Department of Root Physiology, Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Moscow, Russia.
Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México.
Ann Bot. 2018 Nov 3;122(5):811-822. doi: 10.1093/aob/mcx216.
Information on cell cycle duration (T) in the root apical meristem (RAM) provides insight into root growth, development and evolution. We have previously proposed a simple method for evaluating T based on the dynamics of root growth (V), the number of cells in the RAM (Nm) and the length of fully elongated cells (l), which we named the rate-of-cell-production (RCP) method. Here, a global analysis was performed to confirm the reliability of this method in a range of angiosperm species and to assess the advantages of this approach.
We measured V, Nm and l from live or fixed cleared primary roots of seedlings or adventitious roots of bulbs and used this information to estimate the average T values in 73 angiosperm species via the RCP method. The results were then compared with published data obtained using the classical but laborious and time-consuming 3H-thymidine method.
In most species examined, the T values obtained by the RCP method were nearly identical to those obtained by the 3H-thymidine method.
The global analysis demonstrated that the relationship between the variables V, Nm and l in roots in the steady state of growth is correctly described by the equation T = (ln2 Nm l)V-1. Thus, the RCP method enables cell cycle duration in the RAM to be rapidly and accurately determined. This method can be performed using live or fixed roots for each individual cell type. The simplicity of the approach suggests that it will be widely used in phenomics, evolutionary ecology and other plant biology studies.
根尖分生组织（RAM）中细胞周期持续时间（T）的信息可深入了解根的生长、发育和进化。我们之前提出了一种基于根生长速度（V）、RAM 中的细胞数量（Nm）和完全伸长细胞的长度（l）来评估 T 的简单方法，我们将其命名为细胞产生率（RCP）方法。在这里，进行了一项全局分析，以确认该方法在一系列被子植物物种中的可靠性，并评估该方法的优势。
我们从幼苗的活体或固定清除的主根或鳞茎的不定根中测量 V、Nm 和 l，并使用这些信息通过 RCP 方法估算 73 种被子植物物种中的平均 T 值。然后，将结果与使用经典但费力且耗时的 3H-胸腺嘧啶方法获得的已发表数据进行比较。
在所检查的大多数物种中，通过 RCP 方法获得的 T 值与通过 3H-胸腺嘧啶方法获得的值几乎相同。
全球分析表明，在生长稳态下根中 V、Nm 和 l 之间的变量关系通过方程 T =（ln2 Nm l）V-1 正确描述。因此，RCP 方法能够快速准确地确定 RAM 中的细胞周期持续时间。该方法可以使用活体或固定的根进行每个单独的细胞类型。该方法的简单性表明它将广泛用于表型、进化生态学和其他植物生物学研究。
