アカカノコユリの発芽, 茎伸長, 花芽分化, 花らい発育におけるジベレリンの役割

Abstract

In order to clarify the use of Gibberellin (GA) in cut flower and pot plant production of Lilium speciosum rubrum. and the role of the GA′s in shoot emergence and elonga ion; flower differentiation and development, these experiments were devised to study:1. The response to exogenous GA′s.2. The levels of endogenous GA-like substances.3. GA-synthesis or GA-reactions to the inhibitor Ancymidol and their interaction.The following results were obtained:1. Endogenous GA-like substances in bulbs decreased dramatically during 60 days of cold storage at 5°C, which is most effective in breaking dormancy and hastening stem emergence, elongation and flowering of L. speciosum rubrum. In contrast, GA-like substances increased during 60 days at 21°C. This 21°C temperature is ineffective in breaking dormancy and hastening shoot emergence and flowering. GA was more effective than CCC and Ancymidol to break dormancy as a bulb soak. These data show that it is not clear what the exact role of GA′s are in stem emergence.2. There was an interaction between shoot elongation and the changes in the endogenous GA-like substances found in the shoot. Shoot elongation was markedly inhibited by Ancymidol, with decreased levels of endogenous GA along with shoot inhibition which was reversed by GA. Such data indicate the important role of GA in shoot elongation.3. Flower differentiation was not inhibited by high concentrations of Ancymidol. Further, application of GA3 or GA4+7 did not induce flower differentiation of stems from noncooled bulbs. It was concluded that GA was not directly involved in flower differentiation of L. speciosum rubrum.4. Flower development was strongly inhibited by Ancymidol and this reaction was reversed by GA. There was a direct reaction between the rate of flower development and the fluctuation of endogenous GA′s. We concluded that GA had an important role in flower development of L. speciosum rubrum.