Plant Networks Can Send Warnings, Spread Viruses

October 1, 2007

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Much like how humans now send instant messages to each other on the Internet, plants such as strawberry and clover can exchange information along linked networks, ongoing research suggests.

These plants spread by sending horizontal stems known as runners along or under the ground. The runners eventually bud off new plants, which often remain connected via the stem system.

"So you end up with a network of plants," said Josef Stuefer, an ecologist at Radboud University in Nijmegen, Netherlands.

Scientists have long known that plants use these networks to share resources like food and water. (Related: "Plants Can Recognize, Communicate With Relatives, Studies Find" [June 14, 2007].)

Stuefer and his colleagues have now found the plants also use the networks to communicate, such as during an attack by leaf-eating insects.

Messaging Plants

The team's research shows that if a caterpillar attacks a strawberry leaf, for instance, the plant quickly passes along a warning of the imminent danger through the network. (Related: "Can Global Warming Cause Caterpillar Outbreaks?" [November 16, 2005].)

The message is sent through the phloem, a tube system plants use to transport organic compounds like carbohydrates, Stuefer said. This suggests the warning is also conveyed by an organic chemical.

Recipients of the message bolster their chemical and mechanical resistance so that they are able to thwart the caterpillar attack.

For example, chemical changes make the leaves less palatable and structural changes make the leaves harder to bite, Stuefer noted.

These defensive actions, in turn, significantly limit caterpillar damage to the plants.

Continued on Next Page >>


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