Abstract
The effect of photoperiod on ent-kaurene biosynthesis was determined in the long-day (LD) plants spinach (Spinacia oleracea L.) and Agrostemma githago L. Further metabolism of ent-kaurene was blocked by application of the growth retardant tetcyclacis, and ent-kaurene accumulation was measured by isotopic dilution using gas chromatography-selected ion monitoring (GC-SIM) (E. Grosselindemann, J.E. Graebe, D. Stöckl, P. Hedden [1991] Plant Physiol 96: 1099-1104). In spinach, the rate of ent-kaurene accumulation in shoots grown under LD conditions was 3 times higher than in shoots grown under short-day (SD) conditions. ent-Kaurene also accumulated in fully expanded leaves, but at a lower rate than in shoots (15 and 55 pmol g-1 dry weight h-1, respectively). In Agrostemma, ent-kaurene accumulated at a rate 2.5 times higher in plants grown under LD conditions than in those grown under SD conditions. In spinach, enhanced ent-kaurene accumulation was detectable after 1 long day, and with exposure to additional long days, the rate of ent-kaurene accumulation increased further. Conversely, when plants were exposed to LD conditions and then returned to SD conditions, the rate of ent-kaurene accumulation decreased. Following tetcyclacis application, ent-kaurene accumulation was observed in all parts of spinach that were analyzed, but there were large quantitative differences between organs of different ages. As the leaves matured, ent-kaurene biosynthesis declined. Petioles accumulated more ent-kaurene than the corresponding leaf blades. It is concluded that stimulation of ent-kaurene biosynthesis by LD conditions leads to a higher rate of gibberellin biosynthesis, which is essential for stem elongation in rosette plants.
Full Text
The Full Text of this article is available as a PDF (509.8 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Chung C. H., Coolbaugh R. C. ent-Kaurene Biosynthesis in Cell-Free Extracts of Excised Parts of Tall and Dwarf Pea Seedlings. Plant Physiol. 1986 Feb;80(2):544–548. doi: 10.1104/pp.80.2.544. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Gilmour S. J., Zeevaart J. A., Schwenen L., Graebe J. E. Gibberellin metabolism in cell-free extracts from spinach leaves in relation to photoperiod. Plant Physiol. 1986 Sep;82(1):190–195. doi: 10.1104/pp.82.1.190. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Grosselindemann E., Graebe J. E., Stöckl D., Hedden P. ent-Kaurene Biosynthesis in Germinating Barley (Hordeum vulgare L., cv Himalaya) Caryopses and Its Relation to alpha-Amylase Production. Plant Physiol. 1991 Aug;96(4):1099–1104. doi: 10.1104/pp.96.4.1099. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Metzger J. D., Zeevaart J. A. Photoperiodic control of gibberellin metabolism in spinach. Plant Physiol. 1982 Feb;69(2):287–291. doi: 10.1104/pp.69.2.287. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Talon M., Zeevaart J. A., Gage D. A. Identification of Gibberellins in Spinach and Effects of Light and Darkness on their Levels. Plant Physiol. 1991 Dec;97(4):1521–1526. doi: 10.1104/pp.97.4.1521. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Zeevaart J. A. Effects of photoperiod on growth rate and endogenous gibberellins in the long-day rosette plant spinach. Plant Physiol. 1971 Jun;47(6):821–827. doi: 10.1104/pp.47.6.821. [DOI] [PMC free article] [PubMed] [Google Scholar]