Phloem pp 135-142 | Cite as

Measurement of Inner Bark and Leaf Osmolality

  • Teemu PaljakkaEmail author
  • Anna Lintunen
  • Yann Salmon
  • Teemu Hölttä
Part of the Methods in Molecular Biology book series (MIMB, volume 2014)


Sugar transport in the phloem is driven by turgor pressure gradients which are created by osmotic gradients resulting from sugars loaded to the phloem at the source tissue and unloaded at the sink tissue. Therefore, osmolality is a key parameter that can be used to evaluate sugar status and get an indication of the driving force for phloem transport. Here we describe how osmotic concentration measurements from inner bark (practically, the phloem) and needles of trees can be measured. This protocol presents the procedure used by Lintunen et al. (Front Plant Sci 7:726, 2016) and Paljakka et al. (Plant Cell Environ 40:2160–2173, 2017), extended by practical advice and discussion of potential errors and caveats. We describe how to implement this procedure for gymnosperm as well as angiosperm trees. This method uses mechanical sap extraction with a centrifuge from inner bark and leaf samples, which have gone through a deep freeze treatment and thawing. The osmotic potential of these samples is then analyzed with a freezing point or vapor pressure osmometer. The aim of these measurements is to study the spatial and temporal dynamics of phloem function.

Key words

Phloem Osmolality Osmotic potential Water potential Conifer Method description 


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Copyright information

© Springer Science+Business Media, LLC, part of Springer Nature 2019

Authors and Affiliations

  • Teemu Paljakka
    • 1
    Email author
  • Anna Lintunen
    • 1
    • 2
  • Yann Salmon
    • 1
    • 2
  • Teemu Hölttä
    • 1
  1. 1.Faculty of Agriculture and Forestry, Institute for Atmospheric and Earth System Research/Forest SciencesUniversity of HelsinkiHelsinkiFinland
  2. 2.Faculty of Science, Institute for Atmospheric and Earth System Research/PhysicsUniversity of HelsinkiHelsinkiFinland

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