Do airborne chemicals from neighboring plants strengthen corn seedlings’ response to a simulated caterpillar attack?

Details

Plants commonly release certain airborne chemicals when damaged or eaten. In these experiments, exposure to these chemicals rapidly prompted intact, undamaged corn seedlings to produce jasmonic acid and release other airborne compounds. Exposure therefore triggered an immediate response as well as preparing the seedlings for a later challenge.

To test that preparation, researchers mechanically damaged previously exposed and unexposed seedlings and applied material regurgitated by caterpillars. Previously exposed seedlings produced significantly more jasmonic acid and released significantly more of a measured group of airborne compounds. But prior exposure did not affect jasmonic acid production after mechanical wounding alone: the enhanced later response depended on the challenge conditions.

Three individual synthetic versions of the plant chemicals had nearly identical preparation effects. Nighttime emissions from caterpillar-attacked plants, rich in these chemicals, also increased later jasmonic acid production and airborne chemical release after caterpillar material was applied.

The experiments support a role for airborne plant signals in preparing chemical defenses. The abstract does not establish whether those stronger responses reduce feeding damage or improve survival during an actual caterpillar attack.