Effects of Chilling and ABA on [3H]Gibberellin A4 Metabolism in Somatic Embryos of Grape (Vitis vinifera L. × V. rupestris Scheele) 1
AUTOR(ES)
Pearce, David
RESUMO
Previous work has indicated that changes in gibberellin (GA) metabolism may be involved in chilling-induced release from dormancy in somatic embryos of grape (Vitis vinifera L. × V. rupestris Scheele). We have chilled somatic embryos of grape for 2, 4, or 8 weeks, then incubated them with [3H]GA4 (of high specific activity, 4.81 × 1010 becquerel per millimole) for 48 hours at 26°C. Chilling had little effect on the total amount of free [3H]GA-like metabolites formed during incubation at 26°C, but did change the relative proportions of individual metabolites. The amount of highly water-soluble [3H] metabolites formed at 26°C decreased in embryos chilled for 4 or 8 weeks. The concentration of endogenous GA precursors (e.g., GA12 aldehyde-, kaurene-, and kaurenoic acid-like substances) increased in embryos chilled for 4 or 8 weeks. Treatment with abscisic acid (ABA) (known to inhibit germination in grape embryos) concurrent with [3H]GA4 treatment at 26°C, reduced the uptake of [3H] GA4 but had little effect on the qualitative spectrum of metabolites. However, in the embryos chilled for 8 weeks and then treated with ABA for 48 hours at 26°C, there was a higher concentration of GA precursors than in untreated control embryos. Chilled embryos thus have an enhanced potential for an increase in free GAs through synthesis from increased amounts of GA precursors, or through a reduced ability to form highly water-soluble GA metabolites (i.e., GA conjugates or polyhydroxylated free GAs).
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1056587Documentos Relacionados
- Metabolism of 3H-Gibberellin A1 and 3H-Gibberellin A4 by Phaseolus coccineus Seedlings
- The Influence of Dwarfing Interstocks on the Distribution and Metabolism of Xylem-Applied [3H]Gibberellin A4 in Apple
- Metabolism of Tritiated Gibberellins in d-5 Dward Maize: II. [3H]Gibberellin A1, [3H]Gibberellin A3, and Related Compounds 1
- Metabolism of [3H]Gibberellin A5 by Immature Seeds of Apricot (Prunus armeniaca L.) 1
- Effects of Light, Abscisic Acid, and 6N-Benzyladenine on the Metabolism of [3H]Gibberellin A4 in Seeds and Seedlings of Lettuce, cv. Grand Rapids 1