Contrasting effects of nitrogen and phosphorus additions on fine root production and morphological traits of different plant functional types in an ombrotrophic peatland

• Published in: Plant and soil 2023-09, Vol.490 (1-2), p.451-467
• Main Authors: Ge, Leming, Chen, Chen, Li, Tong, Bu, Zhao-Jun, Wang, Meng
• Format: Article
• Language: English
• Subjects: Agriculture; Biomedical and Life Sciences; Diameters; Ecology; Fertilization; Growing season; Life Sciences; Morphology; Nitrogen; Outsourcing; Peatlands; Phosphorus; Plant Physiology; Plant Sciences; Plant tissues; Research Article; Roots; Shrubs; Soil Science & Conservation
• ISSN: 0032-079X; 1573-5036
• DOI: 10.1007/s11104-023-06087-3

Background and aims Changes in morphological traits of fine roots indicate shift in adaptive strategies. However, it remains unclear how nitrogen (N) and phosphorus (P) depositions change fine root adaptive strategies in peatlands, both in the growing and non-growing seasons. Methods We collected fine roots from shrubs and herbaceous plants after 2-year N and P additions and measured key morphological traits to evaluate different adaptive strategies. Results During the growing season, P addition significantly increased shrub fine root production (FRP) by decreasing fine root length (FRL) under ambient N condition, while the effect was diminished when P was added in combination with N. Phosphorus addition significantly increased FRP by increasing FRL and fine root diameter (FRD) of herbaceous plants irrespective of N addition rate. Fine roots of shrub and herbaceous plants adopted contrasting adaptive strategies after fertilization. Fine roots of both shrub and herbaceous plants still grew in the non-growing season, but only shrub FRP was significantly decreased after N addition by decreasing root tissue density (RTD). Conclusion Shrub FRP was more responsive to N addition whereas P addition had a stronger impact on herbaceous FRP. Nitrogen and P additions may have led to a shift towards the “outsourcing” strategy for herbaceous fine roots, whereas shrub fine roots tended to adopt the “fast” conservation strategy under P addition. Overall, N addition was disadvantageous to shrubs to survive cold winter. Our findings can advance the understanding of changes in fine root adaptation in northern peatlands under imbalanced N and P deposition.