|We know that plants go through processes called photosynthesis and cellular respiration. In class, we have discovered how plants and trees get their mass, what happens in the processes plants go through, why they go through these processes, and more.
|Does the lack of pigment affect the rate of photosynthesis? We developed the question by noticing the white bit of a plant, which we believed was a lack of pigment, and wondered if the lack of pigments in the bits leaves changed the rate how the plant photosynthesizes.
|The lack of pigment(s) in the plants could either change the rate of photosynthesis in the plant. If they change the rate, it could either slow the rate down or speed it up. We are comparing how fast the plants with lack of pigment go through photosynthesis when placed under a light. We believe...
|To test what pigments are in the leaves, we decided to do a chromatography experiment. To do this, we collected a quarter, chromatography paper, our plants, and some chromatography solvent. We took the plant and placed it on the paper, and rolled the quarter on it so the pigment will transfer...
|To conclude our experiment, we can make the claim that plant leaves without pigment experience photosynthesis at a lower rate than plant leaves with pigments. Plant leaves use chloroplasts to carry out the processes of photosynthesis, and chloroplasts also give plants their green color, so the...
|About this Project
|The students showed great interest in developing the experiment, were curious about the results, asked good questions about factors taht can influence on the experiments, and were always looking for ways to get better and improve their experiment. -- Gabriela Hernandes Villani,...
In our final experiment, we concluded that the lack of pigment caused the rate of photosynthesis to be much lower or almost non-existent. We prepared 4 cups, each with 4 drops of the soap-water mixture, and an even amount of baking soda. We cut out 10 leaves from the red nerve cell plant and 10 bits of the leaves that lacked pigment in each cup. We placed them under the light for 20 minutes, just like we did with our previous leaf disk experiment. After the 20 minutes, only the leaves from the red nerve cell plant had floated. When we came back the next day, some of the leaves from the other plant had floated, but we discovered this is due to the fact there was a little bit of pigment on the edge of the leaves.
We as a team appreciate the time you took to respond to us and thank you for answering all of our questions! We really enjoyed this experience and learned a lot from it.
When we were doing the chromotograpghy experiment to test what pigments were in the leaves, we could not isolate the other pigments in the red nerve cell plant. However, we noticed the white parts on our curly spider plant was a lack of pigment, so we decided to change our research question. Instead of doing how different pigments affect the rate of photosynthesis, we switched our research question to how does the lack of pigment affect the rate of photosynthesis. While this isn't what we wanted to do orignially, we are able to take the data we got from the chromotograpghy and develop a new research question.
While I was preparing to clean up our previous, I noticed one of my cups with leaves had turned clear almost transluscent. I have had these cups sitting on the counter since our last documentation and I noticed the leaves were different. Why is this?
Today we began discussing our final experiment. We took the time to develop a few research questions and decided on one question.
1. Do plants with different pigments affect the rate of photosynthesis?
The two plants we picked out to conduct this experiment are the red nerve cell plant and the curly spider plant. To determine an answer for our research question, we have two processes we plan on going through.
First, we plan on identifying what kinds of pigments are in the different parts of the plants. To do this, we are going to use a chromoatography solvent, chromotography paper, and chambers. We also want to test different areas on the plants. We plan on taking out different bits of the plants that have different colors on each plant to see.
After we identify what pigment(s) are in the plants, we plan on conducting the leaf disk experiment with these plants. We will set it up the same way we set up our last leaf disk experiment. Depending on how many leaves we can get from our plants, we want to put 5-10 leaf disks in each cup with water and the water/soap solution. We also plan on putting an equal amount of baking soda in ecah cup as well. We will place it under the same light we did before and track the rate at which each cups photosynthesize.
Do you have any suggestions for how we should conduct these experiments? If certain bits of the plant that we use have a lack of pigment, could that affect how the plant photosynthesize?
Hello Aiden, Addacie, and Bailey!
That's right! Green Light is not good for photosynthesis because this light is not absorbed. This happens because the chloroplasts are green, thus the green light is reflected.
If we are talking about regular bulbs, the sunlight is more effective because the sun emits a continuous wavelength with more of the beneficial wavelengths for photosynthesis. I'm gonna post a graph about it next, so you can check it.
Let me know if you have more questions,
Hello Aiden, Addacie, and Bailey!
Great to see your progress!! :)
Thanks for the detailed description, this is very important when we are writing about an experiment.
That's right, adding CO2 in the phenol red solution makes the pH decrease and changes its color to yellow. That's why you saw the color change in the cups that you blew with the straw and in the ones in the dark (where respiration is happening, which consumes O2 and releases CO2).
On the other hand, in the cups where photosynthesis is happening, CO2 is being consumed, which increases the pH and changes the color back to pink/red.
The fog you noticed at the top of the tubes is water vapor condensation, that's right.
That's amazing to see how light influences plants and evidence that photosynthesis is occurring, right?
There are many things that can influence photosynthesis, such as chlorophyll content, stomata conductance, leaf water content, and light. Photosynthesis occurs better in blue and red light spectrum, because chlorophyll absorbs light in the red wavelength and the carotenoids (other kind of pigment) absorbs blue light and pass the energy to choropphyl.
That is why you can find some special lights with red and blue lights in gardening stores. Thus, when you use these lights, you will increase the photossynthesis rates and make the plant grows faster.
Can you think of what light is not good for photossynthesis?
Hint: Remember the color definition we learn in physics class.
After finishing our experiments, we have determined that light effects photosynthesis. Light increases the rate that photosynthesis occurs. In the second leaf disk experiment we did, we put two cups in a box in a dark corner and two cups under a light. Each cup had the same amount of baking soda and, 4 drops of a soap and water mixture, and the same amount of leaves. For this experiment, we ended up putting 10 leaves in each cup. After twenty minutes, all of the leaves in the cups under the light had floated. None of the leaves in the dark cups had floated. This is how we determined that light effects the rate of photosynthesis. After conducting this part of our experiment, we decided to switch the cups and leave them overnight. 10/20 of the leaves placed under the light floated and all of the leaves in the dark had no change. This is how we determined that the prescense of light is needed for plantsto photosynthesize.
In our second exeperiment involving the elodea plants, we also discovered that photosynthesis was occuring under the light. Elodea in the light with CO2 intially turned from yellow to pink. The CO2 was moving into the Elodea, being used for photosynthesis. The elodea in the dark with CO2 started yellow and ended the same color. The CO2 was not used up. However, after completing this lab we discovered that due to unclear directions we had set up the elodea experiment incorrectly. We had a cup of phenyl red and blew into it before hand to turn it yellow before adding it to our tubes instead of adding the phenyl red without breathing into it to see how it changes. However, based on the knowledge we have regarding the experiment we conducted, we can determine what would happen if we did it correctly. Elodea in the dark wthout CO2 would start as pink/red and would turn yellow after 24 hours. The elodea is making CO2. CO2 increased in the test tube turning yellow.
What would you do different in these experiments to get better results? Would a different kind of light source change the rate of photosynthesis.
Update from our recent lab. We are currently investigating the role light has on plants. The tubes on the left were left in the light for 24 hours, and the tubes on the right were left in the dark for 24 hours. One tube in each batch contained an elodea plants, and all tubes contained a phenol red solution that we added CO2 to through straws. Based on the color of the solutions, I predict that the plant in the phenol red solution under light went through photosynthesis. The original phenol red solution was a pink color, but when we breathed into the cups through straws to introduce CO2, the solution turned yellow. The plant consumed the CO2 that was in the solution to go through photosynthesis, effectively removing CO2 from the phenol red and changing it back to its original pink color. The top of the tubes are foggy, which is probably O2 gas emitted from the photosynthesis reaction. The tube on the far left had a few leaves in the tube still so that is probably why there is some gas. The tubes in the dark has no visible changes and there is no visible gas in the tubes.
Edit: Looking back on the photos, I realize that the condensation in the tubes on the right is most likely water vapor as a byproduct of photosynthesis. Is this accurate?
Hi Aiden and Bailey!
You are right! The gas that is being formed is oxygen due to the photosynthesis that is going on.
Talking about the errors you mentioned:
"Some errors we noticed in the lab was that right away in one of the cups 4 of the leaves floated when added to the cup. They had sunk in the syringe so we weren't entirely sure where we went wrong when putting them into the cup."
Maybe some air got into it while transferring from the syringe to the cup. Try to open the syringe inside the water in the cups. I think you can remove the plunger and very quickly put your finger to close it, and place it inside the water before release it to free the leaves directly inside the water. Makes sense?
"We also didn't get all the leaves to float in the ones we believe should have. "
Maybe those leaves parts were not good, there are many things that can affect photopsynthesis (besides the environment factor), like chlorophyll content.
Let me know how it goes on Thursday!
Hello. My name is Aiden and I am a student in AP Bio. I am very interested in the field of biology and I plan to continue with biology throughout college. I noticed you like hiking and traveling, so what is your favorite place to travel to or what is a place that you really want to travel to?
Hi Gabriela! To answer your question about the climate, over the past few years of my life I have noticed how the climate has been changing. I, however, am not entirely sure why. I do not have a favorite trip yet, but I will be traveling to Canada soon to skydive, so I believe that will be my favorite trip soon. This lab branched off the question how does CO2 affect photosynthesis. In our leaf disk experiement, we discovered that carbon dioxide is necessary for photosynthesis. While there were some errors in our lab, we got results that were accurate enough to determine this. Some evidence we have includes the fact that the baking soda cup eventually developed bubbles around the leaves and a couple in the breath cup as well. We also noticed that none of the leaves floated in the water cup but almost all the leaves floated in the other two cups. We discovered a gas was produced, but do not have enough evidence to confirm what is is. Do you have any suggestions for creating less errors in this lab if we do another trial?