Changes in ABA turnover and sensitivity that accompany dormancy termination of yellow-cedar (Chamaecyparis nootkatensis) seeds
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...
| Veröffentlicht in: | Journal of experimental botany. - 1985. - 53(2002), 366 vom: 15. Jan., Seite 89-101 |
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| 1. Verfasser: | |
| Weitere Verfasser: | , |
| Format: | Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2002
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| Zugriff auf das übergeordnete Werk: | Journal of experimental botany |
| Schlagworte: | Journal Article Research Support, Non-U.S. Gov't Gibberellins Abscisic Acid 72S9A8J5GW 1-Propanol 96F264O9SV Deuterium AR09D82C7G gibberellic acid |
| Zusammenfassung: | 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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| Beschreibung: | Date Completed 08.04.2002 Date Revised 21.11.2013 published: Print Citation Status MEDLINE |
| ISSN: | 1460-2431 |