Document Detail

The Role of auxin, pH, and stress in the activation of embryogenic cell division in leaf protoplast-derived cells of alfalfa.
MedLine Citation:
PMID:  12177494     Owner:  NLM     Status:  MEDLINE    
Culturing leaf protoplast-derived cells of the embryogenic alfalfa (Medicago sativa subsp. varia A2) genotype in the presence of low (1 microM) or high (10 microM) 2, 4-dichlorophenoxyacetic acid (2,4-D) concentrations results in different cell types. Cells exposed to high 2,4-D concentration remain small with dense cytoplasm and can develop into proembryogenic cell clusters, whereas protoplasts cultured at low auxin concentration elongate and subsequently die or form undifferentiated cell colonies. Fe stress applied at nonlethal concentrations (1 mM) in the presence of 1 microM 2,4-D also resulted in the development of the embryogenic cell type. Although cytoplasmic alkalinization was detected during cell activation of both types, embryogenic cells could be characterized by earlier cell division, a more alkalic vacuolar pH, and nonfunctional chloroplasts as compared with the elongated, nonembryogenic cells. Buffering of the 10 microM 2,4-D-containing culture medium by 10 mM 2-(N-morpholino)ethanesulfonic acid delayed cell division and resulted in nonembryogenic cell-type formation. The level of endogenous indoleacetic acid (IAA) increased transiently in all protoplast cultures during the first 4 to 5 d, but an earlier peak of IAA accumulation correlated with the earlier activation of the division cycle in embryogenic-type cells. However, this IAA peak could also be delayed by buffering of the medium pH by 2-(N-morpholino)ethanesulfonic acid. Based on the above data, we propose the involvement of stress responses, endogenous auxin synthesis, and the establishment of cellular pH gradients in the formation of the embryogenic cell type.
Taras P Pasternak; Els Prinsen; Ferhan Ayaydin; Pál Miskolczi; Geert Potters; Han Asard; Harry A Van Onckelen; Dénes Dudits; Attila Fehér
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Plant physiology     Volume:  129     ISSN:  0032-0889     ISO Abbreviation:  Plant Physiol.     Publication Date:  2002 Aug 
Date Detail:
Created Date:  2002-08-14     Completed Date:  2002-12-03     Revised Date:  2010-09-14    
Medline Journal Info:
Nlm Unique ID:  0401224     Medline TA:  Plant Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1807-19     Citation Subset:  IM    
Laboratory of Cell Division and Differentiation, Institute of Plant Biology, Biological Research Centre, H-6701 Szeged, Hungary.
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MeSH Terms
2,4-Dichlorophenoxyacetic Acid / pharmacology
Alkanesulfonic Acids / pharmacology
Cell Division / drug effects,  physiology
Cells, Cultured
Chloroplasts / physiology
Hydrogen-Ion Concentration
Indoleacetic Acids / pharmacology*
Iron / pharmacology
Medicago sativa / drug effects,  embryology,  physiology*
Morpholines / pharmacology
Plant Leaves / drug effects,  embryology,  physiology*
Protoplasts / cytology,  drug effects,  physiology*
Stress, Mechanical
Reg. No./Substance:
0/Alkanesulfonic Acids; 0/Indoleacetic Acids; 0/Morpholines; 4432-31-9/2-(N-morpholino)ethanesulfonic acid; 7439-89-6/Iron; 87-51-4/indoleacetic acid; 94-75-7/2,4-Dichlorophenoxyacetic Acid

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

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