Michael planted peas in his backyard, and after a month, he noticed several plan
ID: 142276 • Letter: M
Question
Michael planted peas in his backyard, and after a month, he noticed several plants that were much bigger and greener than the others. These plants also produced more peas than the others. Being curious about why these plants were different, Michael pulled up a few and found that there were white bumps on the roots of the healthy plants that were not present on the small plants. Using a microscope in his microbiology lab at school, he found that there were bacteria inside these bumps. In an excited state, he hypothesized that these bacteria were causing the plants to grow more and produce more peas than the other plants, and that the bacteria were probably in the soil where those plants were growing. Describe the steps that Michael should take to test his hypothesis (hint: Robert Koch would have found this easy).
Explanation / Answer
According to the information, the student found a few white bumps in the roots of the pea plants and observed that these plants demonstrated better growth as compared to others. Technically, studies have shown that these bumps correspond to presence of nitrogen-fixing bacteria in the root nodules of the legumenous plants. Since plants cannot generally utilize nitrogen from the soil, these bacteria fix this gaseous nitrogen into soluble form which can be uptaken and utilized by the plants, thus enhancing growth.
In order to confirm the presence of nitrogen fixing bacteria, appropriate biochemical tests can be conducted, such as reduction of nitrites and utilization of gaseous nitrogen to give rise to soluble nitrates in the medium.