Biology Commons^™

Coevolution Of Cyanogenic Bamboos And Bamboo Lemurs On Madagascar, Daniel J. Ballhorn, Fanny Patrika Rakotoarivelo, Stefanie Kautz

Biology Faculty Publications and Presentations

Feeding strategies of specialist herbivores often originate from the coevolutionary arms race of plant defenses and counter-adaptations of herbivores. The interaction between bamboo lemurs and cyanogenic bamboos on Madagascar represents a unique system to study diffuse coevolutionary processes between mammalian herbivores and plant defenses. Bamboo lemurs have different degrees of dietary specialization while bamboos show different levels of chemical defense. In this study, we found variation in cyanogenic potential (HCNp) and nutritive characteristics among five sympatric bamboo species in the Ranomafana area, southeastern Madagascar. The HCNp ranged from 209±72 μmol cyanide* g^-1 dwt in Cathariostachys madagascariensis to no cyanide …

Functional Diversity Of Small And Large Trees Along Secondary Succession In A Tropical Dry Forest, Lucía Sanaphre-Villanueva, Juan Manuel Dupuy, José Luis Andrade, Casandra Reyes-García, Horacio Paz, Paula C. Jackson

Faculty Articles

Functional Diversity is considered an important driver of community assembly in environmental and successional gradients. To understand tree assembly processes in a semideciduous tropical forest, we analyzed the variation of Functional Richness (FRic), Functional Divergence (FDiv), and Functional Evenness (FEve) of small vs. large trees in relation to fallow age after slash-and-burn agriculture and topographical position (flat sites vs. hills). FRic of small trees was lower than null model predicted values across the successional gradient, and decreased unexpectedly in older successional ages. FRic of large trees was higher than null model predictions early in succession and lower in late-successional stands …

Thirty Years Of Compositional Change In An Old-Growth Temperate Forest: The Role Of Topographic Gradients In Oak-Maple Dynamics, Julia I. Chapman, Ryan W. Mcewan

Biology Faculty Publications

Ecological communities are structured in response to spatial and temporal variation of numerous factors, including edaphic conditions, biotic interactions, climatic patterns and disturbance regimes. Widespread anthropogenic factors such as timber harvesting can create long-lasting impacts, obscuring the relationship between community structure and environmental conditions. Minimally impacted systems such as old-growth forests can serve as a useful ecological baseline for predicting long-term compositional shifts. We utilized decadal tree species sampling data (1979–2010) divided into three strata (understory, midstory, overstory) to examine temporal changes in relative abundances and spatial distributions of dominant taxa, as well as overall shifts in community composition, in …

Effects Of Shoreline Dynamics On Saltmarsh Vegetation, Shailesh Sharma, Joshua Goff, Ryan M. Moody, Ashley Mcdonald, Dorothy Byron, Kenneth L. Heck Jr., Sean Powers, Carl Ferraro, Just Cebrian

University Faculty and Staff Publications

We evaluated the impact of shoreline dynamics on fringing vegetation density at mid- and low-marsh elevations at a high-energy site in the northern Gulf of Mexico. Particularly, we selected eight unprotected shoreline stretches (75 m each) at a historically eroding site and measured their inter-annual lateral movement rate using the DSAS method for three consecutive years. We observed high inter-annual variability of shoreline movement within the selected stretches. Specifically, shorelines retrograded (eroded) in year 1 and year 3, whereas, in year 2, shorelines advanced seaward. Despite shoreline advancement in year 2, an overall net erosion was recorded during the survey …

A Heavy Metal P-Type Atpase Oshma4 Prevents Copper Accumulation In Rice Grain, Xin-Yuan Huang, Fenglin Deng, Naoki Yamaji, Shannon R.M. Pinson, Miho Fujii-Kashino, John Danku, Alex Douglas, Mary Lou Guerinot, David Salt, Jian Feng Ma

Dartmouth Scholarship

Rice is a major source of calories and mineral nutrients for over half the world's human population. However, little is known in rice about the genetic basis of variation in accumulation of copper (Cu), an essential but potentially toxic nutrient. Here we identify OsHMA4 as the likely causal gene of a quantitative trait locus controlling Cu accumulation in rice grain. We provide evidence that OsHMA4 functions to sequester Cu into root vacuoles, limiting Cu accumulation in the grain. The difference in grain Cu accumulation is most likely attributed to a single amino acid substitution that leads to different OsHMA4 transport …

Lof1 And Interacting Transcription Factors In Plant Development And Crop Yield, Zoe Yeoh, Elizabeth Luscher, Patricia Springer

Student Publications

Transcription factors (TFs) help ensure proper gene expression in developing tissues, and thus play a role in plant development and plant architecture. LATERAL ORGAN FUSION1, or LOF1, is a TF expressed in the organ boundaries of Arabidopsis thaliana. lof1 mutants have fused axillary branches and cauline leaves, which indicates importance in boundary development. Because transcription factors are known to act in complexes, we wanted to discover what other proteins interact with LOF1. We executed a yeast-2-hybrid (Y2H) screen that identified several TFs as potential interactors: WHIRLY 3 (WHY3), MYB DOMAIN PROTEIN32 (MYB32), HOMEOBOX-LEUCINE ZIPPER PROTEIN4 (HB4), and LIGHT RESPONSE BTB2 …

Mapping Morels: Predicting The Locations Of Morchella Species Through Environmental Factors Using The Gis System, Emily M. Stanevicius

Celebration of Learning

Morel mushrooms, Morechella esculenta and M. deliciosa, are known delicacies across the globe, ranging from exquisite dishes in French cuisine to Eastern palates such as Japanese Matsutake. According to literature, true morels diverged as their own genus about 129 million years, again which has led to the development of more than 177 species and have been part of the human diet since their beginning. However, the elusiveness of morels has contributed to the mushrooms infamy for rarity, and has even been known to sell for more than $40 per pound. This project seeks to aid in the search for morels …

Effect Of Different Miracle-Gro Concentrations On The Growth Of Wisconsin Fast Plants, Eric D. Shershen, Nicholas M. Orslini, David Channon, Marvin Agyeben

Celebration of Learning

The Wisconsin Fast Plant, Brassica rapa (Brassicaceae) seeds were planted in three, six-celled containers and were filled with standard potting soil under continuous grow-lux lighting. After the first week of plant growth, E1and E2 were placed in a separate trays and given 1.0 and 1.5x the recommended amount of Miracle-Gro formula, respectively. The control was left in tap water and all were kept in 1 cm of solution. Every seven days the plants’ heights were recorded, and the total number of flowers were counted. By the fourth week, the average height of the control plants was 105.7 mm, of the …

Evaluating The Myth Of Allelopathy In California Blue Gum Plantations, Kristen Marie Nelson

Master's Theses

It is widely accepted that allelopathy is not only significant, but more or less singular, in the inhibition of understory vegetation in California Eucalyptus globulus (blue gum) plantations. However, there is no published documentation of allelopathy by blue gums against California native species. Here, we present evidence that germination and early seedling growth of five California native species are not inhibited by chemical extracts of blue gum foliage, either at naturally-occurring or artificially concentrated levels. In the greenhouse, seeds were germinated in field-collected soil from mature blue gum plantations and the adjacent native, coastal scrub communities. In petri plates, seeds …

Preserving Biodiversity For A Climate Change Future: A Resilience Assessment Of Three Bay Area Species--Adenostoma Fasciculatum (Chamise), Arctostaphylos Canescens (Hoary Manzanita), And Arctostaphylos Virgata (Marin Manzanita), Alison S. Pollack

Master's Projects and Capstones

Anthropogenic climate change is an undeniable threat to the future of the natural world and human civilization. These shifts will have profound impacts on vegetation, especially for species endemic to isolated regions or sensitive to climate change factors. However, species resilience can predict success into the next century. Resilience is defined as the ability to withstand climate change factors, whereas vulnerability is defined as susceptibility to climate induced stress or damage.

Chaparral and coastal scrub ecosystems within the Bay Area of California provide a unique context for examining resilience, as many species are adapted to high temperatures, drought, and wildfire—all …

Non-Specific Phospholipase C1 Affects Silicon Distribution And Mechanical Strength In Stem Nodes Of Rice, Huasheng Cao, Lin Zhuo, Yuan Su, Linxiao Sun, Xuemin Wang

Biology Department Faculty Works

Silicon, the second abundant element in the crust, is beneficial for plant growth, mechanical strength, and stress responses. Here we show that manipulation of the non‐specific phospholipase C1, NPC1, alters silicon content in nodes and husks of rice (Oryza sativa). Silicon content in NPC1‐overexpressing (OE) plants was decreased in nodes but increased in husks compared to wild‐type, whereas RNAi suppression of NPC1 resulted in the opposite changes to those of NPC1‐OE plants. NPC1 from rice hydrolyzed phospholipids and galactolipids to generate diacylglycerol that can be phosphorylated to phosphatidic acid. Phosphatidic acid interacts with Lsi6, a silicon transporter that is expressed …

Changes In Oxidative Patterns During Dormancy Break By Warm And Cold Stratification In Seeds Of An Edible Fruit Tree, Dilinuer Shalimu, Jia Sun, Carol C. Baskin, Jerry M. Baskin, Liwei Sun, Yujun Liu

Biology Faculty Publications

The transition from seed dormancy to germination is triggered by environmental factors, and in pomegranate (Punica granatum) seeds higher germination percentages are achieved by warm + cold stratification rather than by cold stratification alone. Our objective was to define the pattern of internal oxidative changes in pomegranate seeds as dormancy was being broken by warm + cold stratification and by cold stratification alone. Embryos isolated from seeds after 1–42 days of warm stratification, after 56 days of warm stratification + 7, 28 or 56 days of cold stratification, and after 1–84 days of cold stratification alone, were used …

Photosynthetic Characterization Of Invasive Plant Diversity In Los Angeles County From 1830-2010, Lauren E. Pangburn, Erich Eberts, Victor Carmona-Galindo

Honors Thesis

The increase in atmospheric CO₂ levels due to climate change may greatly impact invasive plant species, which are non-native organisms that spread unchecked in space and negatively impact native organisms. The success of these invasives may be related to specific traits, such as their photosynthetic pathway. We acquired the specimen information for invasive species registered in the Consortium for California Herbaria of the University of California Berkeley to evaluate the community dynamics of 1,000 invasive species in Los Angeles County. We found that both diversity and richness of invasive plant species has increased over a period of 180 years. …

Using Koch’S Postulate To Identify The Causative Agent Of Dieback In Malosma Laurina During Historic Drought In California, Adriana J. Borges, Emily R. Pierce, Mariah K. Taylor, Frida J. Morales

Featured Research

Coastal Southern California has a Mediterranean-type climate, meaning that it experiences warm, dry summers and cool, wet winters. Recently, California has been experiencing an unprecedented drought, possibly as a result of climate change. Malosma laurina is a typically hearty chaparral plant is known for being resistant to drought due to its deep rooting depth, but even it is being negatively affected by drought and is experiencing dieback. Some of this dieback is caused by a Botryospharae fungal infection, which blocks xylem conduits and stops water flow through the plant. With a looming El Niño, this study seeks to understand the …

The Role Of Cellulose Synthase-Like D Genes In Tip Growth Of Physcomitrella Patens, Erin E. Killeavy, Arielle Chaves, Alison Roberts

Senior Honors Projects

Physcomitrella patens is a non-vascular plant with a relatively small genome and is amongst the few eukaryotic organisms that have a high rate of homologous recombination. This is valuable in biological research because it allows for targeted genetic modification of the organism. In vascular plants like Arabidopsis thaliana, a model organism, Cellulose Synthase-like D (CSLD) genes have been discovered to be important in tip growth. This type of growth is observed in the pollen tubes and root hairs of these plant types. The CSLD genes in Arabidopsis were found to play a crucial role in the growth of …

Identification Of N-Acylethanolamine Hydrolyzing Enzyme In Solanum Lycopersicum, Derek A. Stuffle

Undergraduate Honors Theses

N-acylethanolamines (NAEs) are fatty acid derivatives that occur naturally in plant and animal systems. In mammals, they regulate physiological functions, including neurotransmission, immune responses, vasodilation, embryo development and implantation, feeding behavior, and cell proliferation. NAEs are metabolized by fatty acid amide hydrolase (FAAH), which belongs to the amidase signature family. It is hypothesized that putative FAAH functions as the catalyst in the metabolism of N-acylethanolamine in tomato plants. To test the hypothesis, FAAH protein homologs were identified in tomato via in silico analysis. Among the six homologs identified, FAAH1 and FAAH2 were selected for further validation. This study …

Friend Or Foe—Light Availability Determines The Relationship Between Mycorrhizal Fungi, Rhizobia And Lima Bean (Phaseolus Lunatus L.), Daniel J. Ballhorn, Martin Schädler, Jacob D. Elias, Jess A. Millar, Stefanie Kautz

Biology Faculty Publications and Presentations

Plant associations with root microbes represent some of the most important symbioses on earth. While often critically promoting plant fitness, nitrogen-fixing rhizobia and arbuscular mycorrhizal fungi (AMF) also demand significant carbohydrate allocation in exchange for key nutrients. Though plants may often compensate for carbon loss, constraints may arise under light limitation when plants cannot extensively increase photosynthesis. Under such conditions, costs for maintaining symbioses may outweigh benefits, turning mutualist microbes into parasites, resulting in reduced plant growth and reproduction. In natural systems plants commonly grow with different symbionts simultaneously which again may interact with each other. This might add complexity …

A Bioinformatics Approach To Addressing The Responses Of Rice Aleurone Cells To Hormones Abscisic Acid And Gibberellic Acid, Kenneth Arthur Watanabe

UNLV Theses, Dissertations, Professional Papers, and Capstones

The hormone abscisic acid (ABA) is biosynthesized by higher plants in response to various abiotic stresses such as drought and antagonizes the growth and germination-promoting hormone gibberellic acid (GA). The seed is a model system for studying desiccation tolerance and germination. The thin layer of cells surrounding the seed, the aleurone layer, plays a direct role in seed germination and an indirect role in desiccation tolerance. The goal of my research is to address the molecular mechanism underlying the responses of rice aleurone cells to ABA and GA, by taking a genomics approach. An accurate and complete annotation of the …

Investigation Of Parasympathetic Effects Of Lavender Essential Oil In Humans, Haakon Robert Nelson, Rachel Ann Burkhart, Daniel Morin, Nicole Grace Weissenfluh, Michael R. Korn

Montview Journal of Research & Scholarship

The purpose of this study will be to investigate the claim that administration of lavender (Lavandula angustifolia) essential oil (topically, orally, and/or respiratorily) produces a relaxative effect in human subjects. This investigation will theoretically be conducted in two stages. Stage one will focus primarily on determining the presence of therapeutic effects and the relative effectiveness of lavender in several application modalities. Stage two will proceed based on findings from stage one. If significant parasympathetic effects are observed in relation to one or more of the lavender oil modalities described above, a more focused investigation will be conducted in stage two …

Origins And Relationships Of The Mixed Mesophytic Forest Of Oregon-Idaho, China, And Kentucky: Review And Synthesis, Jerry M. Baskin, Carol C. Baskin

Biology Faculty Publications

The Arcto-Tertiary Geoflora concept of Ralph Chaney, that the Mixed Mesophytic Forest of eastern Asia and eastern North America are relicts of a Northern Hemisphere high-latitude circumglobal deciduous forest of the Late Cretaceous–Early Tertiary that migrated south to the temperate zone as an intact unit, was shown by Wolfe and others to be invalid. To explain the origin and development of these disjunct forests, Wolfe and Tiffney developed the boreotropical hypothesis. Accordingly, a paratropical (near-tropical) rainforest flora containing a mixture of tropical, paratropical, and temperate genera developed at several places in the middle latitudes of the Northern Hemisphere in the …

Effects Of Germination Season On Life History Traits And On Transgenerational Plasticity In Seed Dormancy In A Cold Desert Annual, Juan J. Lu, Dun Y. Tan, Carol C. Baskin, Jerry M. Baskin

Biology Faculty Publications

The maternal environment can influence the intensity of seed dormancy and thus seasonal germination timing and post-germination life history traits. We tested the hypotheses that germination season influences phenotypic expression of post-germination life history traits in the cold desert annual Isatis violascens and that plants from autumn- and spring-germinating seeds produce different proportions of seeds with nondeep and intermediate physiological dormancy (PD). Seeds were sown in summer and flexibility in various life history traits determined for plants that germinated in autumn and in spring. A higher percentage of spring- than of autumn-germinating plants survived the seedling stage, and all surviving …

Using Koch’S Postulate To Identify The Causative Agent Of Dieback In Malosma Laurina During Historic Drought In California, Adriana J. Borges, Emily R. Pierce, Mariah K. Taylor, Frida J. Morales

Featured Research

Coastal Southern California has a Mediterranean-type climate, meaning that it experiences warm, dry summers and cool, wet winters. Recently, California has been experiencing an unprecedented drought, possibly as a result of climate change. Malosma laurina is a typically hearty chaparral plant is known for being resistant to drought due to its deep rooting depth, but even it is being negatively affected by drought and is experiencing dieback. Some of this dieback is caused by a Botryospharae fungal infection, which blocks xylem conduits and stops water flow through the plant. With a looming El Niño, this study seeks to understand the …

Influence Of Water Hardness On Accumulation And Effects Of Silver In The Green Alga, Raphidocelis Subcapitata, Aarya Venkat, Adriana L. Amerson, Gretchen K. Bielmyer-Fraser

Georgia Journal of Science

Metal pollution from anthropogenic sources can pose a threat to aquatic systems. Silver is released into the environment from various industrial processes. In excess, silver can accumulate and cause adverse effects in aquatic organisms, particularly those in lower trophic levels, such as phytoplankton. Water chemistry parameters, such as hardness, have been shown to modify toxicity of metals because divalent cations compete with the metal for binding sites on the biological membrane. The objective of this study was to assess population growth and silver accumulation in the green alga, Raphidocelis subcapitata, after silver exposure in waters of varying hardness for 7 …

Allelopathic Compounds In Adenostoma Fasciculatum Leaves May Inhibit Seed Germination Of Ceanothus Megacarpus, Olivia L. Le Sage, Shamiran C. Prater, Christian M. Botello

Featured Research

We investigated the effects the allelopathogen thought to be found in Adenostoma fasciculatum leaves on seed germination in Ceanothus megacarpus seeds. We hypothesized that seeds treated with an extract containing the allelopathogen would not germinate, compared to seeds not treated with the allelopathogen. We hypothesized this because Adenostoma fasciculatum is known to produce an allelopathogen which inhibits growth in nearby plants in a natural environment. We prepared a 70% ethanol extract with Adenostoma fasciculatum leaves and treated 30 scarified Ceanothus megacarpus seeds with it; 30 additional Ceanothus megacarpus seeds were only given 70% ethanol. We placed these seeds in a …

The Effect Of Temperature On Root Nodulation And Growth In Glycine Max, Brooke O’Neill, Katherine Kawachi

Featured Research

This investigation explores the effects of temperature on root nodulation and other plant growth factors in soy bean plants. Vegetative development such as node appearance rate increases as temperatures rise to the species’ optimum level, in which the maximum temperature for growth in C₃ plants is 25 °C. (Hatfield, 2015). We hypothesized that soy bean plants would produce more nodules in 25°C than 35°C, rationalizing the Q₁₀ theory which states that a 10 degree temperature change produces measureable effects in biological and chemical metabolic systems. This idea becomes worthy of experiment when looking at how increasing temperature affects …

Comparison Of Nighttime Stomatal Conductance In Malosma Laurnia And Encelia Californica, Stephanie R. Kaplan, Jessica T. Gash, Hannah H. Ziegler

Featured Research

The experiment aimed to look at the comparison between the nighttime stomatal conductance of Malosma laurina and Encelia californica. Through the use of leaf porometry and subsequent data analysis, it was determined that there was no statistical differnce between either species, due to the fact that the Malosma laurina was a resprouted species, that needed significantly less water than a fully mature M. laurina plant would have needed.

The Effect Of Water Deficit On Photosynthetic Properties Of Salvia Leucophylla, Brianna Scott, Theadora Ordog, Alexis Lordi

Featured Research

California has been in a severe drought in recent years due to anthropogenic warming, and it has had a major effect on chemical and physical properties of native plants. Salvia leucophylla, a common plant in Southern California, has evolved an adaptation to water stress through losing its leaves, known as a drought deciduous plant. Considering the increase of CO2 in the atmosphere, it is absolutely essential for leaves to retain their ability to photosynthesize to maintain the health of the environment through CO2 sequestration. The objective of this experiment was to see how drought levels affect the physical and …

Effects Of Drought On Antimicrobial Properties Of A Chaparral Indicator Species — Adenostoma Fasciculatum, Andrew Shute, Jennifer Duff, Salina Pearce-Harris

Featured Research

The dominant plant type of Pepperdine’s Malibu campus is chaparral, of which an important indicator species is Adenostoma fasciculatum. It is known that A. fasciculatum produces compounds that are deadly to many bacteria. However, California is currently experiencing unprecedented drought, which is pushing plants well beyond their normal stress levels. In this study, we investigated the effect of drought stress on the ability of A. fasciculatum to inhibit growth of bacteria. We hypothesized that extract from drought-stressed plants would be better able to kill bacteria than hydrated ones, because the plant would be induced to produce more antimicrobial compounds …

Root Hydraulic Conductance In Laurel Sumac Experiencing Severe Dieback In The Santa Monica Mountains, Natalie M. Aguirre, Avery N. Davis, Sarah B. Nelson, Stephen D. Davis

Featured Research

Malosma laurina (laurel sumac) is a dominant species in coastal chaparral ecosystems, extending its roots down to an average of 40 feet in rocky, sandy soils. The deep root systems of M. laurina provide structural support for the steep Santa Monica Mountains. The roots also allow M. laurina to draw from the deep water table, increasing its drought tolerance. M. laurina dieback is prevalent in coastal exposures of the Santa Monica Mountains 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 …

Comparing The Electron Transport Rate Of Nico%Ana Glauca And Encelia Californica At Normal And Increased Par, Carter Clinebell, Griffin Duvall, Daniel Suh

Featured Research

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 …