Cellular parameters of the shoot apical meristem in Arabidopsis
Cellular parameters of the shoot apical meristem in Arabidopsis
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DOI：
10.1105/tpc.10.8.1375
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发表时间：
1998-08-01
期刊：
影响因子：
11.6
通讯作者：
Traas, J
中科院分区：
文献类型：
--
作者：
Laufs, P;Grandjean, O;Traas, J
芽顶分生组织（SAM）是一小部分分裂细胞，它们产生了植物的所有空中部位。为了为分析细胞水平分析拟南芥分生组织的框架，我们对Landsberg Erecta和Wassilewskija Ecotypes的积极生长的花序顶点进行了详细的形态计量学研究。为此，在用共聚焦激光扫描显微镜制成的一系列光学切片中确定细胞大小，有丝分裂细胞的空间分布和有丝分裂指数。结果使我们能够鉴定出不同细胞增殖率的花序SAM内的区域。特别是，我们能够定义一个宽四到六个细胞且有丝分裂指数低的中心区域。我们使用此技术将野生型的分生组织与两个突变体的分生组织分生生物进行了比较，即Clavata3-1（Clv3-1）和MGOUN2（MGO2）。 CLV基因提出的功能之一是限制分生组织中心的细胞分裂速率。我们的数据使我们能够拒绝这一假设，因为在CLV3-1突变体的花序分生组织中，有丝分裂指数减少了。我们还观察到在Clv3-1幼苗的分生物中缓慢分裂细胞的targe区。在野生型中无法检测到这种音调。这些结果表明，突变分生组织中的中心区域的大小增加，这与CLV3基因从中心向外围区过渡至关重要的假设是一致的。遗传和显微镜分析表明，MGO2在原始生产中受到了损害，我们先前提出MGO2分生组织的大小增加可能是由于周围细胞积累的积累。我们的形态分析表明，MGO2分生组织与CLV3-1的分生组织具有较大细胞增殖率的外围增大。这证实CLV3-1和MGO2通过影响分生组织功能的不同方面而导致分生组织过度生长。
The shoot apical meristem (SAM) is a small group of dividing cells that generate all of the aerial parts of the plant. With the goal of providing a framework for the analysis of Arabidopsis meristems at the cellular level, we performed a detailed morphometric study of actively growing inflorescence apices of the Landsberg erecta and Wassilewskija ecotypes. For this purpose, cell size, spatial distribution of mitotic cells, and the mitotic index were determined in a series of optical sections made with a confocal laser scanning microscope. The results allowed us to identify zones within the inflorescence SAM with different cell proliferation rates. In particular, we were able to define a central area that was four to six cells wide and had a low mitotic index. We used this technique to compare the meristem of the wild type with the enlarged meristems of two mutants, clavata3-1 (clv3-1) and mgoun2 (mgo2). One of the proposed functions of the CLV genes is to limit cell division rates in the center of the meristem. Our data allowed us to reject this hypothesis, because the mitotic index was reduced in the inflorescence meristem of the clv3-1 mutant. We also observed a targe zone of slowly dividing cells in meristems of clv3-1 seedlings. This tone was not detectable in the wild type. These results suggest that the central area is increased in size in the mutant meristem, which is in line with the hypothesis that the CLV3 gene is necessary for the transition of cells from the central to the peripheral zone. Genetic and microscopic analyses suggest that mgo2 is impaired in the production of primordia, and we previously proposed that the increased size of the mgo2 meristem could be due to an accumulation of cells at the periphery. Our morphometric analysis showed that mgo2 meristems, in contrast to those of clv3-1, have an enlarged periphery with high cell proliferation rates. This confirms that clv3-1 and mgo2 lead to meristem overgrowth by affecting different aspects of meristem function.