The biomechanics of the rose prickle

It is said that every rose has its thorn, but technically speaking, roses have prickles. Prickles are derived from the epidermis of the plant, whereas true thorns are modified stems. Rose prickles defend the plant from herbivores and help the plant support itself on surrounding objects. Liat Levavi and Benny Bar-On investigated the biomechanical properties of the prickles of the dog rose (Rosa canina Linnaeus) with a view towards features that might be used in the design of miniature anchoring platforms. The authors conducted multiscale structural observations using computed tomography and scanning electron microscopy, performed nanomechanical experiments, and ran numerical simulations to explore the properties of the prickles. The authors revealed that the prickle achieves supreme damage resistance capabilities via hierarchical structural adaptations, spanning from the sub-micrometer level to the macroscopic level. The curved tapering shape, microstructural density of the microtubular arrays that make up the prickle’s interior structure, and nanomechanical properties of its cell walls together make the prickle extremely resistant to mechanical failures. These integrated adaptations secure the biomechanical functions of the prickle, even in extreme loading conditions. According to the authors, the structural features of the rose prickle could inform the design of ultra-small anchoring tools for diverse applications including micro-robotics locomotion, biomedical micro-injection, and micromechanical systems.

 

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