ISHS Acta Horticulturae 570: VIII International Symposium on Flowerbulbs
CONTROL OF BULB DORMANCY IN HYACINTH - A MOLECULAR BIOLOGICAL APPROACH |
| Authors: | K. Li, H. Okubo, T. Matsumoto |
| Keywords: | abscisic acid, bulb formation, dormancy, hyacinth, low temperature |
| Abstract:
Studies were conducted to investigate the hypothesis that the induction of bulb formation and the induction of bulb dormancy are the same phenomenon. Hyacinth plants cultured in vitro at 23°C developed leaves without forming bulbs, and formed bulbs with treatment of eight weeks at 4°C (Bach, 1992). Using this difference of growth response, the effects of temperature and growth regulators on bulb formation and the changes in endogenous ABA content were investigated. Shoot explants were taken from in vitro immature leaves of hyacinth (Hyacinthus orientalis L. cv. Delft Blue) and cultured at 25°C on MS medium containing NAA and BA. The explants treated for eight weeks at 5°C formed bulbs four weeks after the completion of the cold treatment at 25°C, whereas bulb formation was suppressed without cold treatment. Addition of ABA to the medium promoted bulb formation without cold treatment. By adding fluridone to the medium, bulb formation of the cold-treated explants was inhibited. Under bulb-forming conditions, endogenous ABA content increased and it was correlated with the increase of bulb-forming rate. These results suggest that bulb formation is induced by low temperature and regulated by ABA. Thus, the controlling methods are; bulb-forming conditions are obtainable by cold treatment or ABA without cold treatment and non-bulb-forming conditions are by non-cold treatment or fluridone with cold treatment. | |
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