Bite-size Biomimicry: Sensitive Plant
What can we learn from the sensitive plant about how to modify shape and protect from biotic or abiotic factors?
Mimosa pudica has the ability to move its leaves in response to insects, herbivory, heat, light, and rain. This strategy is hypothesized to help protect the leaves and minimize damage.
The movement is created by turgor pressure. Just like air keeps a balloon inflated, turgor pressure keeps cells “turgid” (aka full of water). Turgor pressure is facilitated by biochemical pumps at the base of each leaf-let, an area called the “pulvinus” that contains flexor and extensor cells.
When the plant is touched, the concentration of potassium and chloride changes, and water flows out of the extensor cells (which are located on top of the pulvinus) and into the flexor cells (located on the bottom of the pulvinus). When the extensor cells lose their turgor pressure, the leaflet droops/folds inward.
The entire folding process happens very quickly! And the speed of folding changes as the leaves age. AskNature explains this further: “When younger leaves of the sensitive plant were repeatedly exposed to non-damaging stimuli, the younger leaves consistently folded completely, but over time, they decreased the time it took for them to unfold. Conversely, older leaves folded only partially while maintaining similar reopening times. This shows that the plant is able to modulate its behaviour to optimize protection, energy production (photosynthesis), and energy expenditure (folding and unfolding).”
What can we learn from this plant’s mechanism and how can it inspire our own designs? Let me know in the comments if you have ideas!
Watch my TikTok video exploring the Sensitive Plant here.