Changes in Salicylic Acid and Antioxidants during Induced Thermotolerance in Mustard Seedlings

DOI PDF 2 Citations
  • James F. Dat
    Institute of Biological Sciences, University of Wales, Aberystwyth, Ceredigion SY23 3DA, United Kingdom (J.F.D., I.M.S.)
  • Christine H. Foyer
    Environmental Biology Department, Institute of Grassland and Environmental Research, Aberystwyth, Ceredigion SY23 3EB, United Kingdom (J.F.D., C.H.F.)
  • Ian M. Scott
    Institute of Biological Sciences, University of Wales, Aberystwyth, Ceredigion SY23 3DA, United Kingdom (J.F.D., I.M.S.)

Abstract

<jats:title>Abstract</jats:title> <jats:p>Heat-acclimation or salicylic acid (SA) treatments were previously shown to induce thermotolerance in mustard (Sinapis alba L.) seedlings from 1.5 to 4 h after treatment. In the present study we investigated changes in endogenous SA and antioxidants in relation to induced thermotolerance. Thirty minutes into a 1-h heat-acclimation treatment glucosylated SA had increased 5.5-fold and then declined during the next 6 h. Increases in free SA were smaller (2-fold) but significant. Changes in antioxidants showed the following similarities after either heat-acclimation or SA treatment. The reduced-to-oxidized ascorbate ratio was 5-fold lower than the controls 1 h after treatment but recovered by 2 h. The glutathione pool became slightly more oxidized from 2 h after treatment. Glutathione reductase activity was more than 50% higher during the first 2 h. Activities of dehydroascorbate reductase and monodehydroascorbate reductase decreased by at least 25% during the first 2 h but were 20% to 60% higher than the control levels after 3 to 6 h. One hour after heat acclimation ascorbate peroxidase activity was increased by 30%. Young leaves appeared to be better protected by antioxidant enzymes following heat acclimation than the cotyledons or stem. Changes in endogenous SA and antioxidants may be involved in heat acclimation.</jats:p>

Journal

  • Plant Physiology

    Plant Physiology 118 (4), 1455-1461, 1998-12-01

    Oxford University Press (OUP)

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