Impact of Ascophyllum nodosum extract biostimulants on nutrient use efficiency and seedling establishment in wheat and barley

Introduction: Seedling emergence and early crop establishment are critical stages for crop productivity, yet they are highly vulnerable to abiotic stress and nutrient limitation. Although plant biostimulants have emerged as promising tools to enhance crop resilience, their influence on micronutrient dynamics during early development remains poorly understood. This study provides one of the first integrated assessments of micronutrient uptake and remobilisation in two major cereal crops, winter barley and wheat, during early seedling growth. Methods: Three commercial Ascophyllum nodosum extracts (ANE A, ANE B and ANE C) were compared to determine whether compositional differences translated into distinct physiological responses in wheat. Under controlled in-vitro conditions using nutrient-free (0 MS) and reduced-nutrient (1/10 MS) media, ANE A was applied either foliarly or directly to the growth medium. Its influence on nutrients uptake and remobilisation was assessed using ICP-MS. Results: The extracts showed clear functional divergence: ANE A and ANE C significantly increased biomass, with ANE A primarily enhancing root growth and uniquely increasing several micronutrients, while all extracts improved selected macro- and secondary nutrients. Based on its performance, ANE A was selected for detailed mechanistic evaluation. Across both cereals, ANE A significantly increased root biomass (12-26% over controls) and induced distinct shifts in macro- (K, P), secondary- (Ca, Mg) and micronutrient (B, Mn, Cu, Fe, Mo, Zn) accumulation and partitioning. Nutrient use efficiency metrics further confirmed enhanced uptake and translocation, indicating an active role of ANE A in micronutrient mobilisation. Discussion: By revealing how ANE A reprograms early nutrient allocation and improves micronutrient dynamics under nutrient-limited conditions, this study advances mechanistic understanding of ANE-based biostimulants and supports their potential use in resilient, sustainable nutrient management strategies for cereal production.