Biology Commons^™

The Effect Of The Tapia Water Treatment Plant On The Growth Of Lemna Minor, Morgan Clark, Imani Goodman, William Ota, Alora Yarbrough

Featured Research

Human beings are changing not just global temperature but even the makeup of the water in our planet's rivers and streams. The Tapia Water Treatment Facility is located in the upper section of Malibu creek and treats around 9.5 million gallons per day of water which is then released into the Malibu watershed. This water is treated using chemicals not typically found in local streams and these chemicals may be harming the organisms that live downstream of the water treatment plant. Downstream from the Tapia water treatment plant we were able to find increased levels of both nitrates and phosphates …

The Effects Of Human Involvement: A Study Of Transplanted Nassella Pulchra In A Competitive Environment, Miranda Prints, Summer Ngo, Taylor Purdy

Featured Research

When construction began on the Drescher Graduate Campus, the need to preserve a rare native California grass saw the creation of a transplant garden. A perennial bunchgrass, Nassella pulchra (purple needlegrass), was replanted. Based on a hypothesis that Avena fatua (wild oats), a competitor, would have a greater health than the native grass Nassella pulchra, we measured stomatal conductance, fluorescence, evident fitness, and water potential. In our second hypothesis, we proposed that the naturally occurring Nassella pulchra would have a higher stomatal conductance, a higher fluorescence, a higher water potential, and overall higher fitness than the transplanted …

Extensive Dieback In Malosma Laurina In Coastal Exposures Of The Santa Monica Mountains Associated With Unprecedented Drought In California, Gina S. Gilderman, Kaitlyn E. Sauer, Gabriella N. Palmeri

Featured Research

Throughout coastal exposures of the Santa Monica Mountains (SMM) there is a recent emergence of widespread dieback in Laurel Sumac (Malosma laurina). M. laurina is a keystone species of chaparral that dominates the SMM. A significant trait of M. laurina is an extensive root system exceeding 12 m in depth. We hypothesized that M. laurina was weakened by unprecedented drought in California (2013-2015) and predisposed to fungal pathogens. An initial study conducted in the summer of 2015 revealed all stem samples taken from dieback adult M. laurina plants were infected with Botryosphaeria dothidea, while zero stem samples taken …

Botryosphaeria Dothidea Impacts Relative Water Abundance In Malosma Laurina, Andrew Lozano, Michael Gribble, Jared Delapaz

Featured Research

Over the past decade, the California drought has been affecting native chaparral in the Santa Monica Mountains. Some parasitic fungi species such as Botryosphaeria dothidea have taken advantage of the drought by invading open wounds, or cankers, in a plant. When extreme environmental stress such as drought occurs, the immune system of the plant is compromised; the fungus can then multiply within the plant, blocking the vascular tissue. In this study, we aim to determine if there is a relationship between the presence of B. dothidea and an increase in the flammability of the native chaparral species Malosma laurina. …

Extensive Dieback In Malosma Laurina In Coastal Exposures Of The Santa Monica Mountains Associated With Unprecedented Drought In California, Gina S. Gilderman, Kaitlyn E. Sauer, Gabriella N. Palmeri

Featured Research

Throughout coastal exposures of the Santa Monica Mountains (SMM) there is a recent emergence of widespread dieback in Laurel Sumac (Malosma laurina). M. laurina is a keystone species of chaparral that dominates the SMM. A significant trait of M. laurina is an extensive root system exceeding 12 m in depth. We hypothesized that M. laurina was weakened by unprecedented drought in California (2013-2015) and predisposed to fungal pathogens. An initial study conducted in the summer of 2015 revealed all stem samples taken from dieback adult M. laurina plants were infected with Botryosphaeria dothidea, while zero stem samples taken …

Nodes Alter Stem Mechanical Strength In Heteromeles Arbutifolia, Gabriella E. Chan, Caleigh A. Howard, Callie E. Shelley

Featured Research

Our thesis was that the presence of nodes in stems of Heteromeles arbutifolia plants would increase the mechanical strength of the xylem and the bark, allowing the stems to be better protected against harsh weather conditions during the severe California drought. We conducted research on two sample groups, one with nodes and one without nodes. An Instron machine tested the mechanical strength by bending the stems until the xylem broke. Values for MOR (modulus of rupture) and MOE (modulus of elasticity) were measured to determine the overall strength of both groups. We found that the xylem of the stems was …

Root Hydraulic Conductance In Malosma Laurina Experiencing Severe Dieback In The Santa Monica Mountains, Natalie M. Aguirre 5861995, Avery Davis, Sarah Nelson

Seaver College Research And Scholarly Achievement Symposium

Malosma laurina is a dominant species in coastal chaparral ecosystems The deep root systems of M. laurina provide structural support for the steep Santa Monica Mountains and allow M. laurina to tap into the deep water table. M. laurina dieback is prevalent in coastal exposures of the SMM, presumably due to historic drought predisposing plant tissues to infection by the fungal pathogen Botryosphaeria dothidea. In ecosystems that experience annual dry periods, a high hydraulic conductance in roots is necessary to provide plants with sufficient water. A recent study has examined the effect of Botryosphaeria on the hydraulic conductance of M. …

Jewels Of The Orchidaceae, W. John Hayden

Biology Faculty Publications

To temperate-zone plant enthusiasts, the orchid family seems more than a little strange. On the one hand, native orchids grow wild without assistance from people, they are rooted in the soil, and they survive freezing cold winter temperatures. On the other hand, the tropical orchids that we encounter are ornamental plants, pampered by their human caregivers, cultured indoors in pots filled with fir bark or other media designed to mimic the plants’ natural epiphytic habit, and, as a group, these ornamental tropical orchids have essentially zero tolerance to frost. Of course, their flowers, fruits, and seeds define them all as …

Recovery Of Forest Floor Diversity After Removal Of The Nonnative, Invasive Plant Euonymus Fortunei, Kali Z. Mattingly, Ryan W. Mcewan, Robert D. Paratley, Sarah R. Bray, James R. Lempke, Mary A. Arthur

Biology Faculty Publications

The vine Euonymus fortunei (Turcz.) Hand.-Mazz. is invading forests of the eastern United States; as a result, removal of E. fortunei has become a priority of resource managers. This study examined the effectiveness of five techniques for eliminating E. fortunei, restoring plant species richness, and enhancing recolonization by woody species. In 2003, the following five treatments were applied: burn with a propane torch, light exclusion by plastic tarp, burn and glyphosate application, cut (simulated grazing) and glyphosate application, mow and glyphosate application, plus an untreated control. Each treatment was replicated four times in a randomized block design located in …

A Colletotrichum Graminicola Mutant Deficient In The Establishment Of Biotrophy Reveals Early Transcriptional Events In The Maize Anthracnose Disease Interaction, Maria F. Torres, Noushin Ghaffari, Ester A. S. Buiate, Neil Moore, Scott Schwartz, Charles D. Johnson, Lisa J. Vaillancourt

Plant Pathology Faculty Publications

Background: Colletotrichum graminicola is a hemibiotrophic fungal pathogen that causes maize anthracnose disease. It progresses through three recognizable phases of pathogenic development in planta: melanized appressoria on the host surface prior to penetration; biotrophy, characterized by intracellular colonization of living host cells; and necrotrophy, characterized by host cell death and symptom development. A “Mixed Effects” Generalized Linear Model (GLM) was developed and applied to an existing Illumina transcriptome dataset, substantially increasing the statistical power of the analysis of C. graminicola gene expression during infection and colonization. Additionally, the in planta transcriptome of the wild-type was compared with that of …

Drought Responsive Gene Expression Regulatory Divergence Between Upland And Lowland Ecotypes Of A Perennial C4 Grass, John T. Lovell, Scott Schwartz, David B. Lowry, Eugene V. Shakirov, Jason E. Bonnette, Xiaoyu Weng, Mei Wang, Jenifer Johnson, Avinash Sreedasyam, Christopher Plott, Jerry Jenkins, Jeremy Schmutz, Thomas E. Juenger

Biological Sciences Faculty Research

Climatic adaptation is an example of a genotype-by-environment interaction (G×E) of fitness. Selection upon gene expression regulatory variation can contribute to adaptive phenotypic diversity; however, surprisingly few studies have examined how genome-wide patterns of gene expression G×E are manifested in response to environmental stress and other selective agents that cause climatic adaptation. Here, we characterize drought-responsive expression divergence between upland (drought-adapted) and lowland (mesic) ecotypes of the perennial C₄ grass, Panicum hallii, in natural field conditions. Overall, we find that cis-regulatory elements contributed to gene expression divergence across 47% of genes, 7.2% of which exhibit drought-responsive G×E. …

Transcriptome And Biochemical Analysis Of A Flower Color Polymorphism In Silene Littorea (Caryophyllaceae), Inés Casimiro-Soriguer, Eduardo Narbona, Mª L. Buide, José C. Del Valle, Justen B. Whittall

Biology

Flower color polymorphisms are widely used as model traits from genetics to ecology, yet determining the biochemical and molecular basis can be challenging. Anthocyanin-based flower color variations can be caused by at least 12 structural and three regulatory genes in the anthocyanin biosynthetic pathway (ABP). We use mRNA-Seq to simultaneously sequence and estimate expression of these candidate genes in nine samples of Silene littorea representing three color morphs (dark pink, light pink, and white) across three developmental stages in hopes of identifying the cause of flower color variation. We identified 29 putative paralogs for the 15 candidate genes in the …

Conditional Vulnerability Of Plant Diversity To Atmospheric Nitrogen Deposition Across The United States, Samuel M. Simkin, Edith B. Allen, William D. Bowman, Christopher M. Clark, Jayne Belnap, Matthew L. Brooks, Brian S. Cade, Scott L. Collins, Linda H. Geiser, Frank S. Gilliam, Sarah E. Jovan, Linda H. Pardo, Bethany K. Schulz, Carly J. Stevens, Katharine N. Suding, Heather L. Throop, Donald M. Waller

Biological Sciences Faculty Research

Atmospheric nitrogen (N) deposition has been shown to decrease plant species richness along regional deposition gradients in Europe and in experimental manipulations. However, the general response of species richness to N deposition across different vegetation types, soil conditions, and climates remains largely unknown even though responses may be contingent on these environmental factors. We assessed the effect of N deposition on herbaceous richness for 15,136 forest, woodland, shrubland, and grassland sites across the continental United States, to address how edaphic and climatic conditions altered vulnerability to this stressor. In our dataset, with N deposition ranging from 1 to 19 kg …

Traversing Swanton Road, 22nd Ed., James A. West

Academic, Government & Associated Organizational Research Resources

Situated at the northwest end of Santa Cruz County and occupying circa 30 square miles of sharply contrasted terrain, the Scott Creek Watershed concentrates within its geomorphological boundaries, at least 10-12% of California's flora, both native and introduced. Incorporated within this botanical overview but technically not part of the watershed sensu strictu, are the adjacent environs, ranging from the coastal strand up through the Western Terrace to the ocean draining ridge tops... with the Arroyo de las Trancas/Last Chance Ridge defining the western/northwestern boundary and the Molino Creek divide, the southern demarcation. Paradoxically, the use/abuse that the watershed has sustained …

Trait Responses Of Invasive Aquatic Macrophyte Congeners: Colonizing Diploid Outperforms Polyploid, Rebecca E. Drenovsky, Brenda J. Grewell, Meghan J. Skaer Thomason, C. J. Futrell, M. Iannucci

Biology

Understanding traits underlying colonization and niche breadth of invasive plants is key to developing sustainable management solutions to curtail invasions at the establishment phase, when efforts are often most effective. The aim of this study was to evaluate how two invasive congeners differing in ploidy respond to high and low resource availability following establishment from asexual fragments. Because polyploids are expected to have wider niche breadths than diploid ancestors, we predicted that a decaploid species would have superior ability to maximize resource uptake and use, and outperform a diploid congener when colonizing environments with contrasting light and nutrient availability. A …

Tyrosine Phosphorylation Based Homo-Dimerization Of Arabidopsis Rack1a Proteins Regulates Oxidative Stress Signaling Pathways In Yeast, Mercy Sabila, Nabanita Kundu, Deana Smalls, Hemayet Ullah

Department of Biology Faculty Publications

Scaffold proteins are known as important cellular regulators that can interact with multiple proteins to modulate diverse signal transduction pathways. RACK1 (Receptor for Activated C Kinase 1) is a WD-40 type scaffold protein, conserved in eukaryotes, from Chlamydymonas to plants and humans, plays regulatory roles in diverse signal transduction and stress response pathways. RACK1 in humans has been implicated in myriads of neuropathological diseases including Alzheimer and alcohol addictions. Model plant Arabidopsis thaliana genome maintains three different RACK1 genes termed RACK1A, RACK1B, and RACK1C with a very high (85-93%) sequence identity between them. Loss of function mutant in Arabidopsis indicates …

Is Protection Against Florivory Consistent With The Optimal Defense Hypothesis?, Adrienne L. Godschalx, Lauren Stady, Benjamin Watzig, Daniel J. Ballhorn

Biology Faculty Publications and Presentations

Background: Plant defense traits require resources and energy that plants may otherwise use for growth and reproduction. In order to most efficiently protect plant tissues from herbivory, one widely accepted assumption of the optimal defense hypothesis states that plants protect tissues most relevant to fitness. Reproductive organs directly determining plant fitness, including flowers and immature fruit, as well as young, productive leaf tissue thus should be particularly well-defended. To test this hypothesis, we quantified the cyanogenic potential (HCNp)—a direct, chemical defense—systemically expressed in vegetative and reproductive organs in lima bean (Phaseolus lunatus), and we tested susceptibility of these …

Membrane Glycerolipidome Of Soybean Root Hairs And Its Response To Nitrogen And Phosphate Availability, Fang Wei, Brian Fanella, Liang Guo, Xuemin Wang

Biology Department Faculty Works

Root hairs are tubular extensions of specific root epidermal cells important in plant nutrition and water absorption. To determine membrane glycerolipids in root hairs and roots may differ, as well as their respective response to nutrient availability, this study analyzed the membrane glycerolipid species in soybean root hairs and in roots stripped of root hairs, and their response to nitrogen (N) and phosphate (Pi) supplementation. The ratio of phospholipids to galactolipids was 1.5 fold higher in root hairs than in stripped roots. Under Pi deficiency, the ratio of phospholipids to galactolipids in stripped roots decreased with the greatest decrease found …

Sex-Specific Fungal Communities Of The Dioicous Moss Ceratodon Purpureus, Mehmet Ali Balkan

Dissertations and Theses

Mosses display a number of hallmark life history traits that influence their ecology at the population and community level. The long lived separation of sexes observed in the haploid gametophyte (dioicy) is one such feature of particular importance, as it is observed in the majority of bryophytes and creates intraspecific specialization of male and female individuals.

The prevalence of sexually dimorphic mosses raises the possibility of sex-specific interactions with fungi as observed in some vascular plants. Here I investigated how moss sex shapes fungal communities associated with gametophytic tissues of the ubiquitous moss, Ceratodon purpureus. Using greenhouse populations of …

Microbial Biofilm Community Variation In Flowing Habitats: Potential Utility As Bioindicators Of Postmortem Submersion Intervals, Jennifer M. Lang, Racheal Erb, Jennifer L. Pechal, John R. Wallace, Ryan W. Mcewan, Mark Eric Benbow

Biology Faculty Publications

Biofilms are a ubiquitous formation of microbial communities found on surfaces in aqueous environments. These structures have been investigated as biomonitoring indicators for stream heath, and here were used for the potential use in forensic sciences. Biofilm successional development has been proposed as a method to determine the postmortem submersion interval (PMSI) of remains because there are no standard methods for estimating the PMSI and biofilms are ubiquitous in aquatic habitats. We sought to compare the development of epinecrotic (biofilms on Sus scrofa domesticus carcasses) and epilithic (biofilms on unglazed ceramic tiles) communities in two small streams using bacterial automated …

Waracs: Wrappers To Automate The Reconstruction Of Ancestral Character States, Michael Gruenstaeudl

Biological Sciences Faculty Publications

Premise of the study: Reconstructions of ancestral character states are among the most widely used analyses for evaluating the morphological, cytological, or ecological evolution of an organismic lineage. The software application Mesquite remains the most popular application for such reconstructions among plant scientists, even though its support for automating complex analyses is limited. A software tool is needed that automates the reconstruction and visualization of ancestral character states with Mesquite and similar applications. Methods and Results: A set of command line–based Python scripts was developed that (a) communicates standardized input to and output from the software applications Mesquite, BayesTraits, and …

A Comparative Study Of The Flora And Soils Of Great Duck And Little Duck Islands, Maine, Usa, Luka Negoita, Matthew Dickinson, Glen Mittelhauser, Nishanta Rajakaruna

Faculty Publications, Biological Sciences

Strong environmental gradients and varied land-use practices have generated a mosaic of habitats harboring distinct plant communities on islands on the coast of Maine. Botanical studies of Maine's islands, however, are generally limited in number and scope. Baseline studies of Maine's islands are necessary for assessing vegetation dynamics and changes in habitat conditions in relation to environmental impacts imposed by climate change, rising sea levels, invasive species, pests and pathogens, introduced herbivores, and human disturbance. We conducted a survey of the vascular plants and soils of forest, field, and ocean-side communities of Great Duck and Little Duck Islands, ME. These …

Invasive Species In An Urban Flora: History And Current Status In Indianapolis, Indiana, Rebecca W. Dolan

Scholarship and Professional Work - LAS

Invasive plant species are widely appreciated to cause significant ecologic and economic damage in agricultural fields and in natural areas. The presence and impact of invasives in cities is less well documented. This paper characterizes invasive plants in Indianapolis, Indiana. Based on historical records and contemporary accounts, 69 of the 120 species on the official Indiana state list are reported for the city. Most of these plants are native to Asia or Eurasia, with escape from cultivation as the most common mode of introduction. Most have been in the flora of Indianapolis for some time. Eighty percent of Indianapolis’ invasive …

The Role Of Ethylene In Systemic Acquired Resistance In Moss, Keiffer Williams

Undergraduate Honors Thesis Collection

The moss species Physcomitrella patens and Amblystegium serpens were used to categorize the effects of the phytohormone ethylene in the plant-pathogen response mechanism systemic acquired resistance (SAR) in non-vascular plants. The results outlined in this thesis found that individual exposure to the ethylene precursor molecules ACC and ethephon both up-regulated ethylene responsive genes in P. patens, demonstrating a positive response to ethylene exposure in the moss. Exposure to ACC and ethephon in A. serpens followed by inoculation with the fungal pathogen Pythium irregulare demonstrated an ambiguous resistance response induced by ethylene exposure in the moss. The growth rate of P. …

The Endophytes Of Pediomelum Esculentum: A Unique Case In Legume Evolution, Tyrel Ryan Deutscher

Electronic Theses and Dissertations

Pediomelum esculentum (commonly prairie turnip) is a perennial legume of the Great Plains, consisting of a deep taproot and large edible tuber, and has served as a nutritious staple in Native American diets. The tuber is capable of storing up to 20 percent protein by weight. P. esculentum is a legume, but not a prominent nodule former; instead, it grows in nitrogen-limited soils and produces large amounts of protein. This suggests the involvement of biological nitrogen fixation. We have investigated the presence of diazotrophic endophytes in P. esculentum. Bacteria were isolated from wild plants on nitrogen free media, identified …

Comparison Of Pea Seed Germination Due To Manipulation Of Soil Conditions, Ariel M. Kershner

Faculty Curated Undergraduate Works

This experiment was done with the intent to understand optimal soil conditions for pea seed germination. We investigated this using three soil conditions – 100% potting soil, 50% potting soil/50% sand, and 100% sand. Seemingly healthy pea seeds were planted and observed over five weeks. We measured both the total number of sprouts per week and the combined weight of the plants and seeds per condition before planting and after uprooting. We expected to find that the 100% potting soil condition would germinate the best, resulting in the most sprouts and heaviest weight of the condition’s seeds and plants. This …

Role Of Silencing Rna Fgsir34 In Fusarium Graminearum's Pathogenicity To Wheat, Subha Dahal

Electronic Theses and Dissertations

Fusarium graminearum is an ascomycetous fungal pathogen that causes Fusarium head blight (FHB) disease in wheat and other cereal grains. Mycotoxin produced by the fungus, predominantly deoxynivalenol (DON), is considered as an important virulence factor for the spread of disease. Our previous study of a Dicer-like 2 knockdown mutant has led to our hypothesis that a silencing RNA, fgsiR34, might play a key role in regulating DON biosynthesis and some other virulent factors. To test this hypothesis, we generated an fgsiR34 over-expressing mutant (ΔfgsiR34+) using Inverse Repeat Transgene method and studied the pathogenicity of the mutant in …

Effect Of Endophytes In Physcomitrella Patens On Cellular Respiration During Abiotic Stress, Michael Danh

Undergraduate Honors Thesis Collection

Endophytes are bacteria or fungi that ubiquitously reside in plant tissue and do not cause apparent disease. With the mutually symbiotic relationships between plant and endophyte being scientifically evident, it is supported that endophytes provide an augmentative method to absorb nutrients and additional tolerance under abiotic stress for the plant while benefiting from the host plant’s reduced carbon sources. The moss Physcomitrella patens is expected to share the same type of mutualism with endophytes, being able to treat endophytes as endosymbionts and having a reduced carbon reservoir. However, it is unclear if these endophytic relationships alter under abiotic stress. In …

The Role Of Calcium In Pathogen Defense Responses In The Moss Mnium Cuspidatum, Morgan Blake

Undergraduate Honors Thesis Collection

When exposed to stress, whether that be by pathogen, thermal or weather changes, or other components of the environment, plants employ a variety of defense mechanisms depending on the severity of the stress. When attacked by a pathogen, the moss Mnium cuspidatum utilizes an innate, basal response followed by hypersensitive response (HR) and systemic acquired resistance (SAR). Calcium is known to be involved in signaling cascades that mediate defense responses in other organisms. In the present study, lanthanum nitrate (LaNO3), methoxyerapamil (D600), and ethylene glycol tetraacetic acid (EGTA) were used to inhibit the presence of calcium in M. cuspidatum in …

Spanish River Carbonatite: Its Benefits And Potential Use As A Soil Supplement In Agriculture, James J

Theses and Dissertations (Comprehensive)

A critical problem facing agriculture today is being able to consistently and sustainably provide plants with adequate nutrients for growth. With this problem being exacerbated by the ever-increasing human population, new perspectives and techniques are required to ensure global food security. In order to fully realize potential solutions, however, plant growth and nutrition cannot be exclusively focused upon. The soil-microorganism-plant system is comprised of many interconnected and interdependent processes that together support plant growth: it is upon these processes that the focus must be placed. In this work, the agromineral Spanish River Carbonatite (SRC) is characterized using the framework of …