A Plant That Can Smell

BlueCup writes "The question of how a dodder finds a host plant has puzzled researchers. Many thought it simply grew in a random direction, with discovery of a plant to attack being a chance encounter. But the researchers led by Consuelo M. De Moraes found that if they placed tomato plants near a germinating dodder, the parasite headed for the tomato 80 percent of the time. And when they put scent chemicals from a tomato on rubber, 73 percent of the dodder seedlings headed that way. Turns out, it sniffs out it's prey."

Plants that remember people

[Yo Grark]

I can't find anything on google about it, but there was a tale of an experiment where a man went into a greenhouse and hacked up all the plants.

A bunch of scientific equipment was setup to measure plants behaviour/electrical impulses.

They then had 10 people walk through the room and when the man who hacked the plants entered the room the plants sent off strong/furious signals.

I always wondered if this was a true experiment or urban legend...but with this species of plants sensing different kinds of chemicals, it just might have been real.

Yo Grark

Smelling Plants

[pipingguy]

Nothing new here, as apparently, this one [wikipedia.org] smells quite a lot.

Attack of the Killer Plants?

[resistant]

If the genetic engineering wizards could find out how to transplant this characteristic to, say, aquatic plants, perhaps they could modify them to attack the destructive zebra mussels [gma.org] that are such a major problem in the Great Lakes, or to control problem plants such as hydrilla verticillata [wapms.org].

It's an fun thought, even if I lack the background to evaluate its feasibility.

when I first saw it

[khallow]

I was hiking with my parents in the Shining Rock Wildnerness [recreation.gov], an area in western North Carolina. Part of the wilderness was burned out sometime in the 1920's and the burn formed a long lasting grassland along several peaks. We hiked it sometime in the early 90's and it was the first time I saw dodder. It was this strange mat of oranged colored leafless vines, much like this [pompestoncreek.org] growing on a particularly plant (very similar to what is in the photograph, I believe). The strange thing is that we had hiked this trail over many years and had never seen this before. So we wondered at first if it were some new invasive species from elsewhere. Turns out that this was native to the area, but for whatever reason it never had grown this prolifically before. Definitely one of the strangest plants I've ever run across.

Acacia

[Xybot]

The Acacia tree is sensitive to chemicals given off by other Acacia trees when they are damaged. It responds by increasing it's Tannin production in order to help ward off possible predators. I'm not sure of what the scientific definition of smell is, but I'd probably define it as "the ability to sense the existance of airborne chemicals".

And that surprises anyone?

[NerveGas]

    Even *single-cell* flagellates have what can be considered a rusimentary sense of smell, and the capability of changing their locomotion in order to lead them to food. That sort of ability is present all the way up through the multicellular ladder, and "smell" (or response to airborne chemical signals) have been well-known for quite some time in plants.

    Frankly, I'm susprised that they didn't start out with an assumption that smell was involved.

steve

Sample size?

[Anonymous Coward]

They don't mention what their sample size is, i.e., is it 100 plants?

I can toss a coin 4 times, and let's say I get tails 3 times. Simultaneously, if I was tossing another coin nearby, and happen to get 3 tails out of 4 again on it too, can I conclude that the second coin supernaturally knew what the result on the other one was? BTW, the probability that the above happens is 1/16. Also, I can repeat this experiment many times to get this case.

Obviously, those researchers are smart enough. My question is: how can they write such a big article without mentioning about the sample size?

Dodder

[Punctuated_Equilibri]

I got dodder in my garden from a basil plant I bought at a local nursery. That is one vicious weed. It's a parasitic rootless vine, hard to imagine if you've never seen it.

Re:Plants that remember people

[AuMatar]

Mythbusters did this one recently. It was completely busted- the lie detector "signals" were caused by vibrations in the plant from human motion.

Re:Plants that remember people

[nmb3000]

The story goes that scientist conected an EKG machine and watched for signs of brian patterns. When the plant apeared excited they interpreted it as emotion. I didn't think it was actualy true but i found a few posts about it.

Mythbusters actually took a shot at this one [discovery.com] (episode 61). They tried hooking up both a polygraph (as the original guy did) as well as an EKG machine. What they found is that there initially appeared to be a response, but once they isolated themselves from the plant they were testing, the apparent response went away. Kinda dumb, but somewhat interesting.

If you're interested, you can get it here [torrentspy.com] or wait for it to be on Discovery again.

Re:Is that surprising?

[Xerxes314]

Well, I would imagine it has to be a bit more sophisticated than phototropism. I mean, it's easy to detect light, and the side of something that isn't in the light is in shadow. So there's a clear, strong directional signal.

With smell, on the other hand, you have to detect very minute gradients in a trace amount of chemical that's being dispersed in the air. When the front half of your plant is facing a tomato, it's really only seeing a tiny amount more tomato-smell than the back half due to the dispersion of the tomato-smell. Animals can resolve this problem just by moving their noses back and forth; you sample a bunch of locations and then move toward the smellier area. But a plant cannot so easily move about, so how they can detect the gradient is the real mystery.

Artful Dodders

[Doc Ruby]

if they placed tomato plants near a germinating dodder, the parasite headed for the tomato 80 percent of the time. And when they put scent chemicals from a tomato on rubber, 73 percent of the dodder seedlings headed that way.

The shocking revelation is that 7% of the dodders weren't fooled by the simulated tomato smell. Those dodders are seeing the fake tomato patches as a trick. Those are the dodders to watch.

Re:Is this really smelling?

[dubiousmike]

When one smells aren't they absorbing tiny particles of whatever the "object" that is being "smelled" is releasing? Couldn't the plant be reacting to particles of what is it's food that happens to be floating in the air from a particular direction?