Physiological and Enzymatic Responses of Broad Bean to Foliar-Applied Glycine Betaine and α-Tocopherol under Saline Soil Conditions

• Rasha Ahmed Falah1 Huda.A. Atab2

  Author

In light of the economic importance of faba bean, extreme wastage of water, saline soils, and the dominance of traditional water management methods, the presented research transpired in 2025–2026 in fields of the Field Crops Department, Agriculture College - Al-Qasim Green University, Hilla City, Iraq (latitude 32-32.40 North, longitude 45-44.39 East). The latest study aimed to investigate the effects of the response of faba bean to foliar application for glycine betaine and α-tocopherol under saline soil conditions, with four glycine betaine concentrations of 0, 50, 100, and 150 mg L⁻¹ and four α-tocopherol concentrations of 0, 100, 150, and 200 mg^-1 on faba bean .The study proceeded in a randomized complete block design (RCBD) using a split-plot arrangement, with two factors and three replications. The results showed foliar spraying with glycine betaine acid achieved a significant superiority at the concentration of 150 mg L⁻¹, which recorded the highest mean values for total chlorophyll content of 21.816 mg g⁻¹ fresh weight), proline content of 2.304 µmol g⁻¹ dry weight, crop growth rate of 1.058 g m⁻² day⁻¹, net photosynthesis of 1.078 g m⁻² day⁻¹, catalase enzyme activity of CAT; 9.396 absorbance units min⁻¹ g⁻¹ fresh weight, and superoxide dismutase enzyme activity SOD; 15.922 absorbance units min⁻¹ g⁻¹ fresh weight, compared with the control treatment, which recorded the lowest mean values for the studied traits. Foliar spraying with the antioxidant alpha-tocopherol also produced a positive effect at the concentration of 200 mg L⁻¹, recording the highest mean values for leaf total chlorophyll content of 20.749 mg g⁻¹ fresh weight, crop growth rate of 0.634 g m⁻² day⁻¹, net photosynthesis of 0.822 g m⁻² day⁻¹, catalase enzyme activity CAT; 7.861 absorbance units min⁻¹ g⁻¹ fresh weight, and superoxide dismutase enzyme activity SOD; 15.386 absorbance units min⁻¹ g⁻¹ fresh weight. In this experiment, the 100 mg·L⁻¹ treatment group recorded the highest proline content, which reached 1.815 µmol·g⁻¹ dry weight, while the control group had the lowest mean values

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