Are plants sensitive to sound?

Korean researchers claim to have discovered two sound-sensitive genes in rice plants...

Mi-Jeong Jeong and colleagues from the National Institute of Agricultural Biotechnology in Suwon, South Korea, made the discovery by exposing plants to noise and studying how this affected gene activity.

Initially they tried playing 14 samples of classical music to their rice, including Beethoven's Moonlight Sonata, but saw no response. 

Next they tried playing sounds of specific frequencies and began to see a change.  At 125 Hz and 250 Hz the activity of two genes, rbcS and Ald, went up. But when sounds at at 50 Hz were played, the gene activity went down. 

To find out whether other genes could be rendered sound-sensitive, the team linked the genetic elements that control the Ald gene to a 'reporter' gene inserted into the rice called GUS (beta-glucuronidase).  They found that sounds could then also manipulate the levels of GUS.

This suggests that it might be possible to use sound instead of chemicals to control different genetic processes in plants, such as switching on resistance genes to help them fight off pests or ripen more rapidly. 

Not all scientists are convinced though; some say that the new research, which is published in the journal Molecular Breeding, makes use of old techniques and lacks sufficient numbers to make the data credible. Sounds like sour grapes, although it does suggest that it's not just cereals like wheat and barley that have 'ears'...