Department of Biological Sciences, University of Alberta, Edmonton, Canada.
Curr Top Dev Biol. 2010;91:221-65. doi: 10.1016/S0070-2153(10)91008-9.
Reticulate tissue systems exist in most multicellular organisms, and the principles underlying the formation of cellular networks have fascinated philosophers, mathematicians, and biologists for centuries. In particular, the beautiful and varied arrangements of vascular tissues in plants have intrigued mankind since antiquity, yet the organizing signals have remained elusive. Plant vascular tissues form systems of interconnected cell files throughout the plant body. Vascular cells are aligned with one another along continuous lines, and vascular tissues differentiate at reproducible positions within organ environments. However, neither the precise path of vascular differentiation nor the exact geometry of vascular networks is fixed or immutable. Several recent advances converge to reconcile the seemingly conflicting predictability and plasticity of vascular tissue patterns. A control mechanism in which an apical-basal flow of signal establishes a basic coordinate system for body axis formation and vascular strand differentiation, and in which a superimposed level of radial organizing cues elaborates cell patterns, would generate a reproducible tissue configuration in the context of an underlying robust, self-organizing structure, and account for the simultaneous regularity and flexibility of vascular tissue patterns.
组织系统存在于大多数多细胞生物中，细胞网络形成的原理几百年来一直吸引着哲学家、数学家和生物学家。特别是，植物中血管组织的美丽而多样的排列从古至今一直吸引着人类，但组织信号仍然难以捉摸。植物的维管束组织在整个植物体中形成相互连接的细胞束系统。维管束细胞沿着连续的线彼此对齐，并且维管束组织在器官环境中的可重复位置上分化。然而，维管分化的精确路径或维管网络的确切几何形状既不是固定的也不是不变的。最近的一些进展集中在协调维管束组织模式的看似矛盾的可预测性和可塑性上。一种控制机制，其中信号的顶端-基底流建立了用于体轴形成和维管束分化的基本坐标系，并且叠加的径向组织线索水平详细说明细胞模式，将在基础稳健的自组织结构的背景下产生可重复的组织配置，并解释维管束组织模式的同时规律性和灵活性。
