Monday, June 09, 2008

Plant kin recognition? (Caution - Anthropocentrism ahead)

A fascinating story in the New York Times today on kin recognition in plants (see Plants Found to Show Preferences for Their Relatives ).

They report
The sea rocket, researchers report, can distinguish between plants that are related to it and those that are not. And not only does this plant recognize its kin, but it also gives them preferential treatment.

Dodder is unable to grow its own roots or make its own sugars using photosynthesis, the process used by nearly all other plants. As a result, scientists knew that after sprouting from seed, the plant would fairly quickly need to begin growing on and into another plant to extract the nutrients needed to survive.

But even the scientists studying the plant were surprised at the speed and precision with which a dodder seedling could sense and hunt its victim. In time-lapse movies, scientists saw dodder sprouts moving in a circular fashion, in what they discovered was a sampling of the airborne chemicals released by nearby plants, a bit like a dog sniffing the air around a dinner buffet.

The notion that plants sense and respond to their surroundings is apparently controversial. Or, maybe a better way to put it is, the attempts to compare plant to animal neural functions is controversial. So much so that many plant scientists got together to say enough is enough

Thirty-six authors from universities that included Yale and Oxford were exasperated enough to publish an article last year, “Plant Neurobiology: No Brain, No Gain?” in the journal Trends in Plant Science. The scientists chide the new society for discussing possibilities like plant neurons and synapses, urging that the researchers abandon such “superficial analogies and questionable extrapolations.”

I personally think there is an enormous amount of anthropocentrism here. Sure, plants may not have true brains. But even though many people like to think of animals in general and humans in particular as the be all end all of evolution, last time I checked, plants have been evolving for a long time. And there is no reason to think that they do not have all sorts of cool and wacky ways to sense and respond to the world around them.

The same anthropocentric point of view has led scientists to grossly underestimate the complexity of phenomena in microbes too. Microbes in fact can sense and respond to kin, they can count, they can tell time, they have immune systems. In other words, whether small or large, furry or not, simple or complex (in appearance) lots of cool things have evolved in lineages that do not lead up to humans.

Well, everyone. As we continue to delve into the biology of non animals more deeply, we are going to find all sorts of cool things out there. And yes, some of it will be even more complex and interesting and wacky than what we see in animals.

For other stuff on this story see


  1. Growing tips of many plants move in circles, spiraling as they grow up. The phenomenon is known as circumnutation. Twining plants (such as pole beans) use this behaviour to find supports. They don't just swing around until they bump into something; the continued swinging is how they wind themselves around the support.

    The NYT article doesn't cite a source for the dodder work, so I can't easily check whether they stop circumnutating once they sense a prey plant is nearby.

  2. I could not find paper(s) on the dodder work either. But the prior work from Dudley is available in Pubmed Central here


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