Nakamasu Akiko, Suematsu Nobuhiko J, Kimura Seisuke
Graduate School of Medical Sciences, Kyusyu University, Fukuoka, Japan.
Department of Bioresource and Environmental Sciences, Faculty of Life Sciences, Kyoto Sangyo University, Kyoto, Japan.
Dev Dyn. 2017 Dec;246(12):981-991. doi: 10.1002/dvdy.24587. Epub 2017 Oct 13.
Morphogenesis, when accompanied by continuous growth, requires stable positional information to create a balanced shape in an organism. Evenly spaced branches are examples of such morphogenesis. Previously, we created a model that showed when a one-dimensional (1D) ring (a boundary of a 2D field) was periodically deformed based on a stable, doubled iterative pattern during expansion; a nested, regularly spaced, symmetrically branched structure was generated. The characteristic divaricating pattern is common in the leaves of many plant species; however, the divarication symmetry was often broken. To evaluate this type of asymmetry, we investigated several species with dissected or compound leaves.
Sometimes these leaves showed asymmetries in the number of lobes or segments positioned on either side of the secondary axes. The direction of the asymmetry, i.e., which side of a secondary axis has more axes, appeared to be species-specific.
When different growth speeds along axes of a divaricating leaf were introduced into our previous model, robust and directed asymmetries were reproduced. The differences in growth speed could be predicted from the distributions of leaf segments in actual leaves. Developmental Dynamics 246:981-991, 2017. © 2017 Wiley Periodicals, Inc.
形态发生在伴随着持续生长时，需要稳定的位置信息来在生物体中形成平衡的形状。均匀间隔的分支就是这种形态发生的例子。此前，我们创建了一个模型，该模型表明当一维（1D）环（二维场的边界）在扩展过程中基于稳定的、双倍迭代模式周期性变形时，会生成一个嵌套的、规则间隔的、对称分支的结构。这种特征性的分歧模式在许多植物物种的叶子中很常见；然而，分歧对称性常常被打破。为了评估这种不对称性，我们研究了几种具有深裂叶或复叶的物种。
有时这些叶子在次轴两侧的裂片或小叶数量上表现出不对称性。不对称的方向，即次轴的哪一侧有更多的轴，似乎是物种特异性的。
当将分歧叶轴上不同的生长速度引入我们之前的模型时，会再现强烈且有方向性的不对称性。生长速度的差异可以从实际叶子中叶段的分布预测出来。《发育动力学》246:981 - 991，2017年。©2017威利期刊公司。
