Linking root phosphatase activity to root chemical and morphological traits across species – a global synthesis.

Root phosphatase activity (RPA) is an important physiological root trait, serving as hydrolyzing soil organic phosphorus into bioavailable orthophosphate and reflecting plants’ ability to acquire phosphorus. However, the global variation and its link with other root traits remains uncertain. By synthesizing the first global dataset of RPA comprising 607 observations across 258 species, we found that while RPA varies tremendously among species, N-fixers exhibited significantly higher RPA than non-fixers. However, RPA showed minimal variation across different growth forms and mycorrhizal types. Moreover, our results revealed globally widespread coordination and trade-offs between RPA and root morphology, architecture, and mycorrhizal symbiosis that are directly linked to phosphorus acquisition. However, there are few exceptions in certain groups, likely due to outlier species that employ unique strategies. Additionally, root nutrients are good predictors of RPA. RPA aligns closely with the collaboration dimension of the root economics space globally. We suggest that plants employ a range of phosphorus acquisition strategies, which could explain species coexistence in phosphorus-limited soils.