Light, Roots, and Nutrients: Understanding Nitrate Uptake Regulation in Hydroponic Systems

Summary

My PhD research explored nitrate uptake regulation in hydroponics—a system where plants grow in nutrient-rich water without soil, offering sustainable production potential. Experiments with Arabidopsis showed that plants absorb most of the available nitrate but retain only what is needed, releasing the rest back almost simultaneously—a dynamic balance between uptake and use. Plants also prioritize internal nitrogen balance by adjusting allocation between root and shoot, rather than reacting immediately to external changes. Mechanical disturbance of roots, common in hydroponic systems due to oxygenation, significantly reduced growth without affecting nitrate uptake. After conducting extensive hydroponic experiments, I recognized the need for a practical tool to support hydroponic system planning. I developed a dynamic model that estimates how long a setup can sustain plant growth, and whether issues like rising EC, nutrient depletion, or imbalanced nutrient ratios may occur under different environmental conditions, system sizes, and replenishment strategies.