Abstract
Whilst the cytokinins are important promoters of plant cell division in vitro and in vivo, their mode of action remains unknown. Here we report the results of a study showing that a single application of a low dose of a cytokinin to the shoot apical meristem of Sinapis alba L. activates new replicon origins in chromosomal DNA, resulting in the halving of replicon size, and synchronizes the activation of replicon origins. These effects cause a 3.5-fold shortening of the duration of chromosomal DNA replication (S phase of the cell cycle). We hypothesize that one of the proteins involved in the initiation of DNA replication is a target for cytokinins.
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Abbreviations
- BA:
-
N6-benzyladenine
- F:
-
fork rate
- R:
-
size ofmost replicons
- Rs:
-
time taken for replicon to replicate its allotedDNA
- TdR:
-
[3H]thymidine
- Ts:
-
duration of S phase
References
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C. Houssa is grateful to I.R.S.I.A. for the award of a research fellowship. This research was supported by the Belgian Government (Concerted Research Actions and FRFC).
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Houssa, C., Jacqmard, A. & Bernier, G. Activation of replicon origins as a possible target for cytokinins in shoot meristems of Sinapis . Planta 181, 324–326 (1990). https://doi.org/10.1007/BF00195883
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DOI: https://doi.org/10.1007/BF00195883