Shahid Bahonar University of Kerman and Iranian Biotechnology Society Agricultural Biotechnology Journal 2228-6705 18 3 2026 08 23 Effect of lemon juice in the growth, physiological traits, proline and antioxidants of Basil (Ocimum basilicum) plant growing in water stress Effect of lemon juice in the growth, physiological traits, proline and antioxidants of Basil (Ocimum basilicum) plant growing in water stress 373 394 5440 10.22103/jab.2026.27152.1895 FA Afrah Mahdi Al-Dhalimi Assistant Professor, Department of Biology, College of Education for Girls, University of Kufa, Iraq. Journal Article 2026 05 10 ObjectiveBasil (Ocimum basilicum L. ) is a widespread annual plant cultivated in various parts of the world. Water stress is one of the most significant environmental challenges facing plants, including basil, in their growth and development. The aim of this study was to investigate the effect of lemon juice in mitigating the harmful effects of water stress on basil.Materials and methodsThis study was conducted during the autumn season of 2025 in a private nursery in Najaf, Iraq. Seeds were sown on 27/10/2025 in plastic containers in a two-factors factorial experiment. The first factor was water stress, with plants being irrigated (once, twice, and three times a week). The second factor was lemon juice at four concentrations (0, 2, 4, and 6 mL/L). Morphological and physiological parameters were calculated. Relative water content, chlorophyll content, proline and enzymatic antioxidants, proline concentration, peroxidase estimation, catalase enzyme activity, ascorbic acid, total phenolic content (TPC), and total flavonoids content were estimated. The results were analyzed using Genstat 2012 according to the ANOVA method.ResultsThe results of the study indicated the negative effect of reducing irrigation intervals on basil plant growth indicators such as plant height, stem diameter, leaf area and some physiological characteristics such as relative water content, chlorophyll, and shoot fresh weight, with an increase in the leaf content of proline and enzymatic and non-enzymatic antioxidants. The experiment also showed the effect of lemon juice concentrations as a biostimulant that improves the growth indicators under study, enhances enzymatic and non-enzymatic antioxidants, and reduces the harmful effects of water stress.ConclusionThe results of this study showed that water stress can reduce the vegetative growth of basil, but it can increase the defense compounds (proline, enzymes and antioxidants). Irrigation three times a week showed the best growth performance. While, less irrigation enhanced the stress responses. Foliar spraying of lemon juice, especially at concentrations of 2 to 6 ml/l, improved growth and physiological traits and increased stress tolerance. Overall, it can be concluded that the use of lemon juice can be an effective strategy to reduce the negative effects of water stress in basil. ObjectiveBasil (Ocimum basilicum L. ) is a widespread annual plant cultivated in various parts of the world. Water stress is one of the most significant environmental challenges facing plants, including basil, in their growth and development. The aim of this study was to investigate the effect of lemon juice in mitigating the harmful effects of water stress on basil.Materials and methodsThis study was conducted during the autumn season of 2025 in a private nursery in Najaf, Iraq. Seeds were sown on 27/10/2025 in plastic containers in a two-factors factorial experiment. The first factor was water stress, with plants being irrigated (once, twice, and three times a week). The second factor was lemon juice at four concentrations (0, 2, 4, and 6 mL/L). Morphological and physiological parameters were calculated. Relative water content, chlorophyll content, proline and enzymatic antioxidants, proline concentration, peroxidase estimation, catalase enzyme activity, ascorbic acid, total phenolic content (TPC), and total flavonoids content were estimated. The results were analyzed using Genstat 2012 according to the ANOVA method.ResultsThe results of the study indicated the negative effect of reducing irrigation intervals on basil plant growth indicators such as plant height, stem diameter, leaf area and some physiological characteristics such as relative water content, chlorophyll, and shoot fresh weight, with an increase in the leaf content of proline and enzymatic and non-enzymatic antioxidants. The experiment also showed the effect of lemon juice concentrations as a biostimulant that improves the growth indicators under study, enhances enzymatic and non-enzymatic antioxidants, and reduces the harmful effects of water stress.ConclusionThe results of this study showed that water stress can reduce the vegetative growth of basil, but it can increase the defense compounds (proline, enzymes and antioxidants). Irrigation three times a week showed the best growth performance. While, less irrigation enhanced the stress responses. Foliar spraying of lemon juice, especially at concentrations of 2 to 6 ml/l, improved growth and physiological traits and increased stress tolerance. Overall, it can be concluded that the use of lemon juice can be an effective strategy to reduce the negative effects of water stress in basil. https://jab.uk.ac.ir/article_5440_7a2347d96752880e3d58d72e9813cc14.pdf