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BOB HIRSHON (host):
A root navigation system. I’m Bob Hirshon and this is Science Update.
As plant roots burrow into the ground, they wind around rocks and other obstacles to find nutrients and water. Now, scientists at the John Innes Centre in Norwich, England have figured out how they do it. Project leader Liam Dolan explains that roots are covered in elongated cells called root hairs. The hair cells produce oxygen free radicals that help the plant absorb essential calcium for growth. Dolan’s team discovered that the calcium, in turn, makes the root hairs produce more free radicals. As long as that cycle keeps up, the roots keep pushing forward in one direction.
LIAM DOLAN (John Innes Centre, Norwich, England):
Then what happens when they confront an obstacle, is that something, we predict, will break that positive reinforcement cycle, and growth will stop immediately.
He says then the process would start up again on other sides of the root. I’m Bob Hirshon for AAAS, the science society.