THE CONTROL OF THE ORIENTATION OF CELL DIVISIONS IN FERN GAMETOPHYTES
THE CONTROL OF THE ORIENTATION OF CELL DIVISIONS IN FERN GAMETOPHYTES
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DOI：
10.2307/2442134
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发表时间：
1980-01-01
影响因子：
3
通讯作者：
PAOLILLO, DJ
中科院分区：
文献类型：
--
作者：
COOKE, TJ;PAOLILLO, DJ
丝状蕨类植物[Onoclea Sensibilis L.]配子体被用来评估细胞分裂平面是否可参考在向二维生长过渡之前和期间的最小表面积平面。通过将顶端细胞建模为被圆柱体覆盖的半球，顶端细胞的尺寸与横向平面与纵向平面上的最小面积相关的长/宽比有关。显然，丝状生长是由顶端细胞几何形状保持的，该几何形状使横向分割面成为最小表面积的方向，而一旦纵向平面成为最小表面积的位置，就发生了向二维生长的过渡(顶端细胞的纵向分裂)。无论光强度和光质量的变化，新陈代谢调节器的存在，或者实验扰动是否导致向二维生长的转变的相应的选择性抑制，这一假说的预测都是成立的。因此，在这个系统中细胞分裂平面的控制似乎取决于表面积的热力学考虑。基因组在向二维生长的转变中所起的作用是影响顶端细胞的尺寸，而不是诱导特定的形态发生基因的结论是有利的。
Time-lapse observations of filamentous fern [Onoclea sensibilis L.] gametophytes were used to evaluate whether the plane of cell division is referable to the plane of minimal surface area before and during the transition to 2-dimensional growth. Cell dimensions of the apical cell were related to the length/width ratios associated with minimal area in the transverse plane vs. longitudinal plane, by modeling the apical cell as a hemisphere subtended by a cylinder. Apparently, filamentous growth is perpetuated by an apical cell geometry that makes the transverse division plane the orientation of minimal surface area, whereas the transition to 2-dimensional growth (longitudinal division of the apical cell) occurs once the longitudinal plane becomes the position of minimal surface area. The predictions of this hypothesis are fulfilled regardless of variations in light intensity and light quality, the presence of regulators of metabolism or whether the experimental perturbation causes a corresponding selective inhibition of the transition to 2-dimensional growth. Thus, the control of the plane of cell division in this system seems to depend on thermodynamic considerations of surface area. The conclusion that the role of the genome in the transition to 2-dimensional growth involves its influence on apical cell dimensions rather than the induction of specific genes for specific morphogenetic mRNA is favored.