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Pepperdine University Pepperdine Digital Commons All Undergraduate Student Research Undergraduate Student Research 2014 Measuring Photosynthesis to Evaluate Photoprotection by Anthocyanins in Malosma laurina Jorge Bojorkez-Calderon Pepperdine University Hannah Imson Pepperdine University Follow this and additional works at: http://digitalcommons.pepperdine.edu/sturesearch Part of the Biology Commons Recommended Citation Bojorkez-Calderon, Jorge and Imson, Hannah, "Measuring Photosynthesis to Evaluate Photoprotection by Anthocyanins in Malosma laurina" (2014). Pepperdine University, All Undergraduate Student Research. Paper 113. http://digitalcommons.pepperdine.edu/sturesearch/113 This Research Poster is brought to you for free and open access by the Undergraduate Student Research at Pepperdine Digital Commons. It has been accepted for inclusion in All Undergraduate Student Research by an authorized administrator of Pepperdine Digital Commons. For more information, please contact [email protected]. Measuring Photosynthesis to Evaluate Photoprotection by Anthocyanins in Malosma laurina Jorge Bojorkez-Calderon & Hannah Imson Pepperdine University, Seaver College Abstract Anthocyanin, like chlorophyll, is a pigment molecule present in plants. However, while chlorophyll reflects green light, anthocyanin reflects red light, a much lower frequency, and therefore absorbs less energy. Pigment molecules are very involved in photosynthesis in that they absorb the energy needed to push those reactions forward, and carotenoids and anthocyanins function to take absorb excess sunlight (Bliger and Björkman 1990). Anthocyanins in particular, have also been speculated to protect again UV damage (Merzlyak and Chivkunova 2000). Malosma laurina, also known as laurel sumac, utilizes this pigment molecule to help defend against the Mediterranean-like environmental conditions it faces. The juvenile leaves of Malosma are easily identified by their rich red color and soft leaves, while the mature leaves are tougher and green colored. Through the use of Li-6400 XT, the objective of our group is to determine the difference in photo-protection levels between the red, juvenile leaves and the green, juvenile leaves of Malosma laurina. We will be observing the differences in photosynthetic rates, as well as the various fluorescence values. We expect to see lower photosynthetic rates in the red leaves. • CO2 = 400 µmol/mol • Li-6400XT Portable Photosynthesis System • Temperature = 23ºC In order to determine whether or not anthocyanins play an essential role in the photoprotection of Malosma laurina, photosynthesis was measured using the Li-6400XT Portable Photosynthesis System. Constant variables were used to determine any changes in the leaf’s ability to enable the process of photosynthesis. The only variable that was increased throughout the experiment was the amount of photons (Quantum), which was increased in increments of 200 µmol m-2 s-1 from 1000 to 2000 µmol m-2 s-1. All data was collected on Pepperdine’s campus. Results There were several significant differences identified between the red and green leaves of Malosma laurina. While the photosynthetic rates of the green leaves averaged 20, the photosynthetic rate of the much younger red leaves averaged 4. This significant difference is due to the presence of anthocyanin, which absorbs excess light and various energies of light at lower frequencies than chlorophyll can absorb. Therefore, our group can conclude that the presence of anthocyanin is very effective in the photoprotection of the juvenile leaves. 22 4 References 2 Photosynthesis (µmol/m s) Introduction • Juvenile red and green leaf Photosynthesis (µmol/m s) Conclusion • Flow = 300 µmol m-2 s-1 • Laurel Sumac (Malosma laurina) 2 The purpose of this investigation was to observe the differences between the photosynthetic rates and photo-protection of young, red, juvenile leaves of Malosma laurina, and compare it to young, green leaves. To accomplish this, the open-system of Li-6400 XT was brought out into the field to a shrub of Malosma laurina that was flourishing and had both red and green leaves present. Then, data of fluorescence, photosynthetic rate, and conductance was taken from both red leaves and green leaves, and the photosynthetic rates were compared. Through this investigation, we were able to quantify that in young, red leaves, which had anthocyanin, the photosynthetic rate was lower when compared to the young, green leaves on the same plant. Materials and Methods 21 20 19 18 500 1000 1500 2000 3.5 Bilger, W., & Björkman, O. (1990). Role of the xanthophyll cycle in photoprotection elucidated by measurements of light-induced absorbance changes, fluorescence and photosynthesis in leaves of Hedera canariensis. Photosynthesis Research, 25(3), 173-185. 2. Merzlyak, M. N., & Chivkunova, O. B. (2000). Lightstress-induced pigment changes and evidence for anthocyanin photoprotection in apples. Journal of Photochemistry and Photobiology B: Biology, 55(2), 155-163. 3. Pratt, R. B., Ewers, F. W., Lawson, M. C., Jacobsen, A. L., Brediger, M. M., & Davis, S. D. (2005). Mechanisms for tolerating freeze–thaw stress of two evergreen chaparral species: Rhus ovata and Malosma laurina (Anacardiaceae). American Journal of Botany, 92(7), 1102-1113. 3 2.5 500 2500 1000 1500 2000 2500 2 PPFD (µmol/m s) 2 PPFD (µmol/m s) FIGURE 1: Shows the linear relationship of green leaves and the rate of photosynthesis as photons (or sunlight) is increased. TABLE 1: Summarizes the data collected out in the field for both leaves in one plant of Malosma laurina 1. FIGURE 2: Shows the linear relationship of red leaves and the rate of photosynthesis as photons (or sunlight) is increased. Quantum (µmol m-2 s-1) Green Leaf – Photosynthesis (µmol m-2 s-1) Red Leaf – Photosynthesis (µmol m-2 s-1) 1000 18.6 2.57 1200 19.5 3.07 1400 20.2 3.47 1600 20.6 3.50 1800 21.1 3.71 2000 21.4 3.85 Discussion After establishing the linear relationship between the production of photosynthesis and the amount of photons received by a leaf, we were able to determine the rate of photosynthesis between a green leaf and a red leaf found in the same plant of Malosma laurina (figure 1 and 2). Upon further statistical analysis, we decided to execute the Student t-test and compared the two groups to determine the significance of producing anthocyanins. The Student t-test along with an ANOVA analysis, under equal variance, gave us a p-value of 0.001, lower than an alpha set at 0.05, making it statistically significant. The statistical analysis allowed for us to accept our hypothesis, which makes logical sense. Since red leaves tend to have higher anthocyanins, red pigmentation, they utilize most of their energy protecting themselves from harmful UV light (both A and B rays) (Pratt et al. 2005). Green leaves can be thought as more mature, which causes them to utilize the majority of their resources activating the process of photosynthesis. If you look at the data found in table 1, you can already determine that green leaves are working significantly harder, approximately 5-6 times harder, to convert light into energy. Acknowledgements We would like to thank the Natural Science Division at Pepperdine University for their ongoing support during this experiment and for lending us their equipment. We would also like to thank Dr. Stephen Davis for his undivided attention during our initial stages of planning. We truly hope this experiment incorporates a big concept the biology of plants. Thank you!