Natures wonders: plants defensive warning gases (Introduction)

by David Turell , Monday, March 02, 2020, 21:36 (1725 days ago) @ David Turell

An article about goldenrod:

https://www.the-scientist.com/notebook/generations-of-insect-attacks-drive-plants-to-ta...

"When a beetle larva bites into the leaf of a goldenrod plant, a perennial herb known for its bright yellow flowers, it gets a mouthful of food to fuel its growth. But the plant’s perspective is rather different. The bite damages the goldenrod (genus: Solidago), causing it to launch molecular defenses against the insect and to emit a concoction of chemicals that change the physiology of goldenrod plants nearby. It’s as if the plants are communicating about the invader.

***

"A series of papers have shown that when a plant such as goldenrod is damaged, it releases volatile organic compounds (VOCs) that prompt neighboring plants to mount their own chemical defenses against an impending herbivore attack.

***

"The team found that VOCs emitted by goldenrod plants whose predecessors had been sprayed with the insecticide only induced genetically identical plants to mount preemptive chemical defenses to insect invasion—consistent with the kin selection hypothesis. But VOCs emitted by goldenrod whose predecessors hadn’t been sprayed with the insecticide induced the preemptive defense from all the other goldenrod plants around them, even plants that weren’t their kin—consistent with the mutual benefit hypothesis.

"Additionally, the plants exposed to herbivory converged on a shared VOC signal over the course of the study—with all of the goldenrod plants eventually emitting the same chemical signals whether they were genetically identical to the emitter plant or not. Plants treated with insecticide showed no such signal convergence, the researchers reported in Current Biology last September. This sort of convergence on a single chemical signal is thought to benefit plants exposed to herbivory by providing a stronger deterrent against invading insects or a stronger attraction for the herbivores’ natural enemies. Kalske says the study provides the first concrete evidence that plants aren’t merely eavesdropping on one another, and that the emitter derives a benefit from releasing its chemical messages.

***

"Researchers still don’t know much about how the plants actually receive and respond to the VOC cues, Kalske notes, or whether the presence of other types of herbivores, such as mammals, influences similar signal changes. These are questions that the team would still like to answer."

Comment: This ability has been reported in the past about trees. This presents the usual problem: How did the plants discover this mix if chemicals? Only design fits.