Earth News

Matt Walker Editor, Earth News

Remarkable footage has been captured of falling Alsomitra vine seeds, which use paper-thin wings to disperse like giant gliders.

The seeds, which are produced by a football-sized pod, can glide hundreds of metres across the forest.

That ensures that the seeds fall far from their parent, giving the next generation of vines a head start.

A BBC team captured the film of the gliding seeds for the natural history series Life.

The Alsomitra (Alsomitra macrocarpa) vine is a type of climbing gourd, and is also known as the Javan cucumber.

It grows in the forests of Java, Indonesia.

Each pod contains up to 400 individual seeds, each of which peels away from the parent tree in the wind.

Dispersing its seeds in this way is vital to the vine, which must avoid producing new plants that land close, competing for sunlight and soil nutrients.

The wings decay upon landing

The aerodynamics of the giant Alsomitra seeds were studied by two Japanese engineers, Akira Azuma and Yoshinori Okuno more than 20 years ago.

They found that design of the seed is so good that it achieves a descent angle of just 12 degrees, a property that has led to the seed's shape inspiring the design of aircraft.

That means it falls just 0.4m each second, compared to 1m per second for many winged seeds that rotate as they fall.

Once the seed has fallen to the ground, the wings decay, rotting away to leave the germinating seed.

A new vine then grows skyward toward the canopy and sunlight.

At up to 15cm across, and weighing around 300mg, they are among the largest winged seeds produced by any plant. Yet the seed's wings are less than 10 micrometres thick.

Generally, the seeds fall to the ground in broad circles up to 6m across.

However, compared to many other plant seeds, those of the Alsomitra vine can glide in a relatively straight line with a following wind, helping them fall further away from the parent plant.

"Gliding seeds" is broadcast within the Plants episode of the BBC series Life at 2100GMT on BBC One on Monday 7 December.

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