Dandelions control the dispersal of their seeds through asymmetrical attachment, finds study

Do not be disappointed if all the soft seeds of a dandelion do not fly away with a single blow. The gust of the wind of your lungs can be strong, but the natural desire for the dandelion to control the way in which its seeds are scattered is stronger. Researchers from Cornell University and the Australian National University have found that not all seeds are attached to seeds in the same way, which creates a massive difference in the required force to detach them.

It takes much less strength to break the seeds in the positive direction (90 ° towards the Capitoute or the top of the seed head) than in the negative direction (90 ° towards the rod). Pulling a straight dandelion seed is even more difficult, because it would take more than 30 times more force than to pull it from an angle.

The results are published in the Journal of the Royal Society Interface.

Many flower plants aim to disperse their seeds from afar. By extending the seeds far from the mother plant, they reduce competition for limited resources and allow their offspring to colonize new areas, expanding their range. Some plants rely on animals for pollination, others depend on water, but the favorite method of dandelion is the wind.

The dandelions have evolved to develop Pappus, soft white hairs on the seeds, which offer special aerodynamic capacities, ensuring that the seeds are taken in the air and float over longer distances.

Scientists thought that dandelion was a passive character in the situation: the seeds went wherever the wind took them. This notion was quickly disputed, because more and more researchers discovered that the phenomenon of the abcission of non -random seeds, where the detachment of the seeds of a mother plant is not purely arbitrary, but rather dependent on environmental conditions.

Scientists have known for some time that the mechanism of dispersion of seeds in dandelions depends on the direction of the wind, but the underlying mechanism supporting this characteristic has remained poorly understood.

To measure the force necessary to detach dandelion seeds in different directions, the researchers have designed an intelligent configuration. A microstage was installed with a dandelion seed head, including its stem, fixed by a spindle. A single seed was chosen and the center of the Pappus of a seed was then glued to a surgical suture linked to a strength sensor, imitating the attraction of the wind.

They slowly moved the micro-stressing to create a traction effect and recorded the absolute force, which was measured as the cutting edge force recorded when the seed has detached. They explored how management influences the release of seeds by repeating the action of traction of seeds to different angles and directions.

They found that the force necessary to detach a dandelion seed can vary more than ten times depending on the traction direction. The seeds stand out effortlessly when pulled with the wind but stubbornly hung on when pulled against him.

Pulling a straight seed has proven to be the most difficult, requiring a median strength of 45 minutes, which is more than 100 times more than that required in the positive direction.

They also used microscopy to obtain a detailed view of the question of whether the dandelion attachment site is asymmetrical. The measures have shown that the side facing the upper has increased structures that prepare the Pappus and resist the detachment, while the side towards the summit is much lower. This structural imbalance explains why the detachment force changes so much with the management.

The study establishes that if plants cannot control exactly where their seeds land, they can control how they stand out.

The dandelions owe their generalized presence to this intelligent dispersion strategy, which guarantees that each seed drifts towards a new spot adorning the area with bright yellow flowers.

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