Photosynthetic(Phi II) Variation Within Ulmus Morton Species


We are trying to find the photosynthetic variation data in between different tree sizes of the same species using the multispeq. We will be collecting data using the Multispeq Device and an android tablet on Ulmus Morton Tree Species on the North side of MSU's campus three times a week for five weeks. We believe the trees with larger trunk circumferences will have higher Phi II photosynthetic values than trees with smaller trunk circumferences. See Table 1. tree circumferences.

This is done in East Lansing, Michigan, but could be done anywhere in the world. It could also be performed on other species of trees, if desired.

Photosynthesis has been widely studied between many species of trees as an important process in regards to the environment, but research is lacking in regards to photosynthetic rates across different sized trees within the same species. This is done by looking at photosynthetic efficiency and the Phi ll values for each leaf being observed. There have been other similar studies that have applied such measurements, such as the distinction in photosynthetic components between saplings and older trees, which showed a difference (Thomas, Winner, 2000). Depending on the results, it may be possible to relate the photosynthetic rates to deforestation. As bigger trees are cut down for human use, more small trees are left in their place. If photosynthesis is taking longer or is less efficient in smaller trees, it may end up having a larger effect on the environment. This was further supported by the study performed by Niinemets, Sparrow and Cescatii (2005), which found that “Superior light harvesting in young trees resulted from more planar leaf arrangement and less clumped foliage” (Niinemets, Sparrow, Cescatii). In addition, according to Rijkers et. al, “...the ratio of total leaf area to total non-photosynthetic, living tissue decreases with increasing tree height…” which provided additional support to the research project.

The question for this project was whether trees with larger circumferences displayed higher photosynthetic rates than those with smaller circumferences across the same species. The expectation was that larger trees have higher photosynthetic rates than smaller trees within the same species. This assumption was due to the larger amount of leaves on bigger trees, allowing for more sunlight absorption. With this outcome, it may be easier to take a step back and slow down the rate at which large, more mature trees are being cut down, which will create a cleaner environment for future generations. This research will further the field in respect to gathering more data to reiterate the importance of the health of the environment. Five different trees(biological replicates) of variable trunk circumferences within Ulmus Mortons were studied on Michigan State University’s North Campus.

The variety of lighting throughout the day may cause variation in Phi II values that were being tested for. The age of the Ulmus Morton Glossys is not a factor in our study, although they are all approximately 8 years old.

Sampling Method

Table 1. Circumferences of trunks in inches for each of the Ulmus Mortons studied.

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Multispeq device #4 was used along with an android tablet with the Photosynq application on it.

On each tree, 24 leaves(technical replicates) were measured for their Phi II values each time data points were collected, ending with approximately 1,500 data points. Each tree was divided into four quadrants which were North, East, South, and West. The first measurements were taken from the North quadrant, where six leaves were randomly chosen on the lower outskirt. Leaves were never torn off of the tree. This methodology was continued clockwise around the tree in the other three quadrants, totaling 24 leaves per tree. An Analysis of Variation(ANOVA) test was performed for the statistical analysis to determine the differences between the means of Phi II between trees with different circumferences. All data is seen in Figure 2.

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Figure 1. Ulmus Morton Glossy trees locations in MSU north campus. Trees have varying tree circumferences and ages, with five specific trees used in research study.


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 tree is it? (All are Ulmus Morton Glossys) (Multiple Choice)
  2. Cardinal Direction?(lower outskirt) (Multiple Choice)
  3. Leaf Count? (Short Answer)




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