Document Detail

The glutathione system as a stress marker in plant ecophysiology: is a stress-response concept valid?
MedLine Citation:
PMID:  15234995     Owner:  NLM     Status:  MEDLINE    
Environmental stress impacts cause an increased formation of reactive oxygen species (ROS) in the chloroplasts (photo-oxidative stress). The role of glutathione in the antioxidative defence system provides a rationale for its use as a stress marker. However, responses of glutathione concentrations and redox states are not consistent among the large number of available publications. In the present review the hypothesis that stress responses of the glutathione system follow a general ecophysiological stress-response concept is investigated. In this view, an initial response phase would be followed by an acclimation phase where a new steady-state is established. Alternatively, if successful acclimation is not achieved, degradation of the system will follow. Recent publications dealing with responses to photochilling, salinity, and drought are analysed as to whether the results fit the concept. In general, an initial stress response was related to changes in the glutathione redox state, whereas acclimation was marked by increased glutathione concentrations, increased related enzyme activities, and/or a more reduced redox state of glutathione. The latter was interpreted as overcompensation leading to enhanced regeneration of glutathione. Deterioration effects upon strong stress impacts were related to progressive degradation and oxidation of the glutathione pool. A time-course analysis, which has rarely been done in the published literature, showed this sequence of events. When apple trees were subjected to progressing drought, the initial response was a slight oxidation of the glutathione pool, followed by increased glutathione concentrations. When the stress increased, glutathione concentrations dropped and redox state became more oxidized, which marked the degradation of the system. In spite of the general congruency of these results with the suggested stress-response concept, several limitations have to be highlighted: The importance of the glutathione system relative to other components of the photoprotective and antioxidative defence system, as well as relative to stress avoidance strategies, has to be established. It is suggested that a variety of parameters taking into account alternative protection pathways (e.g. photorespiration, light dissipation) and other components of the antioxidative systems should be measured. Within such response patterns the glutathione system is a valuable stress marker in ecophysiological studies.
Michael Tausz; Helena Sircelj; Dieter Grill
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2004-07-02
Journal Detail:
Title:  Journal of experimental botany     Volume:  55     ISSN:  0022-0957     ISO Abbreviation:  J. Exp. Bot.     Publication Date:  2004 Aug 
Date Detail:
Created Date:  2004-08-09     Completed Date:  2005-01-31     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  9882906     Medline TA:  J Exp Bot     Country:  England    
Other Details:
Languages:  eng     Pagination:  1955-62     Citation Subset:  IM    
Forest Science Centre, University of Melbourne, Australia.
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MeSH Terms
Glutathione / metabolism,  physiology*
Models, Biological
Oxidative Stress
Plant Physiological Phenomena*
Plants / metabolism*
Reactive Oxygen Species / metabolism
Sodium Chloride / metabolism
Reg. No./Substance:
0/Reactive Oxygen Species; 70-18-8/Glutathione; 7647-14-5/Sodium Chloride

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