An abscisic acid-related reduced transpiration promotes gradual embolism repair when grapevines are rehydrated after drought

Authors

  • Claudio Lovisolo,

    1. Dipartimento Colture Arboree, Universita’ di Torino, via Leonardo da Vinci 44, I–10095 Grugliasco, Italy;
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    • *

      These authors contributed equally to this work.

  • Irene Perrone,

    1. Dipartimento Colture Arboree, Universita’ di Torino, via Leonardo da Vinci 44, I–10095 Grugliasco, Italy;
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    • *

      These authors contributed equally to this work.

  • Wolfram Hartung,

    1. Julius-von-Sachs Institut, Lehrstuhl Botanik I, Universität Würzburg, Julius-von-Sachs Platz 2, D–97082 Würzburg, Germany
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  • Andrea Schubert

    1. Dipartimento Colture Arboree, Universita’ di Torino, via Leonardo da Vinci 44, I–10095 Grugliasco, Italy;
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Author for correspondence:
Claudio Lovisolo
Tel: +39 0116708926
Fax: +39 0112368926
Email: claudio.lovisolo@unito.it

Summary

  • • Proposed mechanisms of embolism recovery are controversial for plants that are transpiring while undergoing cycles of dehydration and rehydration.
  • • Here, water stress was imposed on grapevines (Vitis vinifera), and the course of embolism recovery, leaf water potential (Ψleaf), transpiration (E) and abscisic acid (ABA) concentration followed during the rehydration process.
  • • As expected, Ψleaf and E decreased upon water stress, whereas xylem embolism and leaf ABA concentration increased. Upon rehydration, Ψleaf recovered in 5 h, whereas E fully recovered only after an additional 48 h. The ABA content of recovering leaves was higher than in droughted controls, both on the day of rewatering and the day after, suggesting that ABA accumulated in roots during drought was delivered to the rehydrated leaves. In recovering plants, xylem embolism in petioles, shoots, and roots decreased during the 24 h following rehydration.
  • • A model is proposed to describe plant recovery after rehydration based on three main points: embolism repair occurs progressively in shoots and further in roots and in petioles, following an almost full recovery of Ψleaf; hydraulic conductance recovers during diurnal transpiring hours, when formation and repair of embolisms occurs in all plant organs; an ABA residual signal in rehydrated leaves hinders stomatal opening even when water relations have recovered, suggesting that an ABA-induced transpiration control promotes gradual embolism repair in rehydrated grapevines.

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