| Changes in ABA turnover and sensitivity that accompany dormancy termination of yellow-cedar (Chamaecyparis nootkatensis) seeds. | |
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MedLine Citation:
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PMID: 11741045 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Yellow-cedar (Chamaecyparis nootkatensis [D. Don] Spach) seeds exhibit prolonged coat-imposed dormancy following their dispersal from the parent plant. Analyses were undertaken using S-(+)-[(3)H] abscisic acid (ABA) to monitor the capacity of embryos to metabolize ABA following their isolation from seeds subjected to various dormancy-breaking and control treatments. Radiolabelled phaseic acid (PA) and dihydrophaseic acid (DPA) were detected in embryos and, to a greater extent in the surrounding media, by 48 h regardless of whether the embryos had been excised from seed previously subjected to only a 3 d soak or to a full dormancy-breaking treatment. Of the two enantiomers of ABA, only the natural S-(+)-ABA effectively inhibited germination of isolated embryos. A metabolism-resistant synthetic ABA analogue S-[8',8',8',9',9',9']-hexadeuteroabscisic acid, S-(+)-d6-ABA, consistently slowed the germination rate of excised embryos to a greater extent than that caused by natural S-(+)-ABA. The deuterium-labelled ring methyl groups of the analogue made it more resistant to oxidation by yellow-cedar embryos and thus rendered the analogue more persistent and possessing greater activity. With increasing time of exposure to moist chilling, yellow-cedar embryos became increasingly insensitive to both ABA and to the analogue. Subjecting seed to chemical treatments (GA(3) in combination with 1-propanol) prior to moist chilling strongly enhanced the germinability of whole seeds. This treatment also had a relatively greater impact on ABA metabolism than did moist chilling alone, as indicated by a greater capacity of S-(+)-d6-ABA to inhibit the germination of embryos as compared to S-(+)-ABA. Moist chilling was most critical for reduced ABA sensitivity of embryos. A change in the embryo's ability to metabolize ABA and reduced embryo sensitivity to ABA are two factors associated with dormancy termination of whole seeds of yellow cedar; a change in only one of these factors is insufficient to elicit high germinability. |
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Authors:
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Nancy Schmitz; Suzanne R Abrams; Allison R Kermode |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Journal of experimental botany Volume: 53 ISSN: 0022-0957 ISO Abbreviation: J. Exp. Bot. Publication Date: 2002 Jan |
Date Detail:
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Created Date: 2001-12-13 Completed Date: 2002-04-08 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 9882906 Medline TA: J Exp Bot Country: England |
Other Details:
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Languages: eng Pagination: 89-101 Citation Subset: IM |
Affiliation:
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Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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1-Propanol
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pharmacology Abscisic Acid / chemistry, metabolism*, pharmacology Chamaecyparis / drug effects, physiology* Deuterium Dose-Response Relationship, Drug Germination / drug effects Gibberellins / pharmacology Isomerism Seeds / drug effects, physiology Time Factors |
| Chemical | |
Reg. No./Substance:
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0/Gibberellins; 21293-29-8/Abscisic Acid; 71-23-8/1-Propanol; 77-06-5/gibberellic acid; 7782-39-0/Deuterium |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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