On any given dandelion, some seeds are destined to go north, while others are fated to fly east, south or west, and every direction in between. In effect, each dandelion seed is programmed to release for a wind coming from one direction and resists winds from other directions, according to research to be presented at the American Physical Society's Division of Fluid Dynamics in Indianapolis on November 20.
Dandelion seeds are susceptible to different wind directions depending on where they are on the seed head, says Jena Shields, a biophysicist at Cornell University. The feathery seeds on the side facing a breeze will let go most easily; the others hold on tens to hundreds of times tighter — until the wind shifts.
[...] Shields measured the force it takes to pluck dandelion seeds by supergluing a fine wire to the tufted ends and pulling them from the seed heads at various angles. This seed-by-seed study mimicked what happens when wind, or a child's breath, pushes them over. Because each seed is most susceptible to winds from distinct directions, it helps prevent seeds from all going the same way, Shields says, and may explain why the plants are so successful at spreading. Once blown off a dandelion, the umbrella-like tuft on a seed carries it on the breeze that pulled it away.
(Score: 3, Disagree) by Runaway1956 on Saturday December 03, @08:40PM
Not many dandlions around here. I accidentally stumbled over a possible explanation, while researching healthy garden soil. It seems that dandelions LOVE compacted soil. Given time, a heavy ground cover of dandelions will loosen the soil, then they won't grow so well. I guess the cause-and-effect is, with loose soil to grown in, all the competition grows healthier, and the dandelions can't get established.
I should apply for some grants to research that!
If you don't have an assault rifle, sell your cloak and buy one. - Jesus