Size Matters: Influence of Available Soil Volume on theRoot Architecture and Plant Response at Transcriptomicand Metabolomic Levels in Barley

Pot size is a critical factor in plant growth experiments, influencing root architecture, nutrient uptake, and overall plantdevelopment as well as sensing of stress. In controlled environments, variation in pot size can impact phenotypic and molecularoutcomes and may bias experimental results. Here, we investigated how pot size affects the root system architecture andmolecular responses of two barley genotypes, the landrace BERE and the modern elite CONCERTO, through assessment ofshoot and root traits and by using X‐ray computed tomography complemented by transcriptomic and metabolomic analyses.The two genotypes showed distinctly different adaptations to changes in pot size. The landrace showed greater stability andadaptability with consistent root traits and enhanced accumulation of osmoprotectant metabolites across different pot sizes withrespect to CONCERTO. Conversely, the elite line was more sensitive to pot size variations, particularly showing altered rootarchitecture and transcriptomic responses. Overall, this study highlights the importance of selecting an appropriate pot size forplant growth experiments, particularly when focused on root traits, and highlights the importance of considering the physio-logical and molecular changes due to growth environment choice in experimental design in barley