Throughout plant development, vascular cells continually form from within a population of seemingly equivalent cells. Vascular cells connect end to end to form continuous strands, and vascular strands connect at both or either end to form networks of exquisite complexity and mesmerizing beauty. Here we argue that experimental evidence gained over the past few decades implicates the plant hormone auxin—its production, transport, perception, and response—in all the steps that lead to the patterned formation of the plant vascular system, from the formation of vascular cells to their connection into vascular networks. We emphasize the organizing principles of the cell- and tissue-patterning process, rather than its molecular subtleties. In the picture that emerges, cells compete for an auxin-dependent, cell-polarizing signal; positive feedback between cell polarization and cell-to-cell movement of the polarizing signal leads to gradual selection of cell files; and selected cell files differentiate into vascular strands that drain the polarizing signal from the neighboring cells. Although the logic of the patterning process has become increasingly clear, the molecular details remain blurry; the future challenge will be to bring them into razor-sharp focus.

中文翻译：

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细胞、链和网络：生长素和血管系统的模式形成

在整个植物发育过程中，维管细胞不断地从看似相同的细胞群中形成。血管细胞首尾相连形成连续的股线，而血管股线在两端或任一端连接形成精致复杂和迷人美丽的网络。在这里，我们认为过去几十年获得的实验证据表明植物激素生长素——它的产生、运输、感知和反应——参与了从血管细胞形成到植物血管系统模式形成的所有步骤到它们与血管网络的连接。我们强调细胞和组织模式化过程的组织原则，而不是其分子的微妙之处。在出现的图片中，细胞竞争依赖生长素的细胞极化信号；细胞极化和极化信号的细胞间运动之间的正反馈导致细胞文件的逐渐选择；和选定的细胞文件分化成维管束，从相邻细胞中排出极化信号。尽管图案化过程的逻辑越来越清晰，但分子细节仍然模糊；未来的挑战将是让他们成为人们关注的焦点。