解开黄瓜卷须盘绕机制

来源：仪方生物 www.yeslab.com

植物卷须盘绕的现象困扰了科学家几个世纪，然而其认为可知。不仅如此，尽管达尔文学说关于中盘绕是由于柔软弹性的茎的作用，但行为机制也不清楚。我们在黄瓜的研究中发现卷须的盘绕卷曲发生在特定细胞的内部纤维带非对称性构建时期。有压力情况下，纤维带和旧卷须显示出较强的盘绕能力，从起初的软性反应到后期有力的张力。我们解释这种行为是利用了物理模型的预胶带、几何参数和数学弹性纤维模型。概括而言，我们的研究阐明了卷曲盘绕起因，量化了达尔文原解说，并揭示关于无捻弹簧与可调谐的机械反应的仿生学应用。


How the Cucumber Tendril Coils and Overwinds

Sharon J. Gerbode,1,2,3* Joshua R. Puzey,4* Andrew G. McCormick,5 L. Mahadevan1,2,4,5†

The helical coiling of plant tendrils has fascinated scientists for centuries, yet the underlying mechanism remains elusive. Moreover, despite Darwin’s widely accepted interpretation of coiled tendrils as soft springs, their mechanical behavior remains unknown. Our experiments on cucumber tendrils demonstrate that tendril coiling occurs via asymmetric contraction of an internal fiber ribbon of specialized cells. Under tension, both extracted fiber ribbons and old tendrils exhibit twistless overwinding rather than unwinding, with an initially soft response followed by strong strain-stiffening at large extensions. We explain this behavior using physical models of prestrained rubber strips, geometric arguments, and mathematical models of elastic filaments. Collectively, our study illuminates the origin of tendril coiling, quantifies Darwin’s original proposal, and suggests designs for biomimetic twistless springs with tunable mechanical responses.