Artificial seed casing made from wood buries itself when wet

The wooden seed carrier screws into the ground when exposed to water.It could be useful for projects that use drones to reforest from the air

To James Dineen

Seed casings made from treated wood are stronger and more versatile than natural self-buried seeds, and may make seed sowing from drones and airplanes more effective.

Many species of plants produce seeds with structures that help protect them or bury them in the soil in response to changes in humidity.genus of plants Elodium It produces seeds with coiled tails that unwind when wet, twisting the seed pods deep into the soil. says Lining Yao of Mellon University.

Yao and her colleagues Elodium and other plants with self-buried seeds design seed carriers that can carry seeds of different sizes and twist them into the soil more effectively in different environments.

After sorting out natural and synthetic materials, the researchers used a biodegradable white oak tree that not only responds to changes in moisture, but is hard enough to drive seeds into the soil. I decided to.

The team has developed a chemical treatment that allows the wood to be tightly coiled. The wood allows him to bend 45 times tighter than other comparable wooden parts, thus exerting more torque when screwing the seed pods into the ground. “Thrust force depends on the stiffness and tightness of the coil body,” says Yao.

The researchers also designed a coil with three tails instead of a single tail. Elodium seed. The added tail makes the coil more likely to be positioned at the right angle for seeds to be driven into the soil when the coil unwinds, especially on flat ground.

Seed pods made of wheat dough and a cellulose coating are attached to carriers and hold seeds and other beneficial payloads such as fungi and nematodes that help fertilize the seeds.

Arugula seeds were placed in 136 carriers and field tested on flat ground, with approximately 66% of the carriers firmly anchored in the soil and 39% of the seeds germinated. The researchers haven’t compared this to seeds planted without the carrier, but Yao says it’s a proof of concept that the carrier works. Weather was also a factor. In one test, more than half of the fixed seeds were displaced after heavy rain.

With better carriers, aerial seeding by plane or drone could be more effective, says Yao. Aerial seeding is useful when large areas need to be planted quickly, such as reforestation projects, or when the area to be sown is difficult to access.

Naomi Nakayama of Imperial College London says researchers still have a lot to do to show the carrier works in the field and that it can be produced at the scale needed for a real planting program. . But she says the new wood opens up new possibilities for soft “wooden robots” that can respond to changes in moisture. “This morphing capability goes far beyond what we were able to achieve before,” she says.