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Seed Movement

June 13, 2007

Some seeds plant themselves.


How some seeds sow themselves. I’m Bob Hirshon and this is Science Update.

The seeds of the wild wheat plant don’t just lie around waiting to be planted. Scientists in Germany and Israel have found that like some other plants, they actively crawl on the ground and bury themselves. Chemist Rivka Elbaum, then at the Max Planck Institute in Germany, says the wild wheat uses a previously unknown technique, involving its two antenna-like projections, called awns. The awns contain two types of cellulose fibers: One contracts when the humidity drops, and the other doesn’t.

RIVKA ELBAUM (Max Planck Institute, Germany):
So you can imagine that the passive part is similar to a bone and then the active part is pulling it, like a muscle.

As the humidity level fluctuates, the awns flex and extend, muscling the seed along. Elbaum says this mechanism may be used by other plants, and could potentially be copied in tiny, man-made machines. I’m Bob Hirshon, for AAAS, the science society.