Moore R, McClelen C E
Department of Biology, Baylor University, Waco, Texas 76798, USA.
Ann Bot. 1985;56:73-81. doi: 10.1093/oxfordjournals.aob.a086996.
In calyptrogen cells of Zea mays, proplastids are distributed randomly throughout the cell, and the endoplasmic reticulum (ER) is distributed parallel to the cell walls. The differentiation of calyptrogen cells into columella statocytes is characterized by the following sequential events: (1) formation of ER complexes at the distal and proximal ends of the cell, (2) differentiation of proplastids into amyloplasts, (3) sedimentation of amyloplasts onto the distal ER complex, (4) breakdown of the distal ER complex and sedimentation of amyloplasts to the bottom of the cell, and (5) formation of sheets of ER parallel to the longitudinal cell walls. Columella statocytes located in the centre of the cap each possess 4530 +/- 780 micrometers2 of ER surface area, an increase of 670 per cent over that of calyptrogen cells. The differentiation of peripheral cells correlates positively with (1) the ER becoming arranged in concentric sheets, (2) amyloplasts and ER becoming randomly distributed, and (3) a 280 per cent increase in ER surface area over that of columella statocytes. These results are discussed relative to graviperception and mucilage secretion, which are functions of columella and peripheral cells, respectively.
在玉米的根冠原细胞中，前质体随机分布于整个细胞，内质网（ER）则平行于细胞壁分布。根冠原细胞分化为柱状细胞的过程具有以下一系列特征性事件：（1）在细胞的远端和近端形成内质网复合体；（2）前质体分化为淀粉体；（3）淀粉体沉降到远端内质网复合体上；（4）远端内质网复合体解体，淀粉体沉降到细胞底部；（5）形成平行于细胞纵向壁的内质网片层。位于根冠中央的柱状细胞每个拥有4530±780平方微米的内质网表面积，比根冠原细胞增加了670%。外周细胞的分化与以下因素呈正相关：（1）内质网排列成同心片层；（2）淀粉体和内质网随机分布；（3）内质网表面积比柱状细胞增加280%。这些结果结合重力感知和黏液分泌进行了讨论，重力感知和黏液分泌分别是柱状细胞和外周细胞的功能。
