December 10, 2012 - When researchers sent plants
to the International Space Station
in 2010, the flora wasn't meant to be decorative. Instead, the seeds of these small, white flowers—called Arabidopsis thaliana—were the subject of an experiment to study how plant roots developed in a weightless environment.Gravity
is an important influence on root growth, but the scientists found that their space plants didn't need it to flourish. The research team from the University of Florida
in Gainesville thinks this ability is related to a plant's inherent ability to orient itself as it grows. Seeds germinated on the International Space Station
sprouted roots that behaved like they would on Earth—growing away from the seed to seek nutrients and water in exactly the same pattern observed with gravity. (Related: "Beyond Gravity.")
Since the flowers were orbiting some 220 miles (350 kilometers) above the Earth
at the time, the NASA-funded experiment suggests that plants still retain an earthy instinct when they don't have gravity as a guide.
"The role of gravity in plant growth and development in terrestrial environments is well understood," said plant geneticist and study co-author Anna-Lisa Paul, with the University of Florida
in Gainesville. "What is less well understood is how plants respond when you remove gravity." (See a video about plant growth.)
The new study revealed that "features of plant growth we thought were a result of gravity acting on plant cells and organs do not actually require gravity," she added.