Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213.
Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213.
Proc Natl Acad Sci U S A. 2018 Dec 4;115(49):12359-12364. doi: 10.1073/pnas.1811296115. Epub 2018 Nov 19.
Morphogenesis is a phenomenon by which a wide variety of functional organs are formed in biological systems. In plants, morphogenesis is primarily driven by differential growth of tissues. Much effort has been devoted to identifying the role of genetic and biomolecular pathways in regulating cell division and cell expansion and in influencing shape formation in plant organs. However, general principles dictating how differential growth controls the formation of complex 3D shapes in plant leaves and flower petals remain largely unknown. Through quantitative measurements on live plant organs and detailed finite-element simulations, we show how the morphology of a growing leaf is determined by both the maximum value and the spatial distribution of growth strain. With this understanding, we develop a broad scientific framework for a morphological phase diagram that is capable of rationalizing four configurations commonly found in plant organs: twisting, helical twisting, saddle bending, and edge waving. We demonstrate the robustness of these findings and analyses by recourse to synthetic reproduction of all four configurations using controlled polymerization of a hydrogel. Our study points to potential approaches to innovative geometrical design and actuation in such applications as building architecture, soft robotics and flexible electronics.
形态发生是一种现象，通过这种现象，生物系统中形成了各种各样的功能器官。在植物中，形态发生主要是由组织的差异生长驱动的。人们已经投入了大量的精力来识别遗传和生物分子途径在调节细胞分裂和细胞扩展以及影响植物器官形状形成中的作用。然而，控制差异生长如何控制植物叶片和花瓣中复杂 3D 形状形成的一般原则在很大程度上仍然未知。通过对活体植物器官的定量测量和详细的有限元模拟，我们展示了生长中的叶片的形态是如何由生长应变的最大值和空间分布共同决定的。有了这个认识，我们为形态相图开发了一个广泛的科学框架，该框架能够使植物器官中常见的四种构型（扭曲、螺旋扭曲、鞍形弯曲和边缘波动）合理化。我们通过使用水凝胶的受控聚合来合成所有四种构型的复制品，证明了这些发现和分析的稳健性。我们的研究为建筑、软机器人和柔性电子等应用中的创新几何设计和驱动指明了潜在的方法。
