Analysis of cell division and elongation underlying the developmental acceleration of root growth in Arabidopsis thaliana
Analysis of cell division and elongation underlying the developmental acceleration of root growth in Arabidopsis thaliana
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DOI：
10.1104/pp.116.4.1515
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发表时间：
1998-04-01
期刊：
影响因子：
7.4
通讯作者：
Baskin, TI
中科院分区：
文献类型：
--
作者：
Beemster, GTS;Baskin, TI
为了研究器官生长速率调节中细胞分裂和扩张之间的关系，我们使用了在20摄氏度下垂直生长的拟南芥主根，其伸长速率在萌发后的第一个14天期间稳步增加。我们测量了纵向速度和细胞长度的空间分布，并计算了细胞扩张和分裂的参数，包括局部细胞产生速率（细胞mm（-1）h（-1））和细胞分裂速率（细胞cell（-1）h（-1））。数据获得的根皮层，也为两种类型的表皮细胞，毛细胞和atrichoblasts。加速根伸长是由越来越长的生长区，而最大应变速率保持不变。生长区的扩大，因此，加速根伸长速率，伴随着几乎成比例地增加细胞生产。这种增加的产量是由越来越多的分裂细胞引起的，而它们的分裂速率几乎保持不变。此外，细胞分裂速率的空间分布基本上是恒定的。分生组织比一般认为的要长，延伸到细胞迅速伸长的区域。在两种表皮细胞类型中，分生组织长度和细胞分裂速率都与皮层细胞非常相似，并且两种表皮细胞类型之间的细胞长度差异起源于分生组织的顶端。这些结果突出了控制分裂细胞数量的重要性，既可以产生具有不同细胞长度的组织，也可以调节器官扩大的速度。
To investigate the relation between cell division and expansion in the regulation of organ growth rate, we used Arabidopsis thaliana primary roots grown vertically at 20 degrees C with an elongation rate that increased steadily during the first 14 d after germination. We measured spatial profiles of longitudinal velocity and cell length and calculated parameters of cell expansion and division, including rates of local cell production (cells mm(-1) h(-1)) and cell division (cells cell(-1) h(-1)). Data were obtained for the root cortex and also for the two types of epidermal cell, trichoblasts and atrichoblasts. Accelerating root elongation was caused by an increasingly longer growth zone, while maximal strain rates remained unchanged. The enlargement of the growth zone and, hence, the accelerating root elongation rate, were accompanied by a nearly proportionally increased cell production. This increased production was caused by increasingly numerous dividing cells, whereas their rates of division remained approximately constant. Additionally, the spatial profile of cell division rate was essentially constant. The meristem was longer than generally assumed, extending well into the region where cells elongated rapidly. In the two epidermal cell types, meristem length and cell division rate were both very similar to that of cortical cells, and differences in cell length between the two epidermal cell types originated at the apex of the meristem. These results highlight the importance of controlling the number of dividing cells, both to generate tissues with different cell lengths and to regulate the rate of organ enlargement.