Radial stem flow and its importance when measuring xylem hydraulic conductance

  • Luciano Pereira
  • Rafael Vasconcelos Ribeiro


Despite the importance of water transport efficiency for plant productivity, the current methods to measure the hydraulic conductance in stem segments are limited and can be tricky. These measurements may be unstable for several hours and there are no satisfactory procedures that allow choosing the moment to get reliable measures. Such instability may be generated by background flow, when there is a flow even without applying water pressure to induce the axial flow. Underlying mechanisms related to background flow are still unknown and based on available literature, we propose that the background flow is affected, or even explained, by the radial water flow and tissue capacitance. For this reason, both phenomena are fundamental for understanding plant water transport, the coupling between the phloem and xylem, and water relations under drought conditions. Besides addressing this issue, we suggest ways to study the radial water flow and capacitance in stem segments.


Water transport Plant hydraulic Background flow Drought Hydraulic efficiency 



L. Pereira and R. V. Ribeiro acknowledge the São Paulo Research Foundation (FAPESP, Brazil) and the National Council for Scientific and Technological Development (CNPq, Brazil) for fellowships granted (FAPESP, Grant no. 2017/14075-3; CNPq, Grant no. 305221/2014-0) and financial support (CNPq, Grant no. 401104/2016-8).


  1. Adams HD, Zeppel MJB, Anderegg WRL et al (2017) A multi-species synthesis of physiological mechanisms in drought-induced tree mortality. Nat Ecol Evol 1:1285–1291. CrossRefPubMedGoogle Scholar
  2. Anderegg WRL, Klein T, Bartlett M et al (2016) Meta-analysis reveals that hydraulic traits explain cross-species patterns of drought-induced tree mortality across the globe. Proc Natl Acad Sci 113:5024–5029. CrossRefPubMedPubMedCentralGoogle Scholar
  3. Bittencourt PRL, Pereira L, Oliveira RS (2016) On xylem hydraulic efficiencies, wood space-use and the safety-efficiency tradeoff. New Phytol 211:1152–1155. CrossRefPubMedGoogle Scholar
  4. Blackman CJ, Brodribb TJ (2011) Two measures of leaf capacitance: insights into the water transport pathway and hydraulic conductance in leaves. Funct Plant Biol 38:118. CrossRefGoogle Scholar
  5. Gleason SM, Westoby M, Jansen S et al (2016) Weak tradeoff between xylem safety and xylem-specific hydraulic efficiency across the world’s woody plant species. New Phytol 209:123–136. CrossRefPubMedGoogle Scholar
  6. Hacke UG, Venturas MD, MacKinnon ED et al (2015) The standard centrifuge method accurately measures vulnerability curves of long-vesselled olive stems. New Phytol 205:116–127. CrossRefPubMedGoogle Scholar
  7. Hölttä T, Vesala T, Sevanto S et al (2006) Modeling xylem and phloem water flows in trees according to cohesion theory and Münch hypothesis. Trees 20:67–78. CrossRefGoogle Scholar
  8. Hölttä T, Mencuccini M, Nikinmaa E (2009) Linking phloem function to structure: analysis with a coupled xylem-phloem transport model. J Theor Biol 259:325–337. CrossRefPubMedGoogle Scholar
  9. Kolb KJ, Sperry JS (1999) Differences in drought adaptation between subspecies of Sagebrush (Artemisia Tridentata). Ecology 80:2373–2384. CrossRefGoogle Scholar
  10. Pereira L, Mazzafera P (2013) A low cost apparatus for measuring the xylem hydraulic conductance in plants. Bragantia 71:583–587. CrossRefGoogle Scholar
  11. Pfautsch S, Renard J, Tjoelker MG, Salih A (2015) Phloem as capacitor: radial transfer of water into xylem of tree stems occurs via symplastic transport in ray parenchyma. Plant Physiol 167:963–971. CrossRefPubMedPubMedCentralGoogle Scholar
  12. Salomón RL, Limousin JM, Ourcival JM et al (2017) Stem hydraulic capacitance decreases with drought stress: implications for modelling tree hydraulics in the Mediterranean oak Quercus ilex. Plant Cell Environ 40:1379–1391. CrossRefPubMedGoogle Scholar
  13. Scoffoni C, Chatelet DS, Pasquet-kok J et al (2016) Hydraulic basis for the evolution of photosynthetic productivity. Nat Plants 2:16072. CrossRefPubMedGoogle Scholar
  14. Sevanto S, Hölttä T, Holbrook NM (2011) Effects of the hydraulic coupling between xylem and phloem on diurnal phloem diameter variation. Plant Cell Environ 34:690–703. CrossRefPubMedGoogle Scholar
  15. Torres-Ruiz JM, Sperry JS, Fernández JE (2012) Improving xylem hydraulic conductivity measurements by correcting the error caused by passive water uptake. Physiol Plant 146:129–135. CrossRefPubMedGoogle Scholar
  16. Waring RH, Whitehead D, Jarvis PG (1979) The contribution of stored water to transpiration in Scots pine. Plant Cell Environ 2:309–317. CrossRefGoogle Scholar
  17. Zwieniecki MA, Melcher PJ, Holbrook NM (2001) Hydraulic properties of individual xylem vessels of Fraxinus americana. J Exp Bot 52:257–264. CrossRefPubMedGoogle Scholar

Copyright information

© Brazilian Society of Plant Physiology 2018

Authors and Affiliations

  1. 1.Department of Plant Biology, Institute of BiologyUniversity of Campinas (UNICAMP)CampinasBrazil

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