Work on this next!
What do we know about plants from our experiences outside of school? What have we discovered in class and background research? What questions about plants interest us?
|Research Question||We wanted to investigate if Pcc could infest, then infect sweet potatoes, a different host than regular potatoes. We wanted to see if changing the host plant product affects the transfer of bacteria into the host, or if other plant products could become infected by Pcc.|
|Predictions||Sweet potatoes will be susceptible to bacterial soft rot, as caused by Pcc, since they share some characteristics with common potatoes. Also, since Pcc is present in soil, so it is reasonable to believe that sweet potatoes will come into contact with the bacteria and become infested, then...|
|Experimental Design||Materials: - Toothpicks marked at .75” from the bottom - 3 sweet potatoes (roughly 5-8” in length, 2-3” in width) - Paring Knife - 6 Zip-lock quart-sized freezer bags - A sharpie - Paper Towels - Inoculum - Tap Water Procedure: 1. Using the paring knife, cut each potato in half...|
|Conclusion||We conclude that further testing is required to accurately determine if bacterial soft rot, caused by Pcc, can occur in sweet potatoes. We may not have acquired bacterial soft rot in our sweet potatoes because the inoculum we used was collected from Russett potato's soft rot. We know that the...|
|School||Mercy McAuley High School|
|Student Level(s)||High School Students (Grades 9,10,11,12)|
As this research project is now in the final stages of wrapping-up, we wish to thank everyone who participated in this inquiry; the students, mentors, teachers and others behind the scenes. We appreciate all of your efforts and contributions to this online learning community.
Scientific exploration is a process of discovery that can be fun! There are many unanswered questions about plants just waiting for new scientists to consider, investigate, and share.
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The PlantingScience team
It’s great to see that teams from your school are wrapping up and posting conclusions. Enjoy the final stages of your project, and feel free to post any final comments or questions you have for your mentors.
I sent on your info and photos to Lina Quesada, a professor at North Carolina State University who studies sweet potato diseases. She said that the rot and white mold you saw on the sweet potatoes was likely Geotrichum sour rot of sweetpotato (https://content.ces.ncsu.edu/geotrichum-sour-rot-of-sweetpotato). This fungus is normally seen in anoxic (no oxygen) environments. Since your sweet potatoes were kept in plastic bags, it could have helped it grow. She said that they are seeing a lot of this disease on sweet potatoes this year because of the hurricane that they had in North Carolina (probably where your sweet potatoes came from) since many farmers fields were underwater (no oxygen) for a long time this summer. It's cool to see how real world events affect the food that you buy in the grocery store.
By the way, our moldy sweet potatoes smelled like yeast, and very sweet and ripe bananas. Does this mean something? We are super curious.
Here’s our final update on our sweet potato experiment. We found some mold on each of the remaining experimental sweet potatoes, #2 and #3. Mainly on the ends of the potatoes were where the mold clusters were found. We cut open the potatoes longways and sliced into transverse sections, but no mold correlation was found where we had poked the potatoes with the inoculum two weeks before. There were no signs of soft rot, even though there were lots of brown spots in the tissue that were soft and squishy, but we attributed that to the mold growth! Besides being very white from dehydration, there wasn’t much to observe. We concluded that further testing would be required for accurate results to be attained about our hypothesis.
The potato would probably lose some mass if it got infected with bacterial soft rot, would it not? Just since the bacteria would eat away at the tissues of the potato, so it would lose mass! Please correct me if I’m wrong! And we only inoculated sweet potatoes this time around, no potatoes or other vegetables. Do you think that anything will happen to the remaining sweet potatoes? I know that you mentioned since sweet potatoes aren’t related to Russett potatoes, that they might not become infected! Thanks for your help!
Today we examined the sweet potatoes after they were incubated for a week. There were no major defects that could be seen on experimental potato #1 when we cut it. We decided that it would be best to wet the paper towels again and wrap them around experimental potatoes #2 and #3 and incubate them for another week. There was one potato that already had some noticeable brown spots and looked very dehydrated, so we decided to turn it into the "fun" potato. The potato was inoculated with tap water on both sides then it was wrapped up in a wet paper towel and inoculated for a week in order to see of there would be changes on the moldy side and on the non-moldy side. We do not have any pictures of the sweet potato before the inoculation because we were not expecting any changes to happen. When we cut the "fun" potato after inoculation, it had a lot of squishy spots and moldy spots, but it did not have an odor. Do you have any idea what happened to the "fun" potato?
Before we looked at our sweet potatoes today, we, as a class, brainstormed some more ideas we could have utilized in our initial project. These might be helpful if other classes are planning on trying this experiment as well!
- Temperature of the control water and Inoculum
- Mass of sweet potatoes
- Distance between each hole
- Exact dimensions of sweet potatoes
- Relative humidity
- Control size of paper towel and how much water qualifies it as “damp”
- Standardize any of these parameters?
These are the pictures from yesterday. We first marked our toothpicks a quarter inch from the bottom so we knew exactly how far to poke them in. Next, we cut the sweet potatoes in half and separated them so one half would be inoculated with water and the other half with the inoculum. We then preoceeded to inoculate the halves the same way we did with the russet potatoes and we will check back up on them in a week. Currently, we are working on the actual writing of the experiment.