Space Plants

Sometime in the next century humans may colonize the Moon or Mars, and researchers are looking for the plants and animals that those settlers from Earth will take with them.

“For a long-term habitation of Mars, you’ll have to grow crops, deal with microbes and so forth,” David Morrison of NASA’s Ames Research Center said. “We have to understand the response of those organisms to the different conditions.”

The National Aeronautics and Space Administration is planning a series of experiments on the International Space Station to find Earth organisms best suited for Mars. Plants and animals will be grown through several generations and then analyzed for genetic changes, Morrison said.

From “A matter of gravity: tooling plants, animals for space” from CNN Interactive, January 27, 1999. Copyright  1998 by Associated Press.Reprinted by permission of the copyright holder.

Analyzing Ideas

  1. What minimum conditions would plants need in order to grow in a space station?
  1. How would the environment in a space station affect plant tropisms?

Helpful Hint: Think about how gravitropism affects plants. Then, think about the nature of gravity in space.

  1. What advantages might plants grown in a space station have over plants grown on Earth?
  1. How could scientists mimic changing seasons in a space station?
  1. Why are plants needed for a “long-term habitation of Mars”?

How Plants Respond to Change

Although plants don’t walk and talk, they do respond to stimuli in their environment. Plants respond to stimuli by growing in a particular direction. Plant growth away from a stimulus is a negative tropism. Plant growth toward a stimulus is a positive tropism.

  1. The plant shown below has just been moved next to a window from a room with no direct light. Sketch what the plant will look like in a few days.

In a few days

  1. Phototropism is a change in the growth of a plant in response to light. Is phototropism positive or negative?
  1. The plant shown below has just been tipped over on its side. Sketch what the plant will look like in a few days. (Hint: The plant will respond to gravity.)

In a few days

  1. Gravitropism is a change in the direction of the growth of a plant in response to gravity. Is gravitropism of most shoot tips positive or negative?

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