Plant Growth Regulation

, Volume 55, Issue 3, pp 165–167 | Cite as

A rapid effect of applied brassinolide on abscisic acid concentrations in Brassica napus leaf tissue subjected to short-term heat stress

  • Leonid V. KurepinEmail author
  • Mirwais M. Qaderi
  • Thomas G. Back
  • David M. Reid
  • Richard P. Pharis
Brief Communication


Three-week old canola (Brassica napus L.) seedlings grown at 20/16°C (day/night) were subjected to short-term (4 and 8 h) heat stress (45°C) or maintained at a normal temperature of 20°C. Half of the plants under each treatment received a 10−6 M solution of brassinolide (BL) 1 h prior to beginning the temperature treatments. The concentration (ng/g dry weight) of endogenous abscisic acid (ABA) was subsequently determined in young leaves via the stable isotope dilution method. Applied BL had no effect on endogenous ABA for plants maintained at normal temperatures. However, ABA concentration was significantly elevated by heat stress alone and doubled by heat stress + BL. These results suggest that the well-known enhancement of tolerance to high temperature stress that can be obtained by BL or 24-epi-BL applications may be caused by a brassinosteroid-induced elevation in endogenous ABA concentration.


Brassinolide Brassinosteroids Abscisic acid Heat stress 



This work was funded by NSERC (Canada) grants to RPP, DMR and TGB.


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Copyright information

© Springer Science+Business Media B.V. 2008

Authors and Affiliations

  • Leonid V. Kurepin
    • 1
    Email author
  • Mirwais M. Qaderi
    • 1
  • Thomas G. Back
    • 2
  • David M. Reid
    • 1
  • Richard P. Pharis
    • 1
  1. 1.Department of Biological SciencesUniversity of CalgaryCalgaryCanada
  2. 2.Department of ChemistryUniversity of CalgaryCalgaryCanada

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