Osmoregulation in water stressed roots: Responses of leaf conductance and photosynthesis

Authors

  • H. Düring
  • P. R. Dry

DOI:

https://doi.org/10.5073/vitis.1995.34.15-17

Keywords:

osmoregulation, water stress, root, shoot communication, leaf conductance, photosynthesis

Abstract

Kober 5 BB vines were subjected to either moderate and slow soil dehydration or to repeated, severe and rapid stress and irrigation cycles. Moderate soil dehydration to 50 % of the soil water capacity led to a small but significant decrease of the osmotic potential at RWC = 100 %, i.e. to osmoregulation in root tips, but not in other parts of the roots. Osmoregulation was associated with the maintenance of a high water status in the root tips and high rates of leaf gas exchange. In a second experiment three severe and rapid drying cycles led to a decrease of the osmotic potential at RWC = 100 % in root tips as well as in unsuberised and suberised roots, the maximum rate being 2.3 bar. In this experiment osmoregulation in roots contributed to a partial increase of the root water status. The observation that, despite a low soil moisture content, leaf conductance and rate of photosynthesis had slightly recovered is discussed.

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Published

2015-08-13

Issue

Vol. 34 No. 1 (1995): Vitis

Section

Article

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