Cucumber and other Cucurbitaceae plants have a high transpiration rate and sensitivity to water deficit stress. Ascorbic acid (AsA) and gamma aminobutyric acid (GABA) participate in a variety of plant processes and increase plant resistance to different stresses. The current study was aimed to assess the efficacy of the foliar application of AsA (100, 200 and 300 mg l⁻¹) and GABA (20 and 40 mM) on growth, physiological parameters and water use efficiency related properties of cucumber plants under deficit irrigation (DI) strategy (0, 25 and 50%). Results showed that the highest values of measured morphological properties were recorded in plants treated with GABA at 40 mM and AsA at 100 mg l⁻¹. The highest water use efficiency was observed in plants sprayed with GABA at 40 mM. Also, foliar spraying of GABA at 40 mM was the best treatment to improve the free proline content of leaves and the activity of antioxidant enzymes under drought stress conditions. Findings of this study showed that foliar application of AsA and GABA can be a useful and inexpensive treatment to improve morphological, physiological and water use efficiency related properties of cucumber plant under water deficit stress.

黄瓜和其他葫芦科植物的蒸腾速率高，并且对水分亏缺胁迫敏感。抗坏血酸（AsA）和γ-氨基丁酸（GABA）参与多种植物过程，并增强植物对不同胁迫的抗性。本研究旨在评估叶面施用AsA（100、200和300 mg l ^-1）和GABA（20和40 mM）对亏缺黄瓜植株生长，生理参数和水分利用效率相关特性的功效灌溉（DI）策略（0％，25％和50％）。结果表明，在以40 mM的GABA和以100 mg l ^-1的AsA处理的植物中记录到最高的形态学特性值。。在喷有40 mM GABA的植物中观察到最高的水分利用效率。同样，在干旱胁迫条件下，以40 mM的叶面喷洒GABA是改善叶片游离脯氨酸含量和抗氧化酶活性的最佳方法。这项研究的结果表明，在缺水胁迫下，叶面施用AsA和GABA是提高黄瓜植株形态，生理和水分利用效率相关特性的有用且廉价的处理方法。