Root Meristem Architecture: The Role of the Quiescent Center

根尖已通过基于组织切片的细胞谱系分析进行了研究。 从这些分析中得出的顶端组织理论导致了这样的观点，即在细胞谱系的焦点处存在“最终的原始细胞”，就在根冠的近端。 人们认为，由于连续的有丝分裂活动，最终的原始细胞产生了形成根的衍生细胞。 1956年发现这些细胞在生长的根中很少分裂，这引发了对根发育的重新评估。 总的来说，这些不活跃的“最终初始”组成了一个称为静止中心（QC）的区域。 自发现以来，植物生物学家一直试图了解QC细胞的作用，为什么它们是静止的，以及静止是如何以及何时出现的。 本提案概述的工作涉及这些问题。 本提案的目的是利用分子、遗传和生理学方法将根的已知生物化学与决定根的细胞结构的生物物理学联系起来。 特别注意将被定向到测量生长素，抗坏血酸和抗坏血酸氧化酶与这些物质的静态中心的属性的相关变化的目标之间的水平，分布和相互作用。 使用各种实验方法，这些物质的水平将被操纵和静态中心和顶端解剖结构的状态进行调查。 这项工作的意义在于提出一个新的假说，以解释和理解静止中心的建立和发展作用，并最终在根中形成模式。

Root apices have been studied through the analysis of cell lineage based on histological sections. Theories of apical organization derived from such analyses led to the view that there existed "ultimate initials" at the focus of the cell lineage, just proximal to the root cap. As a result of continuous mitotic activity, it was believed, the ultimate initials produced derivative cells that formed the root. The discovery in 1956 that these cells rarely divided in a growing root initiated a reassessment of root development. Collectively, these inactive "ultimate initials" comprise a region called the quiescent center (QC). Since its discovery, plant biologists have tried to understand what the QC cells do, why they are quiescent, and how and when quiescence arises. The work outlined in this proposal addresses these questions. The objectives of this proposal are to use molecular, genetic, and physiological approaches to link the known biochemistry of the root to the biophysics which determines the cellular architecture of the root. Specific attention will be directed to measuring the levels, distributions and interactions between auxin, ascorbic acid and ascorbic acid oxidase with the objective of relating changes in these substances to properties of the quiescent center. Using various experimental approaches, levels of these substances will be manipulated and the status of the quiescent center and apical anatomy investigated. The significance of this effort lies in the advancement of a new hypothesis to account for and understand the establishment and developmental role of the quiescent center and ultimately patterning in roots.