叶片是植物进行光合作用和抵御病虫害的主要场所，在形态上表现出极大的多样性，因此是研究植物复杂形态建成和演化的很好模型。单叶和复叶是植物叶片的两种基本形态。国内外对于单叶发育的研究已经取得许多重要进展，但是复叶发育中的很多重要科学问题还没有得到解答。植物复叶原基从茎顶端分生组织的侧翼起始而来，但是对于后续的复叶原基干细胞是如何在时空上响应遗传因子、激素及环境信号的协同作用，最终可塑性地调控复叶的形态建成的，目前所知有限。近年来，该领域受到国内外植物科学家越来越多的关注。文章讨论了复叶形态建成过程中的一些关键问题，并根据当前的研究进展提出了展望。

Leaves are the primary sites for plant photosynthesis and disease-resistance, showing great diversity in shapes. Thus, leaves are the good model for studying the morphogenesis as well as the evolution of complex organs. Simple leaves and compound leaves are two basic forms in nature. Significant progresses have been made in understanding the simple leaf development. However, several key questions for compound leaf development have not been addressed. As we know leaves initiate from the peripheral zone of the shoot apical meristem (SAM). However, how stem cells of compound leaf primordia are regulated by the coordination of genetic factors, hormones and environmental signals, and finally to control the plasticity of compound leaf shape which remains poorly understood. Recent years, more and more plant biologists focus on the molecular mechanism underlying the diversification of compound leaf shapes. Here, we discuss some key progresses in the research of compound leaf development, and point out the hot topics in the future research.