气孔是所有陆地植株地上部表皮中高度分化的细胞结构，在调节植物与外界气体交换中发挥着重要的作用。气孔是由原表皮细胞经过多次不对称分裂和一次对称分裂，历经三次细胞分化而形成，涉及多次细胞分化和细胞分裂。除了已经发现的配基-受体信号转导途径调控气孔发育外，近些年发现植物激素如油菜素内酯可通过磷酸化转录因子蛋白实现对气孔发生的调控。我们最新结果表明生长素参与了气孔多个发育阶段，改变生长素在表皮中分布可导致气孔簇的形成以及前体细胞分化和分裂滞后。我们和其他研究者的结果也表明CDK-CYCLIN参与决定气孔发生和细胞分化、分裂的精细调控。在本项目中我们拟采用遗传学、细胞生物学和生物化学等多种手段，通过对多个生长素和油菜素内酯信号转导途径在气孔发育中作用模式的解析，探讨激素通过CDK-CYCLIN细胞周期蛋白参与气孔细胞分化和分裂的复杂网络途径，进一步揭示植物气孔发生和发育中细胞分化和分裂调控机制。

Stomata, which are vital shoot epidermal cell complexes of all land plants for gas exchange between plants and atmosphere, develop from protodermal cells after a series of cell asymmetric and symmetric divisions, and cell differentiation. Stomatal development is believed regulated by a ligand-receptor signaling module. Recent findings revealed that brassinosteroid regulates stomatal initiation through phosphorylation of a transcriptional factor. Our recent results suggest that auxin is also involved in multiple developmental stages within stomatal development. Alternation of auxin distribution induces the formation of stomatal clusters and a delay in the conversion from asymmetric to symmetric divisions. Our and others data demonstrate that CDK-CYCLIN complexes are required for the fine regulation of stomatal initiation, precusor cell differentiation and divisions within stomatal development. To further understand the molecular mechanism of stomatal initiation and development in epidermis, we are going to use the multiple approaches of genetics, biochemistry and cell biology to explore the existing multiple signaling transduction pathways of auxin and brassinosteroid, and the CDK-CYCLIN mediated regulatory network of phytohormones during the stomata innitiaition and development.