ASHS 2025 Conference

Magnesium (Mg) is a critical macronutrient in plant physiology, playing a central role in photosynthesis, enzyme activation, and energy metabolism. As the core atom in the chlorophyll molecule, magnesium in form of Magnesium Sulphate, directly influences chlorophyll biosynthesis and overall plant health. This study investigated the effects of varying magnesium concentrations from very low (100 mg/L), low (150 mg/L), medium (200 mg/L), high (250 mg/L), on chlorophyll accumulation in watercress. Watercress (Nasturtium officinale) is a fast-growing, nutrient-rich leafy vegetable from the Brassicaceae family. The main objective of the study was to determine the optimal magnesium application level that maximizes the chlorophyll content without causing nutrient imbalances. The experiment was conducted under controlled environmental conditions using a split plot design. Watercress was grown hydroponically using nutrient film techniques throughout key stages of vegetative growth. Chlorophyll content was assessed using SPAD (Soil Plant Analysis Development) meter readings and confirmed through spectrophotometric analysis of chlorophyll extracts. Results revealed that all magnesium treatments led to significant increases in chlorophyll content compared to the untreated control group. The most significancy concentration occurred at 200 mg/L and 250 mg/L concentrations, with 200 mg/L emerging as the most efficient level for promoting chlorophyll accumulation without physiological stress. Enhanced chlorophyll levels correlated with improved leaf coloration; deep green color and overall vigor, suggesting greater photosynthetic efficiency and biomass potential. This study demonstrates that appropriate magnesium fertilization can substantially improve chlorophyll concentration and physiological performance in watercress. These findings offer valuable guidance for growers seeking to optimize yield and quality of leafy greens through targeted nutrient management. Future research should explore supplemental magnesium fertilization effects on biomass accumulation and interactions with other macronutrients.