Corson Francis, Adda-Bedia Mokhtar, Boudaoud Arezki
Laboratoire de Physique Statistique, Ecole Normale Supérieure, UPMC Paris 06, Université Paris Diderot, CNRS, 24 rue Lhomond, 75005 Paris, France.
J Theor Biol. 2009 Aug 7;259(3):440-8. doi: 10.1016/j.jtbi.2009.05.002. Epub 2009 May 14.
Development commonly involves an interplay between signaling, genetic expression and biophysical forces. However, the relative importance of these mechanisms during the different stages of development is unclear. Leaf venation networks provide a fitting context for the examination of these questions. In mature leaves, venation patterns are extremely diverse, yet their local structure satisfies a universal property: at junctions between veins, angles and diameters are related by a vectorial equation analogous to a force balance. Using a cell proliferation model, we reproduce in silico the salient features of venation patterns. Provided that vein cells are given different mechanical properties, tensile forces develop along the veins during growth, causing the network to deform progressively. Our results suggest that the local structure of venation networks results from a reorganization driven by mechanical forces, independently of how veins form. This conclusion is supported by recent observations of vein development in young leaves and by the good quantitative agreement between our simulations and data from mature leaves.
发育通常涉及信号传导、基因表达和生物物理力之间的相互作用。然而，这些机制在发育不同阶段的相对重要性尚不清楚。叶脉网络为研究这些问题提供了一个合适的背景。在成熟叶片中，叶脉模式极其多样，但其局部结构满足一个普遍特性：在叶脉交汇处，角度和直径通过类似于力平衡的矢量方程相关联。使用细胞增殖模型，我们在计算机上再现了叶脉模式的显著特征。假设叶脉细胞具有不同的机械特性，在生长过程中沿叶脉会产生拉力，导致网络逐渐变形。我们的结果表明，叶脉网络的局部结构是由机械力驱动的重组产生的，与叶脉如何形成无关。这一结论得到了最近对幼叶叶脉发育的观察结果以及我们的模拟与成熟叶片数据之间良好定量一致性的支持。
