1. Rhizosphere priming promotes plant nitrogen acquisition by microbial necromass recycling.
- Author
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Pausch J, Holz M, Zhu B, and Cheng W
- Subjects
- Carbon metabolism, Nitrogen Isotopes, Plant Shoots metabolism, Plant Shoots microbiology, Plants metabolism, Plants microbiology, Soil chemistry, Nitrogen metabolism, Plant Roots microbiology, Plant Roots metabolism, Rhizosphere, Soil Microbiology
- Abstract
Nitrogen availability in the rhizosphere relies on root-microorganism interactions, where root exudates trigger soil organic matter (SOM) decomposition through the rhizosphere priming effect (RPE). Though microbial necromass contribute significantly to organically bound soil nitrogen (N), the role of RPEs in regulating necromass recycling and plant nitrogen acquisition has received limited attention. We used
15 N natural abundance as a proxy for necromass-N since necromass is enriched in15 N compared to other soil-N forms. We combined studies using the same experimental design for continuous13 CO2 labelling of various plant species and the same soil type, but considering top- and subsoil. RPE were quantified as difference in SOM-decomposition between planted and unplanted soils. Results showed higher plant N uptake as RPEs increased. The positive relationship between15 N-enrichment of shoots and roots and RPEs indicated an enhanced necromass-N turnover by RPE. Moreover, our data revealed that RPEs were saturated with increasing carbon (C) input via rhizodeposition in topsoil. In subsoil, RPEs increased linearly within a small range of C input indicating a strong effect of root-released C on decomposition rates in deeper soil horizons. Overall, this study confirmed the functional importance of rhizosphere C input for plant N acquisition through enhanced necromass turnover by RPEs., (© 2024 The Authors. Plant, Cell & Environment published by John Wiley & Sons Ltd.)- Published
- 2024
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