2025-03-24 中国科学院(CAS)
Nitrogen enrichment’s impact on plant N:P stoichiometry. (Image by LV’s team)
<関連情報>
- https://english.cas.cn/newsroom/research_news/earth/202503/t20250324_908618.shtml
- https://onlinelibrary.wiley.com/doi/10.1111/gcb.70091
根を考慮した場合の窒素富化に対する植物のN:Pの強い反応 Stronger Response of Plant N:P to Nitrogen Enrichment When Considering Roots
Yu Ning, Feike A. Dijkstra, Xiao-Sa Liang, Xiao-Jing Zhang, Guo-Jiao Yang, Liang-Chao Jiang, Xing-Guo Han, Xiao-Tao Lü
Global Change Biology Published: 14 February 2025
DOI:https://doi.org/10.1111/gcb.70091
ABSTRACT
Nitrogen (N) enrichment leads to an imbalance of N and phosphorus (P) in plants by enhancing plant N:P, with consequences for ecosystem processes and function. However, the evidence for a plant N–P imbalance is predominantly from studies on aboveground tissues. It remains unclear whether imbalanced aboveground responses would be paralleled by similar responses in roots, which contribute to nearly 70% of total biomass in grasslands globally. We measured community-level N:P stoichiometry of both shoots and roots to 1 m depth across a wide-ranging N addition gradient in a temperate steppe after 7–9 years of treatment. Both shoot N:P (SNP) and root N:P (RNP) showed nonlinear responses to increasing N addition rates, where N:P first increased and then saturated. RNP was significantly higher than SNP and saturated at higher N addition rates than SNP (39.0 vs. 16.8 g N m-2 yr.-1). Furthermore, the inter-annual stability of RNP was higher than that of SNP. Consequently, N:P in whole plants was higher than that in shoots, indicating more severe N–P imbalance than based on shoot measurements only. Previous results from aboveground parts might have underestimated the enhancement of N enrichment on plant N:P. Our results imply that belowground food webs with roots as their food resource would be more severely suffering from N–P imbalance than aboveground food webs.
