Document Detail

Emission of isoprene from salt-stressed Eucalyptus globulus leaves.
MedLine Citation:
PMID:  10938376     Owner:  NLM     Status:  MEDLINE    
Eucalyptus spp. are among the highest isoprene emitting plants. In the Mediterranean area these plants are often cultivated along the seashore and cope with recurrent salt stress. Transient salinity may severely but reversibly reduce photosynthesis and stomatal conductance of Eucalyptus globulus leaves but the effect on isoprene emission is not significant. When the stress is relieved, a burst of isoprene emission occurs, simultaneously with the recovery of photosynthetic performance. Later on, photosynthesis, stomatal conductance, and isoprene emission decay, probably because of the onset of leaf senescence. Isoprene emission is not remarkably affected by the stress at different light intensities, CO(2) concentrations, and leaf temperatures. When CO(2) was removed and O(2) was lowered to inhibit both photosynthesis and photorespiration, we found that the residual emission is actually higher in salt-stressed leaves than in controls. This stimulation is particularly evident at high-light intensities and high temperatures. The maximum emission occurs at 40 degrees C in both salt-stressed and control leaves sampled in ambient air and in control leaves sampled in CO(2)-free and low-O(2) air. However, the maximum emission occurs at 45 degrees C in salt-stressed leaves sampled in CO(2)-free and low-O(2) air. Our results suggest the activation of alternative non-photosynthetic pathways of isoprene synthesis in salt-stressed leaves and perhaps in general in leaves exposed to stress conditions. The temperature dependence indicates that this alternative synthesis is also under enzymatic control. If this alternative synthesis still occurs in the chloroplasts, it may involve a thylakoid-bound isoprene synthase.
F Loreto; S Delfine
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Plant physiology     Volume:  123     ISSN:  0032-0889     ISO Abbreviation:  Plant Physiol.     Publication Date:  2000 Aug 
Date Detail:
Created Date:  2000-10-18     Completed Date:  2000-10-18     Revised Date:  2010-09-14    
Medline Journal Info:
Nlm Unique ID:  0401224     Medline TA:  Plant Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1605-10     Citation Subset:  IM    
Consiglio Nazionale delle Ricerche, Istituto di Biochimica ed Ecofisiologia Vegetali, Via Salaria Km 29,300, 00016 Monterotondo Scalo, Rome, Italy.
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MeSH Terms
Butadienes / metabolism*
Carbon Dioxide / metabolism
Eucalyptus / metabolism*,  physiology
Gas Chromatography-Mass Spectrometry
Hot Temperature
Oxygen / metabolism
Photosynthesis / physiology*
Plant Leaves / metabolism*,  physiology
Plants, Medicinal*
Sodium Chloride / metabolism*
Reg. No./Substance:
0/Butadienes; 0/Hemiterpenes; 0/Pentanes; 124-38-9/Carbon Dioxide; 7647-14-5/Sodium Chloride; 7782-44-7/Oxygen; 78-79-5/isoprene

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