Abstract: To establish a technological system of Lagerstroemia indica reflowing regulation, six years old L. indica cultivated with root-controlling containers was used as the test material to study the effects of different pruning intensity and topdressing on its second blossom. The results showed that pruning and topdressing could promote the reflowering of L. indica. The most suitable treatment was pruning 4/5 of the new shoots after the first flower, applying 150-180 g AKANG compound fertilizer at the root once two weeks, spraying 500 times solution of Peters No.2 10-30-20 on the leaf once five days after bud emergence, and applying two kinds of fertilizer respectively. Full-bloom days, length of flower branch and number of inflorescences in this treatment were significantly higher than those in other treatments, the florescence days were at a higher level. During the period of flower control, 1000 times solution of acetamiprid and 800 times solution of Triadimefon were sprayed once two weeks, which could effectively control aphid, powdery mildew and soot disease of L. indica and ensure its normal flower bud differentiation.

Key words: Lagerstroemia indica, pruning intensity, topdressing, reflowering, florescence regulation

摘要： 以控根器栽培的6年生紫薇(Lagerstroemia indica)为试材，在首次花后采用不同修剪强度、辅助追肥等综合调控措施进行处理，建立紫薇二次开花花期调控技术体系。结果表明，植株修剪和追肥均可促进紫薇二次开花。其中，紫薇首花后修剪4/5的抽生新枝，间隔两周根部追施一次150～180 g阿康复合肥，现蕾后间隔5 d叶面喷施一次花多多2号500倍液，两种肥料分别施用两次效果最佳。紫薇二次开花的盛花期、花枝长度及花序数量均显著高于其他处理；花期天数与其他处理相比处于较高水平，控花期间每两周喷施一次1000倍液啶虫脒和800倍液三唑酮，可有效防治紫薇长斑蚜、白粉病和煤烟病，保证紫薇正常花芽分化。

关键词: 紫薇, 修剪强度, 追肥, 二次开花, 花期调控