Document Detail

Structural changes induced by NaCl in companion and transfer cells of Medicago sativa blades.
MedLine Citation:
PMID:  12664282     Owner:  NLM     Status:  MEDLINE    
Medicago sativa var. Gabes is a perennial glycophyte that develops new shoots even in high salinity (150 mM NaCl). In the upper exporting leaves, K(+) is high and Na(+) is low by comparison with the lower leaves, where Na(+) accumulation induces chlorosis after 4 weeks of NaCl treatment. By secondary ion mass spectroscopy, a low Na(+)/K(+) ratio was detected in the phloem complex of blade veins in these lower leaves. By transmission electron microscopy, the ultrastructural features were observed in the phloem complex. In the upper leaves of both control and NaCl-treated plants, companion cells in minor veins were found to be transfer cells. These cells may well be involved in the intravenous recycling of ions and in Na(+) flowing out of exporting leaves. Under the effect of NaCl, companion cells in the main veins develop transfer cell features, which may favor the rate of assimilate transport from exporting leaves toward meristems, allowing the positive balance necessary for the survival in salt conditions. These features no longer assist the lower leaves when transfer cells are necrotized in both minor and main veins of NaCl-treated plants. As transfer cells are the only degenerating phloem constituent, our observations emphasize their role in controlling nutrient (in particular, Na(+)) fluxes associated with the stress response.
N Boughanmi; P Michonneau; M-C Verdus; F Piton; E Ferjani; E Bizid; P Fleurat-Lessard
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Protoplasma     Volume:  220     ISSN:  0033-183X     ISO Abbreviation:  Protoplasma     Publication Date:  2003 Mar 
Date Detail:
Created Date:  2003-03-28     Completed Date:  2004-01-16     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  9806853     Medline TA:  Protoplasma     Country:  Austria    
Other Details:
Languages:  eng     Pagination:  179-87     Citation Subset:  IM    
Laboratoire de Biologie et Physiologie Cellulaires, Faculté des Sciences, Université de Bizerte, Bizerte.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Cell Wall / ultrastructure
Medicago sativa / cytology*,  drug effects,  ultrastructure*
Plant Leaves / cytology,  drug effects
Plant Roots / cytology,  drug effects
Plant Stems / cytology,  drug effects
Potassium / analysis
Sodium Chloride / pharmacology*
Reg. No./Substance:
7440-09-7/Potassium; 7647-14-5/Sodium Chloride

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

Previous Document:  Inhibition of cell proliferation by mechanical agitation involves transient cell cycle arrest at G1 ...
Next Document:  Dodder hyphae invade the host: a structural and immunocytochemical characterization.