Killer Tomatoes/ Emporia State University / ESU_F11_C03

School Level: College
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Research Information


Research Question
What degree of cut and solution, in combination, will produce the best curve of the celery?

Research Predictions
Null hypothesis: If the solutions and cuts are varied there will be no change in the degree of curve in the celery.

Experimental Design
Materials and Methods:
Celery-cut into 10 cm pieces and then into thirds
-one third uncut (with vascular bundles)
-one third half-cut (half vascular bundles removed)
-one third fully cut (vascular bundles completely removed)
Razors and scalpel

Preparation of solutions:
scoopula
petri dish
tape
sharpie-writing on tape labels
NaCl
distilled water
volumetric flasks (1 L and 500 mL)
3-500 mL beakers
triple beam balance

solution 1: distilled water
solution 2: 0.5 M made with distilled water and 14.61 g of NaCl (dissolved in in 500 mL volumetric flask according to resource section of the manual)
solution 3: 1.0 M made with distilled water and 58.44 g NaCl (dissolved in in 1.0 L volumetric flask according to resource section of the manual)

Procedure:
Placed each type of cut (no cut, half-cut, and full cut of vascular bundles) in beakers of 250 mL of the different solutions (distilled water, 1.0 M NaCl solution, and 0.5 M NaCl solution). Refrigerated for 24 hours, checked by drying with a paper towel and recorded the weight of each celery stalk. This last step was repeated at the 48 hour mark and the curvature was also measured, which concluded the data collection.


Research Conclusions
In testing the different cuts and solutions we observed changes in weight and vascular bundle presence. These factors appeared to have a correlation in bending the celery stalks. Celery stalks in the distilled water gained more weight and showed more curvature than similar cuts in the different concentrations of NaCl (which lost weight). All stalks regardless of cut remained crisp in distilled water and were in varying degrees of mushiness in both NaCl solutions. Pronounced veins were observed on the vascular bundle side of the full and half-cut stalks in both NaCl solutions. Veins were more pronounced at the submerged end. Stalks ranging from full vascular bundle presence to removal of the outer bundles showed varying degrees of curvature. In those with more vascular bundle presence the bending seemed to be restricted and was less robust. The stalks with the least amount of vascular presence achieved a greater degree of curvature as measured by a protractor. The most robust bend was achieved in the distilled solution with the outer skin of vascular bundles removed.

The 0.5 M and 1.0 M NaCl solutions verses the distilled water’s effect on the same cuts may be attributed to osmosis. Water was believed to be the cause of the weight gain or loss because osmosis may have caused water to be absorbed or drawn out by the difference in concentration between the cells of the celery to the surrounding solution. The curvatures of the celery in distilled water were measured at a greater degree, which could account for the weight gain. The mushiness of the celery in both NaCl solutions could be due to a loss in hydrostatic pressure through osmosis and not necessarily due to presence of vascular bundles. The vascular bundles appeared to be bloated, but may have actually been more pronounced due to the loss of the hydrostatic pressure in cells surrounding the bundles. Based on the curvature observations in the distilled water, the presence of vascular bundles may have inhibited the ability of the celery to curve. Hydrostatic pressure may not be able to greatly overcome the rigidity of the vascular bundles. Previous knowledge of vascular bundles indicated that the xylem in charge of water transportation are lignified to withstand hydrostatic pressure and in this case due to a loss of hydrostatic pressure, the vascular bundles could appear to be more pronounced on the NaCl solution stalks because they may have lost water due to osmosis.

The sample size was too small for parametric analysis. The variance provided indicated that at least 30 samples would be needed for accurate data analysis. Other factors that were unaccounted for were pH variation due to different levels of potassium between the NaCl salt containers. Chemical and biological factors inside the refrigerator included dead and dying plant material, unknown chemicals, and mold growth.

Further studies might include a larger sample size (at least 30), which should provide enough data for analysis. A clean environment would remove the possibility of contaminants. Checking and measuring weight, not only of the celery, but also the beaker at more frequent intervals (within the first 24 hours especially) could determine the point where hydrostatic pressure is the greatest.



Conversations - use this space to communicate about this project


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November 30, 2011 | 4:20 PM | esuteam9  (Student, Raiders of the Lost Bark - ESU_F11_C09 · 3)


What method was used to measure the amount of curvature of the celery? Also how much difference was seen based on the vascular bundles being present, partially removed or fully removed?
November 21, 2011 | 11:39 AM | david69  (Team Member)

Thanks
The group wanted to thank everyone who commented and especially our mentor for their imput.

We liked the term "untethered curve", we struggled a bit with terminology. Thanks again Dr. Ong

Happy Thanksgiving everyone
November 20, 2011 | 5:37 PM | dmichae4  (Student, Raiders of the Lost Bark - ESU_F11_C09 · 3)


It looks like you had a very thought out and intuitive experiment design. How much did the celery change in weight and curvature from the first 24 hours to the second? Does the "curving" occur early in the process of take a little time to get underway?
November 18, 2011 | 3:26 PM | Kevin Ong  (Scientist/Mentor)

Some things for your to consider.
First - sorry for the lack of response from me as there apparently was a mix up in my email with not getting the updates.

A few observations with the set up you have:
1. Very commendable experiment testing 2 different variables. This would count to a different statistical method if larger number of samples were to be used.

2. It was interesting that the wither salt solution resulted in no curvatures -did the loss of rigidity contribute to the "floppiness" factor that may cause untethered curve?

3. Might consider graphing the data: 2 graphs - Weight x day AND curvature x treatment.

Excellent writeup and surmisation of the data obtained from this experiment.
November 18, 2011 | 12:22 PM | david69  (Team Member)

replies
We decided that since this was more of a pilot study, that cuts made "by eye" would be effective. We were careful to remove as little material as possible.

There is a table of data for the cuts and solutions, I am not sure what you mean by " the 1M solutino had the most effect on tissue structure". Our conclusion was that tissue structure wasn't significantly changed, but that hydrostatic pressure was responsible. (see conclusions) The labeling of the pictures could have been misleading.

Measurements at shorter time intervals are something we would do if attempting this experiment again. (see conclusions)

Our observations didn't show the celery curving and then straightening back out. Are you comparing different solutions or different time intervals?
November 18, 2011 | 9:42 AM | brittany8  (Student, Team FancyPants - ESU_F11_C02 · 3)


How did you completely and accurately remove vascular bundels from the celery?
November 18, 2011 | 9:07 AM | kansas09  (Student, Team PhotosynTHIS! - ESU_F11_C01 · 3)


I think the different cuts in the celery is interesting. I think the cut that appears to be straight down the middle longitudinal seems to have the most curvature in every trial, no matter what the solution concentration was. The 1 M solution had the most affect on the tissue structure, do you think this was fast reacting that the celery's tissues were deteriating before large amounts of absorbtion could be done? How much weight change did the 1M celery have?
November 18, 2011 | 9:01 AM | joefromesu  (Student, Team PhotosynTHIS! - ESU_F11_C01 · 3)

Length of time
it would have been interesting to see a chart of some sort plotting change in curvature over time.
November 18, 2011 | 8:51 AM | ohmrsshady  (Student, Team PhotosynTHIS! - ESU_F11_C01 · 3)


I wonder what could have caused the celery to curve and then straighten back out again?
November 1, 2011 | 2:33 PM | Dr. S  (Scientist/Mentor)


OK, you have several possible lines of attack in your brainstorming - - pick one and design an experiment to test it.
October 14, 2011 | 3:31 PM | david69  (Team Member)

curving celery
I think the problem would be to remove the lignin. If the cellulose were intact, maybe it would stay crisp? removing the lignin would allow the eells to expand and hopefully curve the stalk. There is a good article about turning sawdust into biofuel where they discuss breaking down the lignin with dioxane. We wouldn't have to be concerned about conserving the hydrocarbons, so the procedure would be much less complicated.




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