Swell Idea

Blowing on a dandelion is supposed to bring good luck – to you and the plant, as dispersing a cloud of seeds far and wide helps to ensure at least some survive. But the dandelion doesn’t leave this to chance. Here the head-like pappus at the top of a seed acts like a hygroscope sensing the water halfway through the video. Parts of its structure swell up, pushing or steering the roots of its wing-like hairs (which have been removed here). In wet conditions, the hairs close up, making the seed more likely to fall nearby into a nice moist spot after take-off. Dry seeds stretch out, ready to travel further to find moisture. Researchers developed a mathematical model for the pappus, probing the mechanical properties that may be mimicked in artificial devices like moisture sensing nanorobots to carry chemicals around the body.

Written by John Ankers

John Ankers

Writer

A former researcher in systems biology, John is now an online biology tutor and professional coach supporting the wellbeing of scientists and NHS professionals. He's writing, too, of course.

Website

• Video from work by Madeleine Seale and colleagues
• School of Biological Sciences, University of Edinburgh, Edinburgh, UK
• Video originally published with a Creative Commons Attribution 4.0 International (CC BY 4.0)
• Published in Nature Communications, May 2022