Researchers have uncovered an astonishing mechanism of seed dispersal in nature: the squirting cucumber.

This plant, Ecballium, boasts an extraordinary method of ejecting seeds over considerable distances, with a new study from Kiel University in Germany providing deeper insight into the process.

The mature squirting cucumber fruits are packed with thick liquid, creating significant internal pressure. When ripe, the stems disconnect, causing the fruit to forcefully discharge its seeds.

“This typically occurs when the fruit is fully mature and is disturbed,” Helengoge from Kiel University mentioned in BBC Science Focus.

“The plant aims to scatter its seeds as far as possible, which can propel them over 12 meters (39 feet) from the parent plant.”

Even minimal contact can trigger the fruit’s release, prompting Gorges’s team to utilize CT imaging to construct 3D models of the fruit without causing any damage.

Additionally, a high-speed camera captured the moment the cucumber expelled its seeds at speeds of up to 47 km/h (29 mph).

Gorge observed the maturation process of the fruits, noting that the stems straighten as the cucumber approaches readiness, ultimately hanging at a 52º angle just before bursting. The optimal angle for ballistic projection is theoretically 50º, making the cucumber nearly precise in its seed dispersal.

Like many plants, cucumbers aim to distribute their seeds widely to minimize competition for essential resources like light, water, and nutrients between parent and offspring plants.

While most plants have evolved to rely on wind, water, or animals for seed dispersal, squirting cucumbers have taken an active, ballistic approach.

The research team hopes their findings will inspire others to develop naturally derived solutions for future challenges.

“There are numerous applications in soft robotics, drug delivery systems, and similar technologies where efficient launching systems are needed,” Gorges stated.

About the experts

Helen Gogges is a doctoral student specializing in functional morphology and biomechanics at Kiel University in Germany, focusing on optimizing plant mechanisms for seed distribution.

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