Ionomic profiling reveals temporal dynamics and element-specific allocation patterns of mineral nutrients during melon fruit development

Melon ( Cucumis melo L.) is a globally important horticultural crop requiring precise mineral nutrient management for optimal yield and quality, yet current knowledge of meso- and micronutrient dynamics during fruit development remains particularly limited. Ionomic profiling of nine essential mineral nutrients was performed across four developmental stages (0, 9, 30, and 40 days after anthesis (DAA)) in the different organs of melon plants grown in soilless substrates under greenhouse conditions. The results revealed contrasting patterns between temporal uptake dynamics and element-specific allocation. All elements followed a two-phase pattern of utilization: intensive root uptake during rapid fruit enlargement (0-30 DAA), when 73-86% of the final whole-plant nutrient amounts were accumulated, followed by almost complete cessation of uptake and internal resource remobilization during fruit maturation (30-40 DAA). In contrast, allocation patterns between vegetative organs and fruit were element-specific, with minerals separated into three groups: fruit-preferential allocation for phosphorus and zinc (posing risks of vegetative depletion), restricted fruit allocation for calcium, magnesium, sulfur, iron, and boron (suggesting potential insufficiency in the fruit accumulation of quality-related elements), and intermediate allocation for potassium and manganese. These findings provide a physiological basis for developing element-specific and temporally optimized nutrient management strategies in melon production.