Plants alter their chemistry and taste in response to attacks by predators

Wednesday, August 21, 2013 by: Ethan A. Huff, staff writer
Tags: plants, chemistry alteration, predator attacks

(NaturalNews) There are a variety of ways in which prey animals are known to naturally disguise themselves or flee certain areas to avoid being eaten by predators. But new research out of Wisconsin has found that stationary plants also employ their own protective mechanisms to avoid becoming predator lunch, which includes eavesdropping on the anticipated behavior of herbivores in order to preemptively alter their own chemistry and taste to become more unappealing to predators.

You may have dealt with the problem in your own backyard garden: snails that attack your kale leaves or grubs that feed on the roots of your tomato plants. Insect and animal invaders can be highly problematic when growing food at home, and treating these pests naturally is often a challenge. But plants themselves, it turns out, are naturally capable of thwarting some pests on their own by producing internal repellant chemicals, for instance, or by developing tougher leaves or defensive thorns.

Though the process is by no means foolproof, as plants everywhere are constantly being eaten by predators, it still exists, which may come as a surprise to many people. It sure did to a group of researchers from the University of Wisconsin - Madison (UW-Madison), anyway, which discovered recently that many plants are a whole lot smarter in terms of defending themselves than previously believed.

"You can't run, you can't necessarily hide, so what can you do?" asks John Orrock, a zoology professor at the UW-Madison who helped lead the new research, about how plants naturally defend themselves against predators. "Some plants make themselves less tasty," he says.

Using mustard plants to conduct their experiments, Orrock and his colleagues evaluated how this popular target plant for slugs and snails deters these hungry predators. Recognizing that the two creatures leave behind a trail of slime wherever they go, Orrock collected samples of snail and slug slime and treated both mustard seeds and mustard seedlings with a solution containing the slime to observe how the plants responded.

Much to the team's surprise, the mustard plants detected the slime and consequently mounted defenses to make their leaves less desirable to the predators. Even before any slug or snail actually approached them, the mustard plants were found to be already prepared to deter them, having essentially altered their flavor profile to be far less tasty and desirable.

Plants capable of continually learning new, more advanced ways to defend against predators

Does it matter when plants are exposed to snail slime and other evidence markers of predators? According to the findings, it does, as mustard seedlings exposed to snail slime mounted much more effective defenses than mustard seeds, which are obviously exposed to the substance much earlier in their life cycle. The closer the exposure to the actual impending attack, in other words, the better the plant's defenses.

"That shows that plants are paying attention to generalist herbivore cues and that they turn on their defenses before they even get attacked," says Orrock, referring to how the plants responded after getting "slimed" during tests. "The more recently they receive the information about impending attack, the more likely they are to use the information to defend themselves. Not only do they eavesdrop, they eavesdrop in a sophisticated way."

Now that Orrock and his team better understand how plants defend themselves, they plan to continue researching the genetics behind these developed internal defenses. If mustard plants have the capacity to pick up on cues from generalist snail herbivores, then the entire plant kingdom likely possesses all sorts of other internal defense mechanisms of which modern science is only beginning to scratch the surface.

Sources for this article include:

http://www.sciencedaily.com

http://www.garden.harvard.edu

http://www.scienceworldreport.com