Three, two or three, and three plants were harvested in the first, the second, and the third week, respectively. C, Dry biomass per shoot. D, Water consumption by evapotranspiration. E, Total dry biomass. F, WUE (biomass increase per evapotranspired water) during 23 d. G, Shows 13C composition. H, Shows 13C-derived integrative WUE of wheat plants conferred by exogenous ABA application or drought. Three 40-d-old wheat plants per cylinder analyzed in (C) and (D) were harvested for each treatment to determine the C isotope composition. Mean ±sem; *P < 0.05, **P < 0.01, ***P < 0.001 (one-way ANOVA) compared to plants without exogenous ABA. Zhenyu Yang et al. Plant Physiol. 2019;180:1066-1080 ©2019 by American Society of Plant Biologists