An experiment designed by an Ohio State professor taking place on the space shuttle Columbia mission may provide clues about how plant growth is guided by gravity.
The trial, launched on Jan. 16 and continuing through Feb. 1, is an expansion of work from a previous shuttle mission in 1997. The experiment tests how the absence of gravity changes how simple plants grow, by using a common roof moss to determine the direction in which single cells grow.
OSU professor and cell biologist Fred Sack designed the experiment in hopes of discovering how cells evolved and the role of gravity in that evolution.
Sack explained cells can sense gravity and adjust accordingly to grow. They also tend to grow toward the light, which is up. But in the absence of gravity, the moss grows differently.
“The sample cells of moss were placed in a special container and held in place by special screws, which requires the use of a special screwdriver. All of this was invented and manufactured just for this project,” said Jessica Lucas, a graduate student helping with the experiment.
The moss was then injected with drugs that selectively break down the different types of protein fibers in the cells’ scaffolding.
The results from the 1997 mission concluded something other than expected. Sack and his team expected the moss to grow sporadically and in no apparent pattern.
“What we discovered was that after seven days, the moss was growing in a clockwise spiral pattern,” Sack said.
After the 1997 mission ended with no real explanation as to why the moss grew in the spiral pattern, Sack and his team headed up another experiment to get some answers.
This time they will repeat some of the experiments from the first mission and perform new experiments such as using different lights on the moss to see how they affect growth. Sack is looking to see how early the spirals start and at what point in the cell they start to spiral.
Forty-seven petri dishes containing moss will be grown in a self-contained, mid-deck locker. The moss will grow first in red light and then in darkness.
“We noticed some of the cells growing towards the light and some growing away, forming a line. On Earth if the light is taken away, they grow towards gravity,” Sack said.
Another goal of this mission is to determine the clustering effect of the organelles in the cells in a gravity-free environment.
As the experiments are completed, the astronauts will chemically preserve the moss containers before returning to Earth. After the space shuttle lands, Sack and his team will examine the results of the experiments and take microscope pictures for further study.
