Although roots and shoots exhibit profound differences in their pattern of organogenesis, both apices share the capacity for indeterminate growth. Ongoing molecular and genetic analyses have revealed relatively little overlap between the genes that regulate organogenesis in the root and shoot apices. In the shoot, an ensemble of transcription factors lays the foundations for the leaf, in which indeterminacy is exchanged for more limited and polarized growth. Class-I KNOX genes are downregulated in the anlagen of the leaf early in its establishment, but are maintained in other regions of the shoot apex. This persistent expression of KNOX genes may serve to prevent the precocious determination of apical initial derivatives, and thus may allow the production of a large number of pluripotent cells from a relatively small number of stem cells. Greater commonality between roots and shoots is seen in mechanisms that underlie histogenesis and radial-patterning processes. Recent work suggests that undetermined stem cells in both the root and the shoot may be maintained by related mechanisms, which feature regulation of WUSCHEL-like organizer activities by feedback mechanisms that involve receptor-like kinases.

中文翻译：

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顶端分生组织中细胞命运的测定。

尽管根和芽在器官发生方式上表现出深远的差异，但两个顶点都具有不确定的生长能力。正在进行的分子和遗传分析显示，调节根和芽尖的器官发生的基因之间的重叠很少。在芽中，大量转录因子为叶片奠定了基础，其中不确定性被交换为更有限和两极分化的生长。在其建立初期，I类NOx基因在叶片的胶原蛋白中被下调，但在茎尖的其他区域中被维持。KNOX基因的这种持续表达可以用来防止过早确定顶端起始衍生物，因此可以允许从相对少量的干细胞中产生大量的多能细胞。在组织发生和放射状形成过程的基础机制中，可以看到根与芽之间具有更大的共性。最近的工作表明，在根和芽中未确定的干细胞可能由相关机制维持，这些机制的特征是通过涉及受体样激酶的反馈机制调节WUSCHEL样组织者的活动。