Abstract
When the root-phloem slices ofDaucus carota cv. Hokkaidô-gosun were cultured on a Murashige and Skoog's medium containing 2,4-dichlorophenoxyacetic acid (2,4-D medium) and cyclic AMP or its analogues, tracheary elements were formed in the dark, while they were not formed on the medium containing only 2,4-D in the dark. The number of tracheary elements induced by cyclic AMP was far less than that induced by cytokinin or 8-bromo-cyclic AMP. But when theophylline, an inhibitor of cyclic AMP phosphodiesterase, was used in combination with cyclic AMP in the culture, the number of tracheary elements was significantly increased.
A remarkable increase in cytokinin activity was found in the hydrolyzate of soluble RNA extracted from the slices cultured on the 2,4-D medium containing 8-bromo-cyclic AMP, but only negligible cytokinin activity was detected in the hydrolyzate of soluble RNA extracted from the slices cultured on the 2,4-D medium without 8-bromo-cyclic AMP. Since cytokinin production occurred in the slices cultured in the light, it was supposed that light irradiation might induce cyclic AMP production.
The mechanism of cytokinin production leading to tracheary element formation mediated by cyclic AMP level is discussed.
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Abbreviations
- 2,4-D:
-
2,4-dichlorophenoxyacetic acid
- ZR:
-
zeatin ribonucleoside
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Mizuno, K., Komamine, A. A possible role of cyclic AMP on tracheary element formation in cultured carrot-root slices. Bot Mag Tokyo 91, 213–219 (1978). https://doi.org/10.1007/BF02489358
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DOI: https://doi.org/10.1007/BF02489358