camsdavispgstfall2020 project 17

Project by group camsdavispgstfall2020

Explore Generally, from what we have researched, we understand that plants are also susceptible to infections. With potatoes specifically, a pathogen called Erwiniaatroseptica is common in causing what is known as blackleg in which the plant can decay or die prematurely (without yielding seeds or potatoes). The pathogen often enters through damaged areas (wounds and cuts just like in animals) and will spread (the infection will spread). Farmers prevent potatoes from getting sick by using disease-free seeds and chlorine-generating products, amongst other procedures. Through inoculation of potatoes, we also observed that potatoes exposed to pathogens (from the inoculum consisting of pathogens and dirt on the surface of another potato) lose structure in about five days and completely liquify in about six to seven days. On day 2, the inoculated spots were darker in color and the overall weight decreased, but the potatoes were firm and normal. On day 3, the potatoes were already deformed and mushy, with inoculated spots being dark brown and the plastic bag (in which the potato was kept) being full of water. On day 5, the structure of the potatoes were gone, with most parts of the potato being soft and the plastic bag being filled with water. By day 7, all the potatoes had become a dark yellow/brown liquid. As for questions about plants that interest us: 1. Can plants grow without soil? 2. How do plants absorb the nutrients they need? 3. Are plant diseases genetic? Is there a genetic influence? 4. Do specific pathogens attack specific plants? 5. Do pathogens that affect humans also infect plants? Can plant disease spread to humans and if so are they harmful to humans? 6. What is the relationship between the external environment of a plant and its chances of infection? Resources: 1. Seebold, K. W. (2014, October). Blackleg & Bacterial Soft Rot of Potato. Retrieved October 07, 2020, from 2. Plant, A. (2017, April 21). Managing Blackleg of Potatoes. Retrieved October 07, 2020, from 3. LaPointe, M. (2000, October 10). TIGR Collaborates with Universities of California, Minnesota, Wisconsin, and Cornell on Potato Disease Project. Retrieved October 07, 2020, from 4. Taylor, A. (2017, August 11). Soft rot diseases of potatoes. Retrieved October 07, 2020, from 5. Rupp, J., & Jacobsen, B. (2017, January). Bacterial and Fungal Diseases of Potato and Their Management. Retrieved October 07, 2020, from
Research Question How does exposure to sunlight affect the growth of bacteria in Potato tubers?
Predictions The warmer environment with greater exposure to sunlight would form more bacteria at faster rates, because from our general knowledge (don’t leave your food out, food spoils faster in the summer, etc.), bacteria is expected to grow/reproduce better/faster under warmer conditions.
Experimental Design Control Group: 3 potatoes with no light exposure (under regular storing conditions, ie. pantry) Experimental Groups: 3 potatoes exposed to sunlight (outside with no covering), 3 potatoes outside but not in direct light zone (ie. in the shade) Variables: Indep. Amount of light exposure Dep. Potato rot Length of experiment: Seven Days; a week Materials: potatoes, inoculum, ziplock bags, toothpicks Procedure: 1. Leave an uncleaned potato in water for approximately a week 2. Clean other potatoes (experimental subjects) with bleach 3. Stick a toothpick into the water (which is now inoculum) then stab a potato with the toothpick 4 times. Repeat with each potato. 4. Place each potato in plastic bag (to avoid rotten potato getting on other surfaces) 5. Place one group of potatoes where it will receive lots of sunlight (no objects to interfere with light during the day), place one group of potatoes in an area with no light (like a pantry), and place one group of potatoes in a location in the shade 6. Take pictures, rate the potato using the categorical number range, and record other observations Data: amount of rot in categorical number range Updated Categorical Number Range: 0: potato looks great, no rotten spots 1: one or two bad spots, less than 20% bad 2: 3-5 bad spots, 20-40% bad 3: about half of potato looks bad 4: more than half of potato bad but less than 80% 5: potato is gross, over 80% of potato has spots 6: potato is a mush or complete liquid, indistinguishable as a potato
Investigation Theme Copy PGST
Grade Level High School Students (Grades 9,10,11,12)
School Name California Academy of Mathematics and Science
Session Fall 2020