How do Stinging Nettles Inject Poison?

Описание: The leaves of stinging nettles are covered in 'pipette-like' stingers which penetrate the skin on contact and deposit a small amount of poison. The 'pipette-like' design means that almost all of the poison contained in the stinger can be injected at once if sufficient force is applied to bend the stinger to an angle of 90 degrees. This is demonstrated in laboratory experiments conducted by Kaare Jensen at the Technical University of Denmark. Interview with University of Oxford Mathematician Dr Tom Crawford.

This video is part of a collaboration between FYFD and the Journal of Fluid Mechanics featuring a series of interviews with researchers from the APS DFD 2017 conference.

Sponsored by FYFD, the Journal of Fluid Mechanics, and the UK Fluids Network. Produced by Tom Crawford and Nicole Sharp with assistance from A.J. Fillo.

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Featuring: K. Jensen et al. "Masters of defence: biomechanics of stinging nettles" http://meetings.aps.org/Meeting/DFD17...

The techniques employed by plants and animals to defend themselves are very varied. Some involve extremely refined armaments. Stinging nettles employ hollow needle-like stinging hairs constructed from silica, the mineral from which we make glass, and they are filled with poison. The hairs are remarkably rigid and rarely break. Yet the tip is so sharp that the slightest touch cuts human skin, and so fragile that it breaks at that touch and releases poison into the wound. How the seemingly antagonist mechanical functions of rigidity and fragility are achieved, however, is unknown. We combine experiments on real and synthetic stingers to elucidate the poison injection mechanism. The design of plant stingers is compared to other natural systems and optimal stinging strategies are discussed.

Nature Publication:
Jensen, K.H., Knoblauch, J., Christensen, A.H. et al. Universal elastic mechanism for stinger design. Nat. Phys. (2020). https://doi.org/10.1038/s41567-020-09...

JFM Publication:
'Viscous flow in a soft valve' K Park, A Tixier, AH Christensen, SF Arnbjerg-Nielsen… - Journal of Fluid Mechanics, 2018
https://doi.org/10.1017/jfm.2017.805

Special Thanks To:
Nicole Sharp
A. J. Fillo
Kaare Jensen
Whatcom Community College