Compartmentalized Homeostasis Drives High Bamboo Forest Productivity under Nutrient Imbalance.

Stoichiometric homeostasis, the ability to maintain internal nutrient balance, is central to plant fitness under soil nutrient variability. While traditionally viewed as static, emerging theory posits that it is a conditionally flexible trait, though empirical evidence is scarce. Through large-scale field investigations, nutrient additions, and data synthesis, this study shows that Moso bamboo (Phyllostachys edulis), a fast-growing plant species, employs a unique compartmentalized homeostasis strategy by decoupling nitrogen (N) and phosphorus (P) regulation across tissues. It achieves strict N:P homeostasis in leaves while allowing P flexibility in woody tissues to serve as reservoirs that buffer leaves from soil P limitation and microbial competition. This mechanism, consistently observed in bamboo across wide geographical and soil nutrient gradients, yields lower leaf N:P variability than 75 out of 91 co-occurring tree species, can be one of the critical factors for sustaining ≈25% higher annual productivity than other forests (including evergreen-broadleaf, deciduous-broadleaf, and coniferous forests). These findings reconcile classical views of stoichiometric homeostasis and plasticity by demonstrating a flexible, compartmentalized mechanism that resolves growth-stability conflicts. Recognizing such flexible strategy advances the understanding of eco-evolutionary feedbacks in ecosystem stoichiometry and improves predictions of species adaptability, nutrient cycling, and carbon sequestration under global change.