Which fruit contains thousands of tiny seeds

 

Plants can fly too. They do this in the service of procreation. Many plants such as hazel, birch or grass spread their pollen with the wind - much to the chagrin of hay fever allergy sufferers, whose immune system reacts incorrectly to the harmless, tiny flight companions. The male pollen is used to pollinate the stigmas of the female flowers that remain on the ground.

Pollen and dandelion seeds in the air © dpa

Many other pollen travel as a stowaway. They stick to the bees' bodies when they come to the flowers to drink the nectar. The next time the bees bloom, they will inevitably hit the stigma on which the pollen will stick. From there they finally fuse with the female germ cell of the plant.


Airmail for seeds

Another way plants get airborne is by spreading the seeds that have already been fertilized. With these, the plants ensure that further areas can be opened up as spaciously as possible from their location.

The best known are probably the seeds of the dandelion, which sail through the air on small umbrellas. They fly about 16 kilometers, and when there is an updraft they cover thousands of kilometers - even across oceans.

The most important seed for aircraft construction is that of the Zanonia plant. This tropical cucurbit climbs like a liana on other trees. The fruit is the size of a soccer ball and contains many seeds that have a "wingspan" of about six inches. These weigh only 0.2 grams each. Due to the curved shape of the wings and the favorable weight distribution, the seed can fly up to 240 meters from a 30 meter high tree even in calm conditions.

The aircraft manufacturer Karl Jatho took the Zanonia seed as a model and in 1903 constructed a "flying wing" with a similar shape. Its biplane had the same shape as the Zanonia seed. At the wing tip, however, the aircraft had a different profile to reduce the risk of stalling. Other engineers followed Jatho's example, and several planes in the shape of the Zanonia seed were created.