| Explore | Soft rot bacteria of the genus Erwinia infects potatoes, causing disease and decay. Soft rot bacteria uses enzymes that break down the cell walls of the potatoes. Potatoes are known to have varying resistance levels to this disease. As long as sufficient water and nutrients are available, the bacteria will multiply and spread the disease throughout its potato host (Pérombelon, 2002). |
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| Research Question | How does potato mass effect the degree of rot by soft rot bacteria? |
| Predictions | We predicted that larger potatoes would be affected to a much lesser degree, because the bacteria would take a longer time to infect a larger volume of potato (given the same amount of bacteria is transmitted into each potato). If this was the case, the larger potatoes would, in comparison to the smaller ones: - Have less discoloration - Be more rigid - Have a weaker odor |
| Experimental Design | 1) 3 groups of potatoes were formed based on their size; a “large,” “medium,” and “small” group. The potatoes’ masses were measured and recorded. 2) A toothpick covered in a solution containing soft rot bacteria was inserted to a depth of 5mm four times into each potato. They were pithed on each pole, and on each side, as far away from the other points as possible. (see diagram). 3) Each class, observations were made regarding the state of each potato. |
| Conclusion | Ultimately, our prediction was wrong; the largest potatoes showed the most signs of rot while the smaller ones were less affected. The opposite of what we expected. The mass of the potato had no effect on the amount of rot, but the surface area did. This is likely due to the fact that the bacteria were injected very close to the surface, and spread at that layer while not going any deeper into the potato. |