Plant Biology Commons^™

Current And Potential Distributions Of Three Non-Native Invasive Plants In The Contiguous Usa, Chad C. Jones, Sarah Reichard

Botany Faculty Publications

Biological invasions pose a serious threat to biodiversity, but monitoring for invasive species is time consuming and costly. Understanding where species have the potential to invade enables land managers to focus monitoring efforts. In this paper, we compared two simple types of models to predict the potential distributions of three non-native invasive plants (Geranium robertianum, Hedera spp., and Ilex aquifolium) in the contiguous USA. We developed models based on the climatic requirements of the species as reported in the literature (literature-based) and simple climate envelope models based on the climate where the species already occur (observation-based). We then compared the …

Advances In Serpentine Geoecology: A Retrospective, N Rajakaruna, R S. Boyd

Faculty Publications, Biological Sciences

No abstract provided.

Analysis Of The Accase Mutation Profile Of Italian Ryegrass (Lolium Perenne Ssp. Multiflorum) Accessions Resistant To Accase Inhibitors, Thomas Stark

Inquiry: The University of Arkansas Undergraduate Research Journal

Lolium perenne ssp. multiflorum (Italian ryegrass) resistant to ACCase inhibiting herbicides has been reported in many wheat producing counties across Arkansas. Resistance is believed to be the result of point mutations creating amino acid substitutions in the CT domain of the plastidic ACCase gene. This study explores the occurrence of mutations in the ACCase gene of ryegrass populations. Plant material was collected and DNA was extracted from 10 Arkansas ryegrass populations. Six of the populations were known to be resistant to the ACCase inhibitor diclofop-methyl, while the remaining four populations were known to be susceptible to diclofop-methyl. Two highly conserved …

Roadmap For Future Research On Plant Pathogen Effectors, James R. Alfano

Center for Plant Science Innovation: Faculty Publications

Bacterial and eukaryotic plant pathogens deliver effector proteins into plant cells to promote pathogenesis. Bacterial pathogens containing type III protein secretion systems are known to inject many of these effectors into plant cells. More recently, oomycete pathogens have been shown to possess a large family of effectors containing the RXLR motif, and many effectors are also being discovered in fungal pathogens. Although effector activities are largely unknown, at least a subset suppress plant immunity. A plethora of new plant pathogen genomes that will soon be available thanks to next-generation sequencing technologies will allow the identification of many more effectors. This …

Histone H3 Phosphorylation: Universal Code Or Lineage Specific Dialects?, Heriberto Cerutti, J. Armando Casas-Mollano

Center for Plant Science Innovation: Faculty Publications

Post-translational modifications of histones modulate the functional landscape of chromatin and impinge on many DNA-mediated processes. Phosphorylation of histone H3 plays a role in the regulation of gene expression and in chromosome condensation/segregation. Certain evolutionarily conserved residues on histone H3—namely Thr3, Ser10, Thr11, and Ser28—are phosphorylated during interphase or mitosis in both metazoa and plants. However, many of the kinases involved in these events appear to have evolved independently in different lineages. Likewise, the mechanistic function of specific phosphorylated amino acids, although poorly understood, also seems to differ among eukaryotes. Moreover, some modifications, such as phosphorylation of histone H3 Ser10, …

Protein-Protein Interactions Of Tandem Affinity Purified Protein Kinases From Rice, Jai S. Rohila, Mei Chen, Shuo Chen, Johann Chen, Ronald L. Cerny, Christopher Dardick, Patrick Canlas, Hiroaki Fujii, Michael Gribskov, Siddhartha Kanrar, Lucas Knoflicek, Becky Stevenson, Mingtang Xie, Xia Xu, Xianwu Zheng, Jing-Kang Zhu, Pamela Ronald, Michael E. Fromm

Center for Plant Science Innovation: Faculty Publications

Eighty-eight rice (Oryza sativa) cDNAs encoding rice leaf expressed protein kinases (PKs) were fused to a Tandem Affinity Purification tag (TAP-tag) and expressed in transgenic rice plants. The TAP-tagged PKs and interacting proteins were purified from the T1 progeny of the transgenic rice plants and identified by tandem mass spectrometry. Forty-five TAPtagged PKs were recovered in this study and thirteen of these were found to interact with other rice proteins with a high probability score. In vivo phosphorylated sites were found for three of the PKs. A comparison of the TAP-tagged data from a combined analysis of 129 …

Effectors, Effectors Et Encore Des Effectors: The Xiv International Congress On Molecular-Plant Microbe Interactions, Quebec, Jonathan D. Walton, Tyler J. Avis, James R. Alfano, Mark Gijzen, Pietro Spanu, Kim Hammond-Kosack, Federico Sánchez

Center for Plant Science Innovation: Faculty Publications

The IS-MPMI held its fourteenth meeting in Quebec City July 19-23, 2009. There were 956 attendees from 49 countries. Just over 50% of the participants were students or postdoctoral associates. Hani Antoun (Université Laval, Canada) served as Program Chair, capably assisted by the Local Organizing Committee and the IS-MPMI International Advisory Board. There were eight plenary sessions, 18 concurrent sessions, and over 700 posters.

Participation Of Leaky Ribosome Scanning In Protein Dual Targeting By Alternative Translation Initiation In Higher Plants, Yashitola Wamboldt, Saleem Mohammed, Christian Elowsky, Chris Wittgren, Wilson B. M. De Paula, Sally Ann Mackenzie

Center for Plant Science Innovation: Faculty Publications

Postendosymbiotic evolution has given rise to proteins that are multiply targeted within the cell. Various mechanisms have been identified to permit the expression of proteins encoding distinct N termini from a single gene. One mechanism involves alternative translation initiation (aTI). We previously showed evidence of aTI activity within the Arabidopsis thaliana organellar DNA polymerase gene POLg2. Translation initiates at four distinct sites within this gene, two non-AUG, to produce distinct plastid and mitochondrially targeted forms of the protein. To understand the regulation of aTI in higher plants, we used Polg2 as a model to investigate both cis- and trans …

Intergenic Transcription By Rna Polymerase Ii Coordinates Pol Iv And Pol V In Sirna-Directed Transcriptional Gene Silencing In Arabidopsis, Binglian Zheng, Zhengming Wang, Shengben Li, Bin Yu, Jin -Yuan Liu, Xuemei Chen

Center for Plant Science Innovation: Faculty Publications

Intergenic transcription by RNA Polymerase II (Pol II) is widespread in plant and animal genomes, but the functions of intergenic transcription or the resulting noncoding transcripts are poorly understood. Here, we show that Arabidopsis Pol II is indispensable for endogenous siRNA-mediated transcriptional gene silencing (TGS) at intergenic low-copy-number loci, despite the presence of two other polymerases—Pol IV and Pol V—that specialize in TGS through siRNAs. We show that Pol II produces noncoding scaffold transcripts that originate outside of heterochromatic, siRNA-generating loci. Through these transcripts and physical interactions with the siRNA effector protein ARGONAUTE4 (AGO4), Pol II recruits AGO4/siRNAs to homologous …

The Impacts Of Global Warming On Appalachian Wildflower Phenologies, Rachel D. Wigginton

Mahurin Honors College Capstone Experience/Thesis Projects

Public and private interest in global warming has prompted exploration of the impacts this phenomenon may impart on ecosystem functions. Flowering phenology has been one of the areas many scientists believe is particularly susceptible to the impacts of anthropogenic warming. Over three weekends in spring of 2008, the vernal herb community was surveyed at five sites within the Great Smoky Mountains regions of the southern Appalachian Mountains. The intent was to capture the naturally occurring elevational gradient and determine if the temperature cue for blooming was the same for all co-flowering species in the study. This information would allow for …

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

Featured Research

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 …

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

Featured Research

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

Featured Research

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 …

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

Featured Research

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 …

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

Featured Research

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. …

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

Featured Research

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 …

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

Featured Research

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 …

Effects Of Increased Pco2 And Temperature On The North Atlantic Spring Bloom. Iii. Dimethylsulfoniopropionate, Peter A. Lee, Jamie R. Rudisill, Aimee R. Neeley, Jennifer M. Maucher, David A. Hutchins, Yuanyuan Feng, Clinton E. Hare, Karine Leblanc, Julie M. Rose, Steven W. Wilhelm, Janet M. Rowe, Giacomo R. Ditullio

Department of Plant Pathology: Faculty Publications

The CLAW hypothesis argues that a negative feedback mechanism involving phytoplankton- derived dimethylsulfoniopropionate (DMSP) could mitigate increasing sea surface temperatures that result from global warming. DMSP is converted to the climatically active dimethylsulfide (DMS), which is transferred to the atmosphere and photochemically oxidized to sulfate aerosols, leading to increases in planetary albedo and cooling of the Earth’s atmosphere. A shipboard incubation experiment was conducted to investigate the effects of increased temperature and pCO₂ on the algal community structure of the North Atlantic spring bloom and their subsequent impact on particulate and dissolved DMSP concentrations (DMSP_p and DMSP_{d …}

2009 Wildflower Of The Year: Skunk Cabbage, Symplocarpus Foetidus, W. John Hayden

Biology Faculty Publications

Skunk cabbage is a coarse herbaceous plant. The stem consists of a stout rhizome oriented vertically in the soil. Leaves and flowers arise from the tip of the rhizome which is often not visible, resulting in the appearance of leaves and flowers arising directly from the swampy mires where these plants grow. Flowers appear during the winter, long before the leaves. The flowers are minute, clustered into a ball-like group (spadix) almost entirely enclosed by a fleshy, hood-like, spathe. The spathe ranges from 8 to 15 cm in height, is more or less pear-shaped, widest near the bottom, and tapers …

Skunk Cabbage Flowers: The Heat Is On, W. John Hayden

Biology Faculty Publications

It is a remarkable sight, as striking as it is unexpected: January skunk cabbages emerging from the frozen mires they call home, melting their way through snow and ice. It seems so improbable because in everyday experience plants exist at equilibrium with ambient temperatures. Leave an apple on the front seat of your car in summer, it gets hot; examine your tomato plants on that first frosty morning in autumn, and they are permeated with ice crystals. People, mammals and birds are inherently warm, and pretty much nothing else is. Except, of course, for the exceptions, of which skunk cabbage …

Effects Of Stratification, Warm Treatment, And Mechanical And Acid Scarification On The Emergence Of Yellow-Flowered Alfalfa (Medicago Sativa Subsp. Falcata) Seeds, Diane Narem

The Journal of Undergraduate Research

Yellow-flowered alfalfa (YFA) has great potential to improve rangelands in the Northern Plains. Greater than 99% of YFA seeds from soil were viable but less than 4% germinated under standard laboratory conditions. The objective was to determine if low germination was due to physical or physiological seed dormancy. The experiment utilized a random complete block design with two trials, eight replications per trial. Each replication consisted of ten treatments plus a control, four stratification treatments consisting of a combination of two temperatures (-5°C, -20°C) and two durations (48 hr, 72 hr), one warm treatment (4 min, 60°C), four sandpaper scarification …

Honors Convocation Speech (Text And Audio), Jonathan Dey

Honorees for Teaching Excellence

No abstract provided.

Letter From The Dean, Lalit Verma

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

No abstract provided.

Accumulation Of A 5′ Proximal Subgenomic Rna Of Citrus Tristeza Virus Is Correlated With Encapsidation By The Minor Coat Protein, Siddarame Gowda, Satyanarayana Tatineni, Svetlana Y. Folimonova, Mark E. Hilf, William O. Dawson

Department of Plant Pathology: Faculty Publications

During replication, Citrus tristeza virus (CTV) produces large amounts of two unusual subgenomic (sg) RNAs that are positive-stranded and 5′ coterminal. Although these RNAs are produced in similar amounts and are similar in size, with LMT1 (~750 nt) only slightly larger than LMT2 (~650), we found that the similar sgRNAs are produced differently. We previously showed that the LMT1 RNA is produced by premature termination during genomic RNA synthesis. However, LMT2 production was found to correlate with virion assembly instead of RNA replication. The time course of accumulation of the LMT2 RNA occurred late, coinciding with virion accumulation. The long …

Evolution And Systematic Significance Of Reproductive Structures In The Genus Cuscuta (Dodders, Convolvulaceae): Pollen And Gynoecium, Mark Welsh

Theses and Dissertations (Comprehensive)

The genus Cuscuta (dodders, Convolvulaceae) is one of the most significant lineages of parasitic plants from economic, conservation, and anthropogenic perspectives. Members of the genus are twining stem parasites with no roots, lacking almost completely chlorophyll or its function, and gather required nutrition from their host via specialized haustorial connections. While there are almost 200 described species, problems with species identification exist because many diagnostic characters are restricted to their tiny flowers. Probably contributing to this identification difficulty is the fact that the group has not received taxonomic attention for over 75 years; even knowledge of its basic reproductive biology …

Ecology And Molecular Phylogenetics Of Hydnora (Hydnoraceae) In Southern Africa, Jay Francis Bolin

Biological Sciences Theses & Dissertations

The Hydnoraceae are a clade of root holoparasitic angiosperms that contain two small genera, Hydnora and Prosopanche. This study, focused on Hydnora, presents novel data regarding the pollination biology, germination ecology, parasite-host nutritional relationships, and the molecular systematics of this group. Experimental addition of the primary pollinator, Dermestes maculatus to Hydnora africana chamber flowers demonstrated beetle imprisonment during the carpellate stage. Changes in the inner surfaces of the androecial chamber allowed beetle escape after pollen release. Most beetles escaped, dusted with viable pollen, three days after pollen release. To investigate germination ecology, aqueous root extracts of host and …

Vegetable Growing : A Guide For Home Gardeners In Western Australia, Department Of Agriculture, Western Australia

Bulletins 4000 -

DAFWAs popular publication about vegetable growing for home gardeners.

Choline-Utilizing Microblal Strains For Biologically Controlling Fusarium Head Blight, David A. Schisler, Naseem I. Khan, Michael J. Boehm, Patricia J. Slininger

Department of Plant Pathology: Faculty Publications

Three choline utilizing strains of microorganisms isolated from the anthers of wheat, Aureobasidium pullulans strainAS 55.2, Arthrobacter species strain OH 221.3, and Pseudomonas species strain AS 64.4, are superior antagonists of F. graminearum. These microorganisms are effective for suppression and control of FHB in cereals, particularly in wheat and barley.

Dollar Spot Fungus Sclerotinla Homoeocarpa Produces Oxalic Acid, R. C. Venu, Robert A. Beaulieu, Terrance L. Graham, Ainhoa Martinez Medina, Michael J. Boehm

Department of Plant Pathology: Faculty Publications

Dollar spot, caused by Sclerotinia homoeocarpa,. is one of the most devastating diseases of turfgrass worldwide. Many fungi belonging to the genus Sclerotinia produce oxalic acid along with pectolytic cell wall-degrading enzymes. A series of in vitro experiments showed the relationships among temperature, pH, mycelial growth and acid production. Mycelial growth and acid production were most abundant when S. homoeocarpa was grown between 20 and 30°C. Acid production by S. homoeocarpa appeared to be dependent upon the pH of the environment in which it was grown. High performance liquid chromatography analysis of spent broth revealed the presence of oxalic acid. …

Molecular Characterization Of Citrus Tatter Leaf Virus Historically Associated With Meyer Lemon Trees: Complete Genome Sequence And Development Of Biologically Active In Vitro Transcripts, Satyanarayana Tatineni, Mohammad R. Afunian, Mark E. Hilf, Siddarame Gowda, William O. Dawson, Stephen M. Garnsey

Department of Plant Pathology: Faculty Publications

Citrus tatter leaf virus isolated from Meyer lemon trees (CTLV-ML) from California and Florida induces bud union incompatibility of citrus trees grafted on the widely used trifoliate and trifoliate hybrid rootstocks. The complete genome sequence of CTLV-ML was determined to be 6,495 nucleotides (nts), with two overlapping open reading frames (ORFs) and a poly (A) tail at the 3′ end. The genome organization is similar to other capilloviruses, with ORF1 (nts 37 to 6,354) encoding a putative 242-kDa polyprotein which contains replication-associated domains plus a coat protein (CP), and ORF2 (nts 4,788 to 5,750), which is located within ORF1 in …