Belowground responses of woody plants to nitrogen addition in a phosphorus-rich region of northeast China
- 13 Downloads
Nitrogen addition leads to large increases in shoot growth but limited increases in root growth and reductions in mycorrhizal colonization of Sorbus pohuashanensis and Acanthopanax sessiliflorus.
Soil in the cultivated fields of Changbai Mountain region of China is rich in phosphorus (P) and deficient in nitrogen (N) for most woody plants. However, currently N deposition is increasing and reducing its limitation on plant growth. How N addition shifts carbon investment among shoots, roots and arbuscular mycorrhizal (AM) fungi is not well understood, especially in woody plants growing in the field. We examine the responses of the growth, biomass partitioning and AM colonization of Sorbus pohuashanensis Hedl. and Acanthopanax sessiliflorus Seem. to low and high N fertilization in northeastern China on high-P soil over 3 years. With N addition, both plants increased shoot biomass by 20–45%, and N and P content by 13–30%, while root biomass increased only by 2.1–5.4%. The slower increase in root growth relative to shoot growth resulted in lower root mass fraction. After plant size (ontogeny) was accounted for, root mass fraction still decreased significantly with high N fertilization in both species. Mycorrhizal colonization intensity and AM-colonized root length decreased with an increase in N addition. In this P-rich site, the limited increase in root biomass and large decrease in AM colonization with N addition presumably promoted plant growth and nutrient uptake. Our results imply that the growth of these two species may be improved by increased carbon allocation to shoots, as N addition permitted sufficient nutrient uptake by roots and AM fungi to meet shoot nutrient demand without additional belowground carbon expenditure.
KeywordsArbuscular mycorrhiza Biomass partitioning Carbon investment Sorbus pohuashanensis Acanthopanax sessiliflorus
This work was financially supported by the National Key Basic Research Program of China (2016YFC0500703, 2016YFC0500407), the National Natural Science Foundation of China (31670446, 31270444) and Human Resources and Social Security Department of Jilin Province (2016-28). We thank anonymous reviewers and editor for their comments and suggestions.
Author contribution statement
JG, YG and CH designed the experiment and performed the study. CH and LS helped to establish and maintain the experimental plots. JG analyzed the data and drafted the first version of the manuscript. JG, YG and DME helped with manuscript revisions. All authors read and approved the final version of this manuscript.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
- Bremner JM, Mulvaney CS (1982) Nitrogen-total. In: Page AL, Miller RH, Keeney DR (eds) Methods of soil analysis. American Society of Agronomy, Madison, pp 595–608Google Scholar
- Brouwer R (1983) Functional equilibrium: sense or nonsense? Neth J Agric Sci 31:335–348Google Scholar
- Brundrett M, Bougher N, Dell B, Grove T, Malajczuk N (1996) Working with mycorrhizas in forestry and agriculture. ACIAR monograph. ACIAR, CanberraGoogle Scholar
- Hasselquist NJH, Metcalfe DB, Inselsbacher E, Stangl Z, Oren R, Näsholm T, Högberg P (2016) Greater carbon allocation to mycorrhizal fungi reduces tree nitrogen uptake in a boreal forest. Ecology 97:1012–1022Google Scholar
- Marschner H (1995) Mineral nutrition of higher plants. Academic Press, LondonGoogle Scholar
- Ouimette A (2017) Patterns and drivers of carbon fluxes in temperate forests. Dissertation, University of New HampshireGoogle Scholar
- Poorter H, Nagel O (2000) The role of biomass allocation in the growth response of plants to different levels of light, CO2, nutrients and water: a quantitative review. Aust J Plant Physiol 27:595–607Google Scholar
- Schortemeyer M, Atkin OK, McFarlane N, Evans JR (1999) The impact of elevated atmospheric CO2 and nitrate supply on growth, biomass allocation, nitrogen partitioning and N2 fixation of Acacia melanoxylon. Aust J Plant Physiol 26:737–747Google Scholar
- Smith SE, Read DJ (2008) Mycorrhizal symbiosis, 3rd edn. Academic Press, LondonGoogle Scholar
- Trouvelot A, Kough JL, Gianinazzi-Pearson V (1986) Mesure du taux de mycorhization VA d’un système radiculaire. Recherche de méthodes d’estimation ayant une signification fonctionnelle. In: Gianinazzi-Pearson V, Gianinazzi S (eds) Physiological and genetical aspects of mycorrhizae. INRA Press, Paris, pp 217–221Google Scholar
- Uchinomiya K, Iwasa Y (2014) Optimum resource allocation in the plant–fungus symbiosis for an exponentially growing system. Evol Ecol Res 16:363–372Google Scholar
- Zhang L, Bai Y, Han X (2004) Differential responses of N:P stoichiometry of Leymus chinensis and Carex korshinskyi to N additions in a steppe ecosystem in Nei Mongol. Acta Bot Sinica 46:259–270Google Scholar