Soil salinity is an increasing constraint to leafy vegetable production, often limiting crop yield while simultaneously altering nutritional composition. Understanding the balance between growth suppression and stress-induced nutritional enhancement is therefore critical for sustainable spinach (Spinacia oleracea) cultivation in saline agroecosystems. This study investigated the growth and biochemical responses of spinach to incremental salinity stress (0-6 dS/m NaCl) under controlled conditions. The growth parameters (plant height, the number of leaves, and leaf area), proximate composition (moisture, ash, protein, carbohydrates, crude fat, and fibre), and mineral dynamics (Ca^2 +, Fe^2 +, K+, Mg^2 +) were evaluated using a completely randomised design, supported by ANOVA and robust regression analyses. Salinity reduced vegetative performance overall, with the leaf number declining by approximately 50% at 6 dS/m and plant height showing a net reduction of 13% relative to the control at harvest, despite increases observed at intermediate salinity levels. Leaf expansion exhibited a hormetic response, with moderate salinity (2 dS/m) temporarily enhancing leaf area during the early growth stages. Bulk biochemical analysis revealed salinity-driven trade-offs, where ash (+33%) and protein (+42%) contents increased significantly (p 0. 05). Robust regression confirmed threshold-dependent responses, indicating that moderate salinity (2-4 dS/m) can enhance micronutrient availability without severely disrupting ionic homeostasis. These findings highlight a trade-off between nutritional quality enhancement and growth suppression under salinity stress and support precision irrigation and salinity-resilient breeding strategies to optimise spinach production in saline environments.
Mustapha et al. (Thu,) studied this question.