Photo by V. Miller

Oct. 4, 2006

Lima Beans on Mars

Phaseolus lunatus Growth Patterns in a Simulated Mars Environment: Year Three
Sasha Annalicia Rohret, 16, San Antonio, Texas
Finalist, Intel International Science and Engineering Fair, 2006

Category: Space Science

The purpose of Sasha's project was to observe and record the growth rates of Phaseolus lunatus, or lima beans, in simulated Martian and Earth environments and to determine the greatest percentage of carbon dioxide that can be present in the atmosphere while still allowing growth. She knew that the average concentration of this gas in Earth's atmosphere is 0.03 percent and that the average on Mars is slightly higher, at 0.05 percent.

Sasha hypothesized that exposure to concentrations of carbon dioxide up to 0.15 percent would have a beneficial effect on the growth rates of the beans. Higher concentrations of carbon dioxide would be harmful.

Sasha constructed four airtight tanks and placed 17 lima bean seeds in containers inside each tank. One tank had a Martian atmosphere, containing 0.05 percent carbon dioxide. The second tank had 0.1 percent carbon dioxide, the third 0.15 percent carbon dioxide, and the fourth 0.2 percent carbon dioxide. Each tank also contained 21.7 percent oxygen. The remaining gas was nitrogen.

Sasha measured the plants' growth rates for 3 weeks. She monitored and recorded the temperature and humidity in the four tanks. She then opened the tanks, photographed the plants, and analyzed her data.

Photo by V. Miller

Sasha confirmed her hypothesis. She found that 0.15 percent carbon dioxide is the highest concentration that can be present in the atmosphere without inhibiting plant growth.

2005 ISEF Project: Phaseolus lunatus Growth Patterns in a Simulated Mars Environment—Year Two
http://www.sciencenewsforkids.org/articles/20051019/ScienceFairZone.asp

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