TY - JOUR AU - Valerio, Maria AU - Lovelli, Stella AU - Sofo, Adriano AU - Perniola, Michele AU - Scopa, Antonio AU - Amato, Marianna PY - 2017/03/06 Y2 - 2024/03/28 TI - Root and leaf abscisic acid concentration impact on gas exchange in tomato (Lycopersicon esculentum Mill) plants subjected to partial root-zone drying JF - Italian Journal of Agronomy JA - Ital J Agronomy VL - 12 IS - 1 SE - Original Articles DO - 10.4081/ija.2016.788 UR - https://www.agronomy.it/agro/article/view/788 SP - AB - Partial root-zone drying (PRD) is a deficit irrigation technique with great potential for water saving. A split-root experiment was conducted on tomato in controlled environment in order to test the response of two long-time storage cultivars to PRD. <em>Ponderosa</em> tomato, a cultivar with yellow fruits, was compared to <em>Giallo tondo di Auletta</em>, a local cultivar from southern Campania (Italy). Plants were subjected to three irrigation treatments: plants receiving an amount of water equivalent to 100% of plant evapotranspiration (V100); plants in which 50% of the amount of water given to V100 was supplied (V50); and plants where one root compartment was irrigated at 50% of water requirements and the other compartment was allowed to dry, and thereafter every side was rewetted alternatively (PRD). The highest levels of leaf abscisic acid (ABA) [on average equal to 104 ng g<sup>–1</sup> fresh weight FW)] were measured in PRD and V50, at 70 days after transplantation. Root ABA concentration in both PRD and V50 reached mean values of 149 ng g<sup>–1</sup> FW. There were differences for the irrigation regime in root ABA biosynthesis and accumulation under partial root-zone drying and conventional deficit irrigation (V50). Assimilation rate, stomatal conductance and intercellular CO<sub>2</sub> concentration decreased in relation to the irrigation regime by 22, 36 and 12%, respectively, in PRD, V50 and V100 at 50 days after transplantation. <em>Ponderosa</em> variety accumulated 20% more dry matter than <em>Auletta</em> and significant differences were observed in leaf area. In both PRD and V50 of the two varieties, it was possible to save on average 46% of water. Our results indicate that there is still space to optimise the PRD strategy, to further improve the cumulative physiological effects of the root-sourced signaling system. ER -