Daylight vs. Chlorophyll of Ulmus FS 2016


The purpose of the study is to determine the effect of light intensity on photosynthetic efficiency. According to Zhu et al. (2010) investing more time in increasing the productivity of photosynthesis will yield a higher number of crops and grains for farmers showing photosynthetic efficiency of trees is important. Increased productivity of photosynthesis leading to an increase in crops and will aid in feeding countries and increasing trade. Many scientists have analyzed the effects of light on photosynthetic efficiency. Yajuan Dai et al. (2009) found that 67% shade was the optimal irradiance for T. hemsleyanum cultivation. In addition, Nama et al. (2015) found that high intensity light targets the photosystems of the chloroplast and the accompanied proteins of these systems, leading to an increased efficiency. Miyaji et al. (1997) found that leaves exposed to >70% daylight had a higher rate of photosynthetic production. Lastly, Buck-Sorlin et al. (2011), concluded that PAR readings were highest at noon with a peak at about 320 µmol m−2 s−1.

Our research question asks, how are photosynthetic efficiency, LEF, phiNPQ, and chlorophyll content affected by different times of day at different quadrants on Ulmus mortis trees.We hypothesize that the photosynthetic efficiency will be greater in the morning (11:30am). Our expected outcome is that that measurements taken earlier in the day will have a higher photosynthetic efficiency than those later in the day. Our results will show the effect the amount of daylight has on the photosynthetic efficiency, LEF, phiNPQ, and chlorophyll content. This will provide information as to where to plant trees for optimal photosynthetic production.

As a group, we collect data three times a week. Our trees are located in close vicinity to each other. We collect 120 data points each time we go out. We have split the tree into north, east, south and west quadrants. We then split those quadrants into left and right sections. Then we collect 5 data points from each side of the quadrant. A total of 10 leaves are measured in each quadrant of the tree. We repeat this for all three trees. Using the Multispeq, we get information about the photosynthetic activity, LEF, phiNPQ, and chlorophyll content. Through analysis, these measurement will show how chlorphyll functions under different amounts of light. Before we take the measurement of our leaves, we answer what the tree code is, what time of day (morning or evening) it is, what quadrant the measurement is in, and what data point we are on for that quadrant (1-10). The morning measurements are executed at 11:30 am, whereas, in the evening we record at 3:00pm. We will be analyzing the data by comparing means and looking at all, if any, correlations between time of day and photosynthetic efficiency. This will all be done using various statistic tests and graphs. Our study organism is of the Ulmus genus, specifically the morton species. Our trees are 2008049509, 2008049502, 20080495*08. All of our trees are eight years old.

Random Sampling We are using the Multispeq #123.Our random sampling method includes splitting our tree into north, east, south, and west. We then split the directional quadrants into left and right and taking five samples from each side.


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. Ulmus 'Morton Glossy' (Multiple Choice)
  2. Which quadrant is the sample (Multiple Choice)
  3. Time of Day (Multiple Choice)
  4. What sample number (Multiple Choice)




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