Abstract：
Inflorescence architecture is highly variable across plant lineages yet is critical for facilitating reproductive success. The capitulum-type inflorescence of the Asteraceae is marked as a key morphological innovation that preceded the family\'s diversification and expansion. Despite its evolutionary significance, our understanding of capitulum development and evolution is limited. This review highlights our current perspective on capitulum evolution through the lens of both its molecular and developmental underpinnings. We attempt to summarize our understanding of the capitulum by focusing on two key characteristics: patterning (arrangement of florets on a capitulum) and floret identity specification. Note that these two features are interconnected such that the identity of florets depends on their position along the inflorescence axis. Phytohormones such as auxin seemingly determine both pattern progression and floret identity specification through unknown mechanisms. Floret morphology in a head is controlled by differential expression of floral symmetry genes regulating floret identity specification. We briefly summarize the applicability of the ABCE quartet model of flower development in regulating the floret organ identity of a capitulum in Asteraceae. Overall, there have been promising advancements in our understanding of capitula; however, comprehensive functional genetic analyses are necessary to fully dissect the molecular pathways and mechanisms involved in capitulum development.
摘要：
花序结构在植物谱系中高度可变，但对于促进繁殖成功至关重要。菊科的头状花序被标记为关键的形态创新，先于该科的多样化和扩展。尽管它具有进化意义，我们对capitulum发展和进化的理解是有限的。这篇评论通过其分子和发育基础的镜头强调了我们目前对capitulum进化的看法。我们试图通过关注两个关键特征来总结我们对小花的理解：图案（小花在小花上的排列）和小花身份规范。请注意，这两个特征是相互连接的，因此小花的身份取决于它们沿花序轴的位置。植物激素，例如生长素，似乎通过未知的机制决定了模式进展和小花身份规范。头部的小花形态受调节小花身份规范的花对称基因的差异表达控制。我们简要总结了ABCE四重奏花卉发育模型在调节菊科小花器官身份中的适用性。总的来说,我们对capitula的理解有了可喜的进步；然而，全面的功能遗传分析是必要的，以充分剖析涉及头毛虫发育的分子途径和机制。
