This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Web of Science (36) Citing Articles via Google Scholar Google Scholar Articles by Großelindemann, E. Articles by Hedden, P. Search for Related Content PubMed PubMed Citation Articles by Großelindemann, E. Articles by Hedden, P. Agricola Articles by Großelindemann, E. Articles by Hedden, P.

Development and Growth Regulation

ent-Kaurene Biosynthesis in Germinating Barley (Hordeum vulgare L., cv Himalaya) Caryopses and Its Relation to -Amylase Production ¹

Pflanzenphysiologisches Institut der Universität, Untere Karspüle 2, D-3400 Göttingen, Germany, Department of Agricultural Sciences, University of Bristol, Bristol BS18 9AF, United Kingdom, AFRC Institute of Arable Crops Research, Long Ashton Research Station, Long Ashton, Bristol BS18 9AF, United Kingdom

ent-Kaurene biosynthesis as a prerequisite for gibberellin (GA) biosynthesis was studied in germinating Hordeum vulgare L., cv Himalaya caryopses and correlated, in time, with the appearance of -amylase activity. The rate of ent-kaurene biosynthesis was estimated by inhibiting its further metabolism with plant growth retardants (triapenthenol or tetcyclacis) and measuring its accumulation by isotope dilution using combined gas chromatographymass spectrometry. In the inhibitor-treated caryopses, ent-kaurene accumulation began approximately 24 hours after imbibition and proceeded at a rate of about 1 to 2 picomoles per hour per caryopsis, depending on the batch of seeds. In the absence of inhibitor, ent-kaurene did not accumulate, indicating that it is normally turned over rapidly, presumably to further intermediates of the GA biosynthesis pathway and eventually to GAs. ent-Kaurene accumulation occurred almost exclusively in the shoot, which is, therefore, probably the site of biosynthesis. -Amylase production began between 30 and 36 hours after imbibition and, thus, correlated well with de novo GA biosynthesis, as estimated from ent-kaurene accumulation. However, inhibition of ent-kaurene oxidation by plant growth retardants did not reduce the -amylase production significantly, although it did reduce shoot elongation. We conclude that ent-kaurene is produced in the shoot and is continuously converted to GA, which is essential for normal shoot elongation, but not for the production of -amylase in the aleurone layer.

¹ Supported by grants from the Deutsche Forschungsgemeinschaft.

This article has been cited by other articles:

				H. Kawaide, T. Sassa, and Y. Kamiya Functional Analysis of the Two Interacting Cyclase Domains in ent-Kaurene Synthase from the Fungus Phaeosphaeria sp. L487 and a Comparison with Cyclases from Higher Plants J. Biol. Chem., January 28, 2000; 275(4): 2276 - 2280. [Abstract] [Full Text] [PDF]

				C. A. Helliwell, C. C. Sheldon, M. R. Olive, A. R. Walker, J. A. D. Zeevaart, W. J. Peacock, and E. S. Dennis Cloning of the Arabidopsis ent-kaurene oxidase gene GA3 PNAS, July 21, 1998; 95(15): 9019 - 9024. [Abstract] [Full Text] [PDF]