What's new
TerraForums Venus Flytrap, Nepenthes, Drosera and more talk

Register a free account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members through your own private inbox!

Plants can recognize rivals and fight, study says

jimscott

Tropical Fish Enthusiast
Greenery grows more roots to absorb resources when next to ‘strangers’

Plants can't see or hear, but they can recognize their siblings, and now researchers have found out how: They use chemical signals secreted from their roots, according to a new study.

Back in 2007, Canadian researchers discovered that a common seashore plant, called a sea rocket, can recognize its siblings — plants grown from seeds from the same plant, or mother. They saw that when siblings are grown next to each other in the soil, they "play nice" and don't send out more roots to compete with one another.

But as soon as one of the plants is thrown in with strangers, it begins competing with them by rapidly growing more roots to take up the water and mineral nutrients in the soil.
Story continues below ↓advertisement | your ad here

Researchers from the University of Delaware wanted to find out how the plants were able to identify their kin.

"Plants have no visible sensory markers, and they can't run away from where they are planted," Harsh Bais, assistant professor of plant and soil sciences at the University of Delaware, said in a statement. "It then becomes a search for more complex patterns of recognition."

Bais and doctoral student Meredith Biedrzycki set up a study with wild populations of Arabidopsis thaliana, a small flowering plant that is often used as a model organism in plant research.

They wanted to use wild populations instead of laboratory-bred species, because the latter "always has cousins floating around in the lab," Bais said.

In a series of experiments, young seedlings were exposed to liquid containing the root secretions, called "exudates," from siblings, from strangers (non-siblings), or only their own exudates.

The length of the longest lateral root and of the hypocotyl, the first leaf-like structure that forms on the plant, were measured. A lateral root is a root that extends horizontally outward from the primary root, which grows downward.

Plants exposed to strangers had greater lateral root formation than the plants that were exposed to siblings.

Further, when sibling plants grow next to each other, their leaves will often touch and intertwine, while stranger plants near each other grow rigidly upright and avoid touching, the authors say.

In future studies, Bais hopes to examine questions such as: How might sibling plants grown in large monocultures, like corn, be affected? Are they more susceptible to pathogens? And how do they survive without competing?

"It's possible that when kin are grown together, they may balance their nutrient uptake and not be greedy," Bais speculates.

The research also may have implications for the home gardener.

"Often we'll put plants in the ground next to each other and when they don't do well, we blame the local garden center where we bought them, or we attribute their failure to a pathogen," Bais said. "But maybe there's more to it than that."

The study, funded in part by the National Science Foundation, will be published in the January/February 2010 issue of the journal Communicative & Integrative Biology.
 
Awesome you posted this, I was talking with Dr. Bais about some undergraduate research this summer earlier in the year and my boss just mentioned this the other day at work. Very interesting!
 
do you have a link to this article? i'm sure the wife would like it for her class.

---------- Post added at 09:01 AM ---------- Previous post was at 08:59 AM ----------

edit: never mind - found it.
 
Whew! I was worried my Sarracenia minor would start arm (pitcher) wrasslin' or sompin.
 
Allelopathic plants have been recognized for decades. Many trees secrete chemicals into the surrounding soil to create a "zone of inhibition" preventing the germination of other species -- and sometimes their own, to reduce competition; and the chemicals themselves can be quite noxious -- from various phenols (anti-grazing compounds), coumarins (rodenticides), terpenoids (potential pesticides), and cyanogenic glycosides (chemically converted to hydrogen cyanide should a plant be attacked).

There is nothing particularly peaceable about the plant kingdom at all; and there are even plants which are carnivorous -- or so I've read in the back of a comic book . . .

 
You're right BigBella...it's not only to inhibit other species but also their own!
I have seen the secretions in some of the TC plants...brown areas around the roots. You can easy notice how plants stay smaller when planted too close and always the ones on the exterior of the group grow stronger and bigger...i suspect it's more due to secretions than to the lack of light.
 
I always thought that the "brown rings" seen in tissue culture were just tannins. Perhaps a bit of both?
 
While allelopathy has been recognized and investigated for a couple of decades, as far as I know research like this is relatively new, or at least the subject is less well understood.

Allelopathy is certainly interesting, but there's some special to be said about recognizing not only self from non-self, but recognizing a degree of interrelatedness such that they interact with "strangers" and "relatives" in a different manner. It's not a "prevent other plants from growing" carpet-bombing thing, but a "no strangers allowed!" specific response. I look forward to reading the paper on the study to see if this summary is true to the observations.

Only other examples of things remotely related to this nature are the induction of toxin production in neighbouring plants when one releases a signal as a response to grazing or insect attack.
 
  • #10
While allelopathy has been recognized and investigated for a couple of decades, as far as I know research like this is relatively new, or at least the subject is less well understood.

Allelopathy is certainly interesting, but there's some special to be said about recognizing not only self from non-self, but recognizing a degree of interrelatedness such that they interact with "strangers" and "relatives" in a different manner. It's not a "prevent other plants from growing" carpet-bombing thing, but a "no strangers allowed!" specific response. I look forward to reading the paper on the study to see if this summary is true to the observations.

Only other examples of things remotely related to this nature are the induction of toxin production in neighbouring plants when one releases a signal as a response to grazing or insect attack.

At the outset, the study seems vaguely analogous to the "clone wars" that exist in some invertebrate (Cnidarian) populations -- where asexual anemones from one population can chemically recognize outsiders -- non-related clones -- and "actively" combat them for resources; in their case, the competition is, just as plants, also for space. Some are capable of physically forcing others off rock surfaces. It just seemed logical that that competitive principle might also apply to other sessile organisms -- plants included.

It too am looking forward to reading the study in its entirety; but, in some respects, it still strikes me as old news. This idea, at least, has been circulating around since I was in college, and I am curious to see it confirmed . . .
 
  • #11
At the outset, the study seems vaguely analogous to the "clone wars" that exist in some invertebrate (Cnidarian) populations -- where asexual anemones from one population can chemically recognize outsiders -- non-related clones -- and "actively" combat them for resources; in their case, the competition is, just as plants, is also for space. Some are capable of physically forcing others off rock surfaces. It just seemed logical that that competitive principle might also apply to other sessile organisms -- plants included

I certainly see the resemblance to the common Clone Wars example, but there's a twist here. That's the recognition of a degree of relatedness. I'm curious to see what sort of specificity the mechanism grants. How related is related enough? It's different from clone wars in that regard -- it isn't just a case of self vs nonself. And then there's the question of the workings of the mechanism itself... It stands to reason that such a response should exist, but elucidation of the mechanism would certainly be interesting.
 
Back
Top