The Impact of Seaweed Application on Some Growth and Physiological Parameters and Nutrient Uptake in Arugula Under Deficit Irrigation Conditions

Deficit irrigation is a widely used strategy to optimize water use efficiency in agriculture; however, it often causes stress on plant growth and nutrient uptake. This study was conducted to evaluate the effects of seaweed extract on the dry matter content, some physiological responses, and macro and micro nutrient uptake of arugula (Eruca sativa L.) under deficit irrigation conditions. A controlled plant growing chamber experiment was conducted using three irrigation regimes (I100: full irrigation-control, I75: 25% deficit irrigation and I50: 50% deficit irrigation of field capacity) with and two seaweed extract application (SW0: non seaweed extract and SW1: 2 ml L⁻¹). The experiment was conducted using a factorial design in three replicate randomized blocks. Dry matter content, leaf water content, electrolyte leakage, and the uptake of certain nutrient elements (K, Mg, Fe, Ca, and Na) were measured. The results showed that insufficient irrigation reduced the leaf water content of arugula while increasing electrolyte leakage. Additionally, increased water restriction reduced the uptake of K, Mg, Fe, Ca, and Na. Seaweed application reduced electrolyte leakage by %20 compared to the control and increased the uptake of K, Mg, Fe, and Ca by approximately %7, %6, %10, and %11, respectively. It was observed that plants treated with seaweed reduced Na uptake by approximately %8 compared to untreated plants. Plants treated with seaweed mitigated stress effects under water deficiency and improved yield compared to untreated plants. These findings suggest that seaweed biostimulants could serve as a promising agricultural tool to enhance arugula tolerance to water stress by promoting physiological stability and nutrient uptake under suboptimal water availability.