Tree organ growth and carbon allocation dynamics impact the magnitude and δ13C signal of stem and soil CO2 fluxes

Yu Tang, Pauliina Schiestl-Aalto, Matthias Saurer, Elina Sahlstedt, Liisa Kulmala, Pasi Kolari, Kira Ryhti, Yann Salmon, Tuula Jyske, Yiyang Ding, Jaana Bäck, Katja T. Rinne‐Garmston

Research output: Contribution to journalArticleScientificpeer-review

Abstract

Incomplete knowledge of carbon (C) allocation dynamics in trees hinders accurate modeling and future predictions of tree growth. We studied C allocation dynamics in a mature Pinus sylvestris L. dominated forest with a novel analytical approach, allowing the first comparison of: (i) magnitude and delta C-13 of shoot, stem and soil CO2 fluxes (A(shoot), R-stem and R-soil), (ii) concentration and delta C-13 of compound-specific and/or bulk non-structural carbohydrates (NSCs) in phloem and roots and (iii) growth of stem and fine roots. Results showed a significant effect of phloem NSC concentrations on tracheid growth, and both variables significantly impacted R-stem. Also, concentrations of root NSCs, especially starch, had a significant effect on fine root growth, although no effect of root NSC concentrations or root growth was detected on R-soil. Time series analysis between delta C-13 of A(shoot) and delta C-13 of R-stem or delta C-13 of R-soil revealed strengthened C allocation to stem or roots under high C demands. Furthermore, we detected a significant correlation between delta C-13 of R-stem and delta C-13 of phloem sucrose and glucose, but not for starch or water-soluble carbohydrates. Our results indicate the need to include C allocation dynamics into tree growth models. We recommend using compound-specific concentration and delta C-13 analysis to reveal C allocation processes that may not be detected by the conventional approach that utilizes bulk organic matter.

Original languageEnglish
JournalTree Physiology
Volume42
Issue number12
Number of pages15
ISSN0829-318X
DOIs
Publication statusPublished - Dec 2022
MoE publication typeA1 Journal article-refereed

Fields of Science

  • 1184 Genetics, developmental biology, physiology
  • 4112 Forestry
  • 11831 Plant biology
  • boreal forest
  • compound-specific
  • non-structural carbohydrates (NSCs)
  • Pinus sylvestris
  • starch
  • sucrose
  • water-soluble carbohydrates (WSCs)
  • PINUS-SYLVESTRIS SEEDLINGS
  • SCOTS PINE
  • NORWAY SPRUCE
  • ISOTOPE DISCRIMINATION
  • SUMMER DROUGHT
  • DIOXIDE EFFLUX
  • ELEVATED CO2
  • LARCH TREES
  • RESPIRATION
  • PHLOEM

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