Every autumn season, colder temperatures and decreased daily sunlight cause leaves to change their photosynthetic activity. The value of this study was to conduct research on the photosynthetic activity in colored leaves, a topic rarely found in literature. Gitelson and Merzlyak (1994) showed that as leaves get less sunlight in a day, the tree begins to decrease and eventually stop the production of chlorophyll, a green pigment, leaving other pigments in the leaf such as carotenoids, a yellow, orange, or red pigment. All pigments were used in photosynthesis to capture photons at different absorbance spectrums and different peak absorbances. According to Wei et al. (2013), the photosynthetic efficiency of leaves decreased as the chloroplasts deteriorated during autumn. The goal of the study was the effect of leaf color change of Ginkgo biloba on photosynthesis and to compare this fall’s results to a prior year.


As the leaves changed colors from green to yellow, photosynthesis decreased and this same trend persisted between each year. Chlorophyll is the main pigment Ginkgo leaves use to gather photons and they use carotenoids as secondary pigments. Annually as the leaves changed colors from green to yellow the photosynthetic activities of Ginkgos decreased because leaves slowly stopped the production of chlorophyll which decreased PQ SPAD and photosynthetic efficiency and LEF. Annual study of the photosynthetic activity of Ginkgo biloba trees will further solidify the natural trends of the photosynthetic processes in these trees during the autumnal season.

Experiment Design

The Ginkgo biloba trees we are studying are located on the Michigan State campus, on the east side of the South Kedzie building next to Farm Lane. We will split the tree up into four quadrants (NE, SE, SW, and NW) and then randomly pick (described in Random Sampling Method) 10 leaves from each quadrant from the exterior of the reachable part of the tree. The data collected will be the phi II, SPAD, LEF, NPQt, and Light Intensity. We will be comparing the photosynthetic activity as the leaves change colors. We need to categorize the leaf color into Green, Green/Yellow, Yellow/Green, or Yellow. We take 10 measurements per quadrant, 40 measurements per tree for three trees, which leads to 120 measurements per data collection session. We can check out the MultispeQ device for 2 hours and we can get done with all 120 measurements in about 1 to 1 and half hours. Each member in the group will have 360 total measurements for a group total of 1440 measurements and the laboratory instructor will also take measurements. These measurements are biological sample replicates. One-way ANOVA tests will be performed for each quadrant of each tree for each color to see which quadrants are similar and can be combined. One-way ANOVA tests will also be used to compare all colors. Two sample t-tests will be used to compare fall 2015 data to fall 2016 data.

Random Sampling Method

MultispeQ #124 Tablet #6

  1. During evening hours, 1 p.m. to 5 p. m., locate the Ginkgo biloba trees with codes: 95P063-16, 95P063-17, 95P063-18. These are located on the east side of the South Kedzie building, next to Farm Lane.
  2. Split the tree into four quadrants, Northeast, Southeast, Southwest, and Northwest.
  3. Starting the measuring process in the Northeast quadrant, blindly reach out as far as you can for a random, dry, exterior leaf in any direction. Try not to grab the same leaf more than once in an outing.
  4. Record the tree code, quadrant, measurement number for this quadrant, and the color of the leaf. (i.e. answering the questions in the app)
  5. Place the MultispeQ lens on the leaf avoiding brown parts and holes. Keep the device on the leaf in the leaf's natural position, do not pull the leaf off the tree. Take the measurement. Make sure the data is good, i.e. all positive values.
  6. Repeat steps 2 through 5, for ten total measurements in this quadrant.
  7. Move to the next quadrants in a clockwise direction.
  8. Repeat steps 2 through 5 for each quadrant, for 40 total measurements per tree.
  9. Repeat steps 1 through 8 for the other two trees. Ending with 120 measurements in one data collection session.

Examples of Leaf Color


green small.jpg


green-yellow small.jpg


yellow-green small.jpg




Leaf Photosynthesis - MultispeQ Beta ONLY

Measures photosynthesis-related parameters in <15 seconds, including: Phi2, PhiNPQ, PhiNO, NPQt, qL, LEF, and SPAD. In addition, measures PAR (photosynthetically active radiation), ambient temperature and relative humidity.

Works with the MultispeQ Beta device only


  1. Which Ginkgo biloba Tree code? (Multiple Choice)
  2. What is the color of the leaf? (Multiple Choice)
  3. What is the measurement number/leaf count for this quadrant? (Multiple Choice)
  4. Which quadrant of the tree? (Multiple Choice)




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