Life Sciences Commons^™

Effects Of 2, 4-D On Zea Maize Physiology, Caitlin Thompson, Lori Patrick, Acacia Osbourne, Katrina Brock

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Growth rate, fluorescence and stomatal conductance, in zea was examined to determine the effects of artificial auxin, 2-4-d, on common crop plants. We measured florescence, growth rate, and stomatal conductance. Low concentrations of 2,4-D increased light-adapted fluorescence, anthocyanin levels and height of zea maize. A high concentration of 2,4-D increased anthocyanin levels, but also caused decreased fluorescence and height and spindliness to occur. It appears 2,4-D is only beneficial to monocot crop plants in low quantities. We cannot accurately comment on the accuracy of our data, however, due to several potential sources of error.

Effects Of Dehydration Stress On The Dark Adapted Fluorescence (Fv/Fm) Of Giant Bladder Kelp (Macrocystis Pyrifera), J. Avery Powell, Leah Smith

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The unique semi-diurnal tide system of Southern California suspends beach wrack along the beaches for approximately six hour periods before being washed back into the ocean. It has been noted in prior research that beach wrack is an essential part of Southern California's costal ecology but not much research has been done to learn about the viability of beach wrack as it dehydrates on the beach. To better understand the viability of wrack as it travels through these hydration changes, this study tested the effect of dehydration and rehydration on the fronds of Macrocystis pyrifera as they have been partially …

The Effect Of Proximity To A Highway On The Health Of Malosma Laurina Leaves, Jessica Bermea, Haley Clayton, Jack Klobas

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Due to an increase in air pollutants, heavy metal contaminates, and other adverse ecological conditions that plants near a road endure, it was hypothesized that plant species situated near a road would have a detectable decrease in photosynthetic performance when compared to plants away from the road. This investigation evaluated the in vivo photosynthetic status of two Malasma Laurina pairs with differing microhabitats, adjacent to the Pacific Coast Highway and 100 meters away from a Pacific Coast Highway. Maximum quantum yield and stomatal conductance measurements were recorded for each group. On average, the maximum quantum yield was greater on plants …

The Effect Of Hydration Status On Tensile Strength Of The Leaves Of Elymus Glaucus, Chelsie Corbett, Uri Hong, Scott Davis

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Tensile strength and water potential are both factors that are essential to the life and survival of a plant. Tensile strength is a measure of the amount of force that a plant can undergo before tissue damage and breakage occur. The primary objective of this study was to examine the correlation between tensile strength and leaf hydration status, or water potential. The water potential of leaves of a monocot grass native to North America, Elymus Glaucus, commonly known as blue wildrye, was measured using the Scholander-Hammel Pressure Chamber. The tensile strength of hydrated and of dehydrated leaves was measured …

The Effects Of Agitation Upon Plant Anatomy In Phaseolus Vulgaris, Craig Sutter, Nicholas Huron

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The earthquake that struck Japan’s coast a month ago gained national attention for the damage caused by the tsunami that was caused by the earthquake. Japan’s coast is subject to multiple earthquakes each year with tremors and aftershocks following. The quakes are bound to have an effect on the growth and development of Camellia sinensis, the tea plant, which is one of the most important exports of Japan. Due to the time restraints of this project, C. sinensis were not tested, instead two week old Phaseolus vulgaris were used to show the effects of constant agitation which might mimic …

Effects Of Soil Moisture On Photosynthesis And Fluorescence In Heteromeles Arbutifolia, Ali Alyami, Colin Byrne, Katherine Currie

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Some plants have evolved to increase their chances of survival by being drought-adapted. Among those plant species is Heteromeles arbutifolia, native to California. Logically, the fact that Heteromeles arbutifolia tolerates the low supply of water makes this plant more likely to be within environments where the level of sun exposure is high. Thus, we hypothesized that lowering soil moisture will cause an increase in xylem pressure, causing an increase in photo-protection and florescence, and a decrease in photosynthetic rate. This has not been tested before on a native chaparral plant such as Heteromeles arbutifolia. The experiment was held …

The Effect Of Nitrogen Soil Concentration On Leaf Fluorescence In Zea Mays, Ashton Garbutt, Daniel Rossie, Anup Solsi

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Macronutrients in the soil are essential to the growth and development of a plant. One of the most important nutrients to a plants growth is nitrogen. Nitrogen has been directly correlated to photosynthetic output in various studies and this relationship is the subject of this experiment. Since nitrogen has an effect on photosynthetic rate, there should be a correlation between nitrogen and fluorescence – a form of energy dissipation. This study attempted to show that nitrogen concentration in the soil is inversely proportional to fluorescence of the plant because the more nitrogen in the soil, the more energy should be …

Is There A Relationship Between Water Potential And The Mechanical Strength Of Salix Lasiolepis?, William Cohen, Gina Fitzgerald, Joseph Liao

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Exploring The Open-Close Mechanism Of Dimorphotheca Aurantiaca: Day Versus Night And Cold Versus Hot Temperatures, Tommy Chung, Kathleen Aguilar, Sunny Kim

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In the spring of every year on Pepperdine University’s campus, patches of hills are covered with the South African native flower Dimorphotheca aurantiaca or more commonly known as the African Daisy. An observation of the opening and closing mechanism of the flower triggered an important question: does the flower change its shape based on temperature or the presence of light? At night, the African Daisy closes and then opens up again in the daytime. Because temperature has such strong effects on different species of ectodermic animals and temperature-sensitive plants, we hypothesized that the change in temperature initiates the flower’s morphological …

Root Tensile Strength In A Native And Non-­Native Species Of The Coastal Chaparral Community, Jamie Elmquist, Andrea Lim, Amanda Scholl, Amanda Vest

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Non-­native species are regularly introduced into environments in which they replace existing native species and drastically influence the ecological characteristics of the area and the habitat of the living organisms surrounding them. In the botanical field of study, invasive plant species can choke out native species thus making them endangered or extinct. Specifically in the Santa Monica Mountains of Southern California, there are over 300 non-­native species of plants, each the source of its own repercussions and having both positive and negative effects on the environment. One specific non-­native species, Carpobrotus edulis (ice plant) replaces the native Coreopsis gigante (giant …

The Affect Of Temperature On The Fluorescence Of Heteromeles Arbutifolia (Hollywood) In The Santa Monica Mountains, Patrick Y. Chisum, Adam S. Graham, Arthur C. Sanders

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Presented here is a comparison of the predawn fluorescence of adult Heteromeles arbutifolia growing on the Pepperdine Seaver campus next to the lacrosse field, and adult Heteromeles growing in Tapia canyon. The analysis of the leaf temperature measured by an IR thermometer showed an average of 9.32°C drop when measuring plants in Tapia canyon compared to those growing on the warmer Pepperdine campus. The air temperature measured by the Kestrel and IR thermometer showed Tapia canyon being an average of 7.27°C colder than predawn measurements on Pepperdine campus. Finally, the fluorescence of the plants in both locations was measured using …

Tensile Strength Of Malosma Laurina Leaves In Wet And Dry Conditions, T. Candelore, N. Despenza, L. Garrison, L. Hinther

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Pepperdine University is one located in one of the most diverse places of the world. It is located in the Mediterranean which occupies less than 5% of the earth's landmass and is only found in five areas which includes California. On the campus there are several canyons. One of the canyons is called Winter Canyon. The canyon contained a plant called Malosma laurina which is located in a riparian environment and a chaparral environment. The plant grows in both areas however, our hypothesis was that the dry plants' leaves would demonstrate more plasticity. The soil humidity was also measured to …

Effect Of Petiole-­To-­Branchlet Angle On Tensile Stress And Tensile Strength In Heteromeles Arbutifolia, Matt W. Andrus, Anthony P. Lisankis, Valen C. Anderson

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Heteromeles arbutifolia an important chaparral species of southern California, Is a food source for mule deer (Odocoileus hemionus). This predation has become more pronounced as the climate shifts to hotter, drier, and longer summers. Other species that the deer normally feed on cannot survive these harsh conditions, while Heteromeles arbutifolia is able to persevere (Letourneau, 2004). We decided that there must be mechanisms involved in the petiole of leafs to keep them from being pulled off by deer and strong winds. Our group hypothesized that as the angle between the petiole and branchlet increased, the tensile strength of the petiole …

Effect Of Fertilizer On Leaf Tensile Strength In Salvia Leucophylla, Tawny Lindahl, John Buie, Eiichiro Uemura

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This experiment sought to establish a connection between short term growth in Salvia leucophylla found in Southern California and nutrient availability in the soil. It was hypothesized that adding artificially produced nutrient mix Miracle Grow would increase the strength of the leaves in the herb after one week of addition. Newer leaves were tested in the Instron device for tensile strength after one week, and after data analysis, it was concluded that there was no difference in tensile strength of leaves treated with fertilizer compared with leaves without fertilizer.

Differences In Hydraulic Conductance (Kh) As A Function Of Leaf Area (Ks Leaf) And Xylem Size (Ks Xylem) In Encelia Californica And Venegasia Carpesioides, Tony Audin, Andrew Dudley, Janel Gonzalez

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Southern California and the Santa Monica Mountains experience a climate similar to that of the Mediterranean basin. This means hot, dry summers, mild, wet winters, and large amounts of plant diversity. A major issue that can affect these regions is water availability and processing. To demonstrate this, hydraulic conductance (Kh) was measured as a function of leaf area (KS Leaf) and xylem size (KS Xylem). Two vascular plants were used for this study, Encelia californica and Venegasia carpesioides. This is because they are similar morphologically but are different genus and species. It was hypothesized that the larger plant (V. carpesioides) …

Post-­Fire Alterations In Mechanical Strength Of Leaves In Heteromeles Arbutifolia, Andrew Hair, Madeline Dilascia, Nick Novella, Taylor Wurdeman

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Wildfires in the Santa Monica mountains in Southern California burn down a decent percentage of the local vegetation. However, some plants like Heteromeles Arbutifolia, are considered to be resprouters because they return a mere two years after being burnt down. It is hypothesized that the artificially browsed resprout leaves will have a lower tensile strength than both the young and adult leaves because they use a lower amount of carbohydrates per unit-leaf-area. Data showed that although there was a slight different between the young leaves and the adult leaves of the Heteromeles, there was no statistically significant difference between the …

Comparing Leaf Properties Of Inland And Coastal Malosma Laurina In The Santa Monica Mountains, Rosemary Busch Conn, Lauren Parker, Brittany Sawrey

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Our group chose Malosma laurina, commonly known as Laurel Sumac, to observe and test. We hypothesized that there would be difference in photosynthetic trade-offs and capabilities between coastal and inland populations, specifically with respect to leaves. This was based on the low freezing tolerance in Malosma laurina (Pratt et al. 2005), and hypothesized that based on this stress, resources would be allocated differently in inland leaves than in coastal leaves. This hypothesis was tested using the indices of Normalized Difference Vegetation Index (NDVI), the Photochemical Reflectance Index (PRI), the ratio of green to red reflectance, and Leaf Specific Area …

A Comparison Of The Tensile Strength Of Leaves In Encelia Californica In Canyon And Beach Species, Anna Chowaniec, Annie Lee, Hayley Springs

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Our research is concerned with the further exploration of leaf biomechanics, a relatively unexamined field. The purpose of this experiment was to find a correlation between environmental stress factors and tensile strength of leaves of Encelia californica. We hypothesized the beach species would have a higher tensile strength than canyon species. After evaluating data collected from both Pepperdine’s Presidents Canyon and Malibu beach we found that while the canyon species could withstand a higher maximum load of force, there was no difference between the canyon and the beach species with leaf area taken into account. Using Young’s Modulus, we …

Natural Microorganisms’ Effect On The Growth Of Lasthenia Californica In Post‐Fire Soil, Bryce Lindley, Taylor Miller, Tyler Gibson

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The effect of microorganisms in post‐fire soil on the growth of lasthenia californica was studied by comparing growth in natural soil versus autoclaved soil. It was hypothesized that the seeds from the natural soil would have more growth because the microorganisms have a symbiotic relationship with the plants. Seeds were grown in similar conditions in both autoclaved and natural soil. After 44 days, the plants were uprooted and split into shoots and roots. Shoots and roots were then biomassed. The natural soil had a total shoot biomass of 3.031g and a total root biomass of 89.554g, while the autoclaved soil …

Carbon Dioxide Expulsion By Ceanothus Spinosus In Response To Predawn Sunlight, Eian Carter, Jon Pauwels, Brittany Wilkins

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In our experiment we studied the respiratory qualities of green bark ceanothus (Ceanothus spinosus). Plants are generally thought to undergo respiration during the night, building up carbon dioxide stores that are released in response to light. In resprouts with large root crowns, such as C. spinosus, we expected to see large amounts of carbon dioxide released right after dawn. This can be shown with the use of a portable gas exchange system. In C. spinosus, we compared normal respiration rates, based on carbon dioxide expulsion, to values obtained at predawn. We were able to show that …

Soil Salinity And Stomatal Conductance On Chaparral Plants, Ron King, Lisa Malyak, Kelly Rausch

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In our experiment we evaluated the soil salinity and corresponding stomatal conductance rates of Malosma laurina and Rhus integrifolia located near the coast and farther inland. Our prediction was that stomatal conductance would vary with the change in location of each species. Stomatal conductance was measured using a simple diffusion porometer and soil salinity was measured using a refractometer. We concluded that soil salinity caused a decline in stomatal conductance in both chaparral species. M. laurina was also found to be more sensitive to an increase in soil salinity, as its stomatal conductance rates declined more than that of R. …

Measuring Water Use Efficiency In Large And Small Leaves Of Malosma Laurina, Caitlin Ishibashi, Dan Kaczrowski, Evan Mattiansen

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Our study set out to compare Water Use Efficiency (WUE) levels of Malosma laurina plants in both small and large leaves. We collected a total of 3 data sets, with each set consisting of 5 small leaves and 5 large leaves from a single specimen of Malosma laurina located on Pepperdine’s campus. Parameters including transpiration and photosynthesis were measured to calculate WUE of small and large leaves using an LI- 6400 Gas Exchange System. We hypothesized that small leaves would have a higher WUE rate than large leaves of the M. laurina. Analysis of this data via a paired …

The Effect Of Hydraulic Lift In Quercus Agrifolia On The Health Of Venegasia Carpesioides, Kelly Donovan, Brittany Wagner

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Hydraulic lift was studied in live and dead Quercus agrifolia (Coastal Live Oak) in order to test its impact on surrounding Venegasia carpesioides (Canyon Sunflower). Hydraulic lift causes soil moisture to rise around the base of deep-rooted plants where neighboring plants can utilize this excess water. We predicted that the hydraulic lift of the Coastal Live Oak would increase soil moisture, causing higher stomatal conductance and higher water potential in nearby plants. Pvalues of .5258 and .6392 indicated there were no significant differences in soil moisture or in stomatal conductance of the Canyon Sunflowers. A p-value of .0378 showed a …

The Effects Of Light Intensity And Color Absorption Of Diurnal Leaf Movements Of Malva Parviflora, Amy Lawrence, Ben Young, Matthew Yarborough

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Our group measured the heliotropic response rate of the Malva parviflora under various light environments in order to see the effect that light color and intensity had on daily leaf movement. In our experiment we measured the leaf angle of plants under white, blue, red and green light, as well as plants under shade, over a specific duration of time in order to determine the rate of change. We ran a One-Way Analysis of Variance on leaf angle for light color as well as coverage at a 0.05 level using SPSS 17.0. The ANOVA test showed no significance for light …

Comparison Of Uva Absorbance In Sun And Shade Leaves, James Newton, Kevin Rivera, James Kim

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In observing chaparral species’ resistance to abiotic plant stresses, this investigation sought to study plant defense against UVA radiation in sun and shade leaves. We predicted that sun leaves would have higher absorbance of UV radiation considering their day-long exposure to sunlight.

UVA (350nm-400nm) absorbance in sun and shade leaves of Heteromeles arbutifolia and Malosma laurina were measured using an integrating sphere. Four leaves from each group were surveyed for reflectance and absorbance. Using the spectrophotometer, reflectance in the green wavelengths (500-600nm) was measured and divided by reflectance in the red (600-700nm) to give a quantitative estimation of the redness …

Stomatal Conductance Of Malosma Laurina In Frequently Burned And Non-Frequently Burned Sites, Kamron A. King, Matthew T. Bender, Stephen D. Davis

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In the months following the Malibu fires, the fire zones have experienced and abundance of new growth. Among this new growth, there are differences that can be observed when comparing the top of the Malibu hill (frequent fire zone) to the base of the hill (nonfrequent fire zone). As the chaparral resprouted we noticed the behavior of the Malosma laurina in both frequent and non-frequent fire zones and stomatal conductance, height, and water potential were tested for plants in the two varying zones, with plants in the non-frequent fire zone outperforming their counterparts.

Soil Moisture Adjacent The Roots Of Post-Fire Ceanothus Megacarpus And Malosma Laurina, Kristi Holly, Kelly Sayre, Anson Snow

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Hydraulic lift is a passive process in which a plant will bring water from subsoil to topsoil levels through its roots. In this experiment, we compared the soil moisture levels in the area surrounding two different chaparral species C. megacarpus, a shallow rooted nonsprouter, and M. laurina, a deep-rooted obligate sprouter, in order to determine the hydraulic lift patterns of chaparral as they regrow after fire. Furthermore, the C. Megacarpus had died due to the Malibu fire, while the M. Laurina was resprouting. Therefore, using a Hydrosense Soil Water Measurement System, we measured soil moisture percentages, and the results showed …

The Effect Of Fire Frequency On The Presence Of Native And Nonnative Species In The Santa Monica Mountains, Bobby Boss, Simone Ross, Taryn Thompson

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We surveyed two sites in the Santa Monica Mountains of Southern California that experienced both high and low fire frequency (Figure 1). Our objective was to find out if increased fire frequency allowed for the invasion of non-native species. We collected data on herbaceous coverage and point to plant distance of woody chaparral species. A series of random points were used, and each area was divided up into four equal quadrants using two meter sticks. The individual nearest to the center in each quadrant was then identified and measured. To measure herbaceous coverage, percentages were took of cover of each …

Physiological Performance In Full-Sun Vs. Shaded Post-Fire Malosma Laurina Seedlings, Lindsey A. Murphy, David C. Valencia, Catherine D. Drummond

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Post-fire Malosma laurina regenerates both by resprouting and by disseminating seeds. The objective of this study is to assess seedling performance either in full-sunlight or in artificially shaded treatments. By identifying under which conditions Malosma laurina seedlings grow more effectively, one can predict where post-fire M. laurina seedling communities will thrive. The methodology employed throughout this experiment began by covering existing seedlings with shade cloth held by wooden stakes. These treatments were adjacent to full-sun environments; each of which contained at least two Malosma laurina seedlings. Six experimental sites were set up, and the seedlings in question were monitored for …

Foraging Preference By Wild Deer On Toyon (Heteromeles Arbutifolia) From Santa Catalina Island Versus Malibu, Amelia I. Clark, Brett Smith, Courtney Smith, Stephen D. Davis

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Our group collected samples of Heteromeles Arbutifolia from both Santa Catalina Island and Pepperdine University’s campus in Malibu, CA in order to compare the morphological differences and deer preference between them. In our experiment, we planted the H. Arbutifolia from both locations side by side on a hillside overlooked by the Thorton Administration Center building on Pepperdine’s campus. In the first trial the deer did not consume either of the samples; we believe this was due to the length of time from when the branches were collected from the island to when they were introduced to the deer on campus. …