University Of Tasmania
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Osmotic adjustment and hormonal regulation of stomatal responses to vapour pressure deficit in sunflower

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journal contribution
posted on 2023-05-21, 12:21 authored by Cardoso, AA, Timothy BrodribbTimothy Brodribb, Kane, CN, DaMatta, FM, McAdam, SAM
Dynamic variation of the stomatal pore in response to changes in leaf-air vapour pressure difference (VPD) constitutes a critical regulation of daytime gas exchange. The stomatal response to VPD has been associated with both foliage abscisic acid (ABA) and leaf water potential (W l); however, causation remains a matter of debate. Here, we seek to separate hydraulic and hormonal control of stomatal aperture by manipulating the osmotic potential of sunflower leaves. In addition, we test whether stomatal responses to VPD in an ABA-deficient mutant (w-1) of sunflower are similar to the wild type. Stomatal apertures during VPD transitions were closely linked with foliage ABA levels in sunflower plants with contrasting osmotic potentials. In addition, we observed that the inability to synthesize ABA at high VPD in w-1 plants was associated with no dynamic or steady-state stomatal response to VPD. These results for sunflower are consistent with a hormonal, ABA-mediated stomatal responses to VPD rather than a hydraulic-driven stomatal response to VPD.


Publication title

AOB Plants










School of Natural Sciences


Oxford University Press

Place of publication

United Kingdom

Rights statement

© The Author(s) 2020. This is an Open Access article distributed under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0) License, (, which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.

Repository Status

  • Open

Socio-economic Objectives

Expanding knowledge in the biological sciences