Separating water-potential induced swelling and shrinking from measured radial stem variations reveals a cambial growth and osmotic concentration signal

Tommy Chan, Teemu Holtta, Frank Berninger, Harri Makinen, Pekka Nojd, Maurizio Mencuccini, Eero Nikinmaa

Research output: Contribution to journalArticlepeer-review

Abstract

The quantification of cambial growth over short time periods has been hampered by problems to discern between growth and the swelling and shrinking of a tree stem. This paper presents a model, which separates cambial growth and reversible water-potential induced diurnal changes from simultaneously measured whole stem and xylem radial variations, from field-measured Scots pine trees in Finland. The modelled growth, which includes osmotic concentration changes, was compared with (direct) dendrometer measurements and microcore samples. In addition, the relationship of modelled growth and dendrometer measurements to environmental factors was analysed. The results showed that the water-potential induced changes of tree radius were successfully separated from stem growth. Daily growth predicted by the model exhibited a high correlation with the modelled daily changes of osmotic concentration in phloem, and a temperature dependency in early summer. Late-summer growth saw higher dependency on water availability and temperature. Evaluation of the model against dendrometer measurements showed that the latter masked a true environmental signal in stem growth due to water-potential induced changes. The model provides better understanding of radial growth physiology and offers potential to examine growth dynamics and changes due to osmotic concentration, and how the environment affects growth.

Original languageEnglish
Pages (from-to)233-244
Number of pages12
JournalPlant, Cell and Environment
Volume39
Issue number2
DOIs
Publication statusPublished - Feb 2016

Keywords

  • dendrometer
  • elasticity
  • hydraulic conductance
  • phloem
  • xylem
  • INTRAANNUAL TRACHEID PRODUCTION
  • SCOTS PINE STEMS
  • DIAMETER VARIATIONS
  • WOOD FORMATION
  • ENVIRONMENTAL-FACTORS
  • NORWAY SPRUCE
  • PICEA-ABIES
  • SAP FLOW
  • TRANSPORT MODEL
  • SUGAR-TRANSPORT

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