Mechanisms for minimizing height-related stomatal conductance declines in tall vines

Jean Christophe Domec*, Henry Berghoff, Danielle A. Way, Menachem Moshelion, Sari Palmroth, Katre Kets, Cheng Wei Huang, Ram Oren

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

The ability to transport water through tall stems hydraulically limits stomatal conductance (gs), thereby constraining photosynthesis and growth. However, some plants are able to minimize this height-related decrease in gs, regardless of path length. We hypothesized that kudzu (Pueraria lobata) prevents strong declines in gs with height through appreciable structural and hydraulic compensative alterations. We observed only a 12% decline in maximum gs along 15-m-long stems and were able to model this empirical trend. Increasing resistance with transport distance was not compensated by increasing sapwood-to-leaf-area ratio. Compensating for increasing leaf area by adjusting the driving force would require water potential reaching −1.9 MPa, far below the wilting point (−1.2 MPa). The negative effect of stem length was compensated for by decreasing petiole hydraulic resistance and by increasing stem sapwood area and water storage, with capacitive discharge representing 8–12% of the water flux. In addition, large lateral (petiole, leaves) relative to axial hydraulic resistance helped improve water flow distribution to top leaves. These results indicate that gs of distal leaves can be similar to that of basal leaves, provided that resistance is highest in petioles, and sufficient amounts of water storage can be used to subsidize the transpiration stream.

Original languageAmerican English
Pages (from-to)3121-3139
Number of pages19
JournalPlant, Cell and Environment
Volume42
Issue number11
DOIs
StatePublished - 1 Nov 2019

Bibliographical note

Publisher Copyright:
© 2019 John Wiley & Sons, Ltd

Keywords

  • Pueraria lobata
  • capacitance
  • electrical circuit analogy
  • hydraulic compensation
  • hydraulic resistance
  • lianas
  • long-distance transport

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