The purpose of this experiment is to investigate how normal and increased sunlight affects both indigenous and non-native species in Southern California’s chaparral ecosystem. Encelia californica and Nicotiana glauca were chosen as representative native and invasive species respectively. The electron transport rate (ETR) of the two species are expected to be higher at 2400 PAR (photosynthetic active radiation) than at 2000 PAR. The ETR between the two species is also expected to be different. The difference between species is important for understanding the advantages and disadvantages of species dependent on sunlight exposure. The ETR was measured using a Li-Cor 6400 which could also alter the PAR exposure. The data showed a significant increase in ETR for both species at the higher PAR but showed no significant difference between the two species

Clinebell, Carter

Duvall, Griffin

Suh, Daniel

English

Pepperdine Digital Commons

Pepperdine University Pepperdine Digital Commons Featured Research Undergraduate Student Research 4-7-2016 Comparing the Electron Transport Rate of Nico%ana glauca and Encelia californica at Normal and Increased PAR Carter Clinebell Pepperdine University Griffin Duvall Pepperdine University Daniel Suh Pepperdine University Follow this and additional works at: https://digitalcommons.pepperdine.edu/sturesearch  Part of the Biology Commons, and the Plant Sciences Commons Recommended Citation Clinebell, Carter; Duvall, Griffin; and Suh, Daniel, "Comparing the Electron Transport Rate of Nico%ana glauca and Encelia californica at Normal and Increased PAR" (2016). Pepperdine University, Featured Research. Paper 192. https://digitalcommons.pepperdine.edu/sturesearch/192 This Article 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 Featured Research by an authorized administrator of Pepperdine Digital Commons. For more information, please contact josias.bartram@pepperdine.edu , anna.speth@pepperdine.edu. QU ICK  START ( con t . )   How to change the template color theme You can easily change the color theme of your poster by going to the DESIGN menu, click on COLORS, and choose the color theme of your choice. You can also create your own color theme.        You can also manually change the color of your background by going to VIEW > SLIDE MASTER.  After you finish working on the master be sure to go to VIEW > NORMAL to continue working on your poster.  How to add Text The template comes with a number of pre-formatted placeholders for headers and text blocks. You can add more blocks by copying and pasting the existing ones or by adding a text box from the HOME menu.    Text size Adjust the size of your text based on how much content you have to present. The default template text offers a good starting point. Follow the conference requirements.  How to add Tables To add a table from scratch go to the INSERT menu and  click on TABLE. A drop-down box will help you select rows and columns.  You can also copy and a paste a table from Word or another PowerPoint document. A pasted table may need to be re-formatted by RIGHT-CLICK > FORMAT SHAPE, TEXT BOX, Margins.  Graphs / Charts You can simply copy and paste charts and graphs from Excel or Word. Some reformatting may be required depending on how the original document has been created.  How to change the column configuration RIGHT-CLICK on the poster background and select LAYOUT to see the column options available for this template. The poster columns can also be customized on the Master. VIEW > MASTER.  How to remove the info bars If you are working in PowerPoint for Windows and have finished your poster, save as PDF and the bars will not be included. You can also delete them by going to VIEW > MASTER. On the Mac adjust the Page-Setup to match the Page-Setup in PowerPoint before you create a PDF. You can also delete them from the Slide Master.  Save your work Save your template as a PowerPoint document. For printing, save as PowerPoint or “Print-quality” PDF.  Print your poster When you are ready to have your poster printed go online to PosterPresentations.com and click on the “Order Your Poster” button. Choose the poster type the best suits your needs and submit your order. If you submit a PowerPoint document you will be receiving a PDF proof for your approval prior to printing. If your order is placed and paid for before noon, Pacific, Monday through Friday, your order will ship out that same day. Next day, Second day, Third day, and Free Ground services are offered. Go to PosterPresentations.com for more information.  Student discounts are available on our Facebook page. Go to PosterPresentations.com and click on the FB icon.  ©	  2015	  PosterPresenta/ons.com	  	  	  	  	  2117	  Fourth	  Street	  ,	  Unit	  C	  	  	  	  	  	  	  	  	  	  	  	  	  	  Berkeley	  CA	  94710	  	  	  	  	  posterpresenter@gmail.com	  (—THIS SIDEBAR DOES NOT PRINT—) DES I G N  G U I DE   This PowerPoint 2007 template produces a 36”x48” presentation poster. You can use it to create your research poster and save valuable time placing titles, subtitles, text, and graphics.   We provide a series of online tutorials that will guide you through the poster design process and answer your poster production questions. To view our template tutorials, go online to PosterPresentations.com and click on HELP DESK.  When you are ready to print your poster, go online to PosterPresentations.com  Need assistance? Call us at 1.510.649.3001   QU ICK  START  Zoom in and out  As you work on your poster zoom in and out to the level that is more comfortable to you.   Go to VIEW > ZOOM.  Title, Authors, and Affiliations Start designing your poster by adding the title, the names of the authors, and the affiliated institutions. You can type or paste text into the provided boxes. The template will automatically adjust the size of your text to fit the title box. You can manually override this feature and change the size of your text.   TIP: The font size of your title should be bigger than your name(s) and institution name(s).     Adding Logos / Seals Most often, logos are added on each side of the title. You can insert a logo by dragging and dropping it from your desktop, copy and paste or by going to INSERT > PICTURES. Logos taken from web sites are likely to be low quality when printed. Zoom it at 100% to see what the logo will look like on the final poster and make any necessary adjustments.    TIP:  See if your school’s logo is available on our free poster templates page.  Photographs / Graphics You can add images by dragging and dropping from your desktop, copy and paste, or by going to INSERT > PICTURES. Resize images proportionally by holding down the SHIFT key and dragging one of the corner handles. For a professional-looking poster, do not distort your images by enlarging them disproportionally.        Image Quality Check Zoom in and look at your images at 100% magnification. If they look good they will print well.  ORIGINAL	   DISTORTED	  Corner	  handles	  Good	  prin/ng	  quality	  Bad	  prin/ng	  quality	  RESEARCH POSTER PRESENTATION DESIGN © 2015 www.PosterPresentations.com The purpose of this experiment is to investigate how normal and increased sunlight affects both indigenous and non-native species in Southern California’s chaparral ecosystem. Encelia californica and Nicotiana glauca were chosen as representative native and invasive species respectively. The electron transport rate (ETR) of the two species are expected to be higher at 2400 PAR (photosynthetic active radiation) than at 2000 PAR. The ETR between the two species is also expected to be different. The difference between species is important for understanding the advantages and disadvantages of species dependent on sunlight exposure. The ETR was measured using a Li-Cor 6400 which could also alter the PAR exposure. The data showed a significant increase in ETR for both species at the higher PAR but showed no significant difference between the two species. Abstract	  Introduc?on	  For this experiment, it was necessary to ensure that a wide variety of variables could be held stable in our evaluation of each species. To accomplish this, we utilized a Li-Cor 6400 gas exchange monitor that is capable of stabilizing, monitoring, and altering every necessary variable for our experiment. To ensure that the plants used in this experiment were not subject to varying conditions during development or adulthood we selected 6 plants of each species within a hillside area of approximately 100m2. Additionally, we tried to select plants in similar developmental periods to negate the impact of changing photosynthetic activity during different stages of growth. The bulk of our data was gathered and  processed by the Li-Cor 6400 itself, so the main task for our group was discerning significance from the acquired data. Differences between low and high intensity sunlight, as well as differences between species at a given light level were the focus of our investigation. The measurements carrying the majority of our significance in this experiment were qN/qP (non-photochemical  quenching), Fv’/Fm’ (fluorescence), and PAR itself. These measurements allow us to relate our data to ETR (electron transport rate) which is the ultimate focus of the experiment. We used a student’s t-test to evaluate the significance of our data. To acquire data, the Li-Cor was calibrated to produce a PAR value of 2000 to replicate normal sunlight and 2400 for intense sunlight.   Materials	  and	  Methods	  Based on our t-test, there was a significant difference between average ETR at 2000 and 2400 PAR for both E. californica and N. glauca, but no significant difference between E. californica and N. glauca at either level. The first result is as expected, since the plants are receiving more light energy. Our group hypothesized that there would be a statistically significant difference in the way each plant responded to increased radiation, as N. glauca is an invasive species less specifically adapted to the chaparral ecosystem conditions. However, it turns out that each plant adapted very similarly to an altered PAR level. This means that while we can make inferences about how each species might perform individually in intense sunlight, based on our results we cannot make any predictions about how interspecific competition between the species might change due to a long term change in PAR. A wider variety of PAR’s investigated, or a wider variety of individuals tested at these same PAR’s might have offered greater insight into the interspecific competition between the two. Additionally, performing this same test on a wider variety of species could aid our understanding of the complex relationships between native and invasive species. Our findings are in concordance with those of a study conducted in 2009 including both E. californica and N. glauca. (Funk et al. 2009) While this study included a larger variety of variables and species, it observed the same similar responses by N. glauca and E. californica in Fv’/Fm’ to a change in PAR.    Results	  Conclusions	  The ETR of E. californica and N. glauca are higher at a PAR of 2400 than a PAR of 2000.  There is no significant difference between the ETR of E. californica and N. glauca at either a PAR of 2000 or a PAR of 2000.  As the climate changes and plants are exposed to increased radiation, the photosynthetic rates of these plants will increase. This could imply a less diverse ecosystem that favors these plants. Further research could take a comprehensive look at what types of plants, native and non-native, will most likely thrive in an ecosystem with greater radiation and which will not. References	  Funk, J. L., & Zachary, V. A. (2010). Physiological responses to short-term water and light stress in native and invasive plant species in southern California. Biological Invasions, 12(6), 1685-1694.   DiTomaso, J.M., G.B. Kyser et al. 2013. Weed Control in Natural Areas in the Western United States. Weed Research and Information Center, University of California. 544p.  Information on California plants for education, research and conservation,  with data contributed by public and private institutions and individuals, including the Consortium of California Herbaria.  [web application]. 2016. Berkeley, California: The Calflora Database [a non-profit organization].   Acknowledgements	  We would like to thank Dr. Stephen Davis for his support and guidance as well as the Natural Science Division at Pepperdine University for the supplies to complete this project. We would also like to thank the plants. In a period of unprecedented drought for California, both invasive and indigenous species are under a great deal of environmental stress. When plants are exposed to sunlight, not all of the energy imparted by the sun can be converted into photosynthetic energy. Instead, much of this energy is almost immediately dispersed by fluorescence to prevent radiation damage to the leaf.  A comparison between PAR (photosynthetically active radiation) and ETR (electron transport rate) can accurately detail the amount of available radiation energy converted to photosynthetic energy. PAR measures the number of photons that fall within a suitable range for photosynthesis striking the leaf in a given span of time. Electron transport rate measures the number of electrons moving between the plant’s photosystems in a given span of time, thus elucidating the rate of photosynthesis. In our experiment, we compare ETR in two species at two different PAR levels. Nicotiana glauca, also known as tree tobacco, is an invasive species that has potential to outcompete slower growing native species. Encelia californica is a sagebrush species specific to California and the Santa Monica mountains. It requires full sunlight to thrive, so individuals are at risk of being outcompeted for sunlight by faster growing invasive species. The goal of this experiment is to investigate how intense sunlight affects the photosynthetic activity of adult N. glauca and E. californica respectively. We hypothesized that there would be a notable difference in how N. glauca, an invasive species, and E. californica, a native chaparral species, responded to a change in PAR.  Pepperdine	  University,	  Natural	  Science	  Division	  Carter	  Clinebell,	  Griffin	  Duvall,	  Daniel	  Suh	  Comparing	  the	  Electron	  Transport	  Rate	  of	  	  Nico%ana	  glauca	  and	  Encelia	  californica	  at	  Normal	  and	  Increased	  PAR	  Discussion	  0	  50	  100	  150	  200	  250	  E.	  californica	   N.	  glauca	  ETR	   2000	  2400	  Fig.	  3	  two-­‐tailed	  unpaired	  t-­‐test	  comparing	  	  Encelia	  californica	  and	  Nico%ana	  glauca	  at	  2000	  PAR	   p>0.4	  at	  2400	  PAR	   p>0.8	  Fig.	  4	  one-­‐tailed	  paired	  t-­‐test	  comparing	  2000	  PAR	  and	  2400	  PAR	  E.	  californica	   p=0.019	  N.	  glauca	   p=0.009	  PAR	   mean	   st.dev	  E.	  californica	   2000	   107.234	   +/-­‐	  47.15	  2400	   214.313	   +/-­‐	  45.32	  N.	  glauca	   2000	   147.539	   +/-­‐	  13.20	  2400	   206.025	   +/-­‐	  39.67	  Fig.1	  ETR	  of	  E.	  californica	  and	  	  N.	  glauca	  at	  2000	  and	  2400	  PAR	  The	  difference	  in	  means	  of	  ETR	  between	  species	  was	  not	  significantly	  significant	  (p>0.4;	  fig.	  3)	  at	  either	  exposure.	  The	  difference	  in	  means	  of	  ETR	  was	  significant	  for	  each	  species	  at	  different	  levels	  of	  PAR	  (p<0.02;	  fig.	  4)	  	  	  Fig.	  2	  means	  and	  st.	  dev	  of	  ETR	  

Comparing the Electron Transport Rate of Nico%ana glauca and Encelia californica at Normal and Increased PAR

https://digitalcommons.pepperdine.edu/cgi/viewcontent.cgi?article=1174&context=sturesearch

Comparing the Electron Transport Rate of Nico%ana glauca and Encelia californica at Normal and Increased PAR

Abstract

Similar works

Full text

Available Versions

Pepperdine Digital Commons