Planting Science - Projects: NFA Courtsunis Team 1
You are here: Home / Groups / NFA Courtsunis Fall 2016 Project / Projects / NFA Courtsunis Team 1

NFA Courtsunis Team 1

Project by group nfacoursunisfall2016project

Explore Photosynthesis is an anabolic process by which the energy of sunlight is captured and used to convert carbon dioxide and water into carbohydrates (glucose-C6H12O6) and oxygen gas. The purpose of this lab is to experimentally determine the effects of three different leaf colors: green, white, and purple, on the rate of photosynthesis of the plant, a Tradescantia zebrina, otherwise known by its common name, the Wandering Jew. The rate of photosynthesis can be indirectly measured in sunken leaves by recording the time it takes for the leaves to float to the surface4. In order for the sunken leaves to float, there must be a source of carbon dioxide in the water, because it is a necessary substrate of photosynthesis. As photosynthesis occurs, oxygen will be produced and accumulate in the spaces of the mesophyll layer, and eventually cause the leaves to rise5. During the light reactions of photosynthesis, chemical energy is produced when receptive molecules such as chlorophyll and anthocyanins absorb photons in order to harvest their energy for biological processes1. Chlorophyll is a green pigment responsible for the absorption of light to provide energy for photosynthesis and is present in all plants3. Chlorophyll is responsible for the green color of most plants because it absorbs any orange/red and violet/blue light from the sunlight that reaches the leaf; the light reflected is deficient in red and blue light so to the human eye, it’s green. Anthocyanins absorb blue and green light, and as a result look purple to the human eye. Chlorophyll is still present in the Tradescantia zebrina plant with the purple leaves, but it is masked due to the higher concentration of anthocyanins2. Plants only absorb certain wavelengths, or colors, of visible light, depending on what pigments they contain. The pigments are specific to what wavelengths they absorb, and reflect the wavelengths they do not use. To determine which color leaf contains more pigments, a chromatography of the purple,white, and green leaves was created to compare the amount of pigments of each leaf, to one another. It is a reasonable thought that the leaves which contain a greater number of pigments will be able to carry out photosynthesis at a faster rate. The Tradescantia zebrina plant with the green leaves contains more pigments which allows for an increased absorption of light in the visible spectrum, resulting in a faster rate of photosynthesis compared to that of the Tradescantia zebrina with the purple leaves or that of the Tradescantia zebrina with the white leaves.
Research Question Does leaf color have an affect on the rate of photosynthesis in the Tradescantia zebrina?
Predictions The Tradescantia zebrina plant with the green leaves contains more pigments which allows for an increased absorption of light in the visible spectrum, resulting in a faster rate of photosynthesis compared to that of the Tradescantia zebrina with the purple leaves or that of the Tradescantia zebrina with the white leaves.
Experimental Design Obtain 3 plastic cups and label one for each leaf color using the tape and marker. Measure out 100mL of distilled water and add 100mL to each cup. Add a pinch of sodium bicarbonate and 5 drops of dish soap to each cup. Hole punch 10 leaf discs out of each color of leaf, placing them on separate index cards. Avoid large veins when hole punching. Remove the stoppers from the syringes, and gently place the leaf discs into each syringe, using the paint brushes to push them to the bottom. Place the stopper back into the syringe and push all of the air out, being careful not to crush the leaves. Pull up 5cc of solution into each syringe, and push out any excess air that remains in the syringe. Flick the syringe to keep the leaves in solution. Create a vacuum by covering the open end of the syringe with your finger, pulling down on the stopper, and releasing it to allow it to spring back. Repeat this until all the leaves have sunk. When all the leaves sink, release the solutions in the syringes into the cups from which they came. Place all 3 cups under the light source, making sure they are equidistant, and start the timer. Record the number of discs that have risen after each minute, for a minimum of 10 minutes. Carefully stir the solutions every few minutes using the paint brushes. Repeat 3 times.
Conclusion
Investigation Theme POS
Grade Level High School Students (Grades 9,10,11,12)
School Name Newburgh Free Academy Main Campus
Session Fall 2016

Team

LogoWithTags.png

f_logo_RGB-Black_72.png 2021_Twitter_logo_-_black.png icons8-mail-30.png

ABOUT THE PROGRAM

GET INVOLVED AS A TEACHER  *   GET INVOLVED AS A SCIENTIST MENTOR

SUPPORT US!   *   TERMS OF USE

NSF_Logo.jpg This material is based upon work supported by the National Science Foundation under Grant #2010556 and #1502892. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

Copyright © 2022 PlantingScience -- Powered by HUBzero®, a Purdue project