Abstract:

【Objective】 This experiment was conducted to study the effect of gibberellin and its possible mechanism on flower formation of peach. 【Method】 At the stage of flower induction, 100 mg?L-1 of GA3 was sprayed on the leaves of peach [Prunus persica (L.) Batsch.] cv. Bayuecui. Using the methods of anatomy, immunohistochemistry and semi-quantization, the in situ distribution of GAS and the expression of the key genes involved in peach flower formation in the apical meristem were studied during the period of flowering differentiation. 【Result】 The stage of flowering induction of ‘Bayuecui’ peach in Beijing was before July 10. The flower induction and further differentiation of flower organs of peach were significantly inhibited by leaf-spraying of GA3 at the concentration of 100 mg?L-1 during its flower inducing stage. The flower rate was only 11.67% after treatment. The distribution of GA1 in the apical meristem changed along with the process of flower bud differentiation. From June 13 to July 25, the GA1 signal of the control was detected mainly in the vascular bundle at the base of the flower buds. Meanwhile no GA1 signal was detected in the apical meristem. After being treated by GA3, the distribution was similar to the control from June 13 to July 3. But on July 13, GA1 signal was detected in the apical meristem accompanied by an increase of GA1 signal in the vascular bundle at the base of flower buds. GA1 signal weakened significantly in both vascular bundle and apical meristem on July 25. The expression of gene PpLEAFY and gene MADS6 in flower buds could only be detected on October 10 in GA3 treatment. 【Conclusion】 The critical period of flower induction of ‘Bayuecui’ peach in Beijing was in early July, during which leaf-spraying with 100 mg?L-1 GA3 could inhibit the flower induction and the further differentiation of the flower bud effectively. GA1 in the gibberellin family was the suppressors for flower induction in peach. Its effect was affected by the stages of flower bud differentiation. The expression of the key genes PpLEAFY and MADS6 involved in flower formation were inhibited by GA3 treatment.

Key words: peach [Prunus persica (L.)Batsch.], gibberellin, flowering induction, anatomy, immunohistochemistry, semi-quantization RT-PCR