| Explore | From previous exposure to botany, we are aware of the eventual decomposition of plants, and the vulnerability of plants to different pathogens which may result in soft rot. Furthermore, we have a base knowledge of the organelles of plant cells. During background research, we discovered the mannerism through which pathogens are able to enter plant cells despite the presence of a cell wall: Cellulase is utilized by the pathogens in order to break the cellulose through the process known as cellulolysis. Questions we generated include: “Do plants have ‘immune systems’ similar to human immune systems?”, “Through which applications can plants be protected from cellulase?”, and “Are plant pathogens transmissible to humans?” [Here are our qualitative observations from the first 5 days] - [Potato #1 (inoculated 1 cm)]: - 10/9: no odor, some white flakes - 10/10: There is brown around where the potato was inoculated in only 2/4 spots -10/11: no change -10/12: odor is worsening -10/13: more stench [Potato #2 (inoculated 2 cm)] - 10/9: White flakes around stabbed area (could be bacterial growth), some stench - 10/10: Area around stabbed area is brown - 10/11: Very strong stench, potato is dry -10/12: Interior of the stabs are turning brown -10/13: Not much changes [Potato #3 (inoculated 3 cm)] - 10/9: A lot of white around contact area, some pinkish discoloration. -10/10: Strong smell, insertion points darkened -10/11: Odor is worse -10/12: Exterior of potato is turning a pinkish color -10/13: Smell worsened |
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| Research Question | [Research Question: Does varying the depth of inoculation in a potato affect the amount of bacterial growth?] We wanted to observe how the potato naturally protects itself. While considering the steps of inoculation, we realized that the goal was to observe the bacterial growth on a new potato from the bacteria containing inoculum from the diseased potato. From there, we established that a scientific experiment requires an independent and dependent variable; the struggle, however, was making this viable for an at-home setting. So, the independent variable we chose for this experiment was the different layers of the potato (by stabbing the potatoes at different depths). Taking it one step further than what the template of our experiment was to test, we considered observing and quantifying bacterial growth in various sections of the potato and infer its natural defense mechanisms. This research question ties into our prior knowledge of the structure of a plant. We’ve learned about the plant’s defenses including the rigid cell wall and possibly, outer skin. As a result, our inquiry revolves around the effectiveness of the different defense mechanisms in plants against bacteria. |
| Predictions | Main Prediction: [An increase in depth of inoculation will result in an increase in bacterial growth.] |
| Experimental Design | Please refer to the "Files" section for a PDF of our thorough Experimental Design. Thank you. |
| Investigation Theme | PGST |
| Grade Level | High School Students (Grades 9,10,11,12) |
| School Name | California Academy of Mathematics and Science |
| Session | Fall 2020 |