EGU23-8897, updated on 26 Feb 2023
EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Nitrogen reallocation during alpine plant senescence contributed to plant nutrient conservation and ecosystem nitrogen retention 

Qingzhou Zhao1,2, Gabriel Smith2, Peng Wang1, Lingyan Hu1, Miaojun Ma3, Colin Averill2, Thomas Crowther2, and Shuijin Hu1,4
Qingzhou Zhao et al.
  • 1College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China
  • 2Department of Environmental Systems Science, Institute of Integrative Biology, ETH Zurich, Zurich 8092, Switzerland
  • 3State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou 730000, China
  • 4Department of Entomology & Plant Pathology, North Carolina State University, Raleigh 27695, United States (

To conserve limiting nitrogen (N) in alpine ecosystems, herbaceous plants resorb and reallocate N from senescing tissues. However, the extent of N resorption and reallocation in aboveground tissues, coarse roots, fine roots and their relative contributions to whole-plant N conservation and ecosystem N retention remain poorly understood. Utilizing N stable isotope (15N) as a tracer, we quantified N partitions and N retranslocation efficiencies (NRE, % of N changes for each N pool) during senescence among different plant organs in a Tibetan alpine system. We found that compared to the N pools at the peak biomass stage, substantial 15N infine roots (FR, 39.93%) and aboveground tissues (shoot, 50.94%) was retranslocated primarily to coarse roots (CR, an increase of 79.02% in 15N) and non-extractable soil organic matter (an increase of 37.39% in 15N), corresponding to a temporal shift of plant trait syndrome from poor conservation to strong conservation during senescence. 15N in particulate organic matter and mineral-associated organic matter fractions during the senescence stage increased by 29.80% and 24.30%, respectively, but microbial biomass 15N significantly decreased. Our results illustrate the key role of N retranslocation to coarse roots and organic matter in N retention and the dual role of plant roots and organic matter as N sink and source in the plant-microbe-soil system. These findings suggest that plant N retranslocation and seasonal trait alternation facilitate the spatial and temporal coupling between plant N demand and bioavailable N supply in N-limiting alpine systems.


How to cite: Zhao, Q., Smith, G., Wang, P., Hu, L., Ma, M., Averill, C., Crowther, T., and Hu, S.: Nitrogen reallocation during alpine plant senescence contributed to plant nutrient conservation and ecosystem nitrogen retention , EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-8897,, 2023.