Zhao L, Sack F D
Department of Plant Biology, Ohio State University, 1735 Neil Avenue, Columbus, Ohio 43210.
Am J Bot. 1999 Jul;86(7):929-39.
Stomatal development was studied in wild-type Arabidopsis leaves using light and electron microscopy. Development involves three successive types of stomatal precursor cells: meristemoid mother cells, meristemoids, and guard mother cells (GMCs). The first two types divide asymmetrically, whereas GMCs divide symmetrically. Analysis of cell wall patterns indicates that meristemoids can divide asymmetrically a variable number of times. Before meristemoid division, the nucleus and a preprophase band of microtubules become located on one side of the cell, and the vacuole on the other. Meristemoids are often triangular in shape and have evenly thickened walls. GMCs can be detected by their roughly oval shape, increased starch accumulation, and wall thickenings on opposite ends of the cells. Because these features are also found in developing stomata, stomatal differentiation begins in GMCs. The wall thickenings mark the division site in the GMC since they overlie a preprophase band of microtubules and occur where the cell plate fuses with the parent cell wall. Stomatal differentiation in Arabidopsis resembles that of other genera with kidney-shaped guard cells. This identification of stages in stomatal development in wild-type Arabidopsis provides a foundation for the analysis of relevant genes and of mutants defective in stomatal patterning, cell specification, and differentiation.
利用光学显微镜和电子显微镜对野生型拟南芥叶片的气孔发育进行了研究。发育过程涉及三种连续类型的气孔前体细胞：分生组织母细胞、分生组织细胞和保卫母细胞（GMCs）。前两种类型进行不对称分裂，而保卫母细胞进行对称分裂。细胞壁模式分析表明，分生组织细胞可以不对称分裂可变次数。在分生组织细胞分裂之前，细胞核和微管的前期带位于细胞的一侧，液泡位于另一侧。分生组织细胞通常呈三角形，壁均匀增厚。保卫母细胞可以通过其大致椭圆形的形状、淀粉积累增加以及细胞相对两端的壁增厚来检测。因为在发育中的气孔中也发现了这些特征，所以气孔分化始于保卫母细胞。壁增厚标记了保卫母细胞中的分裂位点，因为它们覆盖在微管的前期带上，并且出现在细胞板与母细胞壁融合的地方。拟南芥中的气孔分化与其他具有肾形保卫细胞的属相似。对野生型拟南芥气孔发育阶段的这种鉴定为分析相关基因以及气孔模式、细胞特化和分化缺陷的突变体提供了基础。
