Foliar stoichiometry under different mycorrhizal types in relation to temperature and precipitation in grassland

Abstract

AimsMycorrhizas play key roles in important ecosystem processes and functions. Carbon (C), nitrogen (N) and phosphorus (P) concentrations and their ratios are very important foliar traits and their cycling constrains most ecosystem processes. Thus, this study addresses the influence of mycorrhizal strategies on these foliar nutrients and their response to climate change.MethodsA new database was established including mycorrhizal types and leaf Cmass, Nmass, Pmass, C: N and N: P of each plant species based on He et al. [(2008) Leaf nitrogen: Phosphorus stoichiometry across Chinese grassland biomes. Oecologia 155:301-10]. The predominant type of mycorrhizal association of each plant species was classified according to the published literature and our own observations. We analyzed leaf Cmass, Nmass, Pmass, C: N and N: P among 112 plant species in 316 samples of ascertained mycorrhizal type in the major grassland biomes of China.Important FindingsThe results show highly significant variation among different mycorrhizal strategy types for foliar C mass, Nmass and N: P. The highest foliar Cmass was observed in ectotrophic mycorrhiza (ECM) type (469.8mg g-1) followed by that in arbuscular mycorrhiza (AM) type (443.884mg g-1) and nonmycorrhizal (NM) type (434.0mg g-1). The foliar N concentration was significantly higher in NM type (31.0mg g-1). However, the AM type had the greater C:N value (19) than the other types although less variation in Cmass and N:P among abuscular types on AM strategy was observed. Foliar traits showed significant variation in response to precipitation (mean growing season and annual precipitation (GSP and MAP)) and temperature (mean growing season and annual temperatures (GST and MAT)) depending on different mycorrhizal strategies and arbuscular types. When the responses of all folia parameters to precipitation and temperature were compared, the influence of GSP on leaf traits was greater than the influence of GST. © 2012 The Author.