Abstract
Winter canola (Brassica napus cv Crystal) is an oilseed crop that requires vernalization (chilling treatment) for the induction of stem elongation and flowering. To investigate the role of gibberellins (GAs) in vernalization-induced events, endogenous GA content and the metabolism of [3H]GAs were examined in 10-week vernalized and nonvernalized plants. Shoot tips were harvested 0, 8, and 18 d postvernalization (DPV), and GAs were purified and quantified using 2H2-internal standards and gas chromatography-selected ion monitoring. Concentrations of GA1, GA3, GA8, GA19, and GA20 were 3.1-, 2.3-, 7.8-, 12.0-, and 24.5-fold higher, respectively, in the vernalized plants at the end of the vernalization treatment (0 DPV) relative to the nonvernalized plants. Thermoregulation apparently occurs prior to GA19 biosynthesis, since vernalization elevated the concentration of all of the monitored GAs. [3H]GA20 or [3H]GA1 was applied to the shoot tips of vernalized and nonvernalized plants, and after 24 h, plants were harvested at 6, 12, and 15 DPV. Following high-performance liquid chromatography analyses, vernalized plants showed increased conversion of [3H]GA20 to a [3H]GA1-like metabolite and reduced conversion of [3H]GA1 or [3H]GA20 to polar 3H-metabolites, putative glucosyl conjugates. These results demonstrate that vernalization influences GA content and GA metabolism, with GAs serving as probable regulatory intermediaries between chilling treatment and subsequent stem growth.
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Selected References
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- Hazebroek J. P., Metzger J. D., Mansager E. R. Thermoinductive Regulation of Gibberellin Metabolism in Thlaspi arvense L. (II. Cold Induction of Enzymes in Gibberellin Biosynthesis). Plant Physiol. 1993 Jun;102(2):547–552. doi: 10.1104/pp.102.2.547. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lang A. THE EFFECT OF GIBBERELLIN UPON FLOWER FORMATION. Proc Natl Acad Sci U S A. 1957 Aug 15;43(8):709–717. doi: 10.1073/pnas.43.8.709. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Metzger J. D. Role of Gibberellins in the Environmental Control of Stem Growth in Thlaspi arvense L. Plant Physiol. 1985 May;78(1):8–13. doi: 10.1104/pp.78.1.8. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Rood S. B., Mandel R., Pharis R. P. Endogenous Gibberellins and Shoot Growth and Development in Brassica napus. Plant Physiol. 1989 Jan;89(1):269–273. doi: 10.1104/pp.89.1.269. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Rood S. B., Pearce D., Pharis R. P. Identification of endogenous gibberellins from oilseed rape. Plant Physiol. 1987 Nov;85(3):605–607. doi: 10.1104/pp.85.3.605. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Rood S. B., Pearce D., Williams P. H., Pharis R. P. A Gibberellin-Deficient Brassica Mutant-rosette. Plant Physiol. 1989 Feb;89(2):482–487. doi: 10.1104/pp.89.2.482. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Rood S. B., Pharis R. P., Koshioka M. Reversible conjugation of gibberellins in situ in maize. Plant Physiol. 1983 Oct;73(2):340–346. doi: 10.1104/pp.73.2.340. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Rood S. B., Williams P. H., Pearce D., Murofushi N., Mander L. N., Pharis R. P. A mutant gene that increases gibberellin production in brassica. Plant Physiol. 1990 Jul;93(3):1168–1174. doi: 10.1104/pp.93.3.1168. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Schneider G., Jensen E., Spray C. R., Phinney B. O. Hydrolysis and reconjugation of gibberellin A20 glucosyl ester by seedlings of Zea mays L. Proc Natl Acad Sci U S A. 1992 Sep 1;89(17):8045–8048. doi: 10.1073/pnas.89.17.8045. [DOI] [PMC free article] [PubMed] [Google Scholar]