School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3BF, UK.
School of Engineering, University of Edinburgh, Edinburgh, EH9 3FF, UK.
Nat Commun. 2022 May 6;13(1):2498. doi: 10.1038/s41467-022-30245-3.
Plants generate motion by absorbing and releasing water. Many Asteraceae plants, such as the dandelion, have a hairy pappus that can close depending on moisture levels to modify dispersal. Here we demonstrate the relationship between structure and function of the underlying hygroscopic actuator. By investigating the structure and properties of the actuator cell walls, we identify the mechanism by which the dandelion pappus closes. We developed a structural computational model that can capture observed pappus closing and used it to explore the critical design features. We find that the actuator relies on the radial arrangement of vascular bundles and surrounding tissues around a central cavity. This allows heterogeneous swelling in a radially symmetric manner to co-ordinate movements of the hairs attached at the upper flank. This actuator is a derivative of bilayer structures, which is radial and can synchronise the movement of a planar or lateral attachment. The simple, material-based mechanism presents a promising biomimetic potential in robotics and functional materials.
植物通过吸收和释放水分来产生运动。许多菊科植物，如蒲公英，具有绒毛状的冠毛，可以根据水分水平关闭，以改变传播方式。在这里，我们展示了基础吸湿致动器的结构和功能之间的关系。通过研究致动器细胞壁的结构和特性，我们确定了蒲公英冠毛关闭的机制。我们开发了一个结构计算模型，可以捕捉到观察到的冠毛关闭，并利用它来探索关键的设计特征。我们发现，致动器依赖于围绕中央腔的血管束和周围组织的径向排列。这允许以径向对称的方式进行不均匀的肿胀，从而协调附着在上侧的毛发的运动。这种致动器是双层结构的衍生物，它是径向的，可以同步平面或横向附件的运动。这种基于简单材料的机制在机器人技术和功能材料中具有很大的仿生潜力。
