花及其组成的花序具有重要的分类学价值，它们的发育过程蕴含了丰富的系统演化信息。蔷薇科广义李属集中了许多水果类和观赏类植物，具有重要的经济价值。由于以往研究采用的分子标记偏少或取样有限，李属属下系统发育关系仍无定论。同时，该属的主要分类性状—花序和花器官形态变异丰富，但它们的形成和演化规律仍不清楚。本项目拟选择李属各亚属、各支系及外类群共40个代表性物种，采用二代测序技术获取叶绿体基因组序列，同时结合10个低拷贝核基因序列，重建李属的系统发育框架；利用扫描电子显微镜观察各分支和各种形态变异类型共22个代表性物种花序和花的发生发育过程；最后，在系统发育框架下，通过祖先状态重建分析，探讨李属花序和花器官形态及发育性状的演化规律。本项目的实施，不仅有助于完善李属属下系统发育关系，阐明花序和花器官多样性的形成和演化规律，也为李属植物育种和资源的保护开发提供参考，具有重要的理论价值和现实意义。

Flowers and inflorescences have important taxonomic value and their developmental process provides abundant information for systematics and evolution. Prunus s.l. (Rosaceae) is an economically important source of various fruits and ornamentals. Our preliminary investigations demonstrated that Prunus varies with respect to inflorescence types and floral organs. Unfortunately, their development and evolution are still unclear. At the same time, the phylogenetic relationships in Prunus remain unresolved, because previous studies used only few molecular markers or few samples. In this project, we will reconstruct a robust phylogeny of Prunus using 40 representative species and outgroups from chloroplast genome sequences obtained by next-generation sequencing and 10 low-copy nuclear genes. We will investigate the formation and development of the inflorescences and floral organs of 22 species using scanning electron microscopy. Lastly, we will reconstruct the ancestral states of flower and inflorescence characters based on the phylogenetic hypothesis. Our work not only will help to resolve remaining questions regarding the phylogenetic relationships in Prunus, but it also will provide fundamental new insights on the evolution of reproductive systems in the genus. Apart from these basic research results, our work will have applications in plant breeding of horticultural varieties and wild resource protection of Prunus.