植物开花是高等植物由营养生长向生殖生长转变的重要生理过程,是个体发育和后代繁衍的中心环节.赤霉素是调节植物生长发育的五大激素之一(Takahashi et al.,1991),赤霉素处理也是人工调控植物成花的最有效途径之一,因而成为近年来成花机制研究领域的一个热点.虽然对模式植物拟南芥(Arabidopsis thaliana)成花相关基因调控机制的研究已经比较成熟,但对高等植物成花研究多集中在生理生化水平.因此,运用分子生物学手段,从基因水平研究外源赤霉素对木本植物白桦(Betula platyphylla)成花的影响具有重要意义.%This study investigated the effect of gibberellin on flower formation of Betula platyphylla and the possible mechanism in the process. In this experiment, different concentrations of GA3(50,100,200 mg·L-1 ) were sprayed on the leaves of B. Platyphylla at the stage of flower induction. The expression of the key genes involved in B. Platyphylla flower formation in the apical meristem was studied during the period of flowering differentiation by RT-PCR. The results showed that flowering induction of B. Platyphylla was in late May in Harbin and flowering transition was significantly inhibited by different concentrations of GA3. The expression of flowering-promoted genes, including LFY, GI, ELF3 and LD, were distinct lower than the control group, while expression of the flowering suppressor gene FLC had no significant changes. Therefore, the exogenous GA3 was of the disincentive during the flowering transition of B. Platyphylla. GA3 plays a negative role in different gene expression of the multiple flowering pathways rather than individual one.
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