Plant roots defy gravity in U.S. study

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Plant roots defy gravity in U.S. study

A group of U.S. researchers has found that plant roots and growth may not be entirely controlled by gravity.

Jeff Williams, an astronaut on the International Space Station, harvests samples. Photo: NASA

The University of Florida's (UF) Institute of Food and Agricultural Sciences found, despite what was previously thought, that roots undergo standard movements called waving and skewing even in the absence of gravity.

The team grew Wassilewskija and Columbia varieties of Arabidopsis thaliana in zero gravity in the International Space Station and on Earth. Plants were grown in nutrient-rich agar solution and photographed every six hours.

Study co-author and UF researcher Anna-Lisa Paul explained that the plant activity in space defied the notion that gravity forces roots to grow away from the seed.

Although differences were recorded between the space- and Earth-based plants, growth patterns were generally similar.

“The skewing and waving of roots has always been thought to [be] dependent on gravity, but as the images from our experiment started to come down from the International Space Station in early 2010, it was clear that gravity was not required after all,” Paul said in a UF media release.

Fellow co-author Rob Ferl said the study provides fundamental insight into plant cultivation in low-gravity environments, such as a space station or the moon.

“As space agriculturalists, we really want to know that when we move to the moon, when we move to Mars, which don’t have the same amount of gravity that we have, can we still grow plants? Will their roots still work right in a fractional gravity environment?” Ferl said in the media release. “And the answer is yes, definitely.”

The NASA-funded experiments were launched in 2010 and returned on space shuttle Endeavour on June 1, 2011.

Biological scientist Claire E. Amalfitano is also an author of the study, published in the current issue of BMC Plant Biology.

Related story: China gears up for space farming

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