How seeds implant themselves in soil can seem magical. Take some varieties of erodium, whose five-petalled flowers of purple, pink, or white look like geraniums.
The seed of these plants is carried inside a thin, tightly wound stalk. During rain or high humidity, the corkscrew-like stalk unwinds and twists the seed into the soil, where it can take root and is safe from hungry birds and harsh environmental conditions.
Inspired by erodium’s magic, Shu Yang, Joseph Bordogna Professor and Chair of Materials Science and Engineering and professor in Chemical and Biomolecular Engineering at Penn Engineering, and a team of collaborators have engineered a biodegradable seed carrier referred to as “E-seed.” Their seed carrier, fashioned from wood veneer, could enable aerial seeding of difficult-to-access areas, and could be used for a variety of seeds or fertilizers and adapted to many different environments.
The team’s research appears in the February issue of Nature.
Erodium’s stalk forms a tightly wound, seed-carrying body with a long, curved tail at the top. When it begins to unwind, the twisting tail engages with the ground, causing the seed carrier to push itself upright. Further unwinding creates torque to drill down into the ground, burying the seed.
But erodium’s one-tailed carrier only works well on soils with crevices. To employ their E-seed carriers in a broader range of environments, the research team developed a three-tailed version that is more efficient at pushing itself upright.
“Geometry can enhance the functionality of the materials beyond what nature offers us. It also makes the design versatile to be applied to other materials,” says Yang.
This story is by Byron Spice. Read more at Penn Engineering Today.