Responses of nutrient capture and fine root morphology of subalpine coniferous tree Picea asperata to nutrient heterogeneity and competition

PLoS One. 2017 Nov 2;12(11):e0187496. doi: 10.1371/journal.pone.0187496. eCollection 2017.

Abstract

Investigating the responses of trees to the heterogeneous distribution of nutrients in soil and simultaneous presence of neighboring roots could strengthen the understanding of an influential mechanism on tree growth and provide a scientific basis for forest management. Here, we conducted two split-pot experiments to investigate the effects of nutrient heterogeneity and intraspecific competition on the fine root morphology and nutrient capture of Picea asperata. The results showed that P. asperata efficiently captured nutrients by increasing the specific root length (SRL) and specific root area (SRA) of first-and second-order roots and decreasing the tissue density of first-order roots to avoid competition for resources and space with neighboring roots. The nutrient heterogeneity and addition of fertilization did not affect the fine root morphology, but enhanced the P and K concentrations in the fine roots in the absence of a competitor. On the interaction between nutrient heterogeneity and competition, competition decreased the SRL and SRA but enhanced the capture of K under heterogeneous soil compared with under homogeneous soil. Additionally, the P concentration, but not the K concentration, was linearly correlated to root morphology in heterogeneous soil, even when competition was present. The results suggested that root morphological features were only stimulated when the soil nutrients were insufficient for plant growth and the nutrients accumulations by root were mainly affected by the soil nutrients more than the root morphology.

MeSH terms

  • Fertilizers
  • Picea / physiology*
  • Plant Roots / growth & development*
  • Plant Roots / metabolism
  • Plant Shoots / growth & development*
  • Plant Shoots / metabolism

Substances

  • Fertilizers

Grants and funding

This study was supported jointly by the National Key R&D Program of China (2017YFC0505002 to DL), the National Natural Science Foundation of China (31400424 to DL, 31570477 to CZ, 31370495 to CY) and West Light Foundation of the Chinese Academy of Sciences (Y4C2021 to DL). study design: DL data collection: DL CY data analysis: DL, HY, CZ decision to publish: DL preparation of the manuscript: DL. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.