Plant Breeding and Genetics Commons^™

Fuzzy Clustering Of Cpp Family In Plants With Evolution And Interaction Analyses, Tao Lu, Yongchao Dou, Chi Zhang

Center for Plant Science Innovation: Faculty Publications

Background: Transcription factors have been studied intensively because they play an important role in gene expression regulation. However, the transcription factors in the CPP family (cystein-rich polycomb-like protein), compared with other transcription factor families, have not received sufficient attention, despite their wide prevalence in a broad spectrum of species, from plants to animals. The total number of known CPP transcription factors in plants is 111 from 16 plants, but only 2 of them have been studied so far, namely TSO1 and CPP1 in Arabidopsis thaliana and soybean, respectively.
Methods: In this work, to study their functions, we applied …

Germinación In Vitro De Laelia Speciosa (Kunth) Schltr., Una Herramienta Para Su Conservación Ex Situ, María Ascención Aguilar-Morales, Ana Laura López-Escamilla

Estudios científicos en el estado de Hidalgo y zonas aledañas

Dentro de la familia Orchideaceae, Laelia speciosa (Kunth) Schltr. es probablemente la orquídea más explotada en México, por lo que es importante establecer estrategias de conservación. El objetivo del presente trabajo fue determinar el mejor medio de cultivo para la germinación in vitro de semillas. Cápsulas maduras e inmaduras de L. speciosa, fueron colectadas en la Reserva de la Biosfera Barranca de Metztitlán, Hidalgo, México y las semillas se sembraron en condiciones in vitro en cuatro tratamientos: Murashige y Skoog (MS) (1962) al 100%; MS al 50%; Knudson C (KC) (1946) al 50% y KC al 100%. A los …

Effects Of Ethylene On Secondary Xylem Formation In Arabidopsis Thaliana, Haley M. Rupp

Dissertations, Master's Theses and Master's Reports - Open

Ethylene has myriad roles as a plant hormone, ranging from senescence and defending against pathogen attacks to fruit ripening and interactions with other hormones. It has been shown to increase cambial activity in poplar, but the effect on wood formation in Arabidopsis hypocotyl has not previously been studied. The Auxin-Regulated Gene involved in Organ Size (ARGOS), which increases organ size by lengthening the time for cell division, was found to be upregulated by ethylene. We tested the effect of ethylene treatment at 10 and 100 µM ACC on three genotypes of Arabidopsis, Col0 (wild-type), an ARGOS deficient mutant (argos), and …

Taxonomy And Dna Barcoding In The Genus Manfreda (Salisb.) Asparagaceae, William David Ritchie

Graduate Theses and Dissertations

The genus Manfreda Salisb. of Asparagaceae is a genus of potential horticultural interest and is currently subject to breeding efforts at the University of Arkansas. A lack of taxonomic clarity however undermines the classification of potential inter - and intrageneric hybrids. The study aims to assess existing species delimitation within the genus Manfreda employing morphology while investigating the potential utility of Consortium for the Barcode of Life Plant (CBOL) DNA Barcodes for identification of specific taxa and an External Transcribed Spacer (ETS) - Internal Transcribed Spacer (ITS) DNA barcode for developed hybridized taxa.

Observation of 855 herbarium specimens facilitated phylogenetic …

Evaluation Of The Recombination Efficiencies Of Flp Proteins, Linh Duy Nguyen

Graduate Theses and Dissertations

Site-specific recombination systems are powerful tools for genetic modification. They have been used to integrate a transgene into a pre-defined locus and to remove marker genes from a transgene locus. Two of the most widely used site-specific recombination systems in plants are the Cre/lox system from the bacteriophage P1 and the FLP/FRT system from the yeast Saccharomyces cerevisiae. The Cre/lox system is well-characterized and is the first choice in application of site-specific recombination system. However, some applications such as marker-free site-specific gene integration require the use of two recombination systems. In addition, the availability of alternative recombination systems can offer …

Fuzzy Clustering Of Cpp Family In Plants With Evolution And Interaction Analyses, Tao Lu, Yongchao Dou, Chi Zhang

Center for Plant Science Innovation: Faculty Publications

Background: Transcription factors have been studied intensively because they play an important role in gene expression regulation. However, the transcription factors in the CPP family (cystein-rich polycomb-like protein), compared with other transcription factor families, have not received sufficient attention, despite their wide prevalence in a broad spectrum of species, from plants to animals. The total number of known CPP transcription factors in plants is 111 from 16 plants, but only 2 of them have been studied so far, namely TSO1 and CPP1 in Arabidopsis thaliana and soybean, respectively.

Methods: In this work, to study their functions, we applied …

Rosette Iron Deficiency Transcript And Microrna Profiling Reveals Links Between Copper And Iron Homeostasis In Arabidopsis Thaliana, Brian M. Waters, Samuel A. Mcinturf, Ricardo J. Stein

Department of Agronomy and Horticulture: Faculty Publications

Iron (Fe) is an essential plant micronutrient, and its deficiency limits plant growth and development on alkaline soils. Under Fe deficiency, plant responses include up-regulation of genes involved in Fe uptake from the soil. However, little is known about shoot responses to Fe deficiency. Using microarrays to probe gene expression in Kas-1 and Tsu-1 ecotypes of Arabidopsis thaliana, and comparison with existing Col-0 data, revealed conserved rosette gene expression responses to Fe deficiency. Fe-regulated genes included known metal homeostasis-related genes, and a number of genes of unknown function. Several genes responded to Fe deficiency in both roots and rosettes. …

The Evolution Of Natural Plant Communities Through Crop Migration And Crop-To-Weed Gene Flow, Meredith G. Schafer

Graduate Theses and Dissertations

With the rising demand for food and biofuels, the efficiency of crop production has become vital to assuring food security. Genetically engineered (GE) crop varieties are broadly thought to be a solution for improving the efficiency of crop production, but concerns regarding their release have heightened as more discoveries have focused on the influence of genetically engineered crops on native and weedy plant species. Risk assessment of GE crop varieties focuses on two main areas: feralization of crop systems and crop-weed hybridization. Risks include naturalization, transgene introgression, and the formation of novel genotypes in natural systems. In this study, roadside …

The Pseudomonas Syringae Hrpj Protein Controls The Secretion Of Type Iii Translocator Proteins And Has A Virulence Role Inside Plant Cells, Emerson Crabill, Andrew Karpisek, James R. Alfano

Center for Plant Science Innovation: Faculty Publications

The bacterial plant pathogen Pseudomonas syringae injects effector proteins into plant cells via a type III secretion system (T3SS), which is required for pathogenesis. The protein HrpJ is secreted by P. syringae and is required for a fully functional T3SS. A hrpJ mutant is non-pathogenic and cannot inject effectors into plant cells or secrete the harpin HrpZ1. Here we show that the hrpJ mutant also cannot secrete the harpins HrpW1 and HopAK1 or the translocator HrpK1, suggesting that these proteins are required in the translocation (injection) of effectors into plant cells. Complementation of the hrpJ mutant with secretion incompetent HrpJ …

Vitamin Deficiencies In Humans: Can Plant Science Help?, Teresa B. Fitzpatrick, Gilles J. C. Basset, Patrick Borel, Fernando Carrari, Dean Dellapenna, Paul D. Fraser, Hanjo Hellmann, Sonia Osorio, Christophe Rothan, Victoriano Valpuesta, Catherine Caris-Veyrat, Alisdair R. Fernie

Center for Plant Science Innovation: Faculty Publications

The term vitamin describes a small group of organic compounds that are absolutely required in the human diet. Although for the most part, dependency criteria are met in developed countries through balanced diets, this is not the case for the five billion people in developing countries who depend predominantly on a single staple crop for survival. Thus, providing a more balanced vitamin intake from high-quality food remains one of the grandest challenges for global human nutrition in the coming decade(s). Here, we describe the known importance of vitamins in human health and current knowledge on their metabolism in plants. Deficits …

Critical Roles Of Rna-Binding Proteins In Mirna Biogenesis In Arabidopsis, Guodong Ren, Bin Yu

Center for Plant Science Innovation: Faculty Publications

MicroRNAs (miRNAs) are key regulators of gene expression and play critical roles in modulating metabolism, development and physiology in animals and plants. miRNA levels are transcriptionally and post-transcriptionally controlled for their proper function. Recent studies have shown that RNA-binding proteins play important roles in producing miRNAs by affecting the accurate and/or efficient processing of precursors of miRNAs. Many of these RNA-binding proteins also have roles in general RNA metabolism, indicating potential connections between miRNA biogenesis and other RNA metabolism. Here, we focus on the function of several RNA-binding proteins in miRNA biogenesis in Arabidopsis.

Post-Transcriptional Control Of Mirna Abundance In Arabidopsis, Guodong Ren, Bin Yu

Center for Plant Science Innovation: Faculty Publications

MicroRNAs (miRNAs) are a class of small non-coding RNAs (small RNAs) that are 20–24nt in length and predominantly repress gene expression at post-transcriptional levels. They regulate many biological processes including development, metabolism and physiology. Numerous studies have revealed that the steady-state levels of miRNA are under sophisticated control to ensure their proper function. In this review, we summarize recent advances on regulation of miRNA processing and stability in plants.

Uridylation Of Mirnas By Hen1 Suppressor1 In Arabidopsis, Guodong Ren, Xuemei Chen, Bin Yu

Center for Plant Science Innovation: Faculty Publications

HEN1-mediated 2′-O-methylation has been shown to be a key mechanism to protect plant microRNAs (miRNAs) and small interfering RNAs (siRNAs) as well as animal piwi-interacting RNAs (piRNAs) from degradation and 3′ terminal uridylation [1–8]. However, enzymes uridylating unmethylated miRNAs, siRNAs, or piRNAs in hen1 are unknown. In this study, a genetic screen identified a second-site mutation hen1 suppressor1-2 (heso1-2) that partially suppresses the morphological phenotypes of the hypomorphic hen1-2 allele and the null hen1-1 allele in Arabidopsis. HESO1 encodes a terminal nucleotidyl transferase that prefers to add untemplated uridine to the 3′ end of RNA, which is …

The Dna- And Rna-Binding Protein Factor Of Dna Methylation 1 Requires Xh Domain-Mediated Complex Formation For Its Function In Rna-Directed Dna Methylation, Meng Xie, Guodong Ren, Chi Zhang, Bin Yu

Center for Plant Science Innovation: Faculty Publications

Studies have identified a sub-group of SGS3-LIKE proteins including FDM1–5 and IDN2 as key components of RNA-directed DNA methylation pathway (RdDM). Although FDM1 and IDN2 bind RNAs with 5' overhangs, their functions in the RdDM pathway remain to be examined. Here we show that FDM1 interacts with itself and with IDN2. Gel filtration suggests that FDM1 may exist as a homodimer in a heterotetramer complex in vivo. The XH domain of FDM1 mediates the FDM1–FDM1 and FDM1–IDN2 interactions. Deletion of the XH domain disrupts FDM1 complex formation and results in loss-of-function of FDM1. These results demonstrate that XH domainmediated …

Metabolic And Gene Expression Changes Triggered By Nitrogen Deprivation In The Photoautotrophically Grown Microalgae Chlamydomonas Reinhardtii And Coccomyxa Sp. C-169, Joseph Msanne, Di Xu, Anji Reddy Konda, J. Armando Casas-Mollano, Tala Awada, Edgar B. Cahoon, Heriberto Cerutti

Center for Plant Science Innovation: Faculty Publications

Microalgae are emerging as suitable feedstocks for renewable biofuel production. Characterizing the metabolic pathways involved in the biosynthesis of energy-rich compounds, such as lipids and carbohydrates, and the environmental factors influencing their accumulation is necessary to realize the full potential of these organisms as energy resources. The model green alga Chlamydomonas reinhardtii accumulates significant amounts of triacylglycerols (TAGs) under nitrogen starvation or salt stress in medium containing acetate. However, since cultivation of microalgae for biofuel production may need to rely on sunlight as the main source of energy for biomass synthesis, metabolic and gene expression changes occurring in Chlamydomonas and …

Rna-Mediated Silencing In Algae: Biological Roles And Tools For Analysis Of Gene Function, Heriberto Cerutti, Xinrong Ma, Joseph Msanne, Timothy Repas

Center for Plant Science Innovation: Faculty Publications

Algae are a large group of aquatic, typically photosynthetic, eukaryotes that include species from very diverse phylogenetic lineages, from those similar to land plants to those related to protist parasites. The recent sequencing of several algal genomes has provided insights into the great complexity of these organisms. Genomic information has also emphasized our lack of knowledge of the functions of many predicted genes, as well as the gene regulatory mechanisms in algae. Core components of the machinery for RNA-mediated silencing show widespread distribution among algal lineages, but they also seem to have been lost entirely from several species with relatively …

Muts Homolog1 Is A Nucleoid Protein That Alters Mitochondrial And Plastid Properties And Plant Response To High Light, Ying-Zhi Xu, Maria P. Arrieta-Montiel, Kamaldeep S. Virdi, Wilson B. M. De Paula, Joshua R. Widhalm, Gilles J. Basset, Jaime I. Davila, Thomas Elthon, Christian G. Elowsky, Shirley J. Sato, Thomas E. Clemente, Sally Ann Mackenzie

Center for Plant Science Innovation: Faculty Publications

Mitochondrial-plastid interdependence within the plant cell is presumed to be essential, but measurable demonstration of this intimate interaction is difficult. At the level of cellular metabolism, several biosynthetic pathways involve both mitochondrial- and plastid-localized steps. However, at an environmental response level, it is not clear how the two organelles intersect in programmed cellular responses. Here, we provide evidence, using genetic perturbation of the MutS Homolog1 (MSH1) nuclear gene in five plant species, that MSH1 functions within the mitochondrion and plastid to influence organellar genome behavior and plant growth patterns. The mitochondrial form of the protein participates in DNA recombination …

Herbicide-Resistant Risk Assessment: Response Of Common Nebraska Weeds To Dicamba Dose, Roberto J. Crespo

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Dicamba-resistant soybeans are being developed to provide an additional herbicide mechanism of action that can be used in soybean, and to provide a tool to help manage or mitigate the evolution of other herbicide-resistant weed populations. The objectives of this thesis were to assess the risk of common Nebraska weeds developing resistance to dicamba, quantify baseline dose-response to dicamba of high-risk weed species, and survey the variability in dicamba dose-response among populations of those species. Twenty-five weed scientists were asked to estimate the risk likelihood of ten weed species evolving resistance to dicamba following the commercialization of dicamba-resistant soybean. Palmer …

Generation Of Transgenic Medicago Sativa Overexpressing "Osmotin-Chitinase" Gene Chimera, Jahnavi Reddy Kancharla

Masters Theses & Specialist Projects

Medicago is widely used as a forage crop. It is often susceptible to various pathogenic infections and exhibits low growth in drought and extreme climatic conditions. In the current study, a strategy was developed for over-expressing an “Osmotin-Chitinase” gene chimera in transgenic Medicago that could potentially confer resistance to different biotic and abiotic stresses. Seed germination of several cultivars of Medicago (M. sativa ssp. sativa, M. sativa ssp. falcata, M. sativa ssp. caerulea, M. truncatula, and M. Rugosa) was tested to determine the cultivars with good germination rates. Among these, M. sativa ssp. sativa showed an …

Crop Updates 2011 - Cereals, David Bowran, Bill Crabtree, Peter Carberry, Peter Burges, Bevan Buirchell, Ben Curtis, Sarah Ellis, Brenda Shackley, Christine Zaicou, Siva Sivapalan, Penny Goldsmith, Gae Plunkett, Darshan Sharma, Mario D'Antuono, Art Diggle, Peter Mangano, Sally Peltzer, Michael Renton, Bill Macleod, Fumie Horiuchi, George Wyatt, Geoff Anderson, Richard Bell, Ross Brennan, Wen Chen, Penny Riffkin

Crop Updates

This session covers eleven papers from different authors:

OPENING, NEW CROP VARIETIES & DECISION SUPPORT

Opening

1. Overview of the 2010 season, David Bowran, Director, Practice and Systems Innovation, Department of Agriculture and Food,

2. My experience in a drought as a farmer and consultant, Bill Crabtree, Morawa, Western Australia

3. Meeting the productivity and sustainability challenges to Australian agriculture until 2030, Peter Carberry, CSIRO Sustainable Agriculture Flagship

New Crop Varieties

4. National Variety Trials (NTV) wheat variety performance – captivity vs broadacre, Peter Burgess, Kalyx Agriculture

5. WALAN2289 – a new lupin variety to replace …

Delivery Of Prolamins To The Protein Storage Vacuole In Maize Aleurone Cells, Francisca C. Reyes, Taijoon Chung, David Holding, Rudolf Jung, Richard Vierstra, Marisa S. Otegui

Center for Plant Science Innovation: Faculty Publications

Zeins, the prolamin storage proteins found in maize (Zea mays), accumulate in accretions called protein bodies inside the endoplasmic reticulum (ER) of starchy endosperm cells. We found that genes encoding zeins, a-globulin, and legumin-1 are transcribed not only in the starchy endosperm but also in aleurone cells. Unlike the starchy endosperm, aleurone cells accumulate these storage proteins inside protein storage vacuoles (PSVs) instead of the ER. Aleurone PSVs contain zeinrich protein inclusions, a matrix, and a large system of intravacuolar membranes. After being assembled in the ER, zeins are delivered to the aleurone PSVs in atypical prevacuolar compartments …

Plant Targets For Pseudomonas Syringae Type Iii Effectors: Virulence Targets Or Guarded Decoys?, Anna Block, James R. Alfano

Center for Plant Science Innovation: Faculty Publications

The phytopathogenic bacterium Pseudomonas syringae can suppress both pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) and effector-triggered immunity (ETI) by the injection of type III effector (T3E) proteins into host cells. T3Es achieve immune suppression using a variety of strategies including interference with immune receptor signaling, blocking RNA pathways and vesicle trafficking, and altering organelle function. T3Es can be recognized directly or indirectly by resistance proteins monitoring specific T3E targets resulting in ETI. It is presently unclear whether the monitored targets represent bona fide virulence targets or guarded decoys. Extensive overlap between PTI and ETI signaling suggests that T3Es may suppress …

Structural And Functional Analysis Of The Type Iii Secretion System From Pseudomonas Fluorescens Q8r1-96, Dmitri V. Mavrodi, Anna Joe, Olga V. Mavrodi, Karl A. Hassan, David M. Weller, Ian T. Paulsen, Joyce E. Loper, James R. Alfano, Linda S. Thomashow

Center for Plant Science Innovation: Faculty Publications

Pseudomonas fluorescens Q8r1-96 represents a group of rhizosphere strains responsible for the suppressiveness of agricultural soils to take-all disease of wheat. It produces the antibiotic 2,4-diacetylphloroglucinol and aggressively colonizes the roots of cereal crops. In this study, we analyzed the genome of Q8r1-96 and identified a type III protein secretion system (T3SS) gene cluster that has overall organization similar to that of the T3SS gene cluster of the plant pathogen Pseudomonas syringae. We also screened a collection of 30 closely related P. fluorescens strains and detected the T3SS genes in all but one of them. The Q8r1-96 genome contained …

Mpk6, Sphinganine And The Lcb2a Gene From Serine Palmitoyltransferase Are Required In The Signaling Pathway That Mediates Cell Death Induced By Long Chain Bases In Arabidopsis, Mariana Saucedo-García, Arturo Guevara-Garcia, Ariadna González-Solís, Felipe Cruz-García, Sonia Vázquez-Santana, Jennifer E. Markham, M. Guadalupe Lozano-Rosas, Charles R. Dietrich, Maricela Ramos-Vega, Edgar B. Cahoon, Marina Gavilanes-Ruíz

Center for Plant Science Innovation: Faculty Publications

• Long chain bases (LCBs) are sphingolipid intermediates acting as second messengers in programmed cell death (PCD) in plants. Most of the molecular and cellular features of this signaling function remain unknown.

• We induced PCD conditions in Arabidopsis thaliana seedlings and analyzed LCB accumulation kinetics, cell ultrastructure and phenotypes in serine palmitoyltransferase (spt), mitogen-activated protein kinase (mpk), mitogenactivated protein phosphatase (mkp1) and lcb-hydroxylase (sbh) mutants.

• The lcb2a-1 mutant was unable to mount an effective PCD in response to fumonisin B1 (FB1), revealing that the LCB2a gene is essential for the …

A Plant Dj-1 Homolog Is Essential For Arabidopsis Thaliana Chloroplast Development, Jiusheng Lin, Tara J. Nazarenus, Jeanine L. Frey, Xinwen Liang, Mark A. Wilson, Julie M. Stone

Center for Plant Science Innovation: Faculty Publications

Protein superfamilies can exhibit considerable diversification of function among their members in various organisms. The DJ-1 superfamily is composed of proteins that are principally involved in stress response and are widely distributed in all kingdoms of life. The model flowering plant Arabidopsis thaliana contains three close homologs of animal DJ-1, all of which are tandem duplications of the DJ-1 domain. Consequently, the plant DJ-1 homologs are likely pseudo-dimeric proteins composed of a single polypeptide chain. We report that one A. thaliana DJ-1 homolog (AtDJ1C) is the first DJ-1 homolog in any organism that is required for viability. Homozygous disruption of …

Two Distinct Roles Of Arabidopsis Homolog Of Trithorax1 (Atx1) At Promoters And Within Transcribed Regions Of Atx1-Regulated Genes, Yong Ding, Zoya Avramova, Michael E. Fromm

Center for Plant Science Innovation: Faculty Publications

The Arabidopsis thaliana trithorax-like protein, ATX1, shares common structural domains, has similar histone methyltransferase (HMT) activity, and belongs in the same phylogenetic subgroup as its animal counterparts. Most of our knowledge of the role of HMTs in trimethylating lysine 4 of histone H3 (H3K4me3) in transcriptional regulation comes from studies of yeast and mammalian homologs. Little is known about the mechanism by which ATX1, or any other HMT of plant origin, affects transcription. Here, we provide insights into how ATX1 influences transcription at regulated genes, playing two distinct roles. At promoters, ATX1 is required for TATA binding protein (TBP) and …

Structure Function Analysis Of An Adp-Ribosyltransferase Type Iii Effector And Its Rna-Binding Target In Plant Immunity, Byeong-Ryool Jeong, Yan Lin, Anna Joe, Ming Guo, Christin Korneli, Huirong Yang, Ping Wang, Min Yu, Ronald Cerny, Dorothee Staiger, James R. Alfano, Yanhui Xu

Center for Plant Science Innovation: Faculty Publications

Background: HopU1 ADP-ribosylates GRP7, suppressing plant immunity.

Results: The HopU1 structure has two novel loops required for GRP7 recognition, and HopU1 ribosylates GRP7 at an arginine in position 49 disrupting its function.

Conclusion: HopU1 targets a conserved arginine in GRP7, disabling its ability to bind immunity-related RNA.

Significance: The mechanistic details of how HopU1 recognizes its substrate reveal how HopU1 contributes to pathogenesis.

Molecular And Chemical Dissection Of Cellulose Biosynthesis In Plants, Darby M. Harris

Theses and Dissertations--Plant and Soil Sciences

Plant cell walls are complex structures that must not only constrain cellular turgor pressure but also allow for structural modification during the dynamic processes of cell division and anisotropic expansion. Cell walls are composed of highly glycosylated proteins and polysaccharides, including pectin, hemicellulose and cellulose. The primary cell wall polysaccharide is cellulose, a polymer composed of high molecular weight !- 1,4-glucan chains. Although cellulose is the most abundant biopolymer on Earth, there is still a lot to learn about its biosynthesis and regulation. This research began by applying a variety of analytical techniques in an attempt to understand differences in …

Plant Immunity Directly Or Indirectly Restricts The Injection Of Type Iii Effectors By The Pseudomonas Syringae Type Iii Secretion System, Emerson Crabill, Anna Joe, Anna Block, Jennifer M. Van Rooyen, James R. Alfano

Center for Plant Science Innovation: Faculty Publications

Plants perceive microorganisms by recognizing microbial molecules known as pathogen-associated molecular patterns (PAMPs) inducing PAMP-triggered immunity (PTI) or by recognizing pathogen effectors inducing effector-triggered immunity (ETI). The hypersensitive response (HR), a programmed cell death response associated with ETI, is known to be inhibited by PTI. Here, we show that PTI-induced HR inhibition is due to direct or indirect restriction of the type III protein secretion system’s (T3SS) ability to inject type III effectors (T3Es). We found that the Pseudomonas syringae T3SS was restricted in its ability to inject a T3E-adenylate cyclase (CyaA) injection reporter into PTI-induced tobacco (Nicotiana tabacum) cells. …

Reestablishing Diversity In Our Hardwood Forests: A Transplant Study Of Five Spring-Flowering Herbs, Danielle Racke

Masters Theses & Specialist Projects

Herbaceous communities are critical to the functioning of forest ecosystems. They recycle nutrients, help prevent erosion, provide critical microhabitats and maintain biodiversity. In the eastern United States, most hardwood forests are growing on land once entirely cleared or used for some form of agriculture. Although some of these forests are nearly 150 years old, they still have depauperate native herbaceous communities when compared to remaining old-growth forests. This long-term depletion may result from dispersal limitation or environmental limitation.

I tested the hypothesis that dispersal was the primary factor contributing to the absence of five spring-flowering herbaceous species in four secondary …