Plant Sciences Commons^™

How Soil Salinity Affects The Stomatal Conductance Of Baccharis Salicifolia (Mulefat/Seepwillow), Andrew Kim, Caroline Wilkerson, Mahala Bayless, Peter Du

Featured Research

This is a poster presentation demonstrating the project our group has been working on. We hypothesize that the stomatal conductance of mulefat will decrease as soil salinity increases in both pre-rain and post-rain conditions because the plant tries to absorb salt water. However, the salt water cannot pass through plant tissue and draws water out of the plant. Since plant requires water for photosynthesis, water being drawn out means less water is available for the plant to do photosynthesis. We have tested our hypothesis by collecting soil samples in Legacy park, and recorded stomatal conductance by using a leaf porometer

How Soil Salinity Affects The Stomatal Conductance Of Baccharis Salicifolia (Mulefat/Seepwillow), Andrew Kim, Caroline Wilkerson, Mahala Bayless, Peter Du

Featured Research

This is a poster presentation demonstrating the project our group has been working on. We hypothesize that the stomatal conductance of mulefat will decrease as soil salinity increases in both pre-rain and post-rain conditions because the plant tries to absorb salt water. However, the salt water cannot pass through plant tissue and draws water out of the plant. Since plant requires water for photosynthesis, water being drawn out means less water is available for the plant to do photosynthesis. We have tested our hypothesis by collecting soil samples in Legacy park, and recorded stomatal conductance by using a leaf porometer

A Comparison Of Different Methods Of Dehydration On Baccharis Salicifolia, Michael Nicholas, Sinjun Hong

Featured Research

Baccharis salicifolia is a native riparian plant living in many places near to the Santa Monica Mountains. One of these locations is Legacy park, which has had many events effect it that has led to some very unfortunate changes. The park’s soil was tested earlier this year by a group of undergraduate students lead by Dr. Stephen Davis and was found to have a very high salinity level. The plants in the park appeared to be struggling to survive and had signs of dehydration and wilting. This led to us questioning the types of dehydration of the plants. Areas of …

A Comparison Of Photosynthetic Rate, Stomatal Conductance, And 
Electron Transport Rate Between Malosma Laurina And Encelia Californica, Yujin Choi, Isabella Armstrong, Catherina Haas, Micah Kim

Featured Research

In the Santa Monica Mountains, there are two main vegetation types: chaparral, which makes up __% of plants in these mountains, and coastal sagebrush, which makes up __%. Despite California’s acute environmental stress, both of these plants manage to survive, and even thrive in some cases. We were interested in seeing if in spite of these vast anatomical and physiological differences, these plants were able to survive at similar health rates, measured in photosynthetic rate, stomatal conductance, and electron transport rate (ETR). We have decided to choose 2 plants from 2 different leaf types of different vegetation types: Malosma laurina …

Comparison Of Photosynthesis, Stomatal Conductance, And Water Potential Between Native Rhus Integrifolia And Invasive Nicotiana Glauca, Tiffany J. Egbo, Emma J. Navarro, Malaun A. Phillips, Cameron I. Zohary

Featured Research

Invasive species, such as Nicotiana glauca, are a prominent part of the Santa Monica Mountains, and could be responsible for displacing native species such as Rhus integrifolia. It was observed in the field that Nicotiana glauca was doing better than Rhus integrifolia, so our group decided to indirectly test this. Because of the invasiveness of its species, it is essential to measure the health of a native species to see if the invasive species is posing as a massive threat. Water potential, stomatal conductance, fluorescence, photosynthetic rates and electron transport rates were compared among the two plants …

A Student’S Perspective On Engagement In Ecological Research During Their First Semester In College, Natalie M. Aguirre, Karagan L. Smith, Cristian M. Garcia, Cheryl Swift, Stephen D. Davis

Biology

Pepperdine University and Whittier College jointly initiated a new first-year seminar series in the fall of 2016 that engaged students in authentic research, their first semester on campus. The goals are listed below. Assessment of these goals included both qualitative focus groups and quantitative survey questionnaires administered by an outside assessment agency, WestEd.org.

Ninety-two percent of students reported that their first-year seminar improved learning in concurrent courses and ninety to ninety-three percent of students said their first-year seminar increased their interest in STEM. In addition, students self-reported a significant improvement in all aspects of their ability to plan and conduct …

Post Drought Recovery In Malosma Laurina After Severe Dieback During California’S Historic Drought Of 2012-2016, Karagan L. Smith, Guinevere X. Mesh, Natalie M. Aguirre, Gabriella N. Palmeri, Helen I. Holmlund, Stephen D. Davis

Biology

Malosma laurina is a species of chaparral shrub that dominates coastal exposures of the Santa Monica Mountains of southern California. Between 2012 and 2016, protracted drought with half normal rainfall over a five-year period (175 mm), led to severe dieback, exceeding 50% whole plant mortality at some sites. The drought dissipated in 2017 with an annual rainfall that exceeded the 140-yr normal by 108 mm. As a result of this elevated annual rainfall in 2017, we were interested in documenting the potential for full recovery of Malosma laurina as a keystone species of coastal chaparral shrub communities. We tested the …

Bioaccumulation Of Zinc In Bermuda Grass (Cynodon Dactylon), Drew Fisher, H. Marie Surratt, Louise Gebauer, Andrew Palaski

Featured Research

Phytoremediation is the plant based process to remove toxins such as heavy metals from the soil. In this experiment, we hypothesized Bermuda grass (Cyndon dactylon) will absorb a detectable level of zinc, a nontoxic metal, from the soil. We grew two separate groups of grass: the control and the experimental, which was watered with zinc acetate. Neither of the groups produced enough yield within the weeks given to the experiment, but if it went according to plan, we would have used flame atomic absorption spectroscopy to evaluate the relative concentrations of zinc. Significant uptake of zinc could reveal a possible …

A Comparison Of Electron Transport Rate, Photosynthetically Active Radiation, Light-Adapted Fluorescence, And Dark-Adapted Fluorescence Between Stipa Pulchra And Pennisetium Setaceum, Sydney Adams, Brandon Chuck, Agatha Heng, Amelia Vento, Stephen D. Davis

Featured Research

The purpose of this investigation was to provide an explanation into how the invasive species Pennisetium setaceum, Fountain Grass, is able to outcompete the native California grassland species Stipa pulchra, Purple Needle Grass. We used a light adapted and a dark adapted fluorometer to measure the photosynthetic radiation (PAR), leaf temperature, alpha (α), light adapted fluorescence (Fv’/Fm’), dark adapted fluorescence (Fv/Fm), and the electron transport rate (ETR) on young Fountain Grass and Purple Needlegrass. After collecting and analyzing the data, we concluded that the dark adapted fluorescence (Fv/Fm) was the only statistically significant measurement where the Fv/Fm of S. pulchra …

A Comparison Of Electron Transport Rate, Photosynthetically Active Radiation, Light-Adapted Fluorescence, And Dark-Adapted Fluorescence Between Stipa Pulchra And Pennisetium Setaceum, Sydney Adams, Brandon Chuck, Agatha Heng, Amelia Vento, Stephen D. Davis

Featured Research

The purpose of this investigation was to provide an explanation into how the invasive species Pennisetium setaceum, Fountain Grass, is able to outcompete the native California grassland species Stipa pulchra, Purple Needle Grass. We used a light adapted and a dark adapted fluorometer to measure the photosynthetic radiation (PAR), leaf temperature, alpha (α), light adapted fluorescence (Fv’/Fm’), dark adapted fluorescence (Fv/Fm), and the electron transport rate (ETR) on young Fountain Grass and Purple Needlegrass. After collecting and analyzing the data, we concluded that the dark adapted fluorescence (Fv/Fm) was the only statistically significant measurement where the Fv/Fm of S. pulchra …

A Comparison Of Fluorescence And Etr Between Malosma Laurina And Rhus Integrifolia, Talia Danze, Jennifer Ipe, Viridiana Hernandez-Lopez, Stephen D. Davis, Talia Cao

Featured Research

Malosma laurina and Rhus integrifolia are both native species to the Santa Monica Mountains and belong to the same family, Anacardiaceae. The two natives have lived alongside each other but in recent years M. laurina has been heavily affected by the prolonged drought. The Malosma laurina population in the Santa Monica Mountains has withstood wildfires and droughts, and has remained relatively stable and healthy up until recently. A recent Pepperdine graduate published her findings explaining the high levels of dieback in Malosma laurina and attributed it to the fungus, B. dothidea. We hypothesized that Rhus integrifolia would have higher fluorescence …

A Comparison Of Electron Transport Rate, Photosynthetically Active Radiation, Light-Adapted Fluorescence, And Dark-Adapted Fluorescence Between Stipa Pulchra And Pennisetium Setaceum, Sydney Adams, Brandon Chuck, Agatha Heng, Amelia Vento, Stephen D. Davis

Featured Research

The purpose of this investigation was to provide an explanation into how the invasive species Pennisetium setaceum, Fountain Grass, is able to outcompete the native California grassland species Stipa pulchra, Purple Needle Grass. We used a light adapted and a dark adapted fluorometer to measure the photosynthetic radiation (PAR), leaf temperature, alpha (α), light adapted fluorescence (Fv’/Fm’), dark adapted fluorescence (Fv/Fm), and the electron transport rate (ETR) on young Fountain Grass and Purple Needlegrass. After collecting and analyzing the data, we concluded that the dark adapted fluorescence (Fv/Fm) was the only statistically significant measurement where the Fv/Fm of …

A Comparison Of Electron Transport Rate, Photosynthetically Active Radiation, Light-Adapted Fluorescence, And Dark-Adapted Fluorescence Between Stipa Pulchra And Pennisetium Setaceum, Sydney Adams, Brandon Chuck, Agatha Heng, Amelia Vento, Stephen D. Davis

Featured Research

The purpose of this investigation was to provide an explanation into how the invasive species Pennisetium setaceum, Fountain Grass, is able to outcompete the native California grassland species Stipa pulchra, Purple Needle Grass. We used a light adapted and a dark adapted fluorometer to measure the photosynthetic radiation (PAR), leaf temperature, alpha (α), light adapted fluorescence (Fv’/Fm’), dark adapted fluorescence (Fv/Fm), and the electron transport rate (ETR) on young Fountain Grass and Purple Needlegrass. After collecting and analyzing the data, we concluded that the dark adapted fluorescence (Fv/Fm) was the only statistically significant measurement where the Fv/Fm of S. pulchra …

The Effects Of Soil Suffused With Cool-Fire Ash On The Germination And Early Growth Of Radish Seedlings, Ryan Dalforno, Braden Ritchey, Jay Ogle

Featured Research

In this study, the effects of cool fire ash in soil with varying amounts of water were observed in terms of the germination and early growth of garden radish (Raphanus raphanistrum subsp. sativus) seedlings. Measurements regarding plant growth, field capacity, and seedling leaf quantum yield were taken and compared between four (4) trios of pots separately containing radish seedlings planted in ashy and frequently-watered soil (A_w), ashy and infrequently-watered soil (A_d), normal unmodified garden soil that was watered frequently (N_w) and normal soil that was watered infrequently (N_d). While the …

Testing For The Presence Of Botryosphaeria Dothidea In Branches Of Ceanothus Spinosus Undergoing Dieback, Brandon R. Grinovich, Chelsea N. Puncochar, Katarina L. Carter, Stephen D. Davis, Rodney L. Honeycutt, Talia A. Cao, Karagan L. Smith

Featured Research

Botryosphaeria dothidea is an opportunistic pathogen found in some of the cavitated branches of the vegetation in the Santa Monica Mountains. In this study, we focused on finding the presence of Botryosphaeria dothidea in Ceanothus spinosus located on Pepperdine University’s campus. We wanted to test this hypothesis because we observed a large amount of dieback in the Ceanothus spinosus population and wanted to identify a possible contributor. Because of the large number of cavitated branches the Ceanothus spinosus contained, we hypothesized they contained fungus. To test this, we took twenty samples of twenty different Ceanothus spinosus, isolated the fungus …