This process stopped all growth in the moss, capturing their state during flight.Ĭontrol studies conducted at NASA's Kennedy Space Center (KSC) in Florida used hardware and procedures similar to those used aboard each flight. They chemically "fixed" the moss cultures before each mission reentered Earth's atmosphere. Most of the hardware holding the plants was recovered, and 11 of the recovered moss cultures were usable.Īstronauts followed similar experimental procedures on both flights. The second mission was the Space Shuttle Columbia (STS-107), which broke apart during reentry on Feb. But in moss, it is just a single cell that both senses and responds to gravity," he added.Ĭommon roof moss was grown in Petri dishes in lockers aboard Shuttle missions in 19. "In most plants, gravity guides the growth of roots or stems, which are made up of many cells. "The way these tip cells respond to gravity is exceptional," Sack said. When grown in the dark, the tip cells grow away from gravity's pull - this gets the cells out of the soil and into the light. Moss originates from chains of cells with growth only taking place in the tip-most cell of a chain. This gravity response is only seen when moss is kept in the dark, as light overrides gravity's effect. The findings are reported in the online edition of the journal, Planta.Ĭommon roof moss is a relatively primitive plant in which certain cells, called tip cells, are guided by gravity in their growth. "We don't know why moss grew non-randomly in space, but we found distinct spiral patterns," Sack said.
The researchers expected random, unorganized growth as seen with every other type of plant flown in space. He is the study's lead investigator and professor of plant cellular and molecular biology at Ohio State University, Columbus, Ohio. The common roof moss (Ceratodon purpureus) grew in striking, clockwise spirals, according to Fred Sack.
Experiments on moss grown aboard two Space Shuttle missions showed the plants didn't behave as scientists expected them to in the near-absence of gravity.
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