Li Cai, Sheng Hu, Tan Mengxi, Dai Hengyi, Wang Xiaolong, Xu Huacheng, Ding Shiming, Zhao Guoqiang
State Key Laboratory of Lake and Watershed Science for Water Security, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, China.
Faculty of Agriculture, Life, and Environmental Sciences, Zhejiang University, Hangzhou, China.
Nat Commun. 2025 May 13;16(1):4413. doi: 10.1038/s41467-025-59637-x.
Phosphorus (P) availability is vital for global primary productivity, yet it is often immobilized in soils by redox-inert crystalline iron (oxy)hydroxides. Here we show that diel radial oxygen loss (ROL) from plant roots induces redox fluctuations in the rhizosphere, activating these iron minerals and enhancing P mobilization. Nighttime reduction and daytime oxidation drive the formation of reactive metastable iron phases (RMPs) on root surfaces, forming a redox-active iron plaque. These RMPs undergo rapid dissolution-reformation cycles, facilitating P transfer from soil to porewater for plant uptake. Using multiple aquatic plants from agriculturally developed regions, we demonstrate that ROL broadly enhances soil P availability. In rice paddies, ROL-activated P release accounts for 8.7% of global P fertilizer input, contributing an estimated economic value of USD 0.52 billion annually. Our findings uncover a previously overlooked redox mechanism by which plants enhance P acquisition, with broad implications for nutrient cycling and agricultural sustainability.
磷（P）的有效性对全球初级生产力至关重要，然而它常常被氧化还原惰性的结晶铁（氢）氧化物固定在土壤中。在这里，我们表明植物根系的昼夜径向氧损失（ROL）会引起根际的氧化还原波动，激活这些铁矿物并增强磷的活化。夜间还原和白天氧化驱动根表面反应性亚稳铁相（RMPs）的形成，形成氧化还原活性铁斑。这些RMPs经历快速的溶解 - 再形成循环，促进磷从土壤转移到孔隙水中以供植物吸收。使用来自农业发达地区的多种水生植物，我们证明ROL广泛提高了土壤磷的有效性。在稻田中，ROL激活的磷释放占全球磷肥投入的8.7％，每年估计贡献经济价值0.52亿美元。我们的研究结果揭示了一种以前被忽视的氧化还原机制，通过该机制植物增强了磷的获取，对养分循环和农业可持续性具有广泛影响。
