P-acquisition and use

How plants reconfigure their P-acquisition and utilization strategies under P limitation, and the consequences for community assembly, remain unclear. To address this, we integrated a global meta-analysis of grassland N-manipulation studies with a 9-year field experiment in a Eurasian meadow steppe to reveal general patterns and resolve underlying mechanisms.

By tracking three key phenological stages of regreening, flowering, and yellowing in the case study, we unraveled how N enrichment reshapes plant P-acquisition strategies and leaf P fraction dynamics. Across global grasslands, we find N enrichment increased root phosphatase activity, leaf Mn concentrations, and root exudation rate, while decreased root mycorrhizal colonization. In the case study, dominant carboxylates of root shift from low-molecular oxalic acid (90 Da) at regreening stage to high-molecular citric acid (192 Da), tartaric acid (150 Da), and maleic acid (116 Da) at flowering stage, and down to formic acid (46 Da) at yellowing stage, pointing to a potential trade-off between carbon investment and metabolic overflow.