Vol. 7, Issue 1, Part B (2025)

Background: Aeroponic systems offer a highly controllable root-zone environment for high-value horticultural crops, yet the biochemical mechanisms by which mineral nutrient formulations modulate nutrient uptake and plant metabolism in solanaceous vegetables remain insufficiently characterized. Objectives: This study investigated how variable mineral formulations influence growth, yield, nutrient use efficiency, nitrate accumulation and key biochemical traits in aeroponically grown tomato, sweet pepper and eggplant, with a view to deriving nutritionally and agronomically optimized nutrient solutions. Methods: Three solanaceous species were cultivated in a controlled-environment greenhouse using closed-loop aeroponic units. Plants were supplied with a standard mineral formulation or with modified solutions differing in N:K ratio, Ca-Mg supply and inclusion of beneficial elements (Si, Se). Growth and yield traits, fruit quality parameters and mineral composition of leaves, fruits and nutrient solutions were recorded. Biochemical assays quantified antioxidant enzyme activities (superoxide dismutase, catalase, peroxidase), non-enzymatic antioxidants (phenolics, ascorbate, carotenoids) and osmolytes. Apparent N recovery efficiency and fruit nitrate content were calculated. Data were analysed using ANOVA, correlation analysis and principal component analysis. Results: Modified mineral formulations significantly increased marketable yield across all three crops, with the Ca-Mg-Si-balanced treatment producing the largest gains relative to the standard solution. Enhanced yields were accompanied by improved fruit size, firmness and soluble solids, as well as higher N recovery efficiency and more favourable leaf K, Ca and Mg status. Fruit nitrate concentrations remained within safe limits and were lower under Ca-Mg-Si and Se + Si treatments. These optimized formulations also elevated antioxidant enzyme activities and levels of phenolics, ascorbate and carotenoids, indicating a more robust antioxidant system. Multivariate analyses revealed that nutrient use efficiency, antioxidant capacity and yield were tightly associated and clustered with the enriched formulations. Conclusion: Carefully engineered mineral formulations, particularly those enriched with Ca, Mg and Si with optional Se supplementation, can be used as effective biochemical levers to enhance nutrient uptake efficiency, productivity and nutritional quality of aeroponically grown solanaceous vegetables, while maintaining low nitrate levels in edible tissues.