Diurnal dynamics can modify plant–microbial competition for N uptake via C allocation

Plant–microbial competition for N in the rhizosphere affects net primary production and N cycling, and depends on plant physiological factors, including photosynthesis and transpiration. Here, we studied the diurnal competition for N between plants and microorganisms and quantified plant C allocation by maize (Zea mays) and wheat (Triticum aestivum) in a nutrient-poor soil. In situ concurrent pulse 15NO3− and 13CO2 labeling was carried out to trace the N uptake from the soil and C allocation to plant–microorganisms–soil system in the first 12 and 24 h after labeling, corresponding to daytime and nighttime. Plants outcompeted microorganisms for NO3− uptake from the rhizosphere during daytime and nighttime. Diurnal dynamics had a low effect on microbial NO3− uptake, which varied between 7 and 15% of added N for maize and between 3 and 6% of added N for wheat after the first 12 and 24 hours. NO3− uptake by maize was not affected by diurnal dynamics, but NO3− uptake by wheat was higher during daytime than that during nighttime. The 13C allocation to plants and microorganisms was similar between daytime and nighttime. N utilization was closely related to photosynthate partitioning in plant shoots and roots, indicating coupling between C allocation and N utilization. These findings indicate that plants grown in nutrient-poor soils (as used in this study) dominate over microorganisms for N uptake and release newly photosynthesized C for rhizosphere microorganisms. The diurnal dynamics of these plant–microbial interactions are plant species–specific: important for wheat but irrelevant for maize. © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.

Liu M.1, 2 , Xu X. 1, 3 , Nannipieri P.4 , Kuzyakov Y. 1, 5, 6 , Gunina A.7, 8
Springer Verlag
Number of issue
  • 1 Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, 11A, Datun Road, Chaoyang District, Beijing, 100101, China
  • 2 College of Resources and Environment, University of Chinese Academy of Sciences, Yanqi Lake, Huairou District, Beijing, 101408, China
  • 3 CAS Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences (CAS), Beijing, 100101, China
  • 4 Emeritus Professor of Department of Agricultural, Food, Environmental and Forest Sciences and Technologies, University of Florence, P. le delle Cascine 28, Florence, 50144, Italy
  • 5 Department of Soil Science of Temperate Ecosystems, Department of Agricultural Soil Science, University of Göttingen, Büsgenweg 2, Göttingen, 37077, Germany
  • 6 Agro-Technological Institute, RUDN University, Moscow, 117198, Russian Federation
  • 7 Department of Environmental Chemistry, University of Kassel, Witzenhausen, 37213, Germany
  • 8 Tyumen State University, 6 Volodarskogo Street 625003, Tyumen, Russian Federation
13C and 15 N dual labeling; 15N recovery; Diurnal plant–microbial interactions; Microorganisms; Newly assimilated C; Rhizosphere processes
Date of creation
Date of change
Short link

Other records