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1

A brief review of molecular techniques to assess plant diversity.  

PubMed

Massive loss of valuable plant species in the past centuries and its adverse impact on environmental and socioeconomic values has triggered the conservation of plant resources. Appropriate identification and characterization of plant materials is essential for the successful conservation of plant resources and to ensure their sustainable use. Molecular tools developed in the past few years provide easy, less laborious means for assigning known and unknown plant taxa. These techniques answer many new evolutionary and taxonomic questions, which were not previously possible with only phenotypic methods. Molecular techniques such as DNA barcoding, random amplified polymorphic DNA (RAPD), amplified fragment length polymorphism (AFLP), microsatellites and single nucleotide polymorphisms (SNP) have recently been used for plant diversity studies. Each technique has its own advantages and limitations. These techniques differ in their resolving power to detect genetic differences, type of data they generate and their applicability to particular taxonomic levels. This review presents a basic description of different molecular techniques that can be utilized for DNA fingerprinting and molecular diversity analysis of plant species. PMID:20559503

Arif, Ibrahim A; Bakir, Mohammad A; Khan, Haseeb A; Al Farhan, Ahmad H; Al Homaidan, Ali A; Bahkali, Ali H; Sadoon, Mohammad Al; Shobrak, Mohammad

2010-01-01

2

A Brief Review of Molecular Techniques to Assess Plant Diversity  

PubMed Central

Massive loss of valuable plant species in the past centuries and its adverse impact on environmental and socioeconomic values has triggered the conservation of plant resources. Appropriate identification and characterization of plant materials is essential for the successful conservation of plant resources and to ensure their sustainable use. Molecular tools developed in the past few years provide easy, less laborious means for assigning known and unknown plant taxa. These techniques answer many new evolutionary and taxonomic questions, which were not previously possible with only phenotypic methods. Molecular techniques such as DNA barcoding, random amplified polymorphic DNA (RAPD), amplified fragment length polymorphism (AFLP), microsatellites and single nucleotide polymorphisms (SNP) have recently been used for plant diversity studies. Each technique has its own advantages and limitations. These techniques differ in their resolving power to detect genetic differences, type of data they generate and their applicability to particular taxonomic levels. This review presents a basic description of different molecular techniques that can be utilized for DNA fingerprinting and molecular diversity analysis of plant species. PMID:20559503

Arif, Ibrahim A.; Bakir, Mohammad A.; Khan, Haseeb A.; Al Farhan, Ahmad H.; Al Homaidan, Ali A.; Bahkali, Ali H.; Sadoon, Mohammad Al; Shobrak, Mohammad

2010-01-01

3

PLANT DIVERSITY  

EPA Science Inventory

Habitat change statistics and species-area curves were used to estimate the effects of alternative future scenarios for agriculture on plant diversity in Iowa farmlands. Study areas were two watersheds in central Iowa of about 50 and 90 square kilometers, respectively. Future s...

4

ASSESSMENT OF PLANT DIVERSITY AND PRIORITIZATION OF COMMUNITIES FOR CONSERVATION IN MORNAULA RESERVE FOREST  

Microsoft Academic Search

Assessment of plant diversity of the Reserve Forests of the west Himalaya and prioritization of communities for conservation have not been given much attention. Therefore, the study has been conducted in a biodiversity rich Mornaula Reserve Forest between 1500-2200m to analyse the structure, composition of the forest communities including richness of economically important, native, endemic and rare-endangered species, and prioritize

S. PANT-S. S. SAMANT

5

Evolution & Diversity in Plants.  

ERIC Educational Resources Information Center

Summarizes recent findings that help in understanding how evolution has brought about the diversity of plant life that presently exists. Discusses basic concepts of evolution, diversity and classification, the three-line hypothesis of plant evolution, the origin of fungi, and the geologic time table. Included are 31 references. (CW)

Pearson, Lorentz C.

1988-01-01

6

Assessment of Genetic Diversity in Seed Plants Based on a Uniform ? Criterion.  

PubMed

Despite substantial advances in genotyping techniques and massively accumulated data over the past half century, a uniform measurement of neutral genetic diversity derived by different molecular markers across a wide taxonomical range has not yet been formulated. We collected genetic diversity data on seed plants derived by AFLP, allozyme, ISSR, RAPD, SSR and nucleotide sequences, converted expected heterozygosity (He) to nucleotide diversity (?), and reassessed the relationship between plant genetic diversity and life history traits or extinction risk. We successfully established a uniform ? criterion and developed a comprehensive plant genetic diversity database. The mean population-level and species-level ? values across seed plants were 0.00374 (966 taxa, 155 families, 47 orders) and 0.00569 (728 taxa, 130 families, 46 orders), respectively. Significant differences were recovered for breeding system (p < 0.001) at the population level and geographic range (p = 0.023) at the species level. Selfing taxa had significantly lower ? values than outcrossing and mixed-mating taxa, whereas narrowly distributed taxa had significantly lower ? values than widely distributed taxa. Despite significant differences between the two extreme threat categories (critically endangered and least concern), the genetic diversity reduction on the way to extinction was difficult to detect in early stages. PMID:25470277

Ai, Bin; Kang, Ming; Huang, Hongwen

2014-01-01

7

Understanding plant reproductive diversity  

PubMed Central

Flowering plants display spectacular floral diversity and a bewildering array of reproductive adaptations that promote mating, particularly outbreeding. A striking feature of this diversity is that related species often differ in pollination and mating systems, and intraspecific variation in sexual traits is not unusual, especially among herbaceous plants. This variation provides opportunities for evolutionary biologists to link micro-evolutionary processes to the macro-evolutionary patterns that are evident within lineages. Here, I provide some personal reflections on recent progress in our understanding of the ecology and evolution of plant reproductive diversity. I begin with a brief historical sketch of the major developments in this field and then focus on three of the most significant evolutionary transitions in the reproductive biology of flowering plants: the pathway from outcrossing to predominant self-fertilization, the origin of separate sexes (females and males) from hermaphroditism and the shift from animal pollination to wind pollination. For each evolutionary transition, I consider what we have discovered and some of the problems that still remain unsolved. I conclude by discussing how new approaches might influence future research in plant reproductive biology. PMID:20008389

Barrett, Spencer C. H.

2010-01-01

8

Relationship between plant diversity andRelationship between plant diversity and AMF diversity in grassland ecosystems  

E-print Network

Experimental designdesign 44 Plant Function Groups (PFG)Plant Function Groups (PFG) PR(PR(perennial rhizomeRelationship between plant diversity andRelationship between plant diversity and AMF diversity)replicates (96 plots) A i i (A i i ( AMF community in plant roots (TAMF community in plant roots (T-- RFLP

Bruns, Tom

9

Geographic information system method for assessing chemo-diversity in medicinal plants.  

PubMed

The spatial distribution of wild germplasm of Podophyllum peltatum L. (American mayapple) has been analyzed using the Geographic Information System (GIS) with the objective to develop a method and a database for evaluation of biotic and abiotic factors influencing drug yield, and to map elite genotypes for propagation and improvement. The field assessment followed a standard procedure including geographical coordinates of each accession, leaf biomass randomly harvested, identification of associate species, collection of herbarium specimen, soil sample and digital pictures of the site. By overlaying morphological and chemical data with geomorphic information, a thematic map was created locating the podophyllotoxin-rich accessions and the uniqueness of each site was recorded for post-collection analysis. This work has enabled the establishment of a database of P. peltatum germplasm in Mississippi with drug yield linked to spatial locations for rational utilization of our natural resources. While this method integrates information of well-characterized diverse in situ P. peltatum germplasm, it might become a strategy for curators to reduce cost for establishing and maintaining ex situ collections since the genetic material is geo-referenced. PMID:16395654

Moraes, Rita M; Momm, Henrique G; Silva, Bladimiro; Maddox, Victor; Easson, Gregory L; Lata, Hemant; Ferreira, Daneel

2005-12-01

10

Biodiversity in riverbank techniques for erosion control: assessment of animal and plant species diversity along a natural gradient.  

E-print Network

Biodiversity in riverbank techniques for erosion control: assessment of animal and plant species * Corresponding author: paul.cavaille@cemagref.fr Keywords: beetles, biodiversity, ecological restoration, plant.). However, whether such installations can accommodate natural biodiversity has not been well assessed

Paris-Sud XI, Université de

11

Socioeconomics drive urban plant diversity  

PubMed Central

Spatial variation in plant diversity has been attributed to heterogeneity in resource availability for many ecosystems. However, urbanization has resulted in entire landscapes that are now occupied by plant communities wholly created by humans, in which diversity may reflect social, economic, and cultural influences in addition to those recognized by traditional ecological theory. Here we use data from a probability-based survey to explore the variation in plant diversity across a large metropolitan area using spatial statistical analyses that incorporate biotic, abiotic, and human variables. Our prediction for the city was that land use, along with distance from urban center, would replace the dominantly geomorphic controls on spatial variation in plant diversity in the surrounding undeveloped Sonoran desert. However, in addition to elevation and current and former land use, family income and housing age best explained the observed variation in plant diversity across the city. We conclude that a functional relationship, which we term the “luxury effect,” may link human resource abundance (wealth) and plant diversity in urban ecosystems. This connection may be influenced by education, institutional control, and culture, and merits further study. PMID:12847293

Hope, Diane; Gries, Corinna; Zhu, Weixing; Fagan, William F.; Redman, Charles L.; Grimm, Nancy B.; Nelson, Amy L.; Martin, Chris; Kinzig, Ann

2003-01-01

12

The influence of linear elements on plant species diversity of Mediterranean rural landscapes: assessment of different indices and statistical approaches.  

PubMed

This paper mainly aims to study the linear element influence on the estimation of vascular plant species diversity in five Mediterranean landscapes modeled as land cover patch mosaics. These landscapes have several core habitats and a different set of linear elements--habitat edges or ecotones, roads or railways, rivers, streams and hedgerows on farm land--whose plant composition were examined. Secondly, it aims to check plant diversity estimation in Mediterranean landscapes using parametric and non-parametric procedures, with two indices: Species richness and Shannon index. Land cover types and landscape linear elements were identified from aerial photographs. Their spatial information was processed using GIS techniques. Field plots were selected using a stratified sampling design according to relieve and tree density of each habitat type. A 50x20 m2 multi-scale sampling plot was designed for the core habitats and across the main landscape linear elements. Richness and diversity of plant species were estimated by comparing the observed field data to ICE (Incidence-based Coverage Estimator) and ACE (Abundance-based Coverage Estimator) non-parametric estimators. The species density, percentage of unique species, and alpha diversity per plot were significantly higher (p < 0.05) in linear elements than in core habitats. ICE estimate of number of species was 32% higher than of ACE estimate, which did not differ significantly from the observed values. Accumulated species richness in core habitats together with linear elements, were significantly higher than those recorded only in the core habitats in all the landscapes. Conversely, Shannon diversity index did not show significant differences. PMID:16763745

García del Barrio, J M; Ortega, M; Vázquez De la Cueva, A; Elena-Rosselló, R

2006-08-01

13

Assessing effects of forecasted climate change on the diversity and distribution of European higher plants for 2050  

Microsoft Academic Search

The rapidly increasing atmospheric concentrations of greenhouse gases may lead to significant changes in regional and seasonal climate patterns. Such changes can strongly influence the diversity and distribution of species and, therefore, affect ecosystems and biodiversity. To assess these changes we developed a model, called euromove. The model uses climate data from 1990 to 2050 as compiled from the image

M. Bakkenes; J. R. M. Alkemade; F. Ihle; R. Leemans; J. B. Latour

2002-01-01

14

Plant Diversity in Paraguay  

NSDL National Science Digital Library

This Web site contains a database of Paraguayan plant specimens from the Natural History Museum herbarium in London, as well as all records of collections made during a biological inventory of the Mbaracay Forest Nature Reserve (a project funded by the UK government's Darwin Initiative). In addition to the database, which is searchable by taxonomy or geography via convenient dropdown menus, visitors will find detailed background information on the Darwin Initiative, the vegetation of Paraguay, and the Mbaracay Forest Nature Reserve. The site's attractive and well-designed interface is an added bonus.

2003-01-01

15

COURSE INFORMATION Plant Diversity and Evolution  

E-print Network

plant diversity. 2. The major features and evolutionary origins of vascular plants. 3. The analytical of terminology) 5. Identification of plants using keys 6. Recognition of important vascular plant families (seeCOURSE INFORMATION Fall 2009 Plant Diversity and Evolution (11:704:411) and Advanced Plant

Chen, Kuang-Yu

16

Assessment of 16S rRNA gene-based phylogenetic diversity and promising plant growth-promoting traits of Acinetobacter community from the rhizosphere of wheat.  

PubMed

Strains belonging to the genus Acinetobacter and their plant growth-promoting properties have been reported in the literature. However, there is a paucity of information on the diversity of Acinetobacter species associated with the wheat rhizosphere. In the present investigation, Acinetobacter species diversity was assessed in the rhizosphere of wheat from three agricultural fields where different varieties were cultivated. The Acinetobacter species diversity was assessed by DGGE (Denaturing Gradient Gel Electrophoresis) of 16S rRNA gene PCR products amplified from total soil DNA using genus-specific primers. Ac. calcoaceticus, Ac. baumannii, Ac. lwoffii, Ac. baylyi and Acinetobacter sp. were detected in the rhizosphere of wheat. Prevalence of Acinetobacter species in the rhizosphere of wheat was also investigated by a cultivation-dependent approach. Ac. calcoaceticus, Ac. baumannii, Ac. lwoffii and Acinetobacter sp. were isolated on selective media from the same samples. In vitro characterization of Acinetobacter isolates revealed that majority of these bacteria exhibited plant growth-promoting traits such as nitrogen fixation, siderophore production and mineral solubilization. These Acinetobacter strains may play a favorable role in plant growth promotion while residing in the rhizosphere of wheat. PMID:20116982

Sachdev, Dhara; Nema, Preeti; Dhakephalkar, Prashant; Zinjarde, Smita; Chopade, Balu

2010-10-20

17

Resource availability controls fungal diversity across a plant diversity gradient  

E-print Network

determinants of microbial diversity remain poorly understood. Here, we test two alternative hypotheses and diversity within the experimental plant communities. We used soil microbial biomass as a temporally mechanisms determine the diversity of organisms at multiple scales. Keywords microbial diversity, fungal

Weiblen, George D

18

Plant diversity in mediterranean-climate regions  

Microsoft Academic Search

The high plant diversity of mediterranean-climate regions has attracted much attention over the past few years. This review discusses patterns and determinants of local, differential and regional plant diversity in all five regions. Local diversity shows great variation within and between regions and explanations for these patterns invoke a wide range of hypotheses. Patterns of regional diversity are the result

Richard M. Cowling; Philip W. Rundel; Byron B. Lamont; Mary Kalin Arroyo; Margarita Arianoutsou

1996-01-01

19

Effects of above-ground plant species composition and diversity on the diversity of soil-borne microorganisms  

Microsoft Academic Search

A coupling of above-ground plant diversity and below-ground microbial diversity has been implied in studies dedicated to assessing\\u000a the role of macrophyte diversity on the stability, resilience, and functioning of ecosystems. Indeed, above-ground plant communities\\u000a have long been assumed to drive below-ground microbial diversity, but to date very little is known as to how plant species\\u000a composition and diversity influence

George. A. Kowalchuk; Douwe S. Buma; Wietse de Boer; Peter G. L. Klinkhamer; Johannes A. van Veen

2002-01-01

20

Curvilinear Effects of Invasive Plants on Plant Diversity: Plant Community Invaded by Sphagneticola trilobata  

PubMed Central

The effects of invasive plants on the species diversity of plant communities are controversial, showing either a positive or negative linear relationship. Based on community data collected from forty 5 m×5 m plots invaded by Sphagneticola trilobata in eight cities across Hainan Island, China, we found S. trilobata decreased plant community diversity once its cover was beyond 10%. We demonstrated that the effects of invasive/native plants on the plant diversity of communities invaded by S. trilobata were curvilinear. These effects, which showed peaks under different degrees of vegetation cover, appeared not only for S. trilobata and all invasive plants, but also for all native plants. Invasive plants primarily had negative effects on plant diversity when they became abundant at a much lower cover level (less than 35%), compared with the native plants (over 60%). Thus, it is necessary to distinguish a range for assessing the effects of plants, especially invasive plants. Our results also confirmed that the invasion intensity of invasive alien plants increased with the intensity of local economic development. We highlight and further discuss the critical importance of curvilinear effects of biological invasion to provide ideas regarding the conservation of local biodiversity and the management of invasive plants. PMID:25426856

Zhai, De-Li; Chen, Si-Chong; Si, Chun-Can; Huang, Ping; Wang, Rui-Ping; Zhong, Qiong-Xin; Du, Dao-Lin

2014-01-01

21

Effects of herbivores on grassland plant diversity  

Microsoft Academic Search

The role of herbivores in controlling plant species richness is a critical issue in the conservation and management of grassland biodiversity. Numerous field experiments in grassland plant communities show that herbivores often, but not always, increase plant diversity. Recent work suggests that the mechanisms of these effects involve alteration of local colonization of species from regional species pools or local

Han Olff; Mark E. Ritchie

1998-01-01

22

Experimental Tests of Effects of Plant Productivity and Diversity on Grassland Arthropod Diversity  

Microsoft Academic Search

Because the quantity, quality, and heterogeneity of resources should affect the diversity of consumers, plant productivity, plant composition, and plant diversity may influence the diversity of trophic levels higher up the food chain (''bottom-up'' control of diversity). Increasing plant productivity may increase herbivore diversity by: increasing the abundance of rare resources (''resource rarity hypothesis''), increasing herbivore abun- dance and local

Evan Siemann

1998-01-01

23

Plant-Microbe Interactions: Chemical Diversity in Plant Defense  

NSDL National Science Digital Library

Access to the article is free, however registration and sign-in are required. The chemical diversity within the plant kingdom is likely to be a consequence of niche colonization and adaptive evolution. Plant-derived natural products have important functions in defense. They also have broader ecological roles and may in addition participate in plant growth and development.

Pawel Bednarek (Max-Planck-Institut für Züchtungsforschung;Department of Plant Microbe Interactions); Anne Osbourn (John Innes Centre;Department of Metabolic Biology)

2009-05-08

24

Fostering Respect Creating Community DIVERSITY ASSESSMENT  

E-print Network

Fostering Respect · Creating Community DIVERSITY ASSESSMENT 2006-07 Executive Report #12;#12;Purdue respect and creating community. Purdue's commitment to access and diversity is reflected in its 2001 dynamic scholarship, and ultimately welcoming the human and intel- lectual diversity that fuel them. Since

25

LETTER Plant diversity controls arthropod biomass and temporal stability  

E-print Network

relationships between plant and consumer diversity occur primarily via changes in plant production leading to changed consumer production rather than via plant diversity directly controlling con- sumer diversity. Our flux to control diversity, production and stability of both plant and consumer communities. Keywords

Minnesota, University of

26

Assessment of Species Diversity in the Montane Cordillera Ecozone  

NSDL National Science Digital Library

The Ecological Monitoring and Assessment Network has released this 1998 publication entitled "Assessment of species diversity in the Montane Cordillera Ecozone." Extending from the eastern Rocky Mountains in Alberta to the western slope of the Cascades in British Columbia, the Montane Cordillera Ecozone is Canada's sixth largest ecozone, covering "more than 49 million hectares." Diverse in topography and climate, the ecozone's landscape ranges "from alpine tundra to dense coniferous forests, grasslands, riparian woodlands, dry sagebrush and Canada's only true desert." The report covers environmental history, habitat types, and human use of the area, in addition to emphasizing species diversity (namely insects, mammals, fish, plants, fungi, birds, and amphibians and reptiles).

1999-01-01

27

Plant Diversity of Central French Guiana  

NSDL National Science Digital Library

From the New York Botanical Garden's Virtual Herbarium, this "specimen database of flowering plant collections is part of a larger project designed to document the fungal and plant diversity of central French Guiana." A greater goal of the project "is to provide the fungal and plant inventories needed for understanding the evolution and ecological relationships of the fungi, plants, and animals that inhabit this, one of the last tropical wilderness areas of the world." The website provides engines for basic searches as well as detailed searches with fields for Scientific Name (e.g. Family, Genus, Species), Collector/Number, Collector Location (e.g. Country, City, Province/State, County), Type Status, Substrate, and more. Site visitors can also locate specimen records by browsing a Families list and link to more information at the Fungal and Plant Diversity of Central French Guiana Homepage.

28

Functional and phylogenetic diversity of woody plants drive herbivory in a highly diverse forest  

PubMed Central

Biodiversity loss may alter ecosystem processes, such as herbivory, a key driver of ecological functions in species-rich (sub)tropical forests. However, the mechanisms underlying such biodiversity effects remain poorly explored, as mostly effects of species richness – a very basic biodiversity measure – have been studied. Here, we analyze to what extent the functional and phylogenetic diversity of woody plant communities affect herbivory along a diversity gradient in a subtropical forest.We assessed the relative effects of morphological and chemical leaf traits and of plant phylogenetic diversity on individual-level variation in herbivory of dominant woody plant species across 27 forest stands in south-east China.Individual-level variation in herbivory was best explained by multivariate, community-level diversity of leaf chemical traits, in combination with community-weighted means of single traits and species-specific phylodiversity measures. These findings deviate from those based solely on trait variation within individual species.Our results indicate a strong impact of generalist herbivores and highlight the need to assess food-web specialization to determine the direction of biodiversity effects. With increasing plant species loss, but particularly with the concomitant loss of functional and phylogenetic diversity in these forests, the impact of herbivores will probably decrease – with consequences for the herbivore-mediated regulation of ecosystem functions. PMID:24460549

Schuldt, Andreas; Assmann, Thorsten; Bruelheide, Helge; Durka, Walter; Eichenberg, David; Härdtle, Werner; Kröber, Wenzel; Michalski, Stefan G; Purschke, Oliver

2014-01-01

29

A hierarchical perspective of plant diversity  

USGS Publications Warehouse

Predictive models of plant diversity have typically focused on either a landscapea??s capacity for richness (equilibrium models), or on the processes that regulate competitive exclusion, and thus allow species to coexist (nonequilibrium models). Here, we review the concepts and purposes of a hierarchical, multiscale model of the controls of plant diversity that incorporates the equilibrium model of climatic favorability at macroscales, nonequilibrium models of competition at microscales, and a mixed model emphasizing environmental heterogeneity at mesoscales. We evaluate the conceptual model using published data from three spatially nested datasets: (1) a macroscale analysis of ecoregions in the continental and western U.S.; (2) a mesoscale study in California; and (3) a microscale study in the Siskiyou Mountains of Oregon and California. At the macroscale (areas from 3889 km2 to 638,300 km2), climate (actual evaporation) was a strong predictor of tree diversity (R2 = 0.80), as predicted by the conceptual model, but area was a better predictor for vascular plant diversity overall (R2 = 0.38), which suggests different types of plants differ in their sensitivity to climatic controls. At mesoscales (areas from 1111 km2 to 15,833 km2 ), climate was still an important predictor of richness (R2 = 0.52), but, as expected, topographic heterogeneity explained an important share of the variance (R2 = 0.19), showed positive correlations with diversity of trees, shrubs, and annual and perennial herbs, and was the primary predictor of shrub and annual plant species richness. At microscales (0.1 ha plots), spatial patterns of diversity showed a clear unimodal pattern along a climatea??driven productivity gradient and a negative relationship with soil fertility. The strong decline in understory and total diversity at the most productive sites suggests that competitive controls, as predicted, can override climatic controls at this scale. We conclude that this hierarchical, multiscale model provides a sound basis to understand and analyze plant species diversity. Specifically, future research should employ the principles in this paper to explore climatic controls on species richness of different life forms, better quantify environmental heterogeneity in landscapes, and analyze how these largea??scale factors interact with local nonequilibrium dynamics to maintain plant diversity.

Sarr, Daniel; Hibbs, D.E.; Huston, M.

2005-01-01

30

The Tight Link: Beetle and Plant Diversity  

NSDL National Science Digital Library

This week's In The News focuses on the evolutionary link between beetle (Coleoptera) and flowering plant (Angiosperm) diversity. In an article published in the July 24, 1998 issue of Science, Harvard University evolutionary entomologist Brian Farrell shed new light on insect-plant evolution when he revealed "a tight link between plant and beetle diversity." Farrell found that the incredible diversity of beetles--a whopping 330,000 species are estimated today--is linked to the rise of the angiosperms some 100,000,000 years ago. According to Farrell, although some beetles maintained their preference for older plant classes such as cycads and conifers, "well over 100,000 new species of beetles arose because of that move to angiosperms." The significance of these findings, says Farrell, "show how moving into a new environment, where there's no competition, can free you for an explosive, adaptive radiation." The nine resources provided offer insights and information on beetle and plant diversity, and several evolutionary resources as well.

Payne, Laura X.

1998-01-01

31

Plant species diversity in Amazonian forests M. R. Silman  

E-print Network

#12;#12;10 Plant species diversity in Amazonian forests M. R. Silman 10.1 INTRODUCTION Looking diverse on the planet, estimated to harbor 30,000 species of vascular plants, with 5,000±10,000 species of Neotropical forests as spectacularly diverse, how diversity is distributed across the landscape is less well

Silman, Miles R.

32

Plant diversity predicts beta but not alpha diversity of soil microbes across grasslands worldwide  

USGS Publications Warehouse

Aboveground–belowground interactions exert critical controls on the composition and function of terrestrial ecosystems, yet the fundamental relationships between plant diversity and soil microbial diversity remain elusive. Theory predicts predominantly positive associations but tests within single sites have shown variable relationships, and associations between plant and microbial diversity across broad spatial scales remain largely unexplored. We compared the diversity of plant, bacterial, archaeal and fungal communities in one hundred and forty-five 1 m2 plots across 25 temperate grassland sites from four continents. Across sites, the plant alpha diversity patterns were poorly related to those observed for any soil microbial group. However, plant beta diversity (compositional dissimilarity between sites) was significantly correlated with the beta diversity of bacterial and fungal communities, even after controlling for environmental factors. Thus, across a global range of temperate grasslands, plant diversity can predict patterns in the composition of soil microbial communities, but not patterns in alpha diversity.

Prober, Suzanne M.; Leff, Jonathan W.; Bates, Scott T.; Borer, Elizabeth T.; Firn, Jennifer; Harpole, W. Stanley; Lind, Eric M.; Seabloom, Eric W.; Adler, Peter B.; Bakker, Jonathan D.; Cleland, Elsa E.; DeCrappeo, Nicole; DeLorenze, Elizabeth; Hagenah, Nicole; Hautier, Yann; Hofmockel, Kirsten S.; Kirkman, Kevin P.; Knops, Johannes M. H.; La Pierre, Kimberly J.; MacDougall, Andrew S.; McCulley, Rebecca L.; Mitchell, Charles E.; Risch, Anita C.; Schuetz, Martin; Stevens, Carly J.; Williams, Ryan J.; Fierer, Noah

2015-01-01

33

Plant diversity predicts beta but not alpha diversity of soil microbes across grasslands worldwide.  

PubMed

Aboveground-belowground interactions exert critical controls on the composition and function of terrestrial ecosystems, yet the fundamental relationships between plant diversity and soil microbial diversity remain elusive. Theory predicts predominantly positive associations but tests within single sites have shown variable relationships, and associations between plant and microbial diversity across broad spatial scales remain largely unexplored. We compared the diversity of plant, bacterial, archaeal and fungal communities in one hundred and forty-five 1 m(2) plots across 25 temperate grassland sites from four continents. Across sites, the plant alpha diversity patterns were poorly related to those observed for any soil microbial group. However, plant beta diversity (compositional dissimilarity between sites) was significantly correlated with the beta diversity of bacterial and fungal communities, even after controlling for environmental factors. Thus, across a global range of temperate grasslands, plant diversity can predict patterns in the composition of soil microbial communities, but not patterns in alpha diversity. PMID:25430889

Prober, Suzanne M; Leff, Jonathan W; Bates, Scott T; Borer, Elizabeth T; Firn, Jennifer; Harpole, W Stanley; Lind, Eric M; Seabloom, Eric W; Adler, Peter B; Bakker, Jonathan D; Cleland, Elsa E; DeCrappeo, Nicole M; DeLorenze, Elizabeth; Hagenah, Nicole; Hautier, Yann; Hofmockel, Kirsten S; Kirkman, Kevin P; Knops, Johannes M H; La Pierre, Kimberly J; MacDougall, Andrew S; McCulley, Rebecca L; Mitchell, Charles E; Risch, Anita C; Schuetz, Martin; Stevens, Carly J; Williams, Ryan J; Fierer, Noah

2015-01-01

34

Straight Talk about Cognitive Assessment and Diversity.  

ERIC Educational Resources Information Center

Discusses three reasons explaining heightened interest in alternative assessment in the context of diversity issues in school psychology: inadequacy of traditional test use with language populations for whom tests were not designed; the hope that alternative assessment will eliminate, reduce, or camouflage average score differences between…

Frisby, Craig L.

1999-01-01

35

Effects of above-ground plant species composition and diversity on the diversity of soil-borne microorganisms.  

PubMed

A coupling of above-ground plant diversity and below-ground microbial diversity has been implied in studies dedicated to assessing the role of macrophyte diversity on the stability, resilience, and functioning of ecosystems. Indeed, above-ground plant communities have long been assumed to drive below-ground microbial diversity, but to date very little is known as to how plant species composition and diversity influence the community composition of micro-organisms in the soil. We examined this relationship in fields subjected to different above-ground biodiversity treatments and in field experiments designed to examine the influence of plant species on soil-borne microbial communities. Culture-independent strategies were applied to examine the role of wild or native plant species composition on bacterial diversity and community structure in bulk soil and in the rhizosphere. In comparing the influence of Cynoglossum officinale (hound's tongue) and Cirsium vulgare (spear thistle) on soil-borne bacterial communities, detectable differences in microbial community structure were confined to the rhizosphere. The colonisation of the rhizosphere of both plants was highly reproducible, and maintained throughout the growing season. In a separate experiment, effects of plant diversity on bacterial community profiles were also only observed for the rhizosphere. Rhizosphere soil from experimental plots with lower macrophyte diversity showed lower diversity, and bacterial diversity was generally lower in the rhizosphere than in bulk soil. These results demonstrate that the level of coupling between above-ground macrophyte communities and below-ground microbial communities is related to the tightness of the interactions involved. Although plant species composition and community structure appear to have little discernible effect on microbial communities inhabiting bulk soil, clear and reproducible changes in microbial community structure and diversity are observed in the rhizosphere. PMID:12448746

Kowalchuk, George A; Buma, Douwe S; de Boer, Wietse; Klinkhamer, Peter G L; van Veen, Johannes A

2002-08-01

36

Assessing bacterial diversity in a seawater-processing wastewater treatment plant by 454-pyrosequencing of the 16S rRNA and amoA genes  

PubMed Central

Summary The bacterial community composition of activated sludge from a wastewater treatment plant (Almería, Spain) with the particularity of using seawater was investigated by applying 454-pyrosequencing. The results showed that Deinococcus-Thermus, Proteobacteria, Chloroflexi and Bacteroidetes were the most abundant retrieved sequences, while other groups, such as Actinobacteria, Chlorobi, Deferribacteres, Firmicutes, Planctomycetes, Spirochaetes and Verrumicrobia were reported at lower proportions. Rarefaction analysis showed that very likely the diversity is higher than what could be described despite most of the unknown microorganisms probably correspond to rare diversity. Furthermore, the majority of taxa could not be classified at the genus level and likely represent novel members of these groups. Additionally, the nitrifiers in the sludge were characterized by pyrosequencing the amoA gene. In contrast, the nitrifying bacterial community, dominated by the genera Nitrosomonas, showed a low diversity and rarefaction curves exhibited saturation. These results suggest that only a few populations of low abundant but specialized bacteria are responsible for removal of ammonia in these saline wastewater systems. PMID:23574645

Sánchez, Olga; Ferrera, Isabel; González, Jose M; Mas, Jordi

2013-01-01

37

Understanding local and regional plant diversity: species pools, species saturation, and the multi-scalar effects of plant productivity  

E-print Network

-scalar effects of plant productivity Joel M. Gramling A dissertation submitted to the faculty of the University saturation, and the multi-scalar effects of plant productivity (Under the direction of Robert K. Peet. The generality of the productivity-diversity relationship is assessed across ecologically-distinct plant

Peet, Robert K.

38

An experimental test of the effect of plant functional group diversity on arthropod diversity  

Microsoft Academic Search

Characteristics used to categorize plant species into functional groups for their effects on ecosystem functioning may also be relevant to higher trophic levels. In addition, plant and consumer diversity should be positively related because more diverse plant communities offer a greater variety of resources for the consumers. Thus, the functional group composition and richness of a plant community may affect

Amy J. Symstad; Evan Siemann; John Haarstad

2000-01-01

39

Herbivory enhances positive effects of plant genotypic diversity.  

PubMed

Both plant diversity and vertebrate herbivores can impact plant fitness and ecosystem functioning, however their interactions have not been explicitly tested. We manipulated plant genotypic diversity of the native plant Oenothera biennis and monitored its survivorship and lifetime fitness with and without one of its major vertebrate consumers, white-tailed deer Odocoileus virginianus. Intense but unmanipulated herbivory by meadow voles Microtus pennsylvanicus killed over 70% of nearly 4000 experimental plants. However, plants grown in genotypically diverse patches suffered fewer vole attacks and had higher survival and reproductive output than plants in monoculture. Moreover, positive effects of genotypic diversity were enhanced by the presence of deer, indicating a non-additive interaction between diversity and trophic-level complexity. Genetic selection analyses showed that the selective value of ecologically important traits depended on plant diversity and exposure to deer, demonstrating that community complexity can promote fitness through multiple ecologically and evolutionarily important feedbacks. PMID:20298460

Parker, John D; Salminen, Juha-Pekka; Agrawal, Anurag A

2010-05-01

40

Functional Diversity of Plant–Pollinator Interaction Webs Enhances the Persistence of Plant Communities  

PubMed Central

Pollination is exclusively or mainly animal mediated for 70% to 90% of angiosperm species. Thus, pollinators provide an essential ecosystem service to humankind. However, the impact of human-induced biodiversity loss on the functioning of plant–pollinator interactions has not been tested experimentally. To understand how plant communities respond to diversity changes in their pollinating fauna, we manipulated the functional diversity of both plants and pollinators under natural conditions. Increasing the functional diversity of both plants and pollinators led to the recruitment of more diverse plant communities. After two years the plant communities pollinated by the most functionally diverse pollinator assemblage contained about 50% more plant species than did plant communities pollinated by less-diverse pollinator assemblages. Moreover, the positive effect of functional diversity was explained by a complementarity between functional groups of pollinators and plants. Thus, the functional diversity of pollination networks may be critical to ecosystem sustainability. PMID:16332160

Dajoz, Isabelle; Meriguet, Jacques; Loreau, Michel

2006-01-01

41

Synthesis and assessment of date palm genetic diversity studies  

Technology Transfer Automated Retrieval System (TEKTRAN)

A thorough assessment of genetic diversity and population differentiation of Phoenix dactylifera are critical for its dynamic conservation and sustainable utilization of its genetic diversity. Estimates of genetic diversity based on phenotypic, biochemical and molecular markers; and fruit quality tr...

42

PLANT DIVERSITY OF WESTERN CHITWAN FLORISTIC APPROACH  

PubMed Central

This paper identifies and documents the plant biodiversity of western Chitwan, Nepal. Specifically, our attention was focussed on the plants of forests, grasslands and common lands based on our “Reciprocal Relation of Population and Environment Study Project” conducted during January-April 1996. This species-diversity of trees, shrubs and herbaceous flora was recorded from 117, 117, and 1049 sampling quadrats of 10×10, 3×3 and 1×1 m2, respectively. The flora of our study plots contains 236 species that belong to 191 genera and 66 families. Of 236 species of plants, 119, 113, 59, 35 and 119 species were recorded from Tikauli forest, National Park forest, forests along the Narayani river, grasslands of National Park and common lands of the western Chitwan, respectively. Dicotyledons represent 184 (77.97%) species of the total flora species followed by monocotyledons (46 spp., 19.49%) and ferns (6 spp., 2.54%), respectively. The five largest families are Leguminosae (38 spp.), Poaceae (27 spp.), Asteraceae (22 spp.), Rubiaceae (10 spp.), and Scrophulariaceae (9 spp.). Hedyotis, Grewia and Lindernia, each with 4 spp., are the most speciose genera in the flora. PMID:22899874

Dangol, D. R.; Shivakoti, G. P.

2012-01-01

43

ORIGINAL PAPER Plant genotypic diversity and environmental stress interact  

E-print Network

(Populus tremuloides Michx.). We found that varying plant geno- typic diversity and watering treatment Populus tremuloides Introduction With growing concerns about species extinctions, many researchers have

Pfrender, Michael

44

Pathogens promote plant diversity through a compensatory response  

Microsoft Academic Search

Pathogens are thought to promote diversity in plant communities by preventing competitive exclusion. Previous studies have focussed primarily on single-plant, single- pathogen interactions, yet the interactions between multiple pathogens and multiple hosts may have non-additive impacts on plant community composition. Here, we report that both a bacterial and a fungal pathogen maintained the diversity of a four-species plant community across

Devon J. Bradley; Gregory S. Gilbert; Jennifer B. H. Martiny

2008-01-01

45

Conserving plant genetic diversity for dependent animal communities  

Microsoft Academic Search

While population genetic diversity has broad application in species conservation, no studies have examined the community-level consequences of this diversity. We show that population genetic diversity (generated by interspecific hybridization) in a dominant riparian tree affects an arthropod community composed of 207 species. In an experimental garden, plant cross type structured the arthropod community of individual trees, and among stands

Gina Marie Wimp; William P. Young; Scott A. Woolbright; Gregory D. Martinsen; Paul Keim; Thomas G. Whitham

2004-01-01

46

REGIONAL AND SEASONAL DIFFERENCES IN PASTURE PLANT DIVERSITY  

Technology Transfer Automated Retrieval System (TEKTRAN)

Most research on the potential benefits of plant diversity, including increased production and resistance to stress, has been carried out in ungrazed areas. Very little information is available on plant species diversity in the pastures of the northeastern United States, and even less on seasonal pa...

47

Plant species richness drives the density and diversity of Collembola in temperate grassland  

NASA Astrophysics Data System (ADS)

Declining biodiversity is one of the most important aspects of anthropogenic global change phenomena, but the implications of plant species loss for soil decomposers are little understood. We used the experimental grassland community of the Jena Experiment to assess the response of density and diversity of Collembola to varying plant species richness, plant functional group richness and plant functional group identity. We sampled the experimental plots in spring and autumn four years after establishment of the experimental plant communities. Collembola density and diversity significantly increased with plant species and plant functional group richness highlighting the importance of the singular hypothesis for soil invertebrates. Generally, grasses and legumes beneficially affected Collembola density and diversity, whereas effects of small herbs usually were detrimental. These impacts were largely consistent in spring and autumn. By contrast, in the presence of small herbs the density of hemiedaphic Collembola and the diversity of Isotomidae increased in spring whereas they decreased in autumn. Beneficial impacts of plant diversity as well as those of grasses and legumes were likely due to increased root and microbial biomass, and elevated quantity and quality of plant residues serving as food resources for Collembola. By contrast, beneficial impacts of small herbs in spring probably reflect differences in microclimatic conditions, and detrimental effects in autumn likely were due to low quantity and quality of resources. The results point to an intimate relationship between plants and the diversity of belowground biota, even at small spatial scales, contrasting the findings of previous studies. The pronounced response of soil animals in the present study was presumably due to the fact that plant communities had established over several years. As decomposer invertebrates significantly impact plant performance, changes in soil biota density and diversity are likely to have major feedbacks on plant community productivity and composition.

Sabais, Alexander C. W.; Scheu, Stefan; Eisenhauer, Nico

2011-05-01

48

Assessment of genetic diversity of sweet potato in puerto rico.  

PubMed

Sweet potato (Ipomoea batatas L.) is the seventh most important food crop due to its distinct advantages, such as adaptability to different environmental conditions and high nutritional value. Assessing the genetic diversity of this important crop is necessary due to the constant increase of demand for food and the need for conservation of agricultural and genetic resources. In Puerto Rico (PR), the genetic diversity of sweet potato has been poorly understood, although it has been part of the diet since Pre-Columbus time. Thus, 137 landraces from different localities around PR were collected and subjected to a genetic diversity analysis using 23 SSR-markers. In addition, 8 accessions from a collection grown in Gurabo, PR at the Agricultural Experimental Station (GAES), 10 US commercial cultivars and 12 Puerto Rican accessions from the USDA repository collection were included in this assessment. The results of the analysis of the 23 loci showed 255 alleles in the 167 samples. Observed heterozygosity was high across populations (0.71) while measurements of total heterozygosity revealed a large genetic diversity throughout the population and within populations. UPGMA clustering method revealed two main clusters. Cluster 1 contained 12 PR accessions from the USDA repository collection, while cluster 2 consisted of PR landraces, US commercial cultivars and the PR accessions from GAES. Population structure analysis grouped PR landraces in five groups including four US commercial cultivars. Our study shows the presence of a high level of genetic diversity of sweet potato across PR which can be related to the genetic makeup of sweet potato, human intervention and out-crossing nature of the plant. The history of domestication and dispersal of sweet potato in the Caribbean and the high levels of genetic diversity found through this study makes sweet potato an invaluable resource that needs to be protected and further studied. PMID:25551388

Rodriguez-Bonilla, Lorraine; Cuevas, Hugo E; Montero-Rojas, Milly; Bird-Pico, Fernando; Luciano-Rosario, Dianiris; Siritunga, Dimuth

2014-01-01

49

Assessment of Genetic Diversity of Sweet Potato in Puerto Rico  

PubMed Central

Sweet potato (Ipomoea batatas L.) is the seventh most important food crop due to its distinct advantages, such as adaptability to different environmental conditions and high nutritional value. Assessing the genetic diversity of this important crop is necessary due to the constant increase of demand for food and the need for conservation of agricultural and genetic resources. In Puerto Rico (PR), the genetic diversity of sweet potato has been poorly understood, although it has been part of the diet since Pre-Columbus time. Thus, 137 landraces from different localities around PR were collected and subjected to a genetic diversity analysis using 23 SSR-markers. In addition, 8 accessions from a collection grown in Gurabo, PR at the Agricultural Experimental Station (GAES), 10 US commercial cultivars and 12 Puerto Rican accessions from the USDA repository collection were included in this assessment. The results of the analysis of the 23 loci showed 255 alleles in the 167 samples. Observed heterozygosity was high across populations (0.71) while measurements of total heterozygosity revealed a large genetic diversity throughout the population and within populations. UPGMA clustering method revealed two main clusters. Cluster 1 contained 12 PR accessions from the USDA repository collection, while cluster 2 consisted of PR landraces, US commercial cultivars and the PR accessions from GAES. Population structure analysis grouped PR landraces in five groups including four US commercial cultivars. Our study shows the presence of a high level of genetic diversity of sweet potato across PR which can be related to the genetic makeup of sweet potato, human intervention and out-crossing nature of the plant. The history of domestication and dispersal of sweet potato in the Caribbean and the high levels of genetic diversity found through this study makes sweet potato an invaluable resource that needs to be protected and further studied. PMID:25551388

Rodriguez-Bonilla, Lorraine; Cuevas, Hugo E.; Montero-Rojas, Milly; Bird-Pico, Fernando; Luciano-Rosario, Dianiris; Siritunga, Dimuth

2014-01-01

50

78 FR 47272 - Monsanto Co.; Availability of Plant Pest Risk Assessment and Environmental Assessment for...  

Federal Register 2010, 2011, 2012, 2013

...soybean is unlikely to pose a plant pest risk and, therefore...comment period include effects on plant and animal diversity, soybean...and prices, and organic soy production; gene flow; and food and...impact (FONSI), and its plant pest risk assessment...

2013-08-05

51

Host plant genus-level diversity is the best predictor of ectomycorrhizal fungal diversity in a Chinese  

E-print Network

for Environmental Research, Halle 06120, Germany Abstract Microbial diversity is generally far higher than plant diversity, but the relationship between microbial diversity and plant diversity remains enigmatic. To shed to explain patterns of soil microbial diversity (Hooper et al. 2000; Waldrop et al. 2006). This hypothe- sis

Bruns, Tom

52

and traditional rural homegardens in Zululand to (1) assess the useful-plant diversity, (2) determine the origin of the species  

E-print Network

also form symbiotic relationships with rhizobial bacteria that fix atmospheric nitrogen in root nodules- garden floras are collectively planted and positioned according to cultural practices passed down

53

Global patterns and determinants of vascular plant diversity  

E-print Network

Global patterns and determinants of vascular plant diversity Holger Kreft* and Walter Jetz *Nees data. Here, we investigate the global-scale species-richness pattern of vascular plants and examine its, such as vascular plants, will long remain elusive. Thus, the method of choice is analyzing the species

Kreft, Holger

54

Plant-Pollinator Coextinctions and the Loss of Plant Functional and Phylogenetic Diversity  

PubMed Central

Plant-pollinator coextinctions are likely to become more frequent as habitat alteration and climate change continue to threaten pollinators. The consequences of the resulting collapse of plant communities will depend partly on how quickly plant functional and phylogenetic diversity decline following pollinator extinctions. We investigated the functional and phylogenetic consequences of pollinator extinctions by simulating coextinctions in seven plant-pollinator networks coupled with independent data on plant phylogeny and functional traits. Declines in plant functional diversity were slower than expected under a scenario of random extinctions, while phylogenetic diversity often decreased faster than expected by chance. Our results show that plant functional diversity was relatively robust to plant-pollinator coextinctions, despite the underlying rapid loss of evolutionary history. Thus, our study suggests the possibility of uncoupled responses of functional and phylogenetic diversity to species coextinctions, highlighting the importance of considering both dimensions of biodiversity explicitly in ecological studies and when planning for the conservation of species and interactions. PMID:24312281

Vieira, Marcos Costa; Cianciaruso, Marcus Vinicius; Almeida-Neto, Mário

2013-01-01

55

MSU Departmental Assessment Plan Department: Plant Sciences and Plant Pathology  

E-print Network

Production option #12;Department of Plant Sciences and Plant Pathology Assessment and Outcomes Progress 2010MSU Departmental Assessment Plan 2009-2010 Department: Plant Sciences and Plant Pathology/Majors/Options Offered by Department List here Plant Sciences major Crop Science option Plant Biology option

Maxwell, Bruce D.

56

B Plant hazards assessment  

SciTech Connect

This document establishes the technical basis in support of Emergency Planning Activities for B Plant on the Hanford Site. The document represents an acceptable interpretation of the implementing guidance document for DOE Order 5500.3A. Through this document, the technical basis for the development of facility specific , Emergency Action Levels and the Emergency Planning Zone is demonstrated.

Broz, R.E.

1994-09-23

57

Effect of snow-cover duration on plant species diversity of alpine meadows on the eastern Qinghai-Tibetan Plateau  

Microsoft Academic Search

Although snow cover plays an important role in structuring plant diversity in the alpine zone, there are few studies on the\\u000a relationship between snow cover and species diversity of alpine meadows on the eastern Qinghai-Tibetan Plateau. To assess\\u000a the effect of snow cover on plant species diversity of alpine meadows, we used ten parallel transects of 60 m × 1

Wennian Chen; Yan Wu; Ning Wu; Peng Luo

2008-01-01

58

Soil microbes drive the classic plant diversity­ productivity pattern  

E-print Network

Ecosystem productivity commonly increases asymptotically with plant species diversity, and determining the mechanisms responsible for this well-known pattern is essential to predict potential changes in ecosystem productivity with ongoing species...

Schnitzer, Stefan A.; Klironomos, John N.; HilleRisLambers, Jannek; Kinkel, Linda L.; Reich, Peter B.; Xiao, Kun; Rillig, Matthias C.; Sikes, Benjamin A.; Callaway, Ragan M.; Mangan, Scott A.; van Nes, Egbert H.; Scheffer, Marten

2011-02-01

59

ORIGINAL PAPER Resident plant diversity and introduced earthworms have  

E-print Network

ORIGINAL PAPER Resident plant diversity and introduced earthworms have contrasting effects such as earthworms can also affect invasibility by reducing leaf litter stocks and influencing soil conditions. In a greenhouse experiment, we simulta- neously manipulated resident species diversity and earthworm presence

Minnesota, University of

60

Plant diversity impacts decomposition and herbivory via changes in aboveground arthropods.  

PubMed

Loss of plant diversity influences essential ecosystem processes as aboveground productivity, and can have cascading effects on the arthropod communities in adjacent trophic levels. However, few studies have examined how those changes in arthropod communities can have additional impacts on ecosystem processes caused by them (e.g. pollination, bioturbation, predation, decomposition, herbivory). Therefore, including arthropod effects in predictions of the impact of plant diversity loss on such ecosystem processes is an important but little studied piece of information. In a grassland biodiversity experiment, we addressed this gap by assessing aboveground decomposer and herbivore communities and linking their abundance and diversity to rates of decomposition and herbivory. Path analyses showed that increasing plant diversity led to higher abundance and diversity of decomposing arthropods through higher plant biomass. Higher species richness of decomposers, in turn, enhanced decomposition. Similarly, species-rich plant communities hosted a higher abundance and diversity of herbivores through elevated plant biomass and C:N ratio, leading to higher herbivory rates. Integrating trophic interactions into the study of biodiversity effects is required to understand the multiple pathways by which biodiversity affects ecosystem functioning. PMID:25226237

Ebeling, Anne; Meyer, Sebastian T; Abbas, Maike; Eisenhauer, Nico; Hillebrand, Helmut; Lange, Markus; Scherber, Christoph; Vogel, Anja; Weigelt, Alexandra; Weisser, Wolfgang W

2014-01-01

61

Plant Diversity Impacts Decomposition and Herbivory via Changes in Aboveground Arthropods  

PubMed Central

Loss of plant diversity influences essential ecosystem processes as aboveground productivity, and can have cascading effects on the arthropod communities in adjacent trophic levels. However, few studies have examined how those changes in arthropod communities can have additional impacts on ecosystem processes caused by them (e.g. pollination, bioturbation, predation, decomposition, herbivory). Therefore, including arthropod effects in predictions of the impact of plant diversity loss on such ecosystem processes is an important but little studied piece of information. In a grassland biodiversity experiment, we addressed this gap by assessing aboveground decomposer and herbivore communities and linking their abundance and diversity to rates of decomposition and herbivory. Path analyses showed that increasing plant diversity led to higher abundance and diversity of decomposing arthropods through higher plant biomass. Higher species richness of decomposers, in turn, enhanced decomposition. Similarly, species-rich plant communities hosted a higher abundance and diversity of herbivores through elevated plant biomass and C:N ratio, leading to higher herbivory rates. Integrating trophic interactions into the study of biodiversity effects is required to understand the multiple pathways by which biodiversity affects ecosystem functioning. PMID:25226237

Ebeling, Anne; Meyer, Sebastian T.; Abbas, Maike; Eisenhauer, Nico; Hillebrand, Helmut; Lange, Markus; Scherber, Christoph; Vogel, Anja; Weigelt, Alexandra; Weisser, Wolfgang W.

2014-01-01

62

Plant Chitinases: Genetic Diversity and Physiological Roles  

Microsoft Academic Search

Chitinase proteins are widely distributed across diverse biological systems. Chitinases hydrolyze chitin, chitosan, lipochitooligosaccharides, peptidoglycan, arabinogalactan and glycoproteins containing N-acetylglucosamine. Analyses of genome-wide sequence and microarray expression profilings show that chitinase genes are represented by large families and the individual member genes are expressed in diverse conditions. Chitinase proteins are members in the group of the pathogenesis-related proteins that are

Anita Grover

2012-01-01

63

Management intensity and topography determined plant diversity in vineyards.  

PubMed

Vineyards are amongst the most intensive forms of agriculture often resulting in simplified landscapes where semi-natural vegetation is restricted to small scattered patches. However, a tendency toward a more sustainable management is stimulating research on biodiversity in these poorly investigated agro-ecosystems. The main aim of this study was to test the effect on plant diversity of management intensity and topography in vineyards located in a homogenous intensive hilly landscape. Specifically, this study evaluated the role of slope, mowing and herbicide treatments frequency, and nitrogen supply in shaping plant diversity and composition of life-history traits. The study was carried out in 25 vineyards located in the area of the Conegliano-Valdobbiadene DOCG (Veneto, NE Italy). In each vineyard, 10 plots were placed and the abundance of all vascular plants was recorded in each plot. Linear multiple regression was used to test the effect of management and topography on plant diversity. Management intensity and topography were both relevant drivers of plant species diversity patterns in our vineyards. The two most important factors were slope and mowing frequency that respectively yielded positive and negative effects on plant diversity. A significant interaction between these two factors was also demonstrated, warning against the detrimental effects of increasing mowing intensity on steep slope where plant communities are more diverse. The response of plant communities to mowing frequency is mediated by a process of selection of resistant growth forms, such in the case of rosulate and reptant species. The other two management-related factors tested in this study, number of herbicide treatments and N fertilization, were less influential. In general, our study corroborates the idea that some simple changes in farming activities, which are compatible with grape production, should be encouraged for improving the natural and cultural value of the landscape by maintaining and improving wild plant diversity. PMID:24098435

Nascimbene, Juri; Marini, Lorenzo; Ivan, Diego; Zottini, Michela

2013-01-01

64

Severe plant invasions can increase mycorrhizal fungal abundance and diversity.  

PubMed

Invasions by non-native plants can alter ecosystem functions and reduce native plant diversity, but relatively little is known about their effect on belowground microbial communities. We show that invasions by knapweed (Centaurea stoebe) and leafy spurge (Euphorbia esula, hereafter spurge)--but not cheatgrass (Bromus tectorum)--support a higher abundance and diversity of symbiotic arbuscular mycorrhizal fungi (AMF) than multi-species native plant communities. The higher AMF richness associated with knapweed and spurge is unlikely due to a co-invasion by AMF, because a separate sampling showed that individual native forbs hosted a similar AMF abundance and richness as exotic forbs. Native grasses associated with fewer AMF taxa, which could explain the reduced AMF richness in native, grass-dominated communities. The three invasive plant species harbored distinct AMF communities, and analyses of co-occurring native and invasive plants indicate that differences were partly driven by the invasive plants and were not the result of pre-invasion conditions. Our results suggest that invasions by mycotrophic plants that replace poorer hosts can increase AMF abundance and richness. The high AMF richness in monodominant plant invasions also indicates that the proposed positive relationship between above and belowground diversity is not always strong. Finally, the disparate responses among exotic plants and consistent results between grasses and forbs suggest that AMF respond more to plant functional group than plant provenance. PMID:23486251

Lekberg, Ylva; Gibbons, Sean M; Rosendahl, Søren; Ramsey, Philip W

2013-07-01

65

Environmental filtering explains variation in plant diversity along resource gradients.  

PubMed

The mechanisms that shape plant diversity along resource gradients remain unresolved because competing theories have been evaluated in isolation. By testing multiple theories simultaneously across a >2-million-year dune chronosequence in an Australian biodiversity hotspot, we show that variation in plant diversity is not explained by local resource heterogeneity, resource partitioning, nutrient stoichiometry, or soil fertility along this strong resource gradient. Rather, our results suggest that diversity is determined by environmental filtering from the regional flora, driven by soil acidification during long-term pedogenesis. This finding challenges the prevailing view that resource competition controls local plant diversity along resource gradients, and instead reflects processes shaping species pools over evolutionary time scales. PMID:25258078

Laliberté, Etienne; Zemunik, Graham; Turner, Benjamin L

2014-09-26

66

Evolution of sexThe evolution of plant sexual diversity  

Microsoft Academic Search

Charles Darwin recognized that flowering plants have an unrivalled diversity of sexual systems. Determining the ecological and genetic factors that govern sexual diversification in plants is today a central problem in evolutionary biology. The integration of phylogenetic, ecological and population-genetic studies have provided new insights into the selective mechanisms that are responsible for major evolutionary transitions between reproductive modes.

Spencer C. H. Barrett

2002-01-01

67

Polyamine biosynthetic diversity in plants and algae.  

PubMed

Polyamine biosynthesis in plants differs from other eukaryotes because of the contribution of genes from the cyanobacterial ancestor of the chloroplast. Plants possess an additional biosynthetic route for putrescine formation from arginine, consisting of the enzymes arginine decarboxylase, agmatine iminohydrolase and N-carbamoylputrescine amidohydrolase, derived from the cyanobacterial ancestor. They also synthesize an unusual tetraamine, thermospermine, that has important developmental roles and which is evolutionarily more ancient than spermine in plants and algae. Single-celled green algae have lost the arginine route and are dependent, like other eukaryotes, on putrescine biosynthesis from the ornithine. Some plants like Arabidopsis thaliana and the moss Physcomitrella patens have lost ornithine decarboxylase and are thus dependent on the arginine route. With its dependence on the arginine route, and the pivotal role of thermospermine in growth and development, Arabidopsis represents the most specifically plant mode of polyamine biosynthesis amongst eukaryotes. A number of plants and algae are also able to synthesize unusual polyamines such as norspermidine, norspermine and longer polyamines, and biosynthesis of these amines likely depends on novel aminopropyltransferases similar to thermospermine synthase, with relaxed substrate specificity. Plants have a rich repertoire of polyamine-based secondary metabolites, including alkaloids and hydroxycinnamic amides, and a number of polyamine-acylating enzymes have been recently characterised. With the genetic tools available for Arabidopsis and other model plants and algae, and the increasing capabilities of comparative genomics, the biological roles of polyamines can now be addressed across the plant evolutionary lineage. PMID:20227886

Fuell, Christine; Elliott, Katherine A; Hanfrey, Colin C; Franceschetti, Marina; Michael, Anthony J

2010-07-01

68

High plant diversity in Eocene South America: Evidence from Patagonia  

USGS Publications Warehouse

Tropical South America has the highest plant diversity of any region today, but this richness is usually characterized as a geologically recent development (Neogene or Pleistocene). From caldera-lake beds exposed at Laguna del Hunco in Patagonia, Argentina, paleolatitude ???47??S, we report 102 leaf species. Radioisotopic and paleomagnetic analyses indicate that the flora was deposited 52 million years ago, the time of the early Eocene climatic optimum, when tropical plant taxa and warm, equable climates reached middle latitudes of both hemispheres. Adjusted for sample size, observed richness exceeds that of any other Eocene leaf flora, supporting an ancient history of high plant diversity in warm areas of South America.

Wilf, P.; Cuneo, N.R.; Johnson, K.R.; Hicks, J.F.; Wing, S.L.; Obradovich, J.D.

2003-01-01

69

Diversity reduces invasibility in experimental plant communities: the role of plant species  

Microsoft Academic Search

Several studies have presented experimental evidence that diversity reduces invasibility in grassland communities. The interpretation of these results has been disputed recently and it was proposed that sampling effects were responsible for the observed decrease of invasibility with diversity. The experiments performed to date were not designed to adequately separate sampling from diversity effects. Using the establishment of native plant

Jasper van Ruijven; Gerlinde B. De Deyn; Frank Berendse

2003-01-01

70

Additive and interactive effects of plant genotypic diversity on arthropod communities and plant fitness  

E-print Network

LETTER Additive and interactive effects of plant genotypic diversity on arthropod communities with monocultures. The effects of genotypic diversity on arthropod communities were due to a combination diversity can have similar qualitative and quantitative effects on arthropod communities. Our findings also

Agrawal, Anurag

71

Using Phylogenetic, Functional and Trait Diversity to Understand Patterns of Plant Community Productivity  

E-print Network

Using Phylogenetic, Functional and Trait Diversity to Understand Patterns of Plant Community decades of research showing that increasing plant diversity results in greater community productivity has approach, and 7) a phylogenetic diversity measure, summing phylogenetic branch lengths connecting community

Minnesota, University of

72

Native plant diversity increases herbivory to non-natives.  

PubMed

There is often an inverse relationship between the diversity of a plant community and the invasibility of that community by non-native plants. Native herbivores that colonize novel plants may contribute to diversity-invasibility relationships by limiting the relative success of non-native plants. Here, we show that, in large collections of non-native oak trees at sites across the USA, non-native oaks introduced to regions with greater oak species richness accumulated greater leaf damage than in regions with low oak richness. Underlying this trend was the ability of herbivores to exploit non-native plants that were close relatives to their native host. In diverse oak communities, non-native trees were on average more closely related to native trees and received greater leaf damage than those in depauperate oak communities. Because insect herbivores colonize non-native plants that are similar to their native hosts, in communities with greater native plant diversity, non-natives experience greater herbivory. PMID:25232143

Pearse, Ian S; Hipp, Andrew L

2014-11-01

73

Plant Species Diversity and Pasture Management  

Technology Transfer Automated Retrieval System (TEKTRAN)

Farmers face many challenges in pasture management, such as evolving agri-environmental schemes to protect natural resources, and need new management techniques to remain sustainable. Ecological research indicates that increased plant biodiversity benefits ecosystem functions such as primary product...

74

Diversity Strategies for Nuclear Power Plant Instrumentation and Control Systems  

SciTech Connect

This report presents the technical basis for establishing acceptable mitigating strategies that resolve diversity and defense-in-depth (D3) assessment findings and conform to U.S. Nuclear Regulatory Commission (NRC) requirements. The research approach employed to establish appropriate diversity strategies involves investigation of available documentation on D3 methods and experience from nuclear power and nonnuclear industries, capture of expert knowledge and lessons learned, determination of best practices, and assessment of the nature of common-cause failures (CCFs) and compensating diversity attributes. The research described in this report does not provide guidance on how to determine the need for diversity in a safety system to mitigate the consequences of potential CCFs. Rather, the scope of this report provides guidance to the staff and nuclear industry after a licensee or applicant has performed a D3 assessment per NUREG/CR-6303 and determined that diversity in a safety system is needed for mitigating the consequences of potential CCFs identified in the evaluation of the safety system design features. Succinctly, the purpose of the research described in this report was to answer the question, 'If diversity is required in a safety system to mitigate the consequences of potential CCFs, how much diversity is enough?' The principal results of this research effort have identified and developed diversity strategies, which consist of combinations of diversity attributes and their associated criteria. Technology, which corresponds to design diversity, is chosen as the principal system characteristic by which diversity criteria are grouped to form strategies. The rationale for this classification framework involves consideration of the profound impact that technology-focused design diversity provides. Consequently, the diversity usage classification scheme involves three families of strategies: (1) different technologies, (2) different approaches within the same technology, and (3) different architectures within the same technology. Using this convention, the first diversity usage family, designated Strategy A, is characterized by fundamentally diverse technologies. Strategy A at the system or platform level is illustrated by the example of analog and digital implementations. The second diversity usage family, designated Strategy B, is achieved through the use of distinctly different technologies. Strategy B can be described in terms of different digital technologies, such as the distinct approaches represented by general-purpose microprocessors and field-programmable gate arrays. The third diversity usage family, designated Strategy C, involves the use of variations within a technology. An example of Strategy C involves different digital architectures within the same technology, such as that provided by different microprocessors (e.g., Pentium and Power PC). The grouping of diversity criteria combinations according to Strategies A, B, and C establishes baseline diversity usage and facilitates a systematic organization of strategic approaches for coping with CCF vulnerabilities. Effectively, these baseline sets of diversity criteria constitute appropriate CCF mitigating strategies for digital safety systems. The strategies represent guidance on acceptable diversity usage and can be applied directly to ensure that CCF vulnerabilities identified through a D3 assessment have been adequately resolved. Additionally, a framework has been generated for capturing practices regarding diversity usage and a tool has been developed for the systematic assessment of the comparative effect of proposed diversity strategies (see Appendix A).

Wood, Richard Thomas [ORNL; Belles, Randy [ORNL; Cetiner, Mustafa Sacit [ORNL; Holcomb, David Eugene [ORNL; Korsah, Kofi [ORNL; Loebl, Andy [ORNL; Mays, Gary T [ORNL; Muhlheim, Michael David [ORNL; Mullens, James Allen [ORNL; Poore III, Willis P [ORNL; Qualls, A L [ORNL; Wilson, Thomas L [ORNL; Waterman, Michael E. [U.S. Nuclear Regulatory Commission

2010-02-01

75

Changes in microbial heterotrophic diversity along five plant successional sequences  

Microsoft Academic Search

Little is known about the changes in microbial diversity associated with ecosystem development. We measured microbial heterotrophic evenness (a component of diversity) and other soil\\/humus properties (including basal respiration, substrate-induced respiration, pH, total C, N and P) at different stages in the development of five different ecosystems, with plant assemblages being used to define the phase in the successional sequence.

L. A Schipper; B. P Degens; G. P Sparling; L. C Duncan

2001-01-01

76

Herbivores and nutrients control grassland plant diversity via light limitation.  

PubMed

Human alterations to nutrient cycles and herbivore communities are affecting global biodiversity dramatically. Ecological theory predicts these changes should be strongly counteractive: nutrient addition drives plant species loss through intensified competition for light, whereas herbivores prevent competitive exclusion by increasing ground-level light, particularly in productive systems. Here we use experimental data spanning a globally relevant range of conditions to test the hypothesis that herbaceous plant species losses caused by eutrophication may be offset by increased light availability due to herbivory. This experiment, replicated in 40 grasslands on 6 continents, demonstrates that nutrients and herbivores can serve as counteracting forces to control local plant diversity through light limitation, independent of site productivity, soil nitrogen, herbivore type and climate. Nutrient addition consistently reduced local diversity through light limitation, and herbivory rescued diversity at sites where it alleviated light limitation. Thus, species loss from anthropogenic eutrophication can be ameliorated in grasslands where herbivory increases ground-level light. PMID:24670649

Borer, Elizabeth T; Seabloom, Eric W; Gruner, Daniel S; Harpole, W Stanley; Hillebrand, Helmut; Lind, Eric M; Adler, Peter B; Alberti, Juan; Anderson, T Michael; Bakker, Jonathan D; Biederman, Lori; Blumenthal, Dana; Brown, Cynthia S; Brudvig, Lars A; Buckley, Yvonne M; Cadotte, Marc; Chu, Chengjin; Cleland, Elsa E; Crawley, Michael J; Daleo, Pedro; Damschen, Ellen I; Davies, Kendi F; DeCrappeo, Nicole M; Du, Guozhen; Firn, Jennifer; Hautier, Yann; Heckman, Robert W; Hector, Andy; HilleRisLambers, Janneke; Iribarne, Oscar; Klein, Julia A; Knops, Johannes M H; La Pierre, Kimberly J; Leakey, Andrew D B; Li, Wei; MacDougall, Andrew S; McCulley, Rebecca L; Melbourne, Brett A; Mitchell, Charles E; Moore, Joslin L; Mortensen, Brent; O'Halloran, Lydia R; Orrock, John L; Pascual, Jesús; Prober, Suzanne M; Pyke, David A; Risch, Anita C; Schuetz, Martin; Smith, Melinda D; Stevens, Carly J; Sullivan, Lauren L; Williams, Ryan J; Wragg, Peter D; Wright, Justin P; Yang, Louie H

2014-04-24

77

Herbivores and nutrients control grassland plant diversity via light limitation  

USGS Publications Warehouse

Human alterations to nutrient cycles and herbivore communities are affecting global biodiversity dramatically. Ecological theory predicts these changes should be strongly counteractive: nutrient addition drives plant species loss through intensified competition for light, whereas herbivores prevent competitive exclusion by increasing ground-level light, particularly in productive systems. Here we use experimental data spanning a globally relevant range of conditions to test the hypothesis that herbaceous plant species losses caused by eutrophication may be offset by increased light availability due to herbivory. This experiment, replicated in 40 grasslands on 6 continents, demonstrates that nutrients and herbivores can serve as counteracting forces to control local plant diversity through light limitation, independent of site productivity, soil nitrogen, herbivore type and climate. Nutrient addition consistently reduced local diversity through light limitation, and herbivory rescued diversity at sites where it alleviated light limitation. Thus, species loss from anthropogenic eutrophication can be ameliorated in grasslands where herbivory increases ground-level light.

Borer, Elizabeth T.; Seabloom, Eric W.; Gruner, Daniel S.; Harpole, W. Stanley; Hillebrand, Helmut; Lind, Eric M.; Alder, Peter B.; Alberti, Juan; Anderson, T. Michael; Bakker, Jonathan D.; Biederman, Lori; Blumenthal, Dana; Brown, Cynthia S.; Brudvig, Lars A.; Buckley, Yvonne M.; Cadotte, Marc; Chu, Cheng-Jin; Cleland, Elsa E.; Crawley, Michael J.; Daleo, Pedro; Damschen, Ellen I.; Davies, Kendi F.; DeCrappeo, Nicole M.; Du, Guozhen; Firn, Jennifer; Hautier, Yann; Heckman, Robert W.; Hector, Andy; HilleRisLambers, Janneke; Iribarne, Oscar; Klein, Julia A.; Knops, Johannes M.H.; La Pierre, Kimberly J.; Leakey, Andrew D.B.; Li, Wei; MacDougall, Andrew S.; McCulley, Rebecca L.; Melbourne, Brett A.; Mitchell, Charles E.; Moore, Joslin L.; Mortensen, Brent; O'Halloran, Lydia R.; Orrock, John L.; Pascual, Jesús; Prober, Suzanne M.; Pyke, David A.; Risch, Anita C.; Schuetz, Martin; Smith, Melinda D.; Stevens, Carly J.; Sullivan, Lauren L.; Williams, Ryan J.; Wragg, Peter D.; Wright, Justin P.; Yang, Louie H.

2014-01-01

78

Mycorrhizae Influence Plant Community Structure and Diversity in Tallgrass Prairie  

Microsoft Academic Search

In grassland ecosystems, symbiotic associations between plants and mycor- rhizal fungi are widespread and have important influences on the life histories, demography, and species interactions of plants, and on belowground ecosystem processes. To assess the consequences of the symbiosis at the plant community level, we conducted a 5-yr field experiment in tallgrass prairie to investigate the influence of arbuscular mycorrhizal

David C. Hartnett; Gail W. T. Wilson

1999-01-01

79

Genotypic and phenotypic diversity in populations of plant-probiotic Pseudomonas spp. colonizing roots  

NASA Astrophysics Data System (ADS)

Several soil microorganisms colonizing roots are known to naturally promote the health of plants by controlling a range of plant pathogens, including bacteria, fungi, and nematodes. The use of theses antagonistic microorganisms, recently named plant-probiotics, to control plant-pathogenic fungi is receiving increasing attention, as they may represent a sustainable alternative to chemical pesticides. Many years of research on plant-probiotic microorganisms (PPM) have indicated that fluorescent pseudomonads producing antimicrobial compounds are largely involved in the suppression of the most widespread soilborne pathogens. Phenotype and genotype analysis of plant-probiotic fluorescent pseudomonads (PFP) have shown considerable genetic variation among these types of strains. Such variability plays an important role in the rhizosphere competence and the biocontrol ability of PFP strains. Understanding the mechanisms by which genotypic and phenotypic diversity occurs in natural populations of PFP could be exploited to choose those agricultural practices which best exploit the indigenous PFP populations, or to isolate new plant-probiotic strains for using them as inoculants. A number of different methods have been used to study diversity within PFP populations. Because different resolutions of the existing microbial diversity can be revealed depending on the approach used, this review first describes the most important methods used for the assessment of fluorescent Pseudomonas diversity. Then, we focus on recent data relating how differences in genotypic and phenotypic diversity within PFP communities can be attributed to geographic location, climate, soil type, soil management regime, and interactions with other soil microorganisms and host plants. It becomes evident that plant-related parameters exert the strongest influence on the genotypic and phenotypic variations in PFP populations.

Picard, Christine; Bosco, Marco

2008-01-01

80

THE EFFECTIVENESS OF QUADRATS FOR MEASURING VASCULAR PLANT DIVERSITY  

EPA Science Inventory

Quadrats are widely used for measuring characteristics of vascular plant communities. It is well recognized that quadrat size affects measurements of frequency and cover. The ability of quadrats of varying sizes to adequately measure diversity has not been established. An exha...

81

ORIGINAL PAPER Dry grassland plant diversity conservation using  

E-print Network

ORIGINAL PAPER Dry grassland plant diversity conservation using low-intensity sheep and goat+Business Media B.V. 2008 Abstract After abandonment, dry grassland (Festuco-Brometea) areas decline due to gradual overgrowing by woody species and the expansion of perennial tall grass species. Dry grassland

Janouskova, Martina

82

Genetic diversity and distinctiveness in Scottish alpine plants  

Microsoft Academic Search

Background: Many alpine plants are rare in Scotland. Their persistence depends on their ability to withstand habitat fragmentation and loss due to changes in land use, increased grazing pressure, and climate change.Aims: We use a phylogeographic approach to address the origin and genetic diversity of Scottish populations, which is relevant for their future management and protection.Methods: We review phylogeographic studies

Kristine B. Westergaard; Inger G. Alsos; Dorothee Ehrich; Pernille B. Eidesen; Peter M. Hollingsworth; Christian Brochmann

2008-01-01

83

PLANT DIVERSITY OF THE CAPE REGION OF SOUTHERN AFRICA  

Microsoft Academic Search

ABSTRACT Comprising a land area of ca. 90,000 km,, less than one twentieth (5%) the land area of the southern African subcontinent, the Cape Floristic Region (CFR) is, for its size, one of the world’s richest areas of plant species diversity. A new synoptic flora for the Region has made possible an accurate reassessment of the flora, which has an

Peter Goldblatt; John C. Manning

84

Plant Ecology & Diversity Vol. 1, No. 2, November 2008, 197207  

E-print Network

://www.informaworld.com TPED A bridge or a barrier? Beringia's influence on the distribution and diversity of tundra plants Of bridges and barriers in Beringia Eric G. DeChaine* Department of Biology, Western Washington University strongly suggests that Beringia was a refugium for tundra taxa throughout the Quaternary (the last 2

DeChaine, Eric

85

Arctic plant diversity in the Early Eocene greenhouse  

PubMed Central

For the majority of the Early Caenozoic, a remarkable expanse of humid, mesothermal to temperate forests spread across Northern Polar regions that now contain specialized plant and animal communities adapted to life in extreme environments. Little is known on the taxonomic diversity of Arctic floras during greenhouse periods of the Caenozoic. We show for the first time that plant richness in the globally warm Early Eocene (approx. 55–52 Myr) in the Canadian High Arctic (76° N) is comparable with that approximately 3500 km further south at mid-latitudes in the US western interior (44–47° N). Arctic Eocene pollen floras are most comparable in richness with today's forests in the southeastern United States, some 5000 km further south of the Arctic. Nearly half of the Eocene, Arctic plant taxa are endemic and the richness of pollen floras implies significant patchiness to the vegetation type and clear regional richness of angiosperms. The reduced latitudinal diversity gradient in Early Eocene North American plant species demonstrates that extreme photoperiod in the Arctic did not limit taxonomic diversity of plants. PMID:22072610

Harrington, Guy J.; Eberle, Jaelyn; Le-Page, Ben A.; Dawson, Mary; Hutchison, J. Howard

2012-01-01

86

LETTER Diversity of plant evolutionary lineages promotes arthropod Russell Dinnage,1  

E-print Network

communities. Drawing on 11 years of data from a long-term plant diversity experi- ment, we show that evolutionary history of plant communities ­ measured as phylogenetic diversity ­ strongly predicts diversity, community ecology, ecosystem function, phylogenetic diversity, trophic levels. Ecology Letters (2012) 15

Haddad, Nick

87

Diversity Dynamics of SilurianEarly Carboniferous Land Plants in South China  

E-print Network

Diversity Dynamics of Silurian­Early Carboniferous Land Plants in South China Conghui Xiong1 in the global pattern of plant evolution. These land plant events do not correspond well temporally with those land plants of South China, a relatively continuous regional record. Plant diversity increased

Benton, Michael

88

United in Diversity: Mechanosensitive Ion Channels in Plants.  

PubMed

Mechanosensitive (MS) ion channels are a common mechanism for perceiving and responding to mechanical force. This class of mechanoreceptors is capable of transducing membrane tension directly into ion flux. In plant systems, MSion channels have been proposed to play a wide array of roles, from the perception of touch and gravity to the osmotic homeostasis of intracellular organelles. Three families of plant MS ion channels have been identified: the MscS-like (MSL), Mid1-complementing activity (MCA), and two-pore potassium (TPK) families. Channels from these families vary widely in structure and function, localize to multiple cellular compartments, and conduct chloride, calcium, and/or potassium ions. However, they are still likely to represent only a fraction of the MS ion channel diversity in plant systems. Expected final online publication date for the Annual Review of Plant Biology Volume 66 is April 29, 2015. Please see http://www.annualreviews.org/catalog/pubdates.aspx for revised estimates. PMID:25494462

Hamilton, Eric S; Schlegel, Angela M; Haswell, Elizabeth S

2014-12-01

89

Effects of plant diversity on invertebrate herbivory in experimental grassland.  

PubMed

The rate at which a plant species is attacked by invertebrate herbivores has been hypothesized to depend on plant species richness, yet empirical evidence is scarce. Current theory predicts higher herbivore damage in monocultures than in species-rich mixtures. We quantified herbivore damage by insects and molluscs to plants in experimental plots established in 2002 from a species pool of 60 species of Central European Arrhenatherum grasslands. Plots differed in plant species richness (1, 2, 4, 8, 16, 60 species), number of functional groups (1, 2, 3, 4), functional group and species composition. We estimated herbivore damage by insects and molluscs at the level of transplanted plant individuals ("phytometer" species Plantago lanceolata, Trifolium pratense, Rumex acetosa) and of the entire plant community during 2003 and 2004. In contrast to previous studies, our design allows specific predictions about the relative contributions of functional diversity, plant functional identity, and species richness in relation to herbivory. Additionally, the phytometer approach is new to biodiversity-herbivory studies, allowing estimates of species-specific herbivory rates within the larger biodiversity-ecosystem functioning context. Herbivory in phytometers and experimental communities tended to increase with plant species richness and the number of plant functional groups, but the effects were rarely significant. Herbivory in phytometers was in some cases positively correlated with community biomass or leaf area index. The most important factor influencing invertebrate herbivory was the presence of particular plant functional groups. Legume (grass) presence strongly increased (decreased) herbivory at the community level. The opposite pattern was found for herbivory in T. pratense phytometers. We conclude that (1) plant species richness is much less important than previously thought and (2) plant functional identity is a much better predictor of invertebrate herbivory in temperate grassland ecosystems. PMID:16231192

Scherber, Christoph; Mwangi, Peter N; Temperton, Vicky M; Roscher, Christiane; Schumacher, Jens; Schmid, Bernhard; Weisser, Wolfgang W

2006-03-01

90

Intraspecific plant chemical diversity and its relation to herbivory.  

PubMed

Several aromatic plant species are well known for their high intraspecific variation in terpene composition. Within these species, different chemotypes can be distinguished, which are characterised by one major metabolite and distinct satellite compounds in lower abundance. Such intraspecific differences in plant quality should have major effects on herbivorous insects but may also be partly shaped by their feeding activities. In the present study, the effects of selected Tanacetum vulgare L. chemotypes on herbivore presence and preferences were investigated, and the naturally occurring diversity of T. vulgare was explored at a small spatial scale. A distinct distribution pattern of aphids and miners was found on different chemotypes of different origin of T. vulgare, with species-specific preferences of different herbivorous species. Larvae of two generalist noctuid species performed worse on most chemotypes of T. vulgare than on other plant species. Furthermore, the specific terpene composition of T. vulgare influenced larval development of these two generalist species. The naturally occurring chemical diversity of T. vulgare plants in an area smaller than 3 km(2) was extremely high, exhibiting 14 different chemotypes. Several individual patches of T. vulgare consisted of more than one chemotype. In conclusion, the existing chemotypical pattern of T. vulgare plants leads to a species-specific distribution of herbivores but may in turn be the result of contrasting selection pressures of various specialist and generalist herbivores. PMID:21053017

Kleine, Sandra; Müller, Caroline

2011-05-01

91

Vole disturbances and plant diversity in a grassland metacommunity.  

PubMed

We studied the disturbance associated with prairie vole burrows and its effects on grassland plant diversity at the patch (1 m(2)) and metacommunity (>5 ha) scales. We expected vole burrows to increase patch-scale plant species diversity by locally reducing competition for resources or creating niche opportunities that increase the presence of fugitive species. At the metacommunity scale, we expected burrows to increase resource heterogeneity and have a community composition distinct from the matrix. We measured resource variables and plant community composition in 30 paired plots representing disturbed burrows and undisturbed matrix patches in a cool-season grassland. Vole disturbance affected the mean values of nine resource variables measured and contributed more to resource heterogeneity in the metacommunity than matrix plots. Disturbance increased local plant species richness, metacommunity evenness, and the presence and abundance of fugitive species. To learn more about the contribution of burrow and matrix habitats to metacommunity diversity, we compared community similarity among burrow and matrix plots. Using Sorenson's similarity index, which considers only presence-absence data, we found no difference in community similarity among burrows and matrix plots. Using a proportional similarity index, which considers both presence-absence and relative abundance data, we found low community similarity among burrows. Burrows appeared to shift the identity of dominant species away from the species dominant in the matrix. They also allowed subordinate species to persist in higher abundances. The patterns we observed are consistent with several diversity-maintaining mechanisms, including a successional mosaic and alternative successional trajectories. We also found evidence that prairie voles may be ecosystem engineers. PMID:17440750

Questad, Erin J; Foster, Bryan L

2007-08-01

92

Drivers of Spatial Variation in Plant Diversity Across the Central Arizona-Phoenix Ecosystem  

Microsoft Academic Search

We examined how growth of the Phoenix urban landscape has changed spatial patterns in native Sonoran desert plant diversity. Combining data from the U.S. Census with a probability-based field inventory, we used spatial and multivariate statistics to show how plant diversity across the region is influenced by human actions. Spatial variations in plant diversity among sites were best explained by

Diane Hope; Corinna Gries; David Casagrande; Charles L. Redman; Nancy B. Grimm; Chris Martin

2006-01-01

93

The microbiome of medicinal plants: diversity and importance for plant growth, quality and health  

PubMed Central

Past medicinal plant research primarily focused on bioactive phytochemicals, however, the focus is currently shifting due to the recognition that a significant number of phytotherapeutic compounds are actually produced by associated microbes or through interaction with their host. Medicinal plants provide an enormous bioresource of potential use in modern medicine and agriculture, yet their microbiome is largely unknown. The objective of this review is (i) to introduce novel insights into the plant microbiome with a focus on medicinal plants, (ii) to provide details about plant- and microbe-derived ingredients of medicinal plants, and (iii) to discuss possibilities for plant growth promotion and plant protection for commercial cultivation of medicinal plants. In addition, we also present a case study performed both to analyse the microbiome of three medicinal plants (Matricaria chamomilla L., Calendula officinalis L., and Solanum distichum Schumach. and Thonn.) cultivated on organically managed Egyptian desert farm and to develop biological control strategies. The soil microbiome of the desert ecosystem was comprised of a high abundance of Gram-positive bacteria of prime importance for pathogen suppression under arid soil conditions. For all three plants, we observed a clearly plant-specific selection of the microbes as well as highly specific diazotrophic communities that overall identify plant species as important drivers in structural and functional diversity. Lastly, native Bacillus spec. div. strains were able to promote plant growth and elevate the plants’ flavonoid production. These results underline the numerous links between the plant-associated microbiome and the plant metabolome. PMID:24391634

Köberl, Martina; Schmidt, Ruth; Ramadan, Elshahat M.; Bauer, Rudolf; Berg, Gabriele

2013-01-01

94

Macroevolution and the biological diversity of plants and herbivores.  

PubMed

Terrestrial biodiversity is dominated by plants and the herbivores that consume them, and they are one of the major conduits of energy flow up to higher trophic levels. Here, we address the processes that have generated the spectacular diversity of flowering plants (>300,000 species) and insect herbivores (likely >1 million species). Long-standing macroevolutionary hypotheses have postulated that reciprocal evolution of adaptations and subsequent bursts of speciation have given rise to much of this biodiversity. We critically evaluate various predictions based on this coevolutionary theory. Phylogenetic reconstruction of ancestral states has revealed evidence for escalation in the potency or variety of plant lineages' chemical defenses; however, escalation of defense has been moderated by tradeoffs and alternative strategies (e.g., tolerance or defense by biotic agents). There is still surprisingly scant evidence that novel defense traits reduce herbivory and that such evolutionary novelty spurs diversification. Consistent with the coevolutionary hypothesis, there is some evidence that diversification of herbivores has lagged behind, but has nevertheless been temporally correlated with that of their host-plant clades, indicating colonization and radiation of insects on diversifying plants. However, there is still limited support for the role of host-plant shifts in insect diversification. Finally, a frontier area of research, and a general conclusion of our review, is that community ecology and the long-term evolutionary history of plant and insect diversification are inexorably intertwined. PMID:19815508

Futuyma, Douglas J; Agrawal, Anurag A

2009-10-27

95

Application of diversity to regional ecological assessment: a review with recommendations  

SciTech Connect

Species diversity is frequently considered a primary indicator of ecosystem health, stability, and resilience. As such, species diversity is commonly the major criterion upon which environmental impact statements and ecological assessments are based. This report describes the theoretical development and refinement of the concept of ecological diversity and the various mathematical expressions of diversity. Advantages and disadvantages of each diversity expression are discussed. The application and interpretation of diversity indices for different spatial scales (e.g., specific sites and regional assessments) and variables (e.g., species diversity, habitat diversity, landscape diversity) are contrasted. Recommendations indicate the appropriate diversity indices for regional ecological assessments.

Levenson, J.B.; Stearns, F.W.

1980-03-01

96

Alpha and beta diversity of plants and animals along a tropical land-use gradient.  

PubMed

Assessing the overall biological diversity of tropical rain forests is a seemingly insurmountable task for ecologists. Therefore, researchers frequently sample selected taxa that they believe reflect general biodiversity patterns. Usually, these studies focus on the congruence of alpha diversity (the number of species found per sampling unit) between taxa rather than on beta diversity (turnover of species assemblages between sampling units). Such approaches ignore the potential role of habitat heterogeneity that, depending on the taxonomic group considered, can greatly enhance beta diversity at local and landscape scales. We compared alpha and beta diversity of four plant groups (trees, lianas, terrestrial herbs, epiphytic liverworts) and eight animal groups (birds, butterflies, lower canopy ants, lower canopy beetles, dung beetles, bees, wasps, and the parasitoids of the latter two) at 15 sites in Sulawesi, Indonesia, that represented natural rain forest and three types of cacao agroforests differing in management intensity. In total, we recorded 863 species. Patterns of species richness per study site varied strongly between taxonomic groups. Only 13-17% of the variance in species richness of one taxonomic group could be predicted from the species richness of another, and on average 12-18% of the variance of beta diversity of a given group was predicted by that in other groups, although some taxon pairs had higher values (up to 76% for wasps and their parasitoids). The degree of congruence of patterns of alpha diversity was not influenced by sampling completeness, whereas the indicator value for beta diversity improved when using a similarity index that accounts for incomplete sampling. The indication potential of alpha diversity for beta diversity and vice versa was limited within taxa (7-20%) and virtually nil between them (0-4%). We conclude that different taxa can have largely independent patterns of alpha diversity and that patterns of beta diversity can be more congruent. Thus, conservation plans on a landscape scale need to put more emphasis on the high heterogeneity of agroforests and the overarching role of beta diversity shaping overall diversity patterns. PMID:20014584

Kessler, Michael; Abrahamczyk, Stefan; Bos, Merijn; Buchori, Damayanti; Putra, Dadang Dwi; Gradstein, S Robbert; Höhn, Patrick; Kluge, Jürgen; Orend, Friederike; Pitopang, Ramadhaniel; Saleh, Shahabuddin; Schulze, Christian H; Sporn, Simone G; Steffan-Dewenter, Ingolf; Tjitrosoedirdjo, Sri S; Tscharntke, Teja

2009-12-01

97

Spatial aggregation facilitates coexistence and diversity of wild plant species in field margins  

Microsoft Academic Search

European agri-environment schemes encourage farmers to establish sown field margin strips to protect and enhance wild plant diversity. However, plant diversity in such wild plant sowings based on seed mixtures is often low due to the high competitiveness of few, common species. Here we analysed whether intraspecific aggregation could enhance the performance of less competitive species, and how plant performance

Birte Eleen Wassmuth; Peter Stoll; Teja Tscharntke; Carsten Thies

2009-01-01

98

Nova Acta Leopoldina NF 92, Nr. 342, 6183 (2005) Global Centers of Vascular Plant Diversity  

E-print Network

Nova Acta Leopoldina NF 92, Nr. 342, 61­83 (2005) Global Centers of Vascular Plant Diversity) With 2 Figures and 1 Table Abstract The diversity of vascular plants is very unevenly distributed across.2 % of all vascular plant species. A world map of vascular plant richness is presented based

Kreft, Holger

99

Earthworms and legumes control litter decomposition in a plant diversity gradient.  

PubMed

The role of species and functional group diversity of primary producers for decomposers and decomposition processes is little understood. We made use of the "Jena Biodiversity Experiment" and tested the hypothesis that increasing plant species (1, 4, and 16 species) and functional group diversity (1, 2, 3, and 4 groups) beneficially affects decomposer density and activity and therefore the decomposition of plant litter material. Furthermore, by manipulating the densities of decomposers (earthworms and springtails) within the plant diversity gradient we investigated how the interactions between plant diversity and decomposer densities affect the decomposition of litter belonging to different plant functional groups (grasses, herbs, and legumes). Positive effects of increasing plant species or functional group diversity on earthworms (biomass and density) and microbial biomass were mainly due to the increased incidence of legumes with increasing diversity. Neither plant species diversity nor functional group diversity affected litter decomposition, However, litter decomposition varied with decomposer and plant functional group identity (of both living plants and plant litter). While springtail removal generally had little effect on decomposition, increased earthworm density accelerated the decomposition of nitrogen-rich legume litter, and this was more pronounced at higher plant diversity. The results suggest that earthworms (Lumbricus terrestris L.) and legumes function as keystone organisms for grassland decomposition processes and presumably contribute to the recorded increase in primary productivity with increasing plant diversity. PMID:18705374

Milcu, Alexandru; Partsch, Stephan; Scherber, Christoph; Weisser, Wolfgang W; Scheu, Stefan

2008-07-01

100

Plant diversity hotspots in the Atlantic coastal forests of Brazil.  

PubMed

Plant-diversity hotspots on a global scale are well established, but smaller local hotspots within these must be identified for effective conservation of plants at the global and local scales. We used the distributions of endemic and endemic-threatened species of Myrtaceae to indicate areas of plant diversity and conservation importance within the Atlantic coastal forests (Mata Atlântica) of Brazil. We applied 3 simple, inexpensive geographic information system (GIS) techniques to a herbarium specimen database: predictive species-distribution modeling (Maxent); complementarity analysis (DIVA-GIS); and mapping of herbarium specimen collection locations. We also considered collecting intensity, which is an inherent limitation of use of natural history records for biodiversity studies. Two separate areas of endemism were evident: the Serra do Mar mountain range from Paraná to Rio de Janeiro and the coastal forests of northern Espírito Santo and southern Bahia. We identified 12 areas of approximately 35 km(2) each as priority areas for conservation. These areas had the highest species richness and were highly threatened by urban and agricultural expansion. Observed species occurrences, species occurrences predicted from the model, and results of our complementarity analysis were congruent in identifying those areas with the most endemic species. These areas were then prioritized for conservation importance by comparing ecological data for each. PMID:18950472

Murray-Smith, Charlotte; Brummitt, Neil A; Oliveira-Filho, Ary T; Bachman, Steven; Moat, Justin; Lughadha, Eimear M Nic; Lucas, Eve J

2009-02-01

101

Development and Initial Psychometric Assessment of the Plant Attitude Questionnaire  

NASA Astrophysics Data System (ADS)

Plants are integral parts of ecosystems which determine life on Earth. People's attitudes toward them are however, largely overlooked. Here we present initial psychometric assessment of self-constructed Plant Attitude Scale (PAS) that was administered to a sample of 310 Slovakian students living in rural areas aged 10-15 years. The final version of PAS consists from 29 Likert-scale items that were loaded to four distinct dimensions (Interest, Importance, Urban trees and Utilization). Mean scores revealed that Slovakian students lack positive attitudes toward plants and that gender had no effect on their mean attitude scores. Living in a family with a garden was associated with a more positive attitude toward plants. Further correlative research on diverse samples containing urban children and experimental research examining the impact of gardening in schools on student attitudes toward plants is required.

Fan?ovi?ová, Jana; Prokop, Pavol

2010-10-01

102

Plant and bird diversity in natural forests and in native and exotic plantations in NW Portugal  

NASA Astrophysics Data System (ADS)

Forest ecosystems have been subjected to continuous dynamics between deforestation and forestation. Assessing the effects of these processes on biodiversity could be essential for conservation planning. We analyzed patterns of species richness, diversity and evenness of plants and birds in patches of natural forest of Quercus spp. and in stands of native Pinus pinaster and exotic Eucalyptus globulus in NW Portugal. We analyzed data of forest and non-forest species separately, at the intra-patch, patch and inter-patch scales. Forest plant richness, diversity and evenness were higher in oak forest than in pine and eucalypt plantations. In total, 52 species of forest plants were observed in oak forest, 33 in pine plantation and 28 in eucalypt plantation. Some forest species, such as Euphorbia dulcis, Omphalodes nitida and Eryngium juresianum, were exclusively or mostly observed in oak forest. Forest bird richness and diversity were higher in both oak and pine forests than in eucalypt forest; evenness did not differ among forests. In total, 16 species of forest birds were observed in oak forest, 18 in pine forest and 11 in eucalypt forest. Species such as Certhia brachydactyla, Sitta europaea and Dendrocopos major were common in oak and/or pine patches but were absent from eucalypt stands. Species-area relationships of forest plants and forest birds in oak patches had consistently a higher slope, at both the intra and inter-patch scales, than species-area relationships of forest species in plantations and non-forest species in oak forest. These findings demonstrate the importance of oak forest for the conservation of forest species diversity, pointing the need to conserve large areas of oak forest due to the apparent vulnerability of forest species to area loss. Additionally, diversity patterns in pine forest were intermediate between oak forest and eucalypt forest, suggesting that forest species patterns may be affected by forest naturalness.

Proença, Vânia M.; Pereira, Henrique M.; Guilherme, João; Vicente, Luís

2010-03-01

103

Diverse and bioactive endophytic Aspergilli inhabit Cupressaceae plant family.  

PubMed

Aspergilli are filamentous, cosmopolitan and ubiquitous fungi which have significant impact on human, animal and plant welfare worldwide. Due to their extraordinary metabolic diversity, Aspergillus species are used in biotechnology for the production of a vast array of biomolecules. However, little is known about Aspergillus species that are able to adapt an endophytic lifestyle in Cupressaceae plant family and are capable of producing cytotoxic, antifungal and antibacterial metabolites. In this work, we report a possible ecological niche for pathogenic fungi such as Aspergillus fumigatus and Aspergillus flavus. Indeed, our findings indicate that A. fumigatus, A. flavus, Aspergillus niger var. niger and A. niger var. awamori adapt an endophytic lifestyle inside the Cupressaceous plants including Cupressus arizonica, Cupressus sempervirens var. fastigiata, Cupressus semipervirens var. cereiformis, and Thuja orientalis. In addition, we found that extracts of endophytic Aspergilli showed significant growth inhibition and cytotoxicity against the model fungus Pyricularia oryzae and bacteria such as Bacillus sp., Erwinia amylovora and Pseudomonas syringae. These endophytic Aspergilli also showed in vitro antifungal effects on the cypress fungal phytopathogens including Diplodia seriata, Phaeobotryon cupressi and Spencermartinsia viticola. In conclusion, our findings clearly support the endophytic association of Aspergilli with Cupressaceae plants and their possible role in protection of host plants against biotic stresses. Observed bioactivities of such endophytic Aspergilli may represent a significant potential for bioindustry and biocontrol applications. PMID:24912659

Soltani, Jalal; Moghaddam, Mahdieh S Hosseyni

2014-09-01

104

Cultural Diversity, Mental Retardation, and Assessment: The Case for Nonlabeling.  

ERIC Educational Resources Information Center

The System of Multicultural Pluralistic Assessment (SOMPA) is designed for use in a culturally diverse society. The system was developed on 700 English-speaking caucasian children (hereafter called Anglos) from the anglo core culture, 700 black children, and 700 Latino Children (90 percent were of Mexican-American heritage) five through eleven…

Mercer, Jane R.

105

Assessment of a Diversity Assignment in a PR Principles Course  

ERIC Educational Resources Information Center

This study assesses an assignment for incorporating diversity into the principles of public relations course. The assignment is tailored to the challenges of using an active learning approach in a large lecture class. For the assignment, students write a goal, objectives, strategies, an identification of tactics, and evaluation plans for either…

Gallicano, Tiffany Derville; Stansberry, Kathleen

2012-01-01

106

Tiger Team assessment of the Pinellas Plant  

SciTech Connect

This Document contains findings identified during the Tiger Team Compliance Assessment of the Department of Energy's (DOE's) Pinellas Plant, Pinellas County, Florida. The assessment wa directed by the Department's Office of Environment, Safety, and Health (ES H) from January 15 to February 2, 1990. The Pinellas Tiger Team Compliance Assessment is comprehensive in scope. It covers the Environment Safety and Health, and Management areas and determines the plant's compliance with applicable Federal (including DOE), State, and local regulations and requirements.

Not Available

1990-05-01

107

Diversity, classification and function of the plant protein kinase superfamily  

PubMed Central

Eukaryotic protein kinases belong to a large superfamily with hundreds to thousands of copies and are components of essentially all cellular functions. The goals of this study are to classify protein kinases from 25 plant species and to assess their evolutionary history in conjunction with consideration of their molecular functions. The protein kinase superfamily has expanded in the flowering plant lineage, in part through recent duplications. As a result, the flowering plant protein kinase repertoire, or kinome, is in general significantly larger than other eukaryotes, ranging in size from 600 to 2500 members. This large variation in kinome size is mainly due to the expansion and contraction of a few families, particularly the receptor-like kinase/Pelle family. A number of protein kinases reside in highly conserved, low copy number families and often play broadly conserved regulatory roles in metabolism and cell division, although functions of plant homologues have often diverged from their metazoan counterparts. Members of expanded plant kinase families often have roles in plant-specific processes and some may have contributed to adaptive evolution. Nonetheless, non-adaptive explanations, such as kinase duplicate subfunctionalization and insufficient time for pseudogenization, may also contribute to the large number of seemingly functional protein kinases in plants. PMID:22889912

Lehti-Shiu, Melissa D.; Shiu, Shin-Han

2012-01-01

108

Ex situ cultivation affects genetic structure and diversity in arable plants.  

PubMed

Worldwide, botanical gardens cultivate around 80,000 taxa, corresponding to approximately one-quarter of all vascular plants. Most cultivated taxa are, however, held in a small number of collections, and mostly only in small populations. Lack of genetic exchange and stochastic processes in small populations make them susceptible to detrimental genetic effects, which should be most severe in annual species, as sowing cycles are often short. In order to assess whether ex situ cultivation affects genetic diversity of annuals, five annual arable species with similar breeding systems were assessed with 42 in situ populations being compared to 20 ex situ populations using a random amplified polymorphic DNA (RAPD) analysis approach. Population sizes tended to be lower under ex situ cultivation and levels of genetic diversity also tended to be lower in four of the five species, with differences being significant in only two. Ex situ populations showed incomplete representation of alleles found in the wild. The duration of cultivation did not indicate any effect on genetic diversity. This implies that cultivation strategies resulted in different genetic structures in the garden populations. Although not unequivocally pronounced, differences nonetheless imply that conservation strategies in the involved gardens may need improvement. One option is cold storage of seeds, a practice that is not currently followed in the studied ex situ collections. This may reflect that the respective gardens focus on displaying living plant populations. PMID:22882447

Brütting, C; Hensen, I; Wesche, K

2013-05-01

109

Maintaining channel abandonment processes increases riparian plant diversity within fluvial corridors  

E-print Network

Maintaining channel abandonment processes increases riparian plant diversity within fluvial dynamic alluvial riverine corridors, abandoned channels form and experience hydrogeomorphic processes diversity and community dynamics along terrestrializing abandoned channels have received much less attention

Battles, John

110

How generalist herbivores exploit belowground plant diversity in temperate grasslands.  

PubMed

Belowground herbivores impact plant performance, thereby inducing changes in plant community composition, which potentially leads to cascading effects onto higher trophic levels and ecosystem processes and productivity. Among soil-living insects, external root-chewing generalist herbivores have the strongest impact on plants. However, the lack of knowledge on their feeding behaviour under field conditions considerably hampers achieving a comprehensive understanding of how they affect plant communities. Here, we address this gap of knowledge by investigating the feeding behaviour of Agriotes click beetle larvae, which are common generalist external root-chewers in temperate grassland soils. Utilizing diagnostic multiplex PCR to assess the larval diet, we examined the seasonal patterns in feeding activity, putative preferences for specific plant taxa, and whether species identity and larval instar affect food choices of the herbivores. Contrary to our hypothesis, most of the larvae were feeding-active throughout the entire vegetation period, indicating that the grassland plants are subjected to constant belowground feeding pressure. Feeding was selective, with members of Plantaginaceae and Asteraceae being preferred; Apiaceae were avoided. Poaceae, although assumed to be most preferred, had an intermediate position. The food preferences exhibited seasonal changes, indicating a fluctuation in plant traits important for wireworm feeding choice. Species- and instar-specific differences in dietary choice of the Agriotes larvae were small, suggesting that species and larval instars occupy the same trophic niche. According to the current findings, the food choice of these larvae is primarily driven by plant identity, exhibiting seasonal changes. This needs to be considered when analysing soil herbivore-plant interactions. PMID:24188592

Wallinger, Corinna; Staudacher, Karin; Schallhart, Nikolaus; Mitterrutzner, Evi; Steiner, Eva-Maria; Juen, Anita; Traugott, Michael

2014-08-01

111

How generalist herbivores exploit belowground plant diversity in temperate grasslands  

PubMed Central

Belowground herbivores impact plant performance, thereby inducing changes in plant community composition, which potentially leads to cascading effects onto higher trophic levels and ecosystem processes and productivity. Among soil-living insects, external root-chewing generalist herbivores have the strongest impact on plants. However, the lack of knowledge on their feeding behaviour under field conditions considerably hampers achieving a comprehensive understanding of how they affect plant communities. Here, we address this gap of knowledge by investigating the feeding behaviour of Agriotes click beetle larvae, which are common generalist external root-chewers in temperate grassland soils. Utilizing diagnostic multiplex PCR to assess the larval diet, we examined the seasonal patterns in feeding activity, putative preferences for specific plant taxa, and whether species identity and larval instar affect food choices of the herbivores. Contrary to our hypothesis, most of the larvae were feeding-active throughout the entire vegetation period, indicating that the grassland plants are subjected to constant belowground feeding pressure. Feeding was selective, with members of Plantaginaceae and Asteraceae being preferred; Apiaceae were avoided. Poaceae, although assumed to be most preferred, had an intermediate position. The food preferences exhibited seasonal changes, indicating a fluctuation in plant traits important for wireworm feeding choice. Species- and instar-specific differences in dietary choice of the Agriotes larvae were small, suggesting that species and larval instars occupy the same trophic niche. According to the current findings, the food choice of these larvae is primarily driven by plant identity, exhibiting seasonal changes. This needs to be considered when analysing soil herbivore–plant interactions. PMID:24188592

Wallinger, Corinna; Staudacher, Karin; Schallhart, Nikolaus; Mitterrutzner, Evi; Steiner, Eva-Maria; Juen, Anita; Traugott, Michael

2014-01-01

112

Massive horizontal transfer of mitochondrial genes from diverse land plant donors to the basal  

E-print Network

Massive horizontal transfer of mitochondrial genes from diverse land plant donors to the basal, sequenced a variable number of mitochondrial genes from 28 other diverse land plants, and con- ducted of its 31 known mitochondrial protein genes from other land plants, for a total of 26 foreign genes

Palmer, Jeffrey

113

Root diversity in alpine plants: root length, tensile strength and plant age  

NASA Astrophysics Data System (ADS)

A high diversity of plant species and functional groups is hypothesised to increase the diversity of root types and their subsequent effects for soil stability. However, even basic data on root characteristics of alpine plants are very scarce. Therefore, we determined important root characteristics of 13 plant species from different functional groups, i.e. grasses, herbs and shrubs. We excavated the whole root systems of 62 plants from a machine-graded ski slope at 2625 m a.s.l. and analysed the rooting depth, the horizontal root extension, root length and diameter. Single roots of plant species were tested for tensile strength. The age of herbs and shrubs was determined by growth-ring analysis. Root characteristics varied considerably between both plant species and functional groups. The rooting depth of different species ranged from 7.2 ± 0.97 cm to 20.5 ± 2.33 cm, but was significantly larger in the herb Geum reptans (70.8 ± 10.75 cm). The woody species Salix breviserrata reached the highest horizontal root extensions (96.8 ± 25.5 cm). Most plants had their longest roots in fine diameter classes (0.5

Pohl, M.; Stroude, R.; Körner, C.; Buttler, A.; Rixen, C.

2009-04-01

114

Diversity and distribution of Listeria monocytogenes in meat processing plants.  

PubMed

Listeria monocytogenes is a major concern for the meat processing industry because many listeriosis outbreaks have been linked to meat product consumption. The aim of this study was to elucidate L. monocytogenes diversity and distribution across different Spanish meat processing plants. L. monocytogenes isolates (N = 106) collected from food contact surfaces of meat processing plants and meat products were serotyped and then characterised by multilocus sequence typing (MLST). The isolates were serotyped as 1/2a (36.8%), 1/2c (34%), 1/2b (17.9%) and 4b (11.3%). MLST identified ST9 as the most predominant allelic profile (33% of isolates) followed by ST121 (16%), both of which were detected from several processing plants and meat products sampled in different years, suggesting that those STs are highly adapted to the meat processing environment. Food contact surfaces during processing were established as an important source of L. monocytogenes in meat products because the same STs were obtained in isolates recovered from surfaces and products. L. monocytogenes was recovered after cleaning and disinfection procedures in two processing plants, highlighting the importance of thorough cleaning and disinfection procedures. Epidemic clone (EC) marker ECI was identified in 8.5%, ECIII was identified in 2.8%, and ECV was identified in 7.5% of the 106 isolates. Furthermore, a selection of presumably unrelated ST9 isolates was analysed by multi-virulence-locus sequence typing (MVLST). Most ST9 isolates had the same virulence type (VT11), confirming the clonal origin of ST9 isolates; however, one ST9 isolate was assigned to a new VT (VT95). Consequently, MLST is a reliable tool for identification of contamination routes and niches in processing plants, and MVLST clearly differentiates EC strains, which both contribute to the improvement of L. monocytogenes control programs in the meat industry. PMID:25084653

Martín, Belén; Perich, Adriana; Gómez, Diego; Yangüela, Javier; Rodríguez, Alicia; Garriga, Margarita; Aymerich, Teresa

2014-12-01

115

Soil stability and plant diversity in eco-engineering  

NASA Astrophysics Data System (ADS)

Slopes affected by superficial sliding and subsequently re-stabilised with eco-engineering measures were investigated, particularly related to soil stability and plant diversity. The sites are situated in three different areas of beech-fir-spruce forest associations of the higher montane zone of Switzerland. Climatic and site characteristics, in paraticular soil properties after the sliding event, of the three investigation areas are very similar. However, the number of species (shrubs and trees) used for the initial planting as well as the year of application of the eco-engineering measures differ substantially. In the investigation area Dallenwil-Wirzweli the biological measures taken in 1981 were restricted to one tree species, namely White Alder (Alnus incana). In Klosters, where measures were taken in 1983 as well as in the Arieschbach valley, where eco-engineering was applied in 1998, the initial planting consisted of 15 species either. Investigations in 2005/2006 revealed neither obvious differences among the three areas nor distinct correlations related to the diversity of the initial planting on the on hand and the development of the vegetation cover and soil stability on the other hand. During the available time of development, the soil aggregate stability increased by 30 to 39%. Compared to the corresponding climax association, the relative values of soil aggregate stability varied between 90 and 120%. Concurrently, the dry unit weight decreased between 1.1 and 3.1 kN/m3. The cumulative vegetation cover varied from 110 to 150%. Due to processes of soil development a distinct shift in the grain size distribution was noticed, from a well sorted gravel with clay and sand (GW-GC) to a silty gravel with sand (GM) in Dallenwil-Wirzweli and a silty to clayey gravel with sand (GC-GM) in Klosters and the Arieschbach valley. Furthermore, in all three investigation areas succession processes were observed that are comparable to average rates of natural secondary succession. The number of shrub and tree species recorded in 2005/2006 varied between 12 and 16. According to the recommendations for silvicultural maintenance of protective forests, the shrub- and tree layer consisted of 75 to 100% of the required plant species in view of the potential target association.

Böll, Albert; Gerber, Werner; Rickli, Christian; Graf, Frank

2010-05-01

116

Floral colour diversity in plant communities, bee colour space and a null model  

PubMed Central

Evolutionary biologists have long hypothesized that the diversity of flower colours we see is in part a strategy to promote memorization by pollinators, pollinator constancy, and therefore, a directed and efficient pollen transfer between plants. However, this hypothesis has never been tested against a biologically realistic null model, nor were colours assessed in the way pollinators see them. Our intent here is to fill these gaps. Throughout one year, we sampled floral species compositions at five ecologically distinct sites near Berlin, Germany. Bee-subjective colours were quantified for all 168 species. A model of colour vision was used to predict how similar the colours of sympatric and simultaneously blooming flowers were for bees. We then compared flower colour differences in the real habitats with those of random plant communities. We did not find pronounced deviations from chance when we considered common plants. When we examined rare plants, however, we found significant divergence in two of the five plant communities. At one site, similarly coloured species were found to be more frequent than expected, and at the other two locations, flower colours were indistinguishable from a random distribution. These results fit theoretical considerations that rare plants are under stronger selective pressure to secure pollination than common plants. Our study illustrates the power of linking such distinct biological traditions as community ecology and the neuroethology of bee vision.

Gumbert, A.; Kunze, J.; Chittka, L.

1999-01-01

117

Long-term effects of sowing high or low diverse seed mixtures on plant and gastropod diversity  

NASA Astrophysics Data System (ADS)

A number of studies have reported that consumers affect a range of community-level processes, and in turn their diversity and abundance is influenced by the structure and diversity of the plant community. Although gastropods are important generalist herbivores in many environments, few studies have examined the effects of plant species richness and plant community structure on gastropods. This study investigated gastropod species richness and interactions with various above-ground parameters of the vegetation on an experimental field with four plant treatments: low and high diversity of sown later succession plant species, natural colonization at the start of the experiment and natural colonization after 3 years of continued agricultural practice. The investigated gastropod assemblage contained only seven species and was highly dominated by two of them. Both in pitfalls and with hand-sorting the number of species collected per plot was highest in plots with natural plant colonization. Multivariate analysis revealed that overall gastropod abundance was positively associated with plant height and percentage cover of plants, and negatively with percentage grass cover. The same pattern holds for one of the dominant species-complex ( Cochlicopa lubrica/ lubricella). The other dominant gastropod species ( Deroceras reticulatum) was more abundant in samples with higher percentages of moss cover and higher plant diversity, while less abundant at samples with higher plant cover, indicating that the gastropod species preferences may matter more than just their response to plant diversity. Two plant-gastropod species-level associations were observed: Senecio jacobaea with D. reticulatum and Tanacetum vulgare with Cochlicopa spp. The present study also demonstrated that pitfall-traps are suitable for collecting terrestrial gastropods, at least for species-poor grassland habitats.

Dedov, Ivailo; Stoyanov, Ivailo L.; Penev, Lyubomir; Harvey, Jeffrey A.; Van der Putten, Wim H.; Bezemer, T. Martijn

2006-09-01

118

Diversity in plants and other Collembola ameliorate impacts of Sminthurus viridis on plant community structure  

NASA Astrophysics Data System (ADS)

Five experiments investigated the importance of herbivory by Sminthurus viridis in structuring botanical composition in developing grasslands, and how these effects may be modified by diversity in collembolan and plant species. Differential susceptibility to S. viridis feeding was demonstrated in 23 dicotyledonous and three monocotyledonous plants assayed as seedlings at the first true leaf stage. The composition of seedling communities developing from natural and artificially constructed soil seed banks varied with the level of S. viridis infestation, with plant species least susceptible to herbivory making the greatest contribution to plant biomass. The combined effect of herbivory by S. viridis and Bourletiella hortensis on Trifolium repens biomass was shown to be less than the effect of S. viridis alone, indicating competitive interference. The adverse effects of herbivory by S. viridis on T. repens biomass was reduced by increased diversity of plants growing in association with the legume, and the presence of four non-herbivorous arthropleonan Collembola. S. viridis was shown to reduce seedling numbers, species diversity and biomass in communities developing from the soil seed bank, but the presence of non-herbivorous arthropleonan species reduced the effect of S. viridis. The experiments demonstrate the potential for herbivory by S. viridis to significantly alter species composition in developing grassland communities. However, interactions with collembolan and plant species profoundly modified S. viridis herbivory impacts, either by reducing feeding intensity or enhancing plant growth. These results highlight the fact that data from simple, synthetic systems may be poor predictors of herbivory impacts under field conditions where more complex species interactions occur.

Barker, Gary M.

2006-05-01

119

Bacterial Diversity of Active Sludge in Wastewater Treatment Plant  

NASA Astrophysics Data System (ADS)

A bacterial 16S rDNA gene clone library was constructed to analyze the bacterial diversity of active sludge in Gaobeidian Wastewater Treatment Plant, Beijing. The results indicated that the bacterial diversity of active sludge was very high, and the clones could be divided into 5 different groups. The dominant bacterial community was proteobacteria, which accounted for 76.7%. The dominant succession of bacterial community were as follows: the ?-proteobacteria (39.8%), the uncultured bacteria (22.33%), the ?-proteobacteria (20.15%), the ?-proteobacteria (6.79%), and the ?-proteobacteria (4.85%). Nitrosomonas-like and Nitrospira-like bacteria, such as Nitrosomonas sp. (1.94%) and uncultured Nitrospirae bacterium (11.65%) were also detected, which have played important roles in ammonia and nitrite oxidisers in the system. However, they were only a little amount because of their slow growth and less competitive advantage than heterotrophic bacteria. Denitrifying bacteria like Thauera sp. was at a high percentage, which implies a strong denitrification ability; Roseomonas sp. was also detected in the clone library, which could be related to the degradation of organophosphorus pesticide.

Jiang, Xin; Ma, Mingchao; Li, Jun; Lu, Anhuai; Zhong, Zuoshen

120

AfroDb: A Select Highly Potent and Diverse Natural Product Library from African Medicinal Plants  

PubMed Central

Computer-aided drug design (CADD) often involves virtual screening (VS) of large compound datasets and the availability of such is vital for drug discovery protocols. We assess the bioactivity and “drug-likeness” of a relatively small but structurally diverse dataset (containing >1,000 compounds) from African medicinal plants, which have been tested and proven a wide range of biological activities. The geographical regions of collection of the medicinal plants cover the entire continent of Africa, based on data from literature sources and information from traditional healers. For each isolated compound, the three dimensional (3D) structure has been used to calculate physico-chemical properties used in the prediction of oral bioavailability on the basis of Lipinski’s “Rule of Five”. A comparative analysis has been carried out with the “drug-like”, “lead-like”, and “fragment-like” subsets, as well as with the Dictionary of Natural Products. A diversity analysis has been carried out in comparison with the ChemBridge diverse database. Furthermore, descriptors related to absorption, distribution, metabolism, excretion and toxicity (ADMET) have been used to predict the pharmacokinetic profile of the compounds within the dataset. Our results prove that drug discovery, beginning with natural products from the African flora, could be highly promising. The 3D structures are available and could be useful for virtual screening and natural product lead generation programs. PMID:24205103

Ntie-Kang, Fidele; Zofou, Denis; Babiaka, Smith B.; Meudom, Rolande; Scharfe, Michael; Lifongo, Lydia L.; Mbah, James A.; Mbaze, Luc Meva’a; Sippl, Wolfgang; Efange, Simon M. N.

2013-01-01

121

Biotic and Abiotic Properties Mediating Plant Diversity Effects on Soil Microbial Communities in an Experimental Grassland  

PubMed Central

Plant diversity drives changes in the soil microbial community which may result in alterations in ecosystem functions. However, the governing factors between the composition of soil microbial communities and plant diversity are not well understood. We investigated the impact of plant diversity (plant species richness and functional group richness) and plant functional group identity on soil microbial biomass and soil microbial community structure in experimental grassland ecosystems. Total microbial biomass and community structure were determined by phospholipid fatty acid (PLFA) analysis. The diversity gradient covered 1, 2, 4, 8, 16 and 60 plant species and 1, 2, 3 and 4 plant functional groups (grasses, legumes, small herbs and tall herbs). In May 2007, soil samples were taken from experimental plots and from nearby fields and meadows. Beside soil texture, plant species richness was the main driver of soil microbial biomass. Structural equation modeling revealed that the positive plant diversity effect was mainly mediated by higher leaf area index resulting in higher soil moisture in the top soil layer. The fungal-to-bacterial biomass ratio was positively affected by plant functional group richness and negatively by the presence of legumes. Bacteria were more closely related to abiotic differences caused by plant diversity, while fungi were more affected by plant-derived organic matter inputs. We found diverse plant communities promoted faster transition of soil microbial communities typical for arable land towards grassland communities. Although some mechanisms underlying the plant diversity effect on soil microorganisms could be identified, future studies have to determine plant traits shaping soil microbial community structure. We suspect differences in root traits among different plant communities, such as root turnover rates and chemical composition of root exudates, to structure soil microbial communities. PMID:24816860

Lange, Markus; Habekost, Maike; Eisenhauer, Nico; Roscher, Christiane; Bessler, Holger; Engels, Christof; Oelmann, Yvonne; Scheu, Stefan; Wilcke, Wolfgang; Schulze, Ernst-Detlef; Gleixner, Gerd

2014-01-01

122

Genetic diversity of a relict plant species, Ligularia sibirica (L.) Cass. (Asteraceae)  

Microsoft Academic Search

Rare plant species can be divided into naturally, ‘old rare’ species and anthropogenically, ‘new rare’ species. Many recent studies explored genetic diversity of ‘new rare’ species. Less is, however, known about genetic diversity of ‘old rare’ species. We examined isozyme genetic variability of 20 populations of an ‘old rare’ plant species, Ligularia sibirica (Asteraceae) in the Czech and Slovak Republic.

Anna Šmídová; Zuzana Münzbergová; Ivana Pla?ková

2011-01-01

123

Are herbage yield and yield stability affected by plant species diversity in sown pasture mixtures?  

Technology Transfer Automated Retrieval System (TEKTRAN)

A tenet of plant biodiversity theory in grasslands is that increased diversity contributes to the stability of ecosystems. In managed grasslands, such as pastures, greater stability of herbage production as a result of increased plant species diversity would be beneficial. In this study, I combined ...

124

Links between plant litter chemistry, species diversity, and below-ground ecosystem function  

PubMed Central

Decomposition is a critical source of plant nutrients, and drives the largest flux of terrestrial C to the atmosphere. Decomposing soil organic matter typically contains litter from multiple plant species, yet we lack a mechanistic understanding of how species diversity influences decomposition processes. Here, we show that soil C and N cycling during decomposition are controlled by the composition and diversity of chemical compounds within plant litter mixtures, rather than by simple metrics of plant species diversity. We amended native soils with litter mixtures containing up to 4 alpine plant species, and we used 9 litter chemical traits to evaluate the chemical composition (i.e., the identity and quantity of compounds) and chemical diversity of the litter mixtures. The chemical composition of the litter mixtures was the strongest predictor of soil respiration, net N mineralization, and microbial biomass N. Soil respiration and net N mineralization rates were also significantly correlated with the chemical diversity of the litter mixtures. In contrast, soil C and N cycling rates were poorly correlated with plant species richness, and there was no relationship between species richness and the chemical diversity of the litter mixtures. These results indicate that the composition and diversity of chemical compounds in litter are potentially important functional traits affecting decomposition, and simple metrics like plant species richness may fail to capture variation in these traits. Litter chemical traits therefore provide a mechanistic link between organisms, species diversity, and key components of below-ground ecosystem function. PMID:19064910

Meier, Courtney L.; Bowman, William D.

2008-01-01

125

Assessing Natural Resource Use by Forest-Reliant Communities in Madagascar Using Functional Diversity and Functional Redundancy Metrics  

PubMed Central

Biodiversity plays an integral role in the livelihoods of subsistence-based forest-dwelling communities and as a consequence it is increasingly important to develop quantitative approaches that capture not only changes in taxonomic diversity, but also variation in natural resources and provisioning services. We apply a functional diversity metric originally developed for addressing questions in community ecology to assess utilitarian diversity of 56 forest plots in Madagascar. The use categories for utilitarian plants were determined using expert knowledge and household questionnaires. We used a null model approach to examine the utilitarian (functional) diversity and utilitarian redundancy present within ecological communities. Additionally, variables that might influence fluctuations in utilitarian diversity and redundancy—specifically number of felled trees, number of trails, basal area, canopy height, elevation, distance from village—were analyzed using Generalized Linear Models (GLMs). Eighteen of the 56 plots showed utilitarian diversity values significantly higher than expected. This result indicates that these habitats exhibited a low degree of utilitarian redundancy and were therefore comprised of plants with relatively distinct utilitarian properties. One implication of this finding is that minor losses in species richness may result in reductions in utilitarian diversity and redundancy, which may limit local residents' ability to switch between alternative choices. The GLM analysis showed that the most predictive model included basal area, canopy height and distance from village, which suggests that variation in utilitarian redundancy may be a result of local residents harvesting resources from the protected area. Our approach permits an assessment of the diversity of provisioning services available to local communities, offering unique insights that would not be possible using traditional taxonomic diversity measures. These analyses introduce another tool available to conservation biologists for assessing how future losses in biodiversity will lead to a reduction in natural resources and provisioning services from forests. PMID:21909413

Brown, Kerry A.; Flynn, Dan F. B.; Abram, Nicola K.; Ingram, J. Carter; Johnson, Steig E.; Wright, Patricia

2011-01-01

126

Host-plant genotypic diversity and community genetic interactions mediate aphid spatial distribution  

PubMed Central

Genetic variation in plants can influence the community structure of associated species, through both direct and indirect interactions. Herbivorous insects are known to feed on a restricted range of plants, and herbivore preference and performance can vary among host plants within a species due to genetically based traits of the plant (e.g., defensive compounds). In a natural system, we expect to find genetic variation within both plant and herbivore communities and we expect this variation to influence species interactions. Using a three-species plant-aphid model system, we investigated the effect of genetic diversity on genetic interactions among the community members. Our system involved a host plant (Hordeum vulgare) that was shared by an aphid (Sitobion avenae) and a hemi-parasitic plant (Rhinanthus minor). We showed that aphids cluster more tightly in a genetically diverse host-plant community than in a genetic monoculture, with host-plant genetic diversity explaining up to 24% of the variation in aphid distribution. This is driven by differing preferences of the aphids to the different plant genotypes and their resulting performance on these plants. Within the two host-plant diversity levels, aphid spatial distribution was influenced by an interaction among the aphid's own genotype, the genotype of a competing aphid, the origin of the parasitic plant population, and the host-plant genotype. Thus, the overall outcome involves both direct (i.e., host plant to aphid) and indirect (i.e., parasitic plant to aphid) interactions across all these species. These results show that a complex genetic environment influences the distribution of herbivores among host plants. Thus, in genetically diverse systems, interspecific genetic interactions between the host plant and herbivore can influence the population dynamics of the system and could also structure local communities. We suggest that direct and indirect genotypic interactions among species can influence community structure and processes. PMID:24558568

Zytynska, Sharon E; Frantz, Laurent; Hurst, Ben; Johnson, Andrew; Preziosi, Richard F; Rowntree, Jennifer K

2014-01-01

127

Host-plant genotypic diversity and community genetic interactions mediate aphid spatial distribution.  

PubMed

Genetic variation in plants can influence the community structure of associated species, through both direct and indirect interactions. Herbivorous insects are known to feed on a restricted range of plants, and herbivore preference and performance can vary among host plants within a species due to genetically based traits of the plant (e.g., defensive compounds). In a natural system, we expect to find genetic variation within both plant and herbivore communities and we expect this variation to influence species interactions. Using a three-species plant-aphid model system, we investigated the effect of genetic diversity on genetic interactions among the community members. Our system involved a host plant (Hordeum vulgare) that was shared by an aphid (Sitobion avenae) and a hemi-parasitic plant (Rhinanthus minor). We showed that aphids cluster more tightly in a genetically diverse host-plant community than in a genetic monoculture, with host-plant genetic diversity explaining up to 24% of the variation in aphid distribution. This is driven by differing preferences of the aphids to the different plant genotypes and their resulting performance on these plants. Within the two host-plant diversity levels, aphid spatial distribution was influenced by an interaction among the aphid's own genotype, the genotype of a competing aphid, the origin of the parasitic plant population, and the host-plant genotype. Thus, the overall outcome involves both direct (i.e., host plant to aphid) and indirect (i.e., parasitic plant to aphid) interactions across all these species. These results show that a complex genetic environment influences the distribution of herbivores among host plants. Thus, in genetically diverse systems, interspecific genetic interactions between the host plant and herbivore can influence the population dynamics of the system and could also structure local communities. We suggest that direct and indirect genotypic interactions among species can influence community structure and processes. PMID:24558568

Zytynska, Sharon E; Frantz, Laurent; Hurst, Ben; Johnson, Andrew; Preziosi, Richard F; Rowntree, Jennifer K

2014-01-01

128

Ground Layer Plant Species Turnover and Beta Diversity in Southern-European Old-Growth Forests  

PubMed Central

Different assembly processes may simultaneously affect local-scale variation of species composition in temperate old-growth forests. Ground layer species diversity reflects chance colonization and persistence of low-dispersal species, as well as fine-scale environmental heterogeneity. The latter depends on both purely abiotic factors, such as soil properties and topography, and factors primarily determined by overstorey structure, such as light availability. Understanding the degree to which plant diversity in old-growth forests is associated with structural heterogeneity and/or to dispersal limitation will help assessing the effectiveness of silvicultural practices that recreate old-growth patterns and structures for the conservation or restoration of plant diversity. We used a nested sampling design to assess fine-scale species turnover, i.e. the proportion of species composition that changes among sampling units, across 11 beech-dominated old-growth forests in Southern Europe. For each stand, we also measured a wide range of environmental and structural variables that might explain ground layer species turnover. Our aim was to quantify the relative importance of dispersal limitation in comparison to that of stand structural heterogeneity while controlling for other sources of environmental heterogeneity. For this purpose, we used multiple regression on distance matrices at the within-stand extent, and mixed effect models at the extent of the whole dataset. Species turnover was best predicted by structural and environmental heterogeneity, especially by differences in light availability and in topsoil nutrient concentration and texture. Spatial distances were significant only in four out of eleven stands with a relatively low explanatory power. This suggests that structural heterogeneity is a more important driver of local-scale ground layer species turnover than dispersal limitation in southern European old-growth beech forests. PMID:24748155

Sabatini, Francesco Maria; Burrascano, Sabina; Tuomisto, Hanna; Blasi, Carlo

2014-01-01

129

Environmental Conditions Influence the Plant Functional Diversity Effect on Potential Denitrification  

PubMed Central

Global biodiversity loss has prompted research on the relationship between species diversity and ecosystem functioning. Few studies have examined how plant diversity impacts belowground processes; even fewer have examined how varying resource levels can influence the effect of plant diversity on microbial activity. In a field experiment in a restored wetland, we examined the role of plant trait diversity (or functional diversity, (FD)) and its interactions with natural levels of variability of soil properties, on a microbial process, denitrification potential (DNP). We demonstrated that FD significantly affected microbial DNP through its interactions with soil conditions; increasing FD led to increased DNP but mainly at higher levels of soil resources. Our results suggest that the effect of species diversity on ecosystem functioning may depend on environmental factors such as resource availability. Future biodiversity experiments should examine how natural levels of environmental variability impact the importance of biodiversity to ecosystem functioning. PMID:21311768

Sutton-Grier, Ariana E.; Wright, Justin P.; McGill, Bonnie M.; Richardson, Curtis

2011-01-01

130

Allozyme diversity in the endangered pitcher plant Sarracenia rubra ssp. Alabamensis (Sarraceniaceae) and its close relative S. rubra ssp. rubra.  

PubMed

Genetic variability in the federally endangered pitcher plant Sarracenia rubra ssp. alabamensis was assessed in eight Alabama populations using starch gel electrophoresis. Ten populations of the more widespread Sarracenia rubra ssp. rubra were sampled in the southeastern United States for comparison. Fifteen allozyme loci representing 13 enzyme systems were scored for each species. In contrast to S. oreophila and S. jonesii, two previously analyzed endangered pitcher plants, genetic diversity was high for both S. rubra subspecies. Within ssp. alabamensis the percentage polymorphic loci (Ps) was 80.0, the mean number of alleles per polymorphic locus was (APs) = 2.58, and expected heterozygosity (Hes) was 0.209. Genetic diversity was slightly lower for ssp. rubra (Ps = 73.3, APs = 2.91, and Hes = 0.177). The proportion of total genetic diversity found among populations was fairly low for both species (GST = 0.09 for ssp. alabamensis and 0.14 for ssp. rubra). Little genetic divergence has occurred between the two subspecies as indicated by the lack of diagnostic alleles, the proportion of total genetic diversity between taxa (GST = 0.09), and the genetic identity estimate (I = 0.90). The relatively high genetic diversity found for ssp. alabamensis indicates that the maintenance of its evolutionary potential is possible if population sizes are maintained or increased. Low levels of genetic diversity found within small Georgia ssp. rubra populations indicate that genetic erosion may increase extinction risks for these populations. PMID:21684964

Godt, M; Hamrick, J

1998-06-01

131

Disparate effects of plant genotypic diversity on foliage and litter arthropod communities  

SciTech Connect

Intraspecific diversity within plant species is increasingly recognized as an important influence on the structure of associated arthropod communities, though whether there are congruent responses of above- and belowground communities to intraspecific diversity remains unclear. In this study, we compare the effects of host-plant genotype and genotypic diversity of the perennial plant, Solidago altissima, on the arthropod community associated with living plant tissue (foliage-based community) and microarthropods associated with leaf litter (litter-based community). We found that variation among host-plant genotypes had strong effects on the diversity and composition of foliage-based arthropods, but only weak influence on litter-based microarthropods. Furthermore, host-plant genotypic diversity was positively related to the abundance and diversity of foliage-based arthropods, including herbivore and predator trophic levels. In contrast, there were minimal effects of genotypic diversity in litter on microarthropods. Our study illustrates that incorporating both above- and belowground perspective into community genetics studies leads to very different conclusions about the importance of intraspecific diversity, than when considering aboveground responses in isolation.

Crutsinger, Greg [University of Tennessee, Knoxville (UTK); Reynolds, Nicholas [University of Tennessee, Knoxville (UTK); Classen, Aimee T [ORNL; Sanders, Dr. Nathan James [University of Tennessee, Knoxville (UTK)

2008-01-01

132

Interactive effects of mycorrhizae and a root hemiparasite on plant community productivity and diversity.  

PubMed

Plant communities can be affected both by arbuscular mycorrhizal fungi (AMF) and hemiparasitic plants. However, little is known about the interactive effects of these two biotic factors on the productivity and diversity of plant communities. To address this question, we set up a greenhouse study in which different AMF inocula and a hemiparasitic plant (Rhinanthus minor) were added to experimental grassland communities in a fully factorial design. In addition, single plants of each species in the grassland community were grown with the same treatments to distinguish direct AMF effects from indirect effects via plant competition. We found that AMF changed plant community structure by influencing the plant species differently. At the community level, AMF decreased the productivity by 15-24%, depending on the particular AMF treatment, mainly because two dominant species, Holcus lanatus and Plantago lanceolata, showed a negative mycorrhizal dependency. Concomitantly, plant diversity increased due to AMF inoculation and was highest in the treatment with a combination of two commercial AM strains. AMF had a positive effect on growth of the hemiparasite, and thereby induced a negative impact of the hemiparasite on host plant biomass which was not found in non-inoculated communities. However, the hemiparasite did not increase plant diversity. Our results highlight the importance of interactions with soil microbes for plant community structure and that these indirect effects can vary among AMF treatments. We conclude that mutualistic interactions with AMF, but not antagonistic interactions with a root hemiparasite, promote plant diversity in this grassland community. PMID:18975009

Stein, Claudia; Rissmann, Cornelia; Hempel, Stefan; Renker, Carsten; Buscot, François; Prati, Daniel; Auge, Harald

2009-02-01

133

Single nucleotide polymorphisms for assessing genetic diversity in castor bean (Ricinus communis)  

PubMed Central

Background Castor bean (Ricinus communis) is an agricultural crop and garden ornamental that is widely cultivated and has been introduced worldwide. Understanding population structure and the distribution of castor bean cultivars has been challenging because of limited genetic variability. We analyzed the population genetics of R. communis in a worldwide collection of plants from germplasm and from naturalized populations in Florida, U.S. To assess genetic diversity we conducted survey sequencing of the genomes of seven diverse cultivars and compared the data to a reference genome assembly of a widespread cultivar (Hale). We determined the population genetic structure of 676 samples using single nucleotide polymorphisms (SNPs) at 48 loci. Results Bayesian clustering indicated five main groups worldwide and a repeated pattern of mixed genotypes in most countries. High levels of population differentiation occurred between most populations but this structure was not geographically based. Most molecular variance occurred within populations (74%) followed by 22% among populations, and 4% among continents. Samples from naturalized populations in Florida indicated significant population structuring consistent with local demes. There was significant population differentiation for 56 of 78 comparisons in Florida (pairwise population ?PT values, p < 0.01). Conclusion Low levels of genetic diversity and mixing of genotypes have led to minimal geographic structuring of castor bean populations worldwide. Relatively few lineages occur and these are widely distributed. Our approach of determining population genetic structure using SNPs from genome-wide comparisons constitutes a framework for high-throughput analyses of genetic diversity in plants, particularly in species with limited genetic diversity. PMID:20082707

2010-01-01

134

Genetic diversity and phylogeny of pink-pigmented facultative methylotrophic bacteria isolated from the phyllosphere of tropical crop plants  

Microsoft Academic Search

Genetic diversity of pink-pigmented facultative methylotrophic bacteria belonging to the genus, Methylobacterium, was assessed using 16S ribosomal RNA (rRNA) gene sequencing, amplified ribosomal DNA restriction analysis (ARDRA), and differential\\u000a carbon-substrate utilization profile in the phyllosphere of cotton, maize, sunflower, soybean, and mentha plants. Methylobacterium populi, Methylobacterium thiocyanatum, Methylobacterium suomiense, M. aminovorans, and Methylobacterium fujisawaense were identified to colonize the phyllosphere

P. Raja; D. Balachandar; S. P. Sundaram

2008-01-01

135

Global Analysis of Proline-Rich Tandem Repeat Proteins Reveals Broad Phylogenetic Diversity in Plant Secretomes  

PubMed Central

Cell walls, constructed by precisely choreographed changes in the plant secretome, play critical roles in plant cell physiology and development. Along with structural polysaccharides, secreted proline-rich Tandem Repeat Proteins (TRPs) are important for cell wall function, yet the evolutionary diversity of these structural TRPs remains virtually unexplored. Using a systems-level computational approach to analyze taxonomically diverse plant sequence data, we identified 31 distinct Pro-rich TRP classes targeted for secretion. This analysis expands upon the known phylogenetic diversity of extensins, the most widely studied class of wall structural proteins, and demonstrates that extensins evolved before plant vascularization. Our results also show that most Pro-rich TRP classes have unexpectedly restricted evolutionary distributions, revealing considerable differences in plant secretome signatures that define unexplored diversity. PMID:21829715

Newman, Aaron M.; Cooper, James B.

2011-01-01

136

Monotropa uniflora plants of eastern Massachusetts form mycorrhizae with a diversity of russulacean fungi.  

PubMed

Plant species in the subfamily Monotropoideae are mycoheterotrophs; they obtain fixed carbon from photosynthetic plants via a shared mycorrhizal network. Previous findings show mycoheterotrophic plants exhibit a high level of specificity to their mycorrhizal fungi. In this study we explore the association of mycorrhizal fungi and Monotropa uniflora (Monotropoideae: Ericaceae) in eastern North America. We collected M. uniflora roots and nearby basidiomycete sporocarps from four sites within a 100 km2 area in eastern Massachusetts. We analyzed DNA sequences of the internal transcribed spacer region (ITS) from the fungal nuclear ribosomal gene to assess the genetic diversity of fungi associating with M. uniflora roots. In this analysis we included 20 ITS sequences from Russula sporocarps collected nearby, 44 sequences of Russula or Lactarius species from GenBank and 12 GenBank sequences of fungi isolated from M. uniflora roots in previous studies. We found that all 56 sampled M. uniflora mycorrhizal fungi were members of the Russulaceae, confirming previous research. The analysis showed that most of the diversity of mycorrhizal fungi spreads across the genus Russula. ITS sequences of the mycorrhizal fungi consisted of 20 different phylotypes: 18 of the genus Russula and two of Lactarius, based on GenBank searches. Of the sampled plants, 57% associated with only three of the 20 mycorrhizal fungi detected in roots, and of the 25 sporocarp phylotypes collected three, were associated with M. uniflora. Furthermore the results indicate that the number of different fungal phylotypes associating with M. uniflora of eastern North America is higher than that of western North America but patterns of fungal species abundance might be similar between mycorrhizae from the two locations. PMID:17139846

Yang, S; Pfister, D H

2006-01-01

137

Measuring the fate of plant diversity: towards a foundation for future monitoring and opportunities for urgent action.  

PubMed

Vascular plants are often considered to be among the better known large groups of organisms, but gaps in the available baseline data are extensive, and recent estimates of total known (described) seed plant species range from 200000 to 422000. Of these, global assessments of conservation status using International Union for the Conservation of Nature (IUCN) categories and criteria are available for only approximately 10000 species. In response to recommendations from the Conference of the Parties to the Convention on Biological Diversity to develop biodiversity indicators based on changes in the status of threatened species, and trends in the abundance and distribution of selected species, we examine how existing data, in combination with limited new data collection, can be used to maximum effect. We argue that future work should produce Red List Indices based on a representative subset of plant species so that the limited resources currently available are directed towards redressing taxonomic and geographical biases apparent in existing datasets. Sampling the data held in the world's major herbaria, in combination with Geographical Information Systems techniques, can produce preliminary conservation assessments and help to direct selective survey work using existing field networks to verify distributions and gather population data. Such data can also be used to backcast threats and potential distributions through time. We outline an approach that could result in: (i) preliminary assessments of the conservation status of tens of thousands of species not previously assessed, (ii) significant enhancements in the coverage and representation of plant species on the IUCN Red List, and (iii) repeat and/or retrospective assessments for a significant proportion of these. This would result in more robust Sampled Red List Indices that can be defended as more representative of plant diversity as a whole; and eventually, comprehensive assessments at species level for one or more major families of angiosperms. The combined results would allow scientifically defensible generalizations about the current status of plant diversity by 2010 as well as tentative comments on trends. Together with other efforts already underway, this approach would establish a firmer basis for ongoing monitoring of the status of plant diversity beyond 2010 and a basis for comparison with the trend data available for vertebrates. PMID:15814350

Nic Lughadha, E; Baillie, J; Barthlott, W; Brummitt, N A; Cheek, M R; Farjon, A; Govaerts, R; Hardwick, K A; Hilton-Taylor, C; Meagher, T R; Moat, J; Mutke, J; Paton, A J; Pleasants, L J; Savolainen, V; Schatz, G E; Smith, P; Turner, I; Wyse-Jackson, P; Crane, P R

2005-02-28

138

Measuring the fate of plant diversity: towards a foundation for future monitoring and opportunities for urgent action  

PubMed Central

Vascular plants are often considered to be among the better known large groups of organisms, but gaps in the available baseline data are extensive, and recent estimates of total known (described) seed plant species range from 200?000 to 422?000. Of these, global assessments of conservation status using International Union for the Conservation of Nature (IUCN) categories and criteria are available for only approximately 10?000 species. In response to recommendations from the Conference of the Parties to the Convention on Biological Diversity to develop biodiversity indicators based on changes in the status of threatened species, and trends in the abundance and distribution of selected species, we examine how existing data, in combination with limited new data collection, can be used to maximum effect. We argue that future work should produce Red List Indices based on a representative subset of plant species so that the limited resources currently available are directed towards redressing taxonomic and geographical biases apparent in existing datasets. Sampling the data held in the world's major herbaria, in combination with Geographical Information Systems techniques, can produce preliminary conservation assessments and help to direct selective survey work using existing field networks to verify distributions and gather population data. Such data can also be used to backcast threats and potential distributions through time. We outline an approach that could result in: (i) preliminary assessments of the conservation status of tens of thousands of species not previously assessed, (ii) significant enhancements in the coverage and representation of plant species on the IUCN Red List, and (iii) repeat and/or retrospective assessments for a significant proportion of these. This would result in more robust Sampled Red List Indices that can be defended as more representative of plant diversity as a whole; and eventually, comprehensive assessments at species level for one or more major families of angiosperms. The combined results would allow scientifically defensible generalizations about the current status of plant diversity by 2010 as well as tentative comments on trends. Together with other efforts already underway, this approach would establish a firmer basis for ongoing monitoring of the status of plant diversity beyond 2010 and a basis for comparison with the trend data available for vertebrates. PMID:15814350

Nic Lughadha, E; Baillie, J; Barthlott, W; Brummitt, N.A; Cheek, M.R; Farjon, A; Govaerts, R; Hardwick, K.A; Hilton-Taylor, C; Meagher, T.R; Moat, J; Mutke, J; Paton, A.J; Pleasants, L.J; Savolainen, V; Schatz, G.E; Smith, P; Turner, I; Wyse-Jackson, P; Crane, P.R

2005-01-01

139

Assessing ecosystem integrity of restored prairie wetlands from species production–diversity relationships  

Microsoft Academic Search

We assessed ecosystem integrity in restored prairie wetlands in eastern South Dakota, U.S.A., by examining the relationship between and diatom diversity and production. We asked three questions: (1) Is production related to species diversity? (2) Can production-diversity relationships be used to distinguish between restored and reference wetlands with the purpose of assessing ecological integrity? (3) Are production-diversity relationships influenced by

Paul M. Mayer; Susan M. Galatowitsch

2001-01-01

140

Plant diversity and conservation in China: planning a strategic bioresource for a sustainable future.  

PubMed

China is one of the richest countries for plant diversity with approximately 33 000 vascular plant species, ranking second in the world. However, the plant diversity in China is increasingly threatened, with an estimated 4000–5000 plant species being threatened or on the verge of extinction, making China, proportionally, one of the highest priorities for global plant biodiversity conservation. Coming in the face of the current ecological crisis, it is timely that China has launched China's Strategy for Plant Conservation (CSPC). China has increasingly recognized the importance of plant diversity in efforts to conserve and sustainably use its plant diversity. More than 3000 nature reserves have been established, covering approximately 16% of the land surface of China. These natural reserves play important roles in plant conservation, covering more than 85% of types of terrestrial natural ecosystems, 40% of types of natural wetlands, 20% of native forests and 65% of natural communities of vascular plants. Meanwhile, the flora conserved in botanical gardens is also extensive. A recent survey shows that the 10 largest botanical gardens have living collections of 43 502 taxa, with a total of 24 667 species in ex situ conservation. These provide an important reserve of plant resources for sustainable economic and social development in China. Plant diversity is the basis for bioresources and sustainable utilization. The 21st century is predicted to be an era of bio-economy driven by advances of bioscience and biotechnology. Bio-economy may become the fourth economy form after agricultural, industrial, and information and information technology economies, having far-reaching impacts on sustainable development in agriculture, forestry, environmental protection, light industry, food supply and health care and other micro-economy aspects. Thus, a strategic and forward vision for conservation of plant diversity and sustainable use of plant resources in the 21st century is of far-reaching significance for sustainable development of Chinese economy and society. PMID:22059249

Huang, Hongwen

2011-01-01

141

Regeneration and tree diversity in natural and planted forests in a Terai - Bhabhar forest in Katarniaghat Wildlife Sanctuary, India  

Microsoft Academic Search

We compared regeneration, tree diversity and floristic diversity of natural and planted tropical deciduous forests (dominated by Shorea robusta and Tectona grandis; Acacia catechu and Syzygium cumini, respectively) in western Uttar Pradesh, India. Species diversity (70 species in natural and 59 species in planted forests) as well as species evenness was higher in natural forests than in planted forests. Natural

D. S. CHAUHAN; C. S. DHANAI; BHUPENDRA SINGH; SHASHI CHAUHAN; N. P. TODARIA; M. A. KHALID

142

Slippery or sticky? Functional diversity in the trapping strategy of Nepenthes carnivorous plants  

E-print Network

Slippery or sticky? Functional diversity in the trapping strategy of Nepenthes carnivorous plants Paysages et Jardin Botanique de Plantes Carnivores, Peyrusse-Massas, France Author for correspondence words: biological trade-off, carnivorous pitcher plant, digestive fluid, leaf wax, Nepenthes, trapping

Forterre, Yoël

143

Modelling vascular plant diversity at the landscape scale using systematic samples  

E-print Network

ORIGINAL ARTICLE Modelling vascular plant diversity at the landscape scale using systematic samples-scale species richness patterns at large spatial extents by linking a systematic sample of vascular plants Europe. Methods Vascular plant species data were collected along transects of 2500-m length within 1-km2

144

MSU Departmental Assessment Plan 2009-2010 Department: Plant Sciences and Plant Pathology  

E-print Network

MSU Departmental Assessment Plan 2009-2010 Department: Plant Sciences and Plant Pathology by Department #12;Assessment and Outcomes Progress 2008-2009--Department of Plant Sciences and Plant Pathology The five areas of undergraduate instruction in the Department of Plant Sciences and Plant Pathology (PSPP

Maxwell, Bruce D.

145

Habitats as complex odour environments: how does plant diversity affect herbivore and parasitoid orientation?  

PubMed

Plant diversity is known to affect success of host location by pest insects, but its effect on olfactory orientation of non-pest insect species has hardly been addressed. First, we tested in laboratory experiments the hypothesis that non-host plants, which increase odour complexity in habitats, affect the host location ability of herbivores and parasitoids. Furthermore, we recorded field data of plant diversity in addition to herbivore and parasitoid abundance at 77 grassland sites in three different regions in Germany in order to elucidate whether our laboratory results reflect the field situation. As a model system we used the herb Plantago lanceolata, the herbivorous weevil Mecinus pascuorum, and its larval parasitoid Mesopolobus incultus. The laboratory bioassays revealed that both the herbivorous weevil and its larval parasitoid can locate their host plant and host via olfactory cues even in the presence of non-host odour. In a newly established two-circle olfactometer, the weevi?s capability to detect host plant odour was not affected by odours from non-host plants. However, addition of non-host plant odours to host plant odour enhanced the weevi?s foraging activity. The parasitoid was attracted by a combination of host plant and host volatiles in both the absence and presence of non-host plant volatiles in a Y-tube olfactometer. In dual choice tests the parasitoid preferred the blend of host plant and host volatiles over its combination with non-host plant volatiles. In the field, no indication was found that high plant diversity disturbs host (plant) location by the weevil and its parasitoid. In contrast, plant diversity was positively correlated with weevil abundance, whereas parasitoid abundance was independent of plant diversity. Therefore, we conclude that weevils and parasitoids showed the sensory capacity to successfully cope with complex vegetation odours when searching for hosts. PMID:24416354

Wäschke, Nicole; Hardge, Kristin; Hancock, Christine; Hilker, Monika; Obermaier, Elisabeth; Meiners, Torsten

2014-01-01

146

Plant Wide Assessment for SIFCO Industries, Inc.  

SciTech Connect

Sifco Industries carreid out a plant wide energy assessment under a collaborative program with the U.S. Department of Energy during October 2004 to September 2005. During the year, personnel from EIS, E3M, DPS, BuyCastings.Com, and Sifco plant facilities and maintenance personnel, as a team collected energy use, construction, process, equipment and operational information about the plant. Based on this information, the team identified 13 energy savings opportunities. Near term savings opportunities have a total potential savings of about $1,329,000 per year and a combined simple payback of about 11 months. Implementation of these recommendations would reduce CO2 emissions by about 16,000,000 pounds per year, which would reduce overall plant CO2 emissions by about 45%. These totals do not include another $830,000 per year in potential savings with an estimated 9-month payback, from converting the forging hammers from steam to compressed air.

Kelly Kissock, Arvind Thekdi et. al.

2005-07-06

147

Native plant diversity resists invasion at both low and high resource levels.  

PubMed

Human modification of the environment is causing both loss of species and changes in resource availability. While studies have examined how species loss at the local level can influence invasion resistance, interactions between species loss and other components of environmental change remain poorly studied. In particular, the manner in which native diversity interacts with resource availability to influence invasion resistance is not well understood. We created experimental plant assemblages that varied in native species (1-16 species) and/or functional richness (defined by rooting morphology and phenology; one to five functional groups). We crossed these diversity treatments with resource (water) addition to determine their interactive effects on invasion resistance to spotted knapweed (Centaurea maculosa), a potent exotic invader in the intermountain West of the United States. We also determined how native diversity and resource addition influenced plant-available soil nitrogen, soil moisture, and light. Assemblages with lower species and functional diversity were more heavily invaded than assemblages with greater species and functional diversity. In uninvaded assemblages, experimental addition of water increased soil moisture and plant-available nitrogen and decreased light availability. The availability of these resources generally declined with increasing native plant diversity. Although water addition increased susceptibility to invasion, it did not fundamentally change the negative relationship between diversity and invasibility. Thus, native diversity provided strong invasion resistance even under high resource availability. These results suggest that the effects of local diversity can remain robust despite enhanced resource levels that are predicted under scenarios of global change. PMID:18027767

Maron, John; Marler, Marilyn

2007-10-01

148

Habitat fragmentation, tree diversity, and plant invasion interact to structure forest caterpillar communities.  

PubMed

Habitat fragmentation and invasive species are two of the most prominent threats to terrestrial ecosystems. Few studies have examined how these factors interact to influence the diversity of natural communities, particularly primary consumers. Here, we examined the effects of forest fragmentation and invasion of exotic honeysuckle (Lonicera maackii, Caprifoliaceae) on the abundance and diversity of the dominant forest herbivores: woody plant-feeding Lepidoptera. We systematically surveyed understory caterpillars along transects in 19 forest fragments over multiple years in southwestern Ohio and evaluated how fragment area, isolation, tree diversity, invasion by honeysuckle and interactions among these factors influence species richness, diversity and abundance. We found strong seasonal variation in caterpillar communities, which responded differently to fragmentation and invasion. Abundance and richness increased with fragment area, but these effects were mitigated by high levels of honeysuckle, tree diversity, landscape forest cover, and large recent changes in area. Honeysuckle infestation was generally associated with decreased caterpillar abundance and diversity, but these effects were strongly dependent on other fragment traits. Effects of honeysuckle on abundance were moderated when fragment area, landscape forest cover and tree diversity were high. In contrast, negative effects of honeysuckle invasion on caterpillar diversity were most pronounced in fragments with high tree diversity and large recent increases in area. Our results illustrate the complex interdependencies of habitat fragmentation, plant diversity and plant invasion in their effects on primary consumers and emphasize the need to consider these processes in concert to understand the consequences of anthropogenic habitat change for biodiversity. PMID:25015121

Stireman, John O; Devlin, Hilary; Doyle, Annie L

2014-09-01

149

DIVERSITY AND INVASIBILITY OF SOUTHERN APPALACHIAN PLANT COMMUNITIES  

Microsoft Academic Search

We propose that the relationship between diversity and community invasi- bility depends on the degree to which community composition is driven by immigration processes. When immigration is enhanced by high propagule pressure or low-intensity disturbance, the relationship between diversity and exotic species invasion should be pos- itive. Only when such immigration processes are limited should competitive interactions lead to a

Rebecca L. Brown; Robert K. Peet

2003-01-01

150

Exploiting a wheat EST database to assess genetic diversity.  

PubMed

Expressed sequence tag (EST) markers have been used to assess variety and genetic diversity in wheat (Triticum aestivum). In this study, 1549 ESTs from wheat infested with yellow rust were used to examine the genetic diversity of six susceptible and resistant wheat cultivars. The aim of using these cultivars was to improve the competitiveness of public wheat breeding programs through the intensive use of modern, particularly marker-assisted, selection technologies. The F(2) individuals derived from cultivar crosses were screened for resistance to yellow rust at the seedling stage in greenhouses and adult stage in the field to identify DNA markers genetically linked to resistance. Five hundred and sixty ESTs were assembled into 136 contigs and 989 singletons. BlastX search results showed that 39 (29%) contigs and 96 (10%) singletons were homologous to wheat genes. The database-matched contigs and singletons were assigned to eight functional groups related to protein synthesis, photosynthesis, metabolism and energy, stress proteins, transporter proteins, protein breakdown and recycling, cell growth and division and reactive oxygen scavengers. PCR analyses with primers based on the contigs and singletons showed that the most polymorphic functional categories were photosynthesis (contigs) and metabolism and energy (singletons). EST analysis revealed considerable genetic variability among the Turkish wheat cultivars resistant and susceptible to yellow rust disease and allowed calculation of the mean genetic distance between cultivars, with the greatest similarity (0.725) being between Harmankaya99 and Sönmez2001, and the lowest (0.622) between Aytin98 and Izgi01. PMID:21637582

Karakas, Ozge; Gurel, Filiz; Uncuoglu, Ahu Altinkut

2010-10-01

151

Protein change in plant evolution: tracing one thread connecting molecular and phenotypic diversity  

PubMed Central

Proteins change over the course of evolutionary time. New protein-coding genes and gene families emerge and diversify, ultimately affecting an organism’s phenotype and interactions with its environment. Here we survey the range of structural protein change observed in plants and review the role these changes have had in the evolution of plant form and function. Verified examples tying evolutionary change in protein structure to phenotypic change remain scarce. We will review the existing examples, as well as draw from investigations into domestication, and quantitative trait locus (QTL) cloning studies searching for the molecular underpinnings of natural variation. The evolutionary significance of many cloned QTL has not been assessed, but all the examples identified so far have begun to reveal the extent of protein structural diversity tolerated in natural systems. This molecular (and phenotypic) diversity could come to represent part of natural selection’s source material in the adaptive evolution of novel traits. Protein structure and function can change in many distinct ways, but the changes we identified in studies of natural diversity and protein evolution were predicted to fall primarily into one of six categories: altered active and binding sites; altered protein–protein interactions; altered domain content; altered activity as an activator or repressor; altered protein stability; and hypomorphic and hypermorphic alleles. There was also variability in the evolutionary scale at which particular changes were observed. Some changes were detected at both micro- and macroevolutionary timescales, while others were observed primarily at deep or shallow phylogenetic levels. This variation might be used to determine the trajectory of future investigations in structural molecular evolution. PMID:24124420

Bartlett, Madelaine E.; Whipple, Clinton J.

2013-01-01

152

Ecological Effects of Roads on the Plant Diversity of Coastal Wetland in the Yellow River Delta  

PubMed Central

The 26 sample sites in 7 study plots adjacent to asphalt road and earth road in coastal wetland in the Yellow River Delta were selected to quantify plant diversity using quadrat sampling method in plant bloom phase of July and August 2012. The indice of ?T and Jaccard's coefficient were applied to evaluate the species diversity. The results showed that the plant diversities and alien plants were high in the range of 0–20?m to the road verge. There were more exotics and halophytes in plots of asphalt roadside than that of earth roadside. However, proportion of halophytes in habitats of asphalt roadsides was lower than that of earth roadside. By comparing ?-diversity, there were more common species in the asphalt roadsides than that in the earth roadsides. The similarity of plant communities in studied plots of asphalt roadsides and earth roadsides increased with increasing the distance to road verge. The effect range of roads for plant diversity in study region was about 20?m to road verge. Our results indicate that the construction and maintenance of roads in wetland could increase the plant species diversities of communities and risk of alien species invasion. PMID:25147872

Li, Yunzhao; Du, Siyao; Han, Guangxuan; Qu, Fanzhu; Wang, Guangmei; Fu, Yuqin; Zhan, Chao

2014-01-01

153

Ecological effects of roads on the plant diversity of coastal wetland in the Yellow River Delta.  

PubMed

The 26 sample sites in 7 study plots adjacent to asphalt road and earth road in coastal wetland in the Yellow River Delta were selected to quantify plant diversity using quadrat sampling method in plant bloom phase of July and August 2012. The indice of ? T and Jaccard's coefficient were applied to evaluate the species diversity. The results showed that the plant diversities and alien plants were high in the range of 0-20 m to the road verge. There were more exotics and halophytes in plots of asphalt roadside than that of earth roadside. However, proportion of halophytes in habitats of asphalt roadsides was lower than that of earth roadside. By comparing ?-diversity, there were more common species in the asphalt roadsides than that in the earth roadsides. The similarity of plant communities in studied plots of asphalt roadsides and earth roadsides increased with increasing the distance to road verge. The effect range of roads for plant diversity in study region was about 20 m to road verge. Our results indicate that the construction and maintenance of roads in wetland could increase the plant species diversities of communities and risk of alien species invasion. PMID:25147872

Li, Yunzhao; Yu, Junbao; Ning, Kai; Du, Siyao; Han, Guangxuan; Qu, Fanzhu; Wang, Guangmei; Fu, Yuqin; Zhan, Chao

2014-01-01

154

Disentangling direct and indirect effects of experimental grassland management and plant functional-group manipulation on plant and leafhopper diversity  

PubMed Central

Background Plant biodiversity can affect trophic interactions in many ways, including direct bottom-up effects on insects, but is negatively affected by agricultural intensification. Grassland intensification promotes plant productivity, resulting in changes in plant community composition, and impacts on higher trophic levels. Here, we use a novel grassland management experiment combining manipulations of cutting and fertilization with experimental changes in plant functional group composition (independent of management effects) to disentangle the direct and indirect effects of agricultural management on insect herbivore diversity and abundance. We used leafhoppers as model organisms as they are a key insect taxon in grasslands and react rapidly to management changes. Leafhoppers were sampled between May and September 2010 using standardized sweep netting and pan traps. Results Plant diversity, functional group composition and management regime in grasslands affected leafhopper species richness and abundance. Higher cutting frequencies directly led to decreasing leafhopper species richness, presumably due to the higher disturbance frequency and the reduction in food-resource heterogeneity. In contrast, fertilizer application had only a small indirect negative effect via enhanced aboveground plant biomass, reduced plant diversity and changes in functional group composition. The manipulated increase in grass cover had contrasting direct and indirect effects on leafhopper species richness: grass cover directly increased leafhopper species richness, but negatively affected plant diversity, which in turn was positively related to leafhopper species richness. In conclusion, insect diversity is driven in complex direct and indirect ways by grassland management, including changes in functional group composition. Conclusions The availability of preferred food sources and the frequency of disturbance are important direct and indirect drivers of leafhopper species richness, interacting in complex ways with plant diversity and food resource heterogeneity. PMID:24438134

2014-01-01

155

Resource-based niches provide a basis for plant species diversity and dominance in arctic tundra  

Microsoft Academic Search

Ecologists have long been intrigued by the ways co-occurring species divide limiting resources. Such resource partitioning, or niche differentiation, may promote species diversity by reducing competition. Although resource partitioning is an important determinant of species diversity and composition in animal communities, its importance in structuring plant communities has been difficult to resolve. This is due mainly to difficulties in studying

Robert B. McKane; Loretta C. Johnson; Gaius R. Shaver; Knute J. Nadelhoffer; Edward B. Rastetter; Brian Fry; Anne E. Giblin; Knut Kielland; Bonnie L. Kwiatkowski; James A. Laundre; Georgia Murray

2002-01-01

156

Temporal patterns of vascular plant diversity in southeastern New Hampshire forests  

Microsoft Academic Search

A chronosequence of 22 sites in Durham, NH, was used to study upland successional patterns of species diversity over a span of 14–209 years of forest development and to test the hypothesis that diversity is maximized at mid-succession. Nested quadrat sampling was used to estimate the relative importance values of vascular plant species in the tree, shrub, and herb strata.

Lauren F. Howard; Thomas D. Lee

2003-01-01

157

Plant Diversity and Invasives in Blue Oak Savannas of the Southern Sierra Nevada1  

E-print Network

Plant Diversity and Invasives in Blue Oak Savannas of the Southern Sierra Nevada1 Jon E. Keeley2 Abstract Blue oak savannas were found to be substantially more diverse at all scales from localized point of the understory flora in these blue oak savannas, comprising three- fourths of the species at the smallest scale

Standiford, Richard B.

158

PLANT-ANIMAL INTERACTIONS -ORIGINAL PAPER Geographic patterns in fruit colour diversity: do leaves constrain  

E-print Network

PLANT-ANIMAL INTERACTIONS - ORIGINAL PAPER Geographic patterns in fruit colour diversity: do leaves constrain the colour of fleshy fruits? Kevin C. Burns Ã? Eliana Cazetta Ã? Mauro Galetti Ã? Alfredo Valido Ã? H 2008 Ã? Springer-Verlag 2008 Abstract We tested for geographic patterns in fruit colour diversity. Fruit

Schaefer, Martin

159

Plant Growth Promotion Potential Is Equally Represented in Diverse Grapevine Root-Associated Bacterial Communities from Different Biopedoclimatic Environments  

PubMed Central

Plant-associated bacteria provide important services to host plants. Environmental factors such as cultivar type and pedoclimatic conditions contribute to shape their diversity. However, whether these environmental factors may influence the plant growth promoting (PGP) potential of the root-associated bacteria is not widely understood. To address this issue, the diversity and PGP potential of the bacterial assemblage associated with the grapevine root system of different cultivars in three Mediterranean environments along a macrotransect identifying an aridity gradient were assessed by culture-dependent and independent approaches. According to 16S rRNA gene PCR-DGGE, the structure of endosphere and rhizosphere bacterial communities was highly diverse (P = 0.03) and was associated with a cultivar/latitudinal/climatic effect. Despite being diverse, the bacterial communities associated with Egyptian grapevines shared a higher similarity with the Tunisian grapevines than those cultivated in North Italy. A similar distribution, according to the cultivar/latitude/aridity gradients, was observed for the cultivable bacteria. Many isolates (23%) presented in vitro multiple stress resistance capabilities and PGP activities, the most frequent being auxin synthesis (82%), insoluble phosphate solubilisation (61%), and ammonia production (70%). The comparable numbers and types of potential PGP traits among the three different environmental settings indicate a strong functional homeostasis of beneficial bacteria associated with grape root. PMID:23878810

Fusi, Marco; Cherif, Ameur; Abou-Hadid, Ayman; El-Bahairy, Usama; Sorlini, Claudia; Daffonchio, Daniele

2013-01-01

160

Diverse Lifestyles and Strategies of Plant Pathogenesis Encoded in the Genomes of Eighteen Doethideomycetes Fungi  

SciTech Connect

The class of Dothideomycetes is one of the largest and most diverse groups of fungi. Many are plant pathogens and pose a serious threat to agricultural crops grown for biofuel, food or feed. Most Dothideomycetes have only a single host and related species can have very diverse host plants. Eighteen genomes of Dothideomycetes have currently been sequenced by the Joint Genome Institute and other sequencing centers. Here we describe the results of comparative analyses of the fungi in this group.

Ohm, Robin A.; Feau, Nicolas; Henrissat, Bernard; Schoch, Conrad L.; Horwitz, Benjamin A.; Barry, Kerrie W.; Condon, Bradford J.; Copeland, Alex C.; Dhillon, Braham; Glaser, Fabien; Hesse, Cedar N.; Kosti, Idit; LaButti, Kurt; Lindquist, Erika A.; Lucas, Susan; Salamov, Asaf A.; Bradshaw, Rosie E.; Ciuffetti, Lynda; Hamelin, Richard C.; Kema, Gert H. J.; Lawrence, Christopher; Scott, James A.; Spatafora, Joseph W.; Turgeon, B. Gillian; de Wit, Pierre J. G. M.; Zhong, Shaobin; Goodwin, Stephen B.; Grigoriev, Igor V.

2012-03-13

161

Interactive effects of mycorrhizae and a root hemiparasite on plant community productivity and diversity  

Microsoft Academic Search

Plant communities can be affected both by arbuscular mycorrhizal fungi (AMF) and hemiparasitic plants. However, little is\\u000a known about the interactive effects of these two biotic factors on the productivity and diversity of plant communities. To\\u000a address this question, we set up a greenhouse study in which different AMF inocula and a hemiparasitic plant (Rhinanthus minor) were added to experimental

Claudia Stein; Cornelia Rißmann; Stefan Hempel; Carsten Renker; François Buscot; Daniel Prati; Harald Auge

2009-01-01

162

Surface erosion at disturbed alpine sites: effects of vegetation cover and plant diversity  

NASA Astrophysics Data System (ADS)

The relationship between plant diversity and soil stability in disturbed alpine terrain is poorly studied. In this paper, we investigated the influence of plant cover and diversity on water run-off and sediment yield on ski slopes. Rainfall simulations were conducted on a micro-scale (25 x 25 cm) to be able to replicate plots with different degrees of vegetation cover. We selected plots with 10%, 30% and 60% of vegetation cover containing different combinations of plant diversities: (i) grass, (ii) herb, (iii) moss/ lichen, and all combinations of these plant groups. Each combination was replicated five times with an applied rain intensity of 375 ml min-1 for about 5 minutes. As could be expected, percent vegetation cover had a large effect on surface erosion: sediment yield decreased with increasing vegetation cover. However, within the plots with 60% cover, sediment yield was lower at higher plant diversity and functional group diversity. The findings of this study support the view that beside the re-establishment of a closed vegetation cover, plant diversity is a relevant factor to reduce surface erosion at disturbed sites in alpine ecosystems.

Martin, C.; Pohl, M.; Alewell, C.; Körner, C.; Buttler, A.; Rixen, C.

2009-04-01

163

Effects of plant diversity on invertebrate herbivory in experimental grassland  

Microsoft Academic Search

The rate at which a plant species is attacked by invertebrate herbivores has been hypothesized to depend on plant species richness, yet empirical evidence is scarce. Current theory predicts higher herbivore damage in monocultures than in species-rich mixtures. We quantified herbivore damage by insects and molluscs to plants in experimental plots established in 2002 from a species pool of 60

Christoph Scherber; Peter N. Mwangi; Vicky M. Temperton; Christiane Roscher; Jens Schumacher; Bernhard Schmid; Wolfgang W. Weisser

2006-01-01

164

?-Diversity of Functional Groups of Woody Plants in a Tropical Dry Forest in Yucatan  

PubMed Central

Two main theories have attempted to explain variation in plant species composition (?-diversity). Niche theory proposes that most of the variation is related to environment (environmental filtering), whereas neutral theory posits that dispersal limitation is the main driver of ?-diversity. In this study, we first explored how ?- and ?-diversity of plant functional groups defined by growth form (trees, shrubs and lianas, which represent different strategies of resource partitioning), and dispersal syndrome (autochory, anemochory and zoochory, which represent differences in dispersal limitation) vary with successional age and topographic position in a tropical dry forest. Second, we examined the effects of environmental, spatial, and spatially-structured environmental factors on ?-diversity of functional groups; we used the spatial structure of sampling sites as a proxy for dispersal limitation, and elevation, soil properties and forest stand age as indicators of environmental filtering. We recorded 200 species and 22,245 individuals in 276 plots; 120 species were trees, 41 shrubs and 39 lianas. We found that ?-diversity was highest for shrubs, intermediate for lianas and lowest for trees, and was slightly higher for zoochorous than for autochorous and anemochorous species. All three dispersal syndromes, trees and shrubs varied in composition among vegetation classes (successional age and topographic position), whilst lianas did not. ?-diversity was influenced mostly by proxies of environmental filtering, except for shrubs, for which the influence of dispersal limitation was more important. Stand age and topography significantly influenced ?-diversity across functional groups, but showed a low influence on ?-diversity –possibly due to the counterbalancing effect of resprouting on plant distribution and composition. Our results show that considering different plant functional groups reveals important differences in both ?- and ?-diversity patterns and correlates that are not apparent when focusing on overall woody plant diversity, and that have important implications for ecological theory and biodiversity conservation. PMID:24040014

López-Martínez, Jorge Omar; Sanaphre-Villanueva, Lucía; Dupuy, Juan Manuel; Hernández-Stefanoni, José Luis; Meave, Jorge Arturo; Gallardo-Cruz, José Alberto

2013-01-01

165

A molecular method to assess Phytophthora diversity in environmental samples.  

PubMed

Current molecular detection methods for the genus Phytophthora are specific to a few key species rather than the whole genus and this is a recognized weakness of protocols for ecological studies and international plant health legislation. In the present study a molecular approach was developed to detect Phytophthora species in soil and water samples using novel sets of genus-specific primers designed against the internal transcribed spacer (ITS) regions. Two different rDNA primer sets were tested: one assay amplified a long product including the ITS1, 5.8S and ITS2 regions (LP) and the other a shorter product including the ITS1 only (SP). Both assays specifically amplified products from Phytophthora species without cross-reaction with the related Pythium s. lato, however the SP assay proved the more sensitive and reliable. The method was validated using woodland soil and stream water from Invergowrie, Scotland. On-site use of a knapsack sprayer and in-line water filters proved more rapid and effective than centrifugation at sampling Phytophthora propagules. A total of 15 different Phytophthora phylotypes were identified which clustered within the reported ITS-clades 1, 2, 3, 6, 7 and 8. The range and type of the sequences detected varied from sample to sample and up to three and five different Phytophthora phylotypes were detected within a single sample of soil or water, respectively. The most frequently detected sequences were related to members of ITS-clade 6 (i.e. P. gonapodyides-like). The new method proved very effective at discriminating multiple species in a given sample and can also detect as yet unknown species. The reported primers and methods will prove valuable for ecological studies, biosecurity and commercial plant, soil or water (e.g. irrigation water) testing as well as the wider metagenomic sampling of this fascinating component of microbial pathogen diversity. PMID:22226752

Scibetta, Silvia; Schena, Leonardo; Chimento, Antonio; Cacciola, Santa O; Cooke, David E L

2012-03-01

166

[Diversity and tissue distribution of fungal endophytes in Alpinia officinarum: an important south-China medicinal plant].  

PubMed

In the present study, terminal-restriction fragment length polymorphism (T-RFLP) technique was applied to assess the diversity and tissue distribution of the fungal endophyte communities of Alpinia officinarum collected from Longtang town in Xuwen county, Guangdong province, China, at which the pharmacological effect of the medicine plant is traditional considered to be the significantly higher than that in any other growth areas in China. A total of 28 distinct Terminal-Restriction Fragment (T-RFs) were detected with HhaI Mono-digestion targeted amplified fungal nuclear ribosomal internal transcribed spacer region sequences (rDNA ITS) from the root, rhizome, stem, and leaf internal tissues of A. officinarum plant, indicating that at least 28 distinct fungal species were able to colonize the internal tissue of the host plant. The rDNA ITS-T-RFLP profiles obtained from different tissues of the host plant were obvious distinct. And the numbers of total T-RFs, and the dominant T-RFs detected from various tissues were significantly different. Based on the obtained T-RFLP profiles, Shannon's diversity index and the Shannon's evenness index were calculated, which were significantly different among tissues (P < 0.05). Furthermore, two types of active chemicals, total volatile oils by water vapor distillation method and galangin by methanol extraction-HPLC method, were examined in the each tissue of the tested plant. Both of tested components were detected in all of the four tissues of the medicine plant with varying contents. And the highest was in rhizome tissue. Correlation analysis revealed there were significant negative correlations between both of the tested active components contents and calculated Shannon's diversity index, as well as the Shannon's evenness index of the fungal endophyte communities of the host plant (P = 0, Pearson correlation coefficient ? -0.962), and significant positive correlations between both of the tested active components contents and 325 bp dominant T-RF linkage to Pestalotiopsis (P = 0, Pearson correlation coefficient ? 0.975). In conclusion, A. officinarum is colonized by diverse fungal endophytes communities. The diversity of the fungal endophytes was found in the A. officinarum varied with differences of the tissue types of the host plants and was closely correlated with the accumulation of main active components, total volatile oils and galangin contents in the host plant tissue. PMID:25509281

Zhou, Ren-Chao; Huang, Juan; Li, Ze-En; Li, Shu-Bin

2014-08-01

167

Host-plants shape insect diversity: phylogeny, origin, and species diversity of native Hawaiian leafhoppers (Cicadellidae: Nesophrosyne).  

PubMed

Herbivorous insects and the plants on which they specialize, represent the most abundant terrestrial life on earth, yet their inter-specific interactions in promoting species diversification remains unclear. This study utilizes the discreet geologic attributes of Hawai'i and one of the most diverse endemic herbivore radiations, the leafhoppers (Hemiptera: Cicadellidae: Nesophrosyne), as a model system to understand the role of host-plant use in insect diversification. A comprehensive phylogeny is reconstructed to examine the origins, species diversification, and host-plant use of the native Hawaiian leafhoppers. Results support a monophyletic Nesophrosyne, originating from the Western Pacific basin, with a sister-group relationship to the genus Orosius. Nesophrosyne is characterized by high levels of endemicity according to individual islands, volcanoes, and geologic features. Clades demonstrate extensive morphologically cryptic diversity among allopatric species, utilizing widespread host-plant lineages. Nesophrosyne species are host-plant specific, demonstrating four dominant patterns of specialization that shape species diversification: (1) diversification through host switching; (2) specialization on widespread hosts with allopatric speciation; (3) repeated, independent shifts to the same hosts; and, (4) absence or low abundance on some host. Finally, evidence suggests competing herbivore radiations limit ecological opportunity for diversifying insect herbivores. Results provide evolutionary insights into the mechanisms that drive and shape this biodiversity. PMID:22884527

Bennett, Gordon M; O'Grady, Patrick M

2012-11-01

168

Diversity of use and local knowledge of wild edible plant resources in Nepal  

PubMed Central

Background Wild edible plants (WEP) provide staple and supplement foods, as well as cash income to local communities, thus favouring food security. However, WEP are largely ignored in land use planning and implementation, economic development, and biodiversity conservation. Moreover, WEP-related traditional knowledge is rapidly eroding. Therefore, we designed this study to fulfill a part of the knowledge gap by providing data on diversity, traditional knowledge, economic potential, and conservation value of WEP from Nepal. Methods The information was collected through focus group discussions and key informant interviews. Percentage of general utility of the plants among the study communities was evaluated using the Chi-square (?2) test of homogeneity. High priority species were identified after consultation with the local stakeholders followed by scoring based on defined criteria. Pairwise ranking was used to assess ethnoecological knowledge to identify the threats to WEP. Results We documented 81 species belonging to Angiosperms (74), Pteridophytes (5), and Fungi (2). Most of the species were used as fruits (44 species) followed by vegetables (36). Almost half of the species (47%) were also used for purposes other than food. From the species with market value (37% of the total), 10 were identified as high priority species. Pairwise ranking revealed that WEP are threatened mostly by habitat destruction, land-use change and over-harvesting. Some of these plants are crop wild relatives and could thus be used for crop improvement. Interestingly, our study also revealed that young people who spend most of the time in the forest as herdsmen are particularly knowledgeable of wild fruit plants. Conclusion We provide empirical evidence from a relatively large area of Nepal about diversity and status of WEP, as well as methodological insights about the proper knowledge holders to consult. Regarding the unique and important knowledge they have on WEP, young people should be included when recruiting participants to ethnobotanical studies or to any type of consultation about WEP. The habit of using wild edible plants is still alive and is a traditional culinary practice that demonstrates rich traditional knowledge of local people. WEP were found to be important for livelihood as well as showing great potential for crop improvement. Priority species should be promoted for income generation activities through sustainable collection and trade. Communities should engage in minimizing the threats to these valuable resources. PMID:22546349

2012-01-01

169

Strategies to Enhance Plant Structure and Diversity in Crested Wheatgrass Seedings  

Microsoft Academic Search

Crested wheatgrass (Agropyron cristatum sensu amplo (L.) Gaertn.) is an introduced, caespitose grass that has been seeded on millions of acres of Western rangelands. In some areas, crested wheatgrass seedings overlap with critical sage-grouse (Centrocercus urophasianus; C. minimus) habitat, raising the question of how plant diversity might be restored in these closed plant communities. A three-step process is described to

Mike Pellant; Cindy R. Lysne

2005-01-01

170

STATUS OF PLANT DIVERSITY AT KUFRI (SOONE VALLEY) PUNJAB, PAKISTAN AND PREVAILING THREATS THEREIN  

Microsoft Academic Search

To examine the species composition in the Soone Valley, Punjab, Pakistan, the Kufri site was selected on the basis of some ecological attributes i.e., topography, soil type and the nature of prevailing disturbances. Data regarding the composition of plant diversity revealed that among the woody leguminous plants Acacia modesta was the most commonly occurring species. Propsopis juliflora occurred very commonly

KAFEEL AHMAD; ZAFAR IQBAL KHAN; MUHAMMAD ASHRAF; MUMTAZ HUSSAIN; MUHAMMAD IBRAHIM; EHSAN ELAHI VALEEM

2008-01-01

171

Diversity dynamics of silurian-early carboniferous land plants in South china.  

PubMed

New megafossil and microfossil data indicate four episodes in the diversification of Silurian-Early Carboniferous land plants of South China, a relatively continuous regional record. Plant diversity increased throughout, but the rising curve was punctuated by three major falls. There were peaks of origination in the Ludlow-Pragian, Givetian, late Famennian and Visean and peaks of extinction in the Pragian-Emsian, Givetian and early Tournaisian. Speciation and extinction rates were highest in the Lochkovian-Pragian and became progressively lower in subsequent stages. High correlation coefficients indicate that these events are associated with the availability of land habitat contingent on eustatic variations and increasing numbers of cosmopolitan genera. Meanwhile, proportions of endemic genera declined gradually. Due to less endemism and more migrations, both speciation and species extinction rates reduced. The changes of diversity and the timing of the three extinctions of land plants in South China are similar to those known already from Laurussia. However, the largest events in the Lochkovian-Pragian and subsequent smaller ones have not been seen in the global pattern of plant evolution. These land plant events do not correspond well temporally with those affecting land vertebrates or marine invertebrates. In South China, the diversity curve of land plants is generally opposite to that of marine faunas, showing a strong effect of eustatic variations. The increasing diversity of both land vertebrates and plants was punctuated above the Devonian-Carboniferous boundary, known as Romer's Gap, implying common underlying constraints on macroevolution of land animals and plants. PMID:24073276

Xiong, Conghui; Wang, Deming; Wang, Qi; Benton, Michael J; Xue, Jinzhuang; Meng, Meicen; Zhao, Qi; Zhang, Jing

2013-01-01

172

Folia Geobotanica 38: 443452, 2003 CALCICOLE PLANT DIVERSITY IN SWITZERLAND MAY  

E-print Network

question of whether plant species richness differs depending on calcareous or acidic substrate has thus farFolia Geobotanica 38: 443­452, 2003 CALCICOLE PLANT DIVERSITY IN SWITZERLAND MAY REFLECT A VARIETY contrasts with an overbalance of acidic topsoils, as derived from a large representative sample in Swiss

173

Successful herbivore attack due to metabolic diversion of a plant chemical defense  

Microsoft Academic Search

Plants protect themselves against herbivory with a diverse array of repellent or toxic secondary metabolites. However, many herbivorous insects have developed counteradaptations that enable them to feed on chemically defended plants without apparent negative effects. Here, we present evidence that larvae of the specialist insect, Pieris rapae (cabbage white butterfly, Lepidoptera: Pieridae), are biochemically adapted to the glucosinolate-myrosinase system, the

Ute Wittstock; Niels Agerbirk; Einar J. Stauber; Carl Erik Olsen; Michael Hippler; Thomas Mitchell-Olds; Jonathan Gershenzon; Heiko Vogel

2004-01-01

174

A non-stationary spatial generalized linear mixed model approach for studying plant diversity  

Microsoft Academic Search

We analyze the multivariate spatial distribution of plant species diversity, distributed across three ecologically distinct land uses, the urban residential, urban non-residential, and desert. We model these data using a spatial generalized linear mixed model. Here plant species counts are assumed to be correlated within and among the spatial locations. We implement this model across the Phoenix metropolis and surrounding

Anandamayee Majumdar; Corinna Gries; Jason Walker

2011-01-01

175

Diversity Dynamics of Silurian–Early Carboniferous Land Plants in South China  

PubMed Central

New megafossil and microfossil data indicate four episodes in the diversification of Silurian–Early Carboniferous land plants of South China, a relatively continuous regional record. Plant diversity increased throughout, but the rising curve was punctuated by three major falls. There were peaks of origination in the Ludlow–Pragian, Givetian, late Famennian and Visean and peaks of extinction in the Pragian–Emsian, Givetian and early Tournaisian. Speciation and extinction rates were highest in the Lochkovian–Pragian and became progressively lower in subsequent stages. High correlation coefficients indicate that these events are associated with the availability of land habitat contingent on eustatic variations and increasing numbers of cosmopolitan genera. Meanwhile, proportions of endemic genera declined gradually. Due to less endemism and more migrations, both speciation and species extinction rates reduced. The changes of diversity and the timing of the three extinctions of land plants in South China are similar to those known already from Laurussia. However, the largest events in the Lochkovian–Pragian and subsequent smaller ones have not been seen in the global pattern of plant evolution. These land plant events do not correspond well temporally with those affecting land vertebrates or marine invertebrates. In South China, the diversity curve of land plants is generally opposite to that of marine faunas, showing a strong effect of eustatic variations. The increasing diversity of both land vertebrates and plants was punctuated above the Devonian–Carboniferous boundary, known as Romer's Gap, implying common underlying constraints on macroevolution of land animals and plants. PMID:24073276

Xiong, Conghui; Wang, Deming; Wang, Qi; Benton, Michael J.; Xue, Jinzhuang; Meng, Meicen; Zhao, Qi; Zhang, Jing

2013-01-01

176

Assessing the Effectiveness of Undergraduate Diversity Courses Using the Multicultural Experiences Questionnaire  

ERIC Educational Resources Information Center

The Multicultural Experiences Questionnaire (MEQ) is a validated and easy-to-administer tool for assessing individuals' multicultural competencies (Narvaez & Hill, 2010). The current study examined the utility of the MEQ for assessing the impact of undergraduate diversity courses. A total of 137 students in six university-designated diversity…

You, Di; Matteo, Elizabeth

2013-01-01

177

Plant Diversity in Live Fences and Pastures, Two Examples from the Mexican Humid Tropics  

NASA Astrophysics Data System (ADS)

This study analyzes the potential uses of live fences and pastures as reservoirs of plant diversity for two regions with different management histories, Los Tuxtlas (LT) and Uxpanapa (UX), Veracruz, México. We studied two habitats, live fences and pastures, analyzed their species richness, diversity, structure and plant composition and classified species according to plant regeneration modes (light-demanding and shade tolerant), seed dispersal syndrome and their local uses. We recorded 62 species of trees at LT and 48 at UX. Live fences were more diverse than pastures in both regions. The LT site showed to analyze the relationship a higher diversity of plants in regeneration stages than the one at UX. However, UX had higher diversity of adult plants in the pastures than LT. Composition and structure of live fences were different between regions, as well as within live fences and pastures, 53 % of species were light-demanding and 40 % were shade tolerant; 70 % of the species were dispersed by birds. Differences between sites are associated with the modifications in live fences structure, which changed according to managerial practices and the use of local species; this may influence plant regeneration modes as well as the visits of avian dispersal agents. In LT, all species found in live fences were useful to humans, whereas in UX, less than half were used by the local population. Our results underline the importance of live fences and isolated trees in pasture habitats as potential sites to host native and useful species from tropical rain forests in livestock landscapes.

Ruiz-Guerra, Betsabé; Rosas, Noé Velázquez; López-Acosta, Juan Carlos

2014-09-01

178

Plant Diversity and Multifunctional Management of Grassland Agriculture  

Technology Transfer Automated Retrieval System (TEKTRAN)

Managing for multiple ecosystem functions and services requires greater ecosystem diversity and complexity. Complex ecosystems, such as forage and grazing lands, may provide multiple benefits and require multiple species. In this paper, I provide a brief perspective from our research conducted in th...

179

[Agrobacterium rubi strains from blueberry plants are highly diverse].  

PubMed

The diversity of a collection of Agrobacterium rubi strains isolated from blueberries from different regions of Argentina was studied by conventional microbiological tests and molecular techniques. Results from biochemical and physiological reactions, as well as from rep-PCR and RFLP analysis of PCR-amplified 23S rDNA showed high phenotypic and genotypic intraspecific variation. PMID:25444133

Abrahamovich, Eliana; López, Ana C; Alippi, Adriana M

2014-01-01

180

Effects of genetic impoverishment on plant community diversity  

Microsoft Academic Search

Summary 1 Established individuals removed at random from populations of 11 long-lived herbaceous species coexisting in a local area of ancient limestone pasture at Cress- brookdale in North Derbyshire were subjected to clonal propagation to produce stocks of genetically identical individuals sufficient to create 36 model communities identical in species composition but widely contrasted in genetic diversity. 2 Three levels

Rosemary E. Booth; J. Philip Grime

2003-01-01

181

PLANT GENETIC DETERMINANTS OF ARTHROPOD COMMUNITY STRUCTURE AND DIVERSITY  

Microsoft Academic Search

To test the hypothesis that genes have extended phenotypes on the community, we quantified how genetic differences among cottonwoods affect the diversity, abundance, and composition of the dependent arthropod com- munity. Over two years, five major patterns were observed in both field and common-garden studies that focused on two species of cottonwoods and their naturally occurring F1 and backcross hybrids

Gina M. Wimp; Gregory D. Martinsen; Kevin D. Floate; Randy K. Bangert; Thomas G. Whitham

2005-01-01

182

Hidden diversity of endophytic fungi in an invasive plant  

Microsoft Academic Search

Fungal endophytes are important in plant ecology and common in plants. We attempted to test cointroduction and host-jumping hypotheses on a community basis by comparing endophytes isolated from invasive spotted knapweed ( Centaurea stoebe , Aster- aceae) in its native and invaded ranges. Of 92 combined, sequence-based haplotypes representing eight classes of Fungi, 78 oc- curred in only one of

Alexey Shipunov; George Newcombe; Anil K. H. Raghavendra; Cort L. Anderson

2008-01-01

183

Negative per capita effects of two invasive plants, Lythrum salicaria and Phalaris arundinacea, on the moth diversity of wetland communities.  

PubMed

Invasive plants have been shown to negatively affect the diversity of plant communities. However, little is known about the effect of invasive plants on the diversity at other trophic levels. In this study, we examine the per capita effects of two invasive plants, purple loosestrife (Lythrum salicaria) and reed canary grass (Phalaris arundinacea), on moth diversity in wetland communities at 20 sites in the Pacific Northwest, USA. Prior studies document that increasing abundance of these two plant species decreases the diversity of plant communities. We predicted that this reduction in plant diversity would result in reduced herbivore diversity. Four measurements were used to quantify diversity: species richness (S), community evenness (J), Brillouin's index (H) and Simpson's index (D). We identified 162 plant species and 156 moth species across the 20 wetland sites. The number of moth species was positively correlated with the number of plant species. In addition, invasive plant abundance was negatively correlated with species richness of the moth community (linear relationship), and the effect was similar for both invasive plant species. However, no relationship was found between invasive plant abundance and the three other measures of moth diversity (J, H, D) which included moth abundance in their calculation. We conclude that species richness within, and among, trophic levels is adversely affected by these two invasive wetland plant species. PMID:18947450

Schooler, S S; McEvoy, P B; Hammond, P; Coombs, E M

2009-06-01

184

Genetic diversity and networks of exchange: a combined approach to assess intra-breed diversity  

PubMed Central

Background Cryopreservation of three endangered Belgian sheep breeds required to characterize their intra-breed genetic diversity. It is assumed that the genetic structure of a livestock breed depends mostly on gene flow due to exchanges between herds. To quantify this relation, molecular data and analyses of the exchanges were combined for three endangered Belgian breeds. Methods For each breed, between 91 and 225 sheep were genotyped with 19 microsatellites. Genetic differentiations between breeds and among herds within a breed were evaluated and the genetic structure of the breeds was described using Bayesian clustering (Structure). Exchanges of animals between 20, 46 and 95 herds according to breed were identified via semi-directed interviews and were analyzed using the concepts of the network theory to calculate average degrees and shortest path lengths between herds. Correlation between the Reynolds’ genetic distances and the shortest path lengths between each pair of herds was assessed by a Mantel test approach. Results Genetic differentiation between breeds was high (0.16). Overall Fst values among herds were high in each breed (0.17, 0.11 and 0.10). Use of the Bayesian approach made it possible to identify genetic groups of herds within a breed. Significant correlations between the shortest path lengths and the Reynolds’ genetic distances were found in each breed (0.87, 0.33 and 0.41), which demonstrate the influence of exchanges between herds on the genetic diversity. Correlation differences between breeds could be explained by differences in the average degree of the animal exchange networks, which is a measure of the number of exchanges per herd. The two breeds with the highest average degree showed the lowest correlation. Information from the exchange networks was used to assign individuals to the genetic groups when molecular information was incomplete or missing to identify donors for a cryobank. Conclusions A fine-scale picture of the population genetic structure at the herd level was obtained for the three breeds. Network analysis made it possible to highlight the influence of exchanges on genetic structure and to complete or replace molecular information in establishing a conservation program. PMID:22620856

2012-01-01

185

Photosynthetic diversity meets biodiversity: The C4 plant example.  

PubMed

Physiological diversification reflects adaptation for specific environmental challenges. As the major physiological process that provides plants with carbon and energy, photosynthesis is under strong evolutionary selection that gives rise to variability in nearly all parts of the photosynthetic apparatus. Here, we discuss how plants, notably those using C4 photosynthesis, diversified in response to environmental challenges imposed by declining atmospheric CO2 content in recent geological time. This reduction in atmospheric CO2 increases the rate of photorespiration and reduces photosynthetic efficiency. While plants have evolved numerous mechanisms to compensate for low CO2, the most effective are the carbon concentration mechanisms of C4, C2, and CAM photosynthesis; and the pumping of dissolved inorganic carbon, mainly by algae. C4 photosynthesis enables plants to dominate warm, dry and often salinized habitats, and to colonize areas that are too stressful for most plant groups. Because C4 lineages generally lack arborescence, they cannot form forests. Hence, where they predominate, C4 plants create a different landscape than would occur if C3 plants were to predominate. These landscapes (mostly grasslands and savannahs) present unique selection environments that promoted the diversification of animal guilds able to graze upon the C4 vegetation. Thus, the rise of C4 photosynthesis has made a significant contribution to the origin of numerous biomes in the modern biosphere. PMID:25264020

Sage, Rowan F; Stata, Matt

2015-01-01

186

Phylogenetic diversity of plants alters the effect of species richness on invertebrate herbivory  

PubMed Central

Long-standing ecological theory proposes that diverse communities of plants should experience a decrease in herbivory. Yet previous empirical examinations of this hypothesis have revealed that plant species richness increases herbivory in just as many systems as it decreases it. In this study, I ask whether more insight into the role of plant diversity in promoting or suppressing herbivory can be gained by incorporating information about the evolutionary history of species in a community. In an old field system in southern Ontario, I surveyed communities of plants and measured levels of leaf damage on 27 species in 38 plots. I calculated a measure of phylogenetic diversity (PSE) that encapsulates information about the amount of evolutionary history represented in each of the plots and looked for a relationship between levels of herbivory and both species richness and phylogenetic diversity using a generalized linear mixed model (GLMM) that could account for variation in herbivory levels between species. I found that species richness was positively associated with herbivore damage at the plot-level, in keeping with the results from several other recent studies on this question. On the other hand, phylogenetic diversity was associated with decreased herbivory. Importantly, there was also an interaction between species richness and phylogenetic diversity, such that plots with the highest levels of herbivory were plots which had many species but only if those species tended to be closely related to one another. I propose that these results are the consequence of interactions with herbivores whose diets are phylogenetically specialized (for which I introduce the term cladophage), and how phylogenetic diversity may alter their realized host ranges. These results suggest that incorporating a phylogenetic perspective can add valuable additional insight into the role of plant diversity in explaining or predicting levels of herbivory at a whole-community scale. PMID:23825795

2013-01-01

187

Biomass and diversity of dry alpine plant communities along altitudinal gradients in the Himalayas.  

PubMed

A non-linear relationship between phytodiversity and altitude has widely been reported, but the relationship between phytomass and altitude remains little understood. We examined the phytomass and diversity of vascular plants along altitudinal gradients on the dry alpine rangelands of Ladakh, western Himalaya. We used generalized linear and generalized additive models to assess the relationship between these vegetation parameters and altitude. We found a hump-shaped relationship between aboveground phytomass and altitude. We suspect that this is engendered by low rainfall and trampling/excessive grazing at lower slopes by domestic livestock, and low temperature and low nutrient levels at higher slopes. We also found a unimodal relationship between plant species-richness and altitude at a single mountain as well as at the scale of entire Ladakh. The species-richness at the single mountain peaked between 5,000 and 5,200 m, while it peaked between 3,500 and 4,000 m at entire Ladakh level. Perhaps biotic factors such as grazing and precipitation are, respectively, important in generating this pattern at the single mountain and entire Ladakh. PMID:21638006

Namgail, Tsewang; Rawat, Gopal S; Mishra, Charudutt; van Wieren, Sipke E; Prins, Herbert H T

2012-01-01

188

Patterns of diversity in plant and soil microbial communities along a productivity gradient in a Michigan old-field  

Microsoft Academic Search

The relationship between plant diversity and productivity has received much attention in ecology, but the relationship of these factors to soil microbial communities has been little explored. The carbon resources that support soil microbial communities are primarily derived from plants, so it is likely that the soil microbial community should respond to changes in plant diversity or productivity, particularly if

L. C. Broughton; K. L. Gross

2000-01-01

189

High-sensitivity measurement of diverse vascular plant-derived biomarkers in high-altitude ice cores  

E-print Network

High-sensitivity measurement of diverse vascular plant-derived biomarkers in high-altitude ice-volatile organic compounds derived from burned and fresh vascular plant sources and preserved in high- altitude ice of diverse vascular plant- derived biomarkers in high-altitude ice cores, Geophys. Res. Lett., 36, L13501

Howat, Ian M.

190

Artisanal fishers’ ethnobotany: from plant diversity use to agrobiodiversity management  

Microsoft Academic Search

Artisanal fishers interact with plants in many ways, and with different intensities. In spite of being characterized by fisheries,\\u000a Caiçaras use plants with varied degrees of management, since the less intensive management actions, extraction of forest products,\\u000a until intensively management actions through the cultivation of the agrobiodiversity. This study presents the results of different\\u000a research projects and includes the North

Nivaldo Peroni; Alpina Begossi; Natalia Hanazaki

2008-01-01

191

Assessing phenotypic, biochemical, and molecular diversity in coriander (Coriandrum sativum L.) germplasm  

Technology Transfer Automated Retrieval System (TEKTRAN)

This research was conducted to elucidate phenotypic and biochemical diversity in 60 coriander (Coriandrum sativum L.) accessions maintained at the North Central Regional Plant Introduction Station and examine relationships between amplified fragment length polymorphisms (AFLP) and patterns of phenot...

192

Fungal diversity, dominance, and community structure in the rhizosphere of clonal Picea mariana plants throughout nursery production chronosequences.  

PubMed

Fungal diversity in the rhizosphere of healthy and diseased clonal black spruce (Picea mariana) plants was analyzed with regard to nursery production chronosequences. The four key production stages were sampled: mother plants (MP), 8-week-old cuttings (B + 0), second-year cuttings (B + 1), and third-year cuttings (B + 2). A total of 45 fungal taxa were isolated and identified based on cultural, phenotypic, and molecular characters. Members of phylum Ascomycota dominated, followed by Basidiomycota and Zygomycota. Diagnosis characters and distance analysis of the internal transcribed spacer rDNA sequences allowed the identification of 39 ascomycetous taxa. Many belong to the order Hypocreales, families Hypocreaceae and Nectriaceae, which contain many clusters of potentially pathogenic taxa (Cylindrocladium, Fusarium, and Neonectria) and are also ecologically associated with antagonistic taxa (Chaetomium, Hypocrea, Microsphaeropsis, Penicillium, Paecilomyces, Verticillium, Trichoderma, and Sporothrix). This is also the first report of a Cylindrocladium canadense association with disease symptoms and relation with Pestalotiopsis, Fusarium, Exserochilum, Rhizoctonia, and Xenochalara fungal consortia. Both production chronosequence and plant health considerably influenced fungal taxa assemblages. Unweighted pair-group arithmetic average clustering showed that isolates from MP, B + 0, and B + 1 plant rhizospheres clustered together within healthy or diseased health classes, whereas isolates from healthy and diseased B + 2 plants clustered together. Canonical correspondence analysis revealed substantial alteration in community assemblages with regard to plant health and yielded a principal axis direction that regrouped taxa associated with diseased plant rhizosphere soil, whereas the opposite axis direction was associated with healthy plants. Two diversity indices were defined and applied to assess the fungal taxa contribution (Tc) and persistence (Pi) throughout the production. PMID:17347891

Vujanovic, V; Hamelin, R C; Bernier, L; Vujanovic, G; St-Arnaud, M

2007-11-01

193

Assessment Matters in Higher Education: Choosing and Using Diverse Approaches.  

ERIC Educational Resources Information Center

This book presents 16 papers on assessment in higher education grouped into four sections on: first, systems approaches to assessment; second, the effectiveness of innovative assessment; third, assessing practice; and fourth, autonomous assessment. The included papers are: (1) "Institutional Strategies for Assessment" (Sally Brown); (2)…

Brown, Sally, Ed.; Glasner, Angela, Ed.

194

Plant monocultures produce more antagonistic soil Streptomyces communities than high-diversity plant communities  

E-print Network

are important to productivity and plant community dynamics in both natural and managed ecosystems. Among soil varied with surrounding plant richness; above- ground biomass production varied with plant speciesPlant monocultures produce more antagonistic soil Streptomyces communities than high

Weiblen, George D

195

The effect of type of marginal land use on the production of biomass and plant diversity.  

PubMed

The objective of this study closely focuses on the settlement of the effect of marginal land use on plant diversity. The location of this study was Sar Firouze Abad region with rainfall of over 350 mm and slope of over 12%. Five treatments in terms of land use (exclusion area, grazed range, fallow, annual medic cultivation, wheat cultivation) done with the repetition of five times. The factors, such as the number of species, the number of plant bases in each species, the percentage of plant cover and biomass in each sampling were measured. The method used here is based upon complete randomized design applying Duncan test and Raunkiaer method for classification of plant species and also Shannon's diversity index of diversity and homogeny utilized. The results show that there are 76 species belonging to 60 genus and 19 families spreading in the region under study. The most dominant families are Fabaceae with 15 species covering 20% and Poaceae with 13 species covering 17%, respectively. According to Raunkiaer method the life form of the region species can be classified as Therophytes 66%, Geophytes 3%, Hemicryptophytes 26% and Chamaephytes 5%. The results also illustrate that the treatment of exclusion area has the most plant diversity, the percentage of plant cover and biomass in comparison with the rest of treatment cultivation and range grazed. PMID:18819552

Amiri, Fazel

2008-04-15

196

Decoupling factors affecting plant diversity and cover on extensive green roofs.  

PubMed

Supplemental irrigation systems are often specified on green roofs to ensure plant cover and growth, both important components of green roof performance and aesthetics. Properties of the growing media environment too can alter the assemblage of plant species able to thrive. In this study we determine how plant cover, above ground biomass and species diversity are influenced by irrigation and growing media. Grass and forb vegetative cover and biomass were significantly greater in organic based growing media but there was no effect of supplemental irrigation, with two warm season grasses dominating in those treatments receiving no supplemental irrigation. On the other hand, plant diversity declined without irrigation in organic media, and having no irrigation in inorganic growing media resulted in almost a complete loss of cover. Sedum biomass was less in inorganic growing media treatments and species dominance shifted when growing media organic content increased. Our results demonstrate that supplemental irrigation is required to maintain plant diversity on an extensive green roof, but not necessarily plant cover or biomass. These results provide evidence that planting extensive green roofs with a mix of plant species can ensure the survival of some species; maintaining cover and biomass when supplemental irrigation is turned off to conserve water, or during extreme drought. PMID:24100190

MacIvor, J Scott; Margolis, Liat; Puncher, Curtis L; Carver Matthews, Benjamin J

2013-11-30

197

Emerging roles for diverse intramembrane proteases in plant biology.  

PubMed

Progress in the field of regulated intramembrane proteolysis (RIP) in recent years has made its impact on plant biology as well. Although this field within plant research is still in its infancy, some interesting observations have started to emerge. Gene encoding orthologs of rhomboid proteases, site-2 proteases (S2P), presenilin/?-secretases, and signal peptide peptidases are found in plant genomes and some of these gene products were identified in different plant cell membranes. The lack of chloroplast-located rhomboid proteases was associated with reduced fertility and aberrations in flower morphology. Mutations in homologues of S2P resulted in chlorophyll deficiency and impaired chloroplast development. An S2P was also implicated in the response to ER stress through cleavage of ER-membrane bZIP transcription factors, allowing their migration to the nucleus and activation of the transcription of BiP chaperones. Other membrane-bound transcription factors of the NAC and PHD families were also demonstrated to undergo RIP and relocalization to the nucleus. These and other new data are expected to shed more light on the roles of intramembrane proteases in plant biology in the future. This article is part of a Special Issue entitled: Intramembrane Proteases. PMID:24099011

Adam, Zach

2013-12-01

198

Using Phylogenetic, Functional and Trait Diversity to Understand Patterns of Plant Community Productivity  

PubMed Central

Background Two decades of research showing that increasing plant diversity results in greater community productivity has been predicated on greater functional diversity allowing access to more of the total available resources. Thus, understanding phenotypic attributes that allow species to partition resources is fundamentally important to explaining diversity-productivity relationships. Methodology/Principal Findings Here we use data from a long-term experiment (Cedar Creek, MN) and compare the extent to which productivity is explained by seven types of community metrics of functional variation: 1) species richness, 2) variation in 10 individual traits, 3) functional group richness, 4) a distance-based measure of functional diversity, 5) a hierarchical multivariate clustering method, 6) a nonmetric multidimensional scaling approach, and 7) a phylogenetic diversity measure, summing phylogenetic branch lengths connecting community members together and may be a surrogate for ecological differences. Although most of these diversity measures provided significant explanations of variation in productivity, the presence of a nitrogen fixer and phylogenetic diversity were the two best explanatory variables. Further, a statistical model that included the presence of a nitrogen fixer, seed weight and phylogenetic diversity was a better explanation of community productivity than other models. Conclusions Evolutionary relationships among species appear to explain patterns of grassland productivity. Further, these results reveal that functional differences among species involve a complex suite of traits and that perhaps phylogenetic relationships provide a better measure of the diversity among species that contributes to productivity than individual or small groups of traits. PMID:19479086

Cadotte, Marc W.; Cavender-Bares, Jeannine; Tilman, David; Oakley, Todd H.

2009-01-01

199

A phylogenetic perspective on the distribution of plant diversity  

PubMed Central

Phylogenetic studies are revealing that major ecological niches are more conserved through evolutionary history than expected, implying that adaptations to major climate changes have not readily been accomplished in all lineages. Phylogenetic niche conservatism has important consequences for the assembly of both local communities and the regional species pools from which these are drawn. If corridors for movement are available, newly emerging environments will tend to be filled by species that filter in from areas in which the relevant adaptations have already evolved, as opposed to being filled by in situ evolution of these adaptations. Examples include intercontinental disjunctions of tropical plants, the spread of plant lineages around the Northern Hemisphere after the evolution of cold tolerance, and the radiation of northern alpine plants into the Andes. These observations highlight the role of phylogenetic knowledge and historical biogeography in explanations of global biodiversity patterns. They also have implications for the future of biodiversity. PMID:18695216

Donoghue, Michael J.

2008-01-01

200

Effects of Plant Biomass, Plant Diversity, and Water Content on Bacterial Communities in Soil Lysimeters: Implications for the Determinants of Bacterial Diversity? †  

PubMed Central

Soils may comprise tens of thousands to millions of bacterial species. It is still unclear whether this high level of diversity is governed by functional redundancy or by a multitude of ecological niches. In order to address this question, we analyzed the reproducibility of bacterial community composition after different experimental manipulations. Soil lysimeters were planted with four different types of plant communities, and the water content was adjusted. Group-specific phylogenetic fingerprinting by PCR-denaturing gradient gel electrophoresis revealed clear differences in the composition of Alphaproteobacteria, Betaproteobacteria, Bacteroidetes, Chloroflexi, Planctomycetes, and Verrucomicrobia populations in soils without plants compared to that of populations in planted soils, whereas no influence of plant species composition on bacterial diversity could be discerned. These results indicate that the presence of higher plant species affects the species composition of bacterial groups in a reproducible manner and even outside of the rhizosphere. In contrast, the environmental factors tested did not affect the composition of Acidobacteria, Actinobacteria, Archaea, and Firmicutes populations. One-third (52 out of 160) of the sequence types were found to be specifically and reproducibly associated with the absence or presence of plants. Unexpectedly, this was also true for numerous minor constituents of the soil bacterial assemblage. Subsequently, one of the low-abundance phylotypes (beta10) was selected for studying the interdependence under particular experimental conditions and the underlying causes in more detail. This so-far-uncultured phylotype of the Betaproteobacteria species represented up to 0.18% of all bacterial cells in planted lysimeters compared to 0.017% in unplanted systems. A cultured representative of this phylotype exhibited high physiological flexibility and was capable of utilizing major constituents of root exudates. Our results suggest that the bacterial species composition in soil is determined to a significant extent by abiotic and biotic factors, rather than by mere chance, thereby reflecting a multitude of distinct ecological niches. PMID:17873072

Zul, Delita; Denzel, Sabine; Kotz, Andrea; Overmann, Jörg

2007-01-01

201

Diversity of heterotrimeric G-protein ? subunits in plants  

PubMed Central

Background Heterotrimeric G-proteins, consisting of three subunits G?, G? and G? are present in most eukaryotes and mediate signaling in numerous biological processes. In plants, G? subunits were shown to provide functional selectivity to G-proteins. Three unconventional G? subunits were recently reported in Arabidopsis, rice and soybean but no structural analysis has been reported so far. Their relationship with conventional G? subunits and taxonomical distribution has not been yet demonstrated. Results After an extensive similarity search through plant genomes, transcriptomes and proteomes we assembled over 200 non-redundant proteins related to the known G? subunits. Structural analysis of these sequences revealed that most of them lack the obligatory C-terminal prenylation motif (CaaX). According to their C-terminal structures we classified the plant G? subunits into three distinct types. Type A consists of G? subunits with a putative prenylation motif. Type B subunits lack a prenylation motif and do not have any cysteine residues in the C-terminal region, while type C subunits contain an extended C-terminal domain highly enriched with cysteines. Comparative analysis of C-terminal domains of the proteins, intron-exon arrangement of the corresponding genes and phylogenetic studies suggested a common origin of all plant G? subunits. Conclusion Phylogenetic analyses suggest that types C and B most probably originated independently from type A ancestors. We speculate on a potential mechanism used by those G? subunits lacking isoprenylation motifs to anchor the G?? dimer to the plasma membrane and propose a new flexible nomenclature for plant G? subunits. Finally, in the light of our new classification, we give a word of caution about the interpretation of G? research in Arabidopsis and its generalization to other plant species. PMID:23113884

2012-01-01

202

Biosynthesis of Plant Volatiles: Nature's Diversity and Ingenuity  

NSDL National Science Digital Library

Plant volatiles (PVs) are lipophilic molecules with high vapor pressure that serve various ecological roles. The synthesis of PVs involves the removal of hydrophilic moieties and oxidation/hydroxylation, reduction, methylation, and acylation reactions. Some PV biosynthetic enzymes produce multiple products from a single substrate or act on multiple substrates. Genes for PV biosynthesis evolve by duplication of genes that direct other aspects of plant metabolism; these duplicated genes then diverge from each other over time. Changes in the preferred substrate or resultant product of PV enzymes may occur through minimal changes of critical residues. Convergent evolution is often responsible for the ability of distally related species to synthesize the same volatile.

Eran Pichersky (University of Michigan;Department of Molecular, Cellular and Developmental Biology); Joseph P. Noel (The Salk Institute for Biological Studies;Howard Hughes Medical Institute, Jack H. Skirball Center for Chemical Biology and Proteomics); Natalia Dudareva (Purdue University;Department of Horticulture and Landscape Architecture)

2006-02-10

203

Assessment of diversity in Harpagophytum with RAPD and ISSR markers provides evidence of introgression.  

PubMed

The genus Harpagophytum has two species: H. procumbens which is an important medicinal plant in southern Africa, and H. zeyheri. Genetic diversity in 96 samples, obtained by germinating seeds collected from Botswana, was assessed using six inter-simple sequence repeat (ISSR) and 10 random amplified polymorphic DNA (RAPD) primers. These DNA markers yielded a total of 138 polymorphic bands. Polymorphism information content (PIC) ranged from 0.06 to 0.39 for ISSR primers, and from 0.09 to 0.43 for RAPD primers. Jaccard's similarity coefficients were highest when seedlings derived from the same fruit capsule were compared, while seedlings from different fruits on the same plant had intermediate values. The lowest values were recorded among seedlings from different plants. These results were consistent with an outcrossing breeding system in Harpagophytum. Analysis of molecular variance revealed significant differentiation (P<0.01) between taxonomic units within Harpagophytum. About 39% of the variability occurred between the two species, H. procumbens and H. zeyheri. Plants with an intermediate morphology, i.e. putative hybrids (PH), showed 21% differentiation when compared with H. procumbens ssp. procumbens (PP), and 19% when compared with H. procumbens ssp. transvaalense (PT) or with H. zeyheri (ZZ). In addition, a deviating variant of PT was identified, here termed 'procumbens new variety' (PN). PN showed only 9% differentiation when compared with PT, 22% when compared with PP or with PH, and 41% when compared with ZZ. Considerable differentiation between the two Harpagophytum species was revealed also by a cluster analysis. Introgression was, however, suggested by the intermediate position of the putative hybrid plants in a principal component analysis while inter-specific gene flow was shown by a Bayesian genetic structure analysis. PMID:25363276

Muzila, Mbaki; Werlemark, Gun; Ortiz, Rodomiro; Sehic, Jasna; Fatih, Moneim; Setshogo, Moffat; Mpoloka, Wata; Nybom, Hilde

2014-10-01

204

Dominant species, rather than diversity, regulates temporal stability of plant communities.  

PubMed

A growing body of empirical evidence suggests that the temporal stability of communities typically increases with diversity. The counterview to this is that dominant species, rather than diversity itself, might regulate temporal stability. However, empirical studies that have explicitly examined the relative importance of diversity and dominant species in maintaining community stability have yielded few clear-cut patterns. Here, using a long-term data set, we examined the relative importance of changes in diversity components and dominance hierarchy following the removal of a dominant C4 grass, Bouteloua gracilis, in stabilizing plant communities. We also examined the relationships between the variables of diversity and dominance hierarchy and the statistical components of temporal stability. We found a significant negative relationship between temporal stability and species richness, number of rare species, and relative abundance of rare species, whereas a significant positive relationship existed between temporal stability and relative abundance of the dominant species. Variances and covariances summed over all species significantly increased with increasing species richness, whereas they significantly decreased with increasing relative abundance of dominant species. We showed that temporal stability in a shortgrass steppe plant community was controlled by dominant species rather than by diversity itself. The generality of diversity-stability relationships might be restricted by the dynamics of dominant species, especially when they have characteristics that contribute to stability in highly stochastic systems. A clear implication is that dominance hierarchies and their changes might be among the most important ecological components to consider in managing communities to maintain ecosystem functioning. PMID:21279386

Sasaki, Takehiro; Lauenroth, William K

2011-07-01

205

Global patterns of plant diversity and floristic knowledge  

E-print Network

documents and pinpoint geographical gaps in our understanding of the global vascular plant flora. Finally was considered good or moderate. Among biomes, adequate data are especially lacking for flooded grasslands if these examples are species- poor compared with other biomes; (2) that flooded grasslands and flooded savannas

Kreft, Holger

206

Genetic diversity, plant adaptation regions, and gene pools of switchgrass  

Technology Transfer Automated Retrieval System (TEKTRAN)

Switchgrass is a perennial grass native to the North American tallgrass prairie and broadly adapted to the central and eastern USA. Movement of plant materials throughout this region creates the potential of contaminating local gene pools with genes that are not native to a locale. The objective o...

207

Plant Community Diversity Influences Allocation to Direct Chemical Defence in Plantago lanceolata  

PubMed Central

Background Forecasting the consequences of accelerating rates of changes in biodiversity for ecosystem functioning requires a mechanistic understanding of the relationships between the structure of biological communities and variation in plant functional characteristics. So far, experimental data of how plant species diversity influences the investment of individual plants in direct chemical defences against herbivores and pathogens is lacking. Methodology/Principal Findings We used Plantago lanceolata as a model species in experimental grasslands differing in species richness and composition (Jena Experiment) to investigate foliar concentrations of the iridoid glycosides (IG), catalpol and its biosynthetic precursor aucubin. Total IG and aucubin concentrations decreased, while catalpol concentrations increased with increasing plant diversity in terms of species or functional group richness. Negative plant diversity effects on total IG and aucubin concentrations correlated with increasing specific leaf area of P. lanceolata, suggesting that greater allocation to light acquisition reduced the investment into these carbon-based defence components. In contrast, increasing leaf nitrogen concentrations best explained increasing concentrations of the biosynthetically more advanced IG, catalpol. Observed levels of leaf damage explained a significant proportion of variation in total IG and aucubin concentrations, but did not account for variance in catalpol concentrations. Conclusions/Significance Our results clearly show that plants growing in communities of varying species richness and composition differ in their defensive chemistry, which may modulate plant susceptibility to enemy attack and consequently their interactions with higher trophic level organisms. PMID:22174766

Mraja, Anne; Unsicker, Sybille B.; Reichelt, Michael; Gershenzon, Jonathan; Roscher, Christiane

2011-01-01

208

Molecular approaches: advantages and artifacts in assessing bacterial diversity  

Microsoft Academic Search

Bacteria account for a major proportion of Earth’s biological diversity. They play essential roles in quite diverse environments\\u000a and there has been an increasing interest in bacterial biodiversity. Research using novel and efficient tools to identify\\u000a and characterize bacterial communities has been the key for elucidating biological activities with potential for industrial\\u000a application. The current approach used for defining bacterial

Daniela Santos Pontes; Cláudia Iracema Lima-Bittencourt; Edmar Chartone-Souza; Andréa Maria Amaral Nascimento

2007-01-01

209

Relationships between arthropod richness, evenness, and diversity are altered by complementarity among plant genotypes.  

PubMed

Biodiversity is quantified via richness (e.g., the number of species), evenness (the relative abundance distribution of those species), or proportional diversity (a combination of richness and evenness, such as the Shannon index, H'). While empirical studies show no consistent relationship between these aspects of biodiversity within communities, the mechanisms leading to inconsistent relationships have received little attention. Here, using common evening primrose (Oenothera biennis) and its associated arthropod community, we show that relationships between arthropod richness, evenness, and proportional diversity are altered by plant genotypic richness. Arthropod richness increased with O. biennis genotypic richness due to an abundance-driven accumulation of species in response to greater plant biomass. Arthropod evenness and proportional diversity decreased with plant genotypic richness due to a nonadditive increase in abundance of a dominant arthropod, the generalist florivore/omnivore Plagiognathas politus (Miridae). The greater quantity of flowers and buds produced in polycultures-which resulted from positive complementarity among O. biennis genotypes-increased the abundance of this dominant insect. Using choice bioassays, we show that floral quality did not change in plant genotypic mixtures. These results elucidate mechanisms for how plant genotypic richness can modify relationships between arthropod richness, evenness, and proportional diversity. More broadly, our results suggest that trophic interactions may be a previously underappreciated factor controlling relationships between these different aspects of biodiversity. PMID:22002039

McArt, Scott H; Cook-Patton, Susan C; Thaler, Jennifer S

2012-04-01

210

Genetic and Phenotypic Diversity of Plant Growth Promoting Bacilli  

Microsoft Academic Search

\\u000a Bacilli are aerobic or facultatively anaerobic, Gram-positive or variable, endospore-forming bacteria that exhibit resistance\\u000a to environmental stress and produce peptide antibiotics, peptide signal molecules, and extracellular enzymes. Bacillus and Paenibacillus genera include the best knowing nitrogen-fixing species. Another characteristic of bacilli is their great potential in producing\\u000a substances that promote direct plant growth by the production of phytohormones (mainly indolic

Anelise Beneduzi; Luciane M. P. Passaglia

211

Nuclear material safeguards for enrichments plants: Part 4, Gas Centrifuge Enrichment Plant: Diversion scenarios and IAEA safeguards activities: Safeguards training course  

SciTech Connect

This publication is Part 4 of a safeguards training course in Nuclear Material Safeguards for enrichment plants. This part of the course deals with diversion scenarios and safeguards activities at gas centrifuge enrichment plants.

Not Available

1988-10-01

212

Rapid compositional change and significant loss of plant species diversity among Triassic-Jurassic palynofloras in East Greenland  

NASA Astrophysics Data System (ADS)

The Triassic-Jurassic (Tr-J; 200Ma) transition coincides with the eruption of massive flood basalts associated with the opening of the Atlantic Ocean. This is thought to have lead to a fourfold increase in palaeoatmospheric carbon dioxide, a consequent rise in global temperatures of between 3 and 6 degrees Celsius, and a rise in atmospheric pollutants such as sulphur dioxide. Recent work has employed either plant macrofossils (mostly leaves) or sporomorphs (pollen and spores) to reconstruct the response of terrestrial vegetation to this episode of major environmental change. Investigations of the macrofossil record at Astartekloft in East Greenland indicate a rapid loss of plant diversity in the Late Rhaetian, culminating in an 80% species turnover at the Tr-J boundary interval. However, evidence for such catastrophic diversity loss is conspicuously absent from the sporomorph record. This fossil group indicates that the Tr-J boundary interval in central and northwest Europe is characterized by compositional change and a transient shift from gymnosperm forests to fern-dominated vegetation. In order to address this uncertainty regarding Tr-J vegetation change according to macrofossils versus sporomorphs, we present an analysis of sporomorph diversity and compositional change across the Tr-J at Astartekloft, East Greenland. Sporomorph diversity was estimated using individual and sample-based rarefaction techniques, and compositional differences between sporomorph samples were assessed using non-metric multidimensional scaling. These analyses reveal that sporomorph assemblages from the Tr-J boundary interval at Astartekloft are between 23 and 27% less taxonomically diverse than other Triassic assemblages, and that this interval is characterized by a dramatic shift in the composition of the standing vegetation. These results are statistically significant and are also unrelated to changes in the environment of deposition. These results indicate that the magnitude of plant diversity loss across the Tr-J in East Greenland is apparently greater in the macrofossil record than the sporomorph record. Comparison of these results with taphonomic work on the representation of different groups of plants in macrofossil and sporomorph records at Astartekloft is used to understand this discrepancy.

Mander, Luke; Kürschner, Wolfram; McElwain, Jennifer

2010-05-01

213

DSM5 Research: Assessing the Mental Health Needs of Older Adults from Diverse Ethnic Backgrounds  

Microsoft Academic Search

This article analyzes current trends and limitations in the design of the Diagnostic and Statistical Manual of Mental Disorders (DSM) with a focus on its application to older adults from diverse ethnic backgrounds. An analysis of 54 articles published between 2001 and 2011 in 4 social science databases that discussed DSM and its applicability to assessing ethnically diverse older adults'

Alexis Lee Rose; Monit Cheung

2012-01-01

214

Raising White Privilege Awareness and Reducing Racial Prejudice: Assessing Diversity Course Effectiveness  

ERIC Educational Resources Information Center

Many diversity courses in psychology originally aimed to reduce student racial bias and raise their awareness of racism. However, quantitative data testing the effectiveness of such courses are lacking. This study assessed a required diversity course's effectiveness in raising awareness of White privilege and racism; increasing support for…

Case, Kim A.

2007-01-01

215

Halophyte plant diversity, coastal habitat types and their conservation status in Cyprus  

Microsoft Academic Search

\\u000a This chapter focuses on the identification, description and determination of the conservation status of the halophytic plant\\u000a diversity and the coastal habitat types of Cyprus. The chapter presents the results of a study that was undertaken during\\u000a 2006–2008 in the coastal zone of Cyprus, which revealed that a total of 457 plant taxa with distinct features are distributed\\u000a along a

M. Öztürk; S. Gucel; A. Guvensen; C. Kadis; C. Kounnamas

216

Aquatic plants diversity in arid zones of Northwest China: patterns, threats and conservation  

Microsoft Academic Search

We investigated aquatic plant diversity by conducting the field investigation and collecting the published data in the arid\\u000a regions of Northwest China. Two hundred and twenty four taxa of vascular aquatic plants representing 64 genera and 34 families\\u000a occur in this area, 8.48% of which are endemic. Among these, 1 genus and 6 species were new state records and 1

Zhongqiang Li; Dan Yu; Wen Xiong; Dong Wang; Manghui Tu

2006-01-01

217

In silico identification of conserved microRNAs in large number of diverse plant species  

Microsoft Academic Search

BACKGROUND: MicroRNAs (miRNAs) are recently discovered small non-coding RNAs that play pivotal roles in gene expression, specifically at the post-transcriptional level in plants and animals. Identification of miRNAs in large number of diverse plant species is important to understand the evolution of miRNAs and miRNA-targeted gene regulations. Now-a-days, publicly available databases play a central role in the in-silico biology. Because,

Ramanjulu Sunkar; Guru Jagadeeswaran

2008-01-01

218

Plant Trait Diversity Buffers Variability in Denitrification Potential over Changes in Season and Soil Conditions  

PubMed Central

Background Denitrification is an important ecosystem service that removes nitrogen (N) from N-polluted watersheds, buffering soil, stream, and river water quality from excess N by returning N to the atmosphere before it reaches lakes or oceans and leads to eutrophication. The denitrification enzyme activity (DEA) assay is widely used for measuring denitrification potential. Because DEA is a function of enzyme levels in soils, most ecologists studying denitrification have assumed that DEA is less sensitive to ambient levels of nitrate (NO3?) and soil carbon and thus, less variable over time than field measurements. In addition, plant diversity has been shown to have strong effects on microbial communities and belowground processes and could potentially alter the functional capacity of denitrifiers. Here, we examined three questions: (1) Does DEA vary through the growing season? (2) If so, can we predict DEA variability with environmental variables? (3) Does plant functional diversity affect DEA variability? Methodology/Principal Findings The study site is a restored wetland in North Carolina, US with native wetland herbs planted in monocultures or mixes of four or eight species. We found that denitrification potentials for soils collected in July 2006 were significantly greater than for soils collected in May and late August 2006 (p<0.0001). Similarly, microbial biomass standardized DEA rates were significantly greater in July than May and August (p<0.0001). Of the soil variables measured—soil moisture, organic matter, total inorganic nitrogen, and microbial biomass—none consistently explained the pattern observed in DEA through time. There was no significant relationship between DEA and plant species richness or functional diversity. However, the seasonal variance in microbial biomass standardized DEA rates was significantly inversely related to plant species functional diversity (p<0.01). Conclusions/Significance These findings suggest that higher plant functional diversity may support a more constant level of DEA through time, buffering the ecosystem from changes in season and soil conditions. PMID:20661464

McGill, Bonnie M.; Sutton-Grier, Ariana E.; Wright, Justin P.

2010-01-01

219

Plant diversity and conservation status of Himalayan Region Poonch Valley Azad Kashmir (Pakistan).  

PubMed

The plant diversity of Himalayan region has been reduced to greater extent due to environmental degradation and human exploitation. Anthropogenic disturbance was the major factor responsible for fragmentation of forest vegetation into small patches. Little research has been conducted in the Himalayan region of Poonch Valley of North eastern Pakistan with reference to plants biodiversity and its conservation. The present research was carried out to provide a checklist of vegetation for biodiversity conservation. A total of 430 vascular and 5 nonvascular plant species with 5 species of Bryophytes (5 families), 13 species of Pteridophytes (6 families), 4 species of Gymnosperms (1 family) and 413 species of angiosperms (95 families) were enumerated from the Poonch valley Azad Kashmir. The genera were classified into three categories according to the number of species. 25 plant communities with phytosociological parameters and diversity indices were reported. Present study revealed that there were 145 threatened, 30 endangered, 68 vulnerable and 47 rare species. It is recorded that extensive grazing, uprooting of plants and soil slope erosion intensify the environmental problems. Since there is maximum exploitation of vegetation, the valley showed a decline in plant diversity. The study was also indicated that the main threats to the biodiversity are expansion of settlement and army installations in the forest area of the valley. For sustainable use In-situ and Ex-situ conservation, controlled harvesting and afforestation may be the solution. Moreover, forest area should be declared prohibited for settlements and army installations. PMID:25176378

Khan, Muhammad Azam; Khan, Mir Ajab; Hussain, Mazhar; Mujtaba, Ghulam

2014-09-01

220

Plant–soil feedbacks provide an additional explanation for diversity–productivity relationships  

PubMed Central

Plant–soil feedbacks (PSFs) have gained attention for their role in plant community dynamics, but their role in productivity has been overlooked. We developed and tested a biomass-specific, multi-species model to examine the role of PSFs in diversity–productivity relationships. The model predicts a negative relationship between PSFs and overyielding: plants with negative PSFs grow more in communities than in monoculture (i.e. overyield), and plants with positive PSFs grow less in communities than in monoculture (i.e. underyield). This effect is predicted to increase with diversity and saturate at low species richness because the proportion of ‘self-cultivated’ soils rapidly decreases as species are added to a community. Results in a set of glasshouse experiments supported model predictions. We found that PSFs measured in one experiment were negatively correlated with overyielding in three-species plant communities measured in a separate experiment. Furthermore, when parametrized with our experimental PSF data, our model successfully predicted species-level overyielding and underyielding. The model was less effective at predicting community-level overyielding and underyielding, although this appeared to reflect large differences between communities with or without nitrogen-fixing plants. Results provide conceptual and experimental support for the role of PSFs in diversity–productivity relationships. PMID:22496190

Kulmatiski, Andrew; Beard, Karen H.; Heavilin, Justin

2012-01-01

221

The Carnivorous Pale Pitcher Plant Harbors Diverse, Distinct, and Time-Dependent Bacterial Communities? †  

PubMed Central

The ability of American carnivorous pitcher plants (Sarracenia) to digest insect prey is facilitated by microbial associations. Knowledge of the details surrounding this interaction has been limited by our capability to characterize bacterial diversity in this system. To describe microbial diversity within and between pitchers of one species, Sarracenia alata, and to explore how these communities change over time as pitchers accumulate and digest insect prey, we collected and analyzed environmental sequence tag (454 pyrosequencing) and genomic fingerprint (automated ribosomal intergenic spacer analysis and terminal restriction fragment length polymorphism) data. Microbial richness associated with pitcher plant fluid is high; more than 1,000 unique phylogroups were identified across at least seven phyla and 50 families. We documented an increase in bacterial diversity and abundance with time and observed repeated changes in bacterial community composition. Pitchers from different plants harbored significantly more similar bacterial communities at a given time point than communities coming from the same genetic host over time. The microbial communities in pitcher plant fluid also differ significantly from those present in the surrounding soil. These findings indicate that the bacteria associated with pitcher plant leaves are far from random assemblages and represent an important step toward understanding this unique plant-microbe interaction. PMID:20097807

Koopman, Margaret M.; Fuselier, Danielle M.; Hird, Sarah; Carstens, Bryan C.

2010-01-01

222

The carnivorous pale pitcher plant harbors diverse, distinct, and time-dependent bacterial communities.  

PubMed

The ability of American carnivorous pitcher plants (Sarracenia) to digest insect prey is facilitated by microbial associations. Knowledge of the details surrounding this interaction has been limited by our capability to characterize bacterial diversity in this system. To describe microbial diversity within and between pitchers of one species, Sarracenia alata, and to explore how these communities change over time as pitchers accumulate and digest insect prey, we collected and analyzed environmental sequence tag (454 pyrosequencing) and genomic fingerprint (automated ribosomal intergenic spacer analysis and terminal restriction fragment length polymorphism) data. Microbial richness associated with pitcher plant fluid is high; more than 1,000 unique phylogroups were identified across at least seven phyla and 50 families. We documented an increase in bacterial diversity and abundance with time and observed repeated changes in bacterial community composition. Pitchers from different plants harbored significantly more similar bacterial communities at a given time point than communities coming from the same genetic host over time. The microbial communities in pitcher plant fluid also differ significantly from those present in the surrounding soil. These findings indicate that the bacteria associated with pitcher plant leaves are far from random assemblages and represent an important step toward understanding this unique plant-microbe interaction. PMID:20097807

Koopman, Margaret M; Fuselier, Danielle M; Hird, Sarah; Carstens, Bryan C

2010-03-01

223

Microbial diversity and complexity in hypersaline environments: a preliminary assessment.  

PubMed

The microbial communities in solar salterns and a soda lake have been characterized using two techniques: BIOLOG, to estimate the metabolic potential, and amplicon length heterogeneity analysis, to estimate the molecular diversity of these communities. Both techniques demonstrated that the halophilic Bacteria and halophilic Archaea populations in the Eilat, Israel saltern are dynamic communities with extensive metabolic potentials and changing community structures. Halophilic Bacteria were detected in Mono Lake and the lower salinity ponds at the Shark Bay saltern in Western Australia, except when the crystallizer samples were stressed by exposure to Acid Green Dye #9899. At Shark Bay, halophilic Archaea were found only in the crystallizer samples. These data confirm both the metabolic diversity and the phylogenetic complexity of the microbial communities and assert the need to develop more versatile media for the cultivation of the diversity of bacteria in hypersaline environments. PMID:11938471

Litchfield, C D; Gillevet, P M

2002-01-01

224

Distribution pattern of plant species diversity in the mountainous region of Ili River Valley, Xinjiang.  

PubMed

In this paper, detrended canonical correspondence analysis was performed to analyze the relationships between diversity indices and environmental gradients, generalized additive model was employed to modal the response curves of diversity indices to the elevation, based on data from field investigation in the mountainous region of the Ili River Valley and a survey of 94 sample plots. Two hundred fifty-nine plant species were recorded in the 94 sample plots investigated, up to 235 species all appeared in the herb layer, and the species of woody plants were very limited. The communities with a complicated vertical structure presented higher values of indices. The distribution pattern of plant species diversity on the northern slope was affected by such factors as elevation, slope aspect, slope gradient, total nitrogen, total potassium, soil water content, organic matter, and that on the southern slope was mainly affected by such factors as slope gradient, elevation, available phosphorus, and soil water content. On the northern slope, Patrick index and Shannon-Wiener index of the plant communities presented a bimodality pattern along altitude; Simpson index and Pielou index showed a partially unimodal pattern. On the southern slope all the distribution pattern of species diversity indices showed two peaks, though Patrick index's bimodality pattern was not an obvious one. These altitudinal patterns were formed by the synthetic action of a variety of environmental factors with elevation playing an important role. PMID:20830518

Xu, Yuanjie; Chen, Yaning; Li, Weihong; Fu, Aihong; Ma, Xiaodong; Gui, Dongwei; Chen, Yapeng

2011-06-01

225

PATTERNS OF ALLOZYME DIVERSITY IN THE THREATENED PLANT ERIGERON PARISHII (ASTERACEAE). (R826102)  

EPA Science Inventory

Thirty-one occurrences of Erigeron parishii, a narrowly endemic plant threatened by mining, were sampled for allozyme diversity. This taxon held considerable genetic variation at the [4 allozyme loci surveyed. Species (e.g., alleles per locus [A] = 4.3 and proportion of polymorph...

226

Aspen (Populus tremuloides) stands and their contribution to plant diversity in a semiarid coniferous landscape  

E-print Network

Aspen (Populus tremuloides) stands and their contribution to plant diversity in a semiarid a field study to determine the relative contributions of aspen (Populus tremuloides), meadow, and conifer Keystone species Á California Introduction Quaking aspen (Populus tremuloides) has been identi- fied

Tate, Kenneth

227

SOCIOECONOMIC DETERMINANTS OF URBAN PLANT DIVERSITY: ANALYSIS AND IMPLICATIONS FOR URBAN CONSERVATION  

Microsoft Academic Search

The study of urban environments has led to a growing interest in connections between social and ecologi- cal factors, although few studies address the ways in which these factors interact to control ecological patterns. Bio- logical variables of spatial heterogeneity, vegetative type, and environmental conditions are influenced by processes of habitat fragmentation and biological interactions to shape urban plant diversity.

AARON B. BERDANIER

228

Suppression of Gene Silencing: A General Strategy Used by Diverse DNA and RNA Viruses of Plants  

Microsoft Academic Search

In transgenic and nontransgenic plants, viruses are both initiators and targets of a defense mechanism that is similar to posttranscriptional gene silencing (PTGS). Recently, it was found that potyviruses and cucumoviruses encode pathogenicity determinants that suppress this defense mechanism. Here, we test diverse virus types for the ability to suppress PTGS. Nicotiana benthamiana exhibiting PTGS of a green fluorescent protein

Olivier Voinnet; Yvonne M. Pinto; David C. Baulcombe

1999-01-01

229

LETTER doi:10.1038/nature10282 High plant diversity is needed to maintain ecosystem  

E-print Network

LETTER doi:10.1038/nature10282 High plant diversity is needed to maintain ecosystem services Forest , and there is consensus that this can decrease ecosystem functioning and services2­7 . It remains unclear, though, whether few8 or many9 of the species in an ecosystem are needed to sustain the provisioning of ecosystem

Minnesota, University of

230

Use of RAPD for the study of diversity within plant germplasm collections  

Microsoft Academic Search

As part of the development of a molecular toolkit for the study of diversity within large plant germplasm collections, RAPD technology has been applied to accessions of rice (Oryza sativa) obtained from the major world collection held at IRRI (the International Rice Research Institute) which supplies germplasm to breeders. Methods for the speedy extraction of DNA representative of a rice

Parminder S Virk; Brian V Ford-Lloyd; Michael T Jackson; H John Newbury

1995-01-01

231

Diverse lifestyles and strategies of plant pathogenesis encoded in the genomes of eighteen Dothideomycetes fungi  

Technology Transfer Automated Retrieval System (TEKTRAN)

The class Dothideomycetes is one of the largest groups of fungi with a high level of ecological diversity including many plant pathogens infecting a broad range of hosts. Here for the first time we compare the sequenced genomes of 18 Dothideomycetes to analyze their evolution, genome organization, a...

232

Diversity and biological activities of endophytic fungi associated with micropropagated medicinal plant Echinacea purpurea (L.) Moench  

Technology Transfer Automated Retrieval System (TEKTRAN)

Echinacea is one of the top ten selling medicinal herbs in Europe and United States. Commercially available formulations may contain different plant parts of three species (Echinacea purpurea, E. pallida, and E. angustifolia). Our study evaluates the diversity of microbial community associated with ...

233

Conservation of genetic diversity in the endangered plant Eriogonum ovalifolium var. vineum (Polygonaceae)  

Microsoft Academic Search

The purpose of his research was to describethe organization of genetic variation in thefederally endangered plant taxon Eriogonumovalifolium var. vineum using allozymes. Such information can help prioritize sites andmanagement choices for capturing andmaintaining genetic variation and can reducethe number of populations necessary to committo conservation, thus reducing costs andconflicts with competing land uses. Information on genetic diversity patterns alsoprovides insight

Maile C. Neel; Norman C. Ellstrand

2003-01-01

234

Plant Diversity: Effects of Grazing System and Stocking Rate in Northern Mixed-Grass Prairie  

Technology Transfer Automated Retrieval System (TEKTRAN)

Effects of grazing system, stocking rate, and grazing system X stocking rate interactions, on plant diversity are poorly understood in rangelands. A grazing system (season-long and short-duration rotational grazing) X stocking rate (light: 16 steers•80 ha-1, moderate: 4 steers•12 ha-1 and heavy: 4 s...

235

Pollinating flies (Diptera): A major contribution to plant diversity and agricultural production  

Technology Transfer Automated Retrieval System (TEKTRAN)

Diptera are one of the three largest and most diverse animal groups of the world. As an often neglected, but important group of pollinators, they play a significant role in agrobiodiversity and biodiversity of plants everywhere. Flies are present in almost all habitats and biomes and for many food p...

236

Plant community diversity relative to human land uses in an Amazon forest colony  

Microsoft Academic Search

We examined numbers of plant species and individuals relative to land use in an agricultural settlement in the Brazilian Amazon. Land uses were forest, cropped after forest, fallows, cropped after fallow, and pasture. These corresponded roughly to farmers' land-use changes over time. Numbers of species and diversity indices were generally highest in forest, but we found quite similar values in

SAM Fujisaka; GERMAN Escobar; ERIK Veneklaas

1997-01-01

237

Diversity of Marine Plants. Man and the Gulf of Mexico Series.  

ERIC Educational Resources Information Center

"Man and the Gulf of Mexico" (MGM) is a marine science curriculum series developed to meet the needs of 10th through 12th grade students in Mississippi and Alabama schools. This MGM unit on the diversity of marine plants is divided into 12 sections. The first section introduces the unit by providing objectives and activities on why people classify…

Irby, Bobby N., Comp.; And Others

238

Alternative splicing and proteome diversity in plants: the tip of the iceberg has just emerged  

Microsoft Academic Search

Alternative splicing has recently emerged as one of the most significant generators of functional complexity in several relatively well-studied animal genomes, but little is known about the extent of this phenomenon in higher plants. However, recent computational and experimental studies discussed here suggest that alternative splicing probably plays a far more significant role in the generation of proteome diversity in

Kemal Kazan

2003-01-01

239

Highly Diverse Endophytic and Soil Fusarium oxysporum Populations Associated with Field-Grown Tomato Plants.  

PubMed

The diversity and genetic differentiation of populations of Fusarium oxysporum associated with tomato fields, both endophytes obtained from tomato plants and isolates obtained from soil surrounding the sampled plants, were investigated. A total of 609 isolates of F. oxysporum were obtained, 295 isolates from a total of 32 asymptomatic tomato plants in two fields and 314 isolates from eight soil cores sampled from the area surrounding the plants. Included in this total were 112 isolates from the stems of all 32 plants, a niche that has not been previously included in F. oxysporum population genetics studies. Isolates were characterized using the DNA sequence of the translation elongation factor 1? gene. A diverse population of 26 sequence types was found, although two sequence types represented nearly two-thirds of the isolates studied. The sequence types were placed in different phylogenetic clades within F. oxysporum, and endophytic isolates were not monophyletic. Multiple sequence types were found in all plants, with an average of 4.2 per plant. The population compositions differed between the two fields but not between soil samples within each field. A certain degree of differentiation was observed between populations associated with different tomato cultivars, suggesting that the host genotype may affect the composition of plant-associated F. oxysporum populations. No clear patterns of genetic differentiation were observed between endophyte populations and soil populations, suggesting a lack of specialization of endophytic isolates. PMID:25304514

Demers, Jill E; Gugino, Beth K; Jiménez-Gasco, María Del Mar

2015-01-01

240

A new image of plantain diversity assessed by SSR, AFLP and MSAP markers.  

PubMed

Using both SSR and AFLP markers, the genetic diversity of 30 plantains constituting a representative sample of the phenotypic diversity was assessed. The results confirmed a very narrow genetic base of this cultivar group. SSR and AFLP data support the hypothesis that these cultivars may have arisen from vegetative multiplication of a single seed. MSAP were used to survey cytosine methylation status at CCGG sites in order to obtain an alternative source of diversity data. A higher degree of polymorphism was revealed allowing the classification of the samples into three clusters. No correlation was observed between the phenotypic classification and methylation diversity. Implications for breeding programs are discussed. PMID:16011003

Noyer, J L; Causse, S; Tomekpe, K; Bouet, A; Baurens, F C

2005-05-01

241

Historical agriculture alters the effects of fire on understory plant beta diversity.  

PubMed

Land-use legacies are known to shape the diversity and distribution of plant communities, but we lack an understanding of whether historical land use influences community responses to contemporary disturbances. Because human-modified landscapes often bear a history of multiple land-use activities, this contingency can challenge our understanding of land-use impacts on plant diversity. We address this contingency by evaluating how beta diversity (the spatial variability of species composition), an important component of regional biodiversity, is shaped by interactions between historical agriculture and prescribed fire, two prominent disturbances that are often coincident in terrestrial ecosystems. At three study locations spanning 450 km in the southeastern United States, we surveyed longleaf pine woodland understory plant communities across 232 remnant and post-agricultural sites with differing prescribed fire regimes. Our results demonstrate that agricultural legacies are a strong predictor of beta diversity, but the direction of this land-use effect differed among the three study locations. Further, although beta diversity increased with prescribed fire frequency at each study location, this effect was influenced by agricultural land-use history, such that positive fire effects were only documented among sites that lacked a history of agriculture at two of our three study locations. Our study not only highlights the role of historical agriculture in shaping beta diversity in a fire-maintained ecosystem but also illustrates how this effect can be contingent upon fire regime and geographic location. We suggest that interactions among historical and contemporary land-use activities may help to explain dissimilarities in plant communities among sites in human-dominated landscapes. PMID:25411111

Mattingly, W Brett; Orrock, John L; Collins, Cathy D; Brudvig, Lars A; Damschen, Ellen I; Veldman, Joseph W; Walker, Joan L

2014-11-20

242

Plant community diversity and native plant abundance decline with increasing abundance of an exotic annual grass  

Microsoft Academic Search

Exotic plants are generally considered a serious problem in wildlands around the globe. However, some argue that the impacts\\u000a of exotic plants have been exaggerated and that biodiversity and other important plant community characteristics are commonly\\u000a improved with invasion. Thus, disagreement exists among ecologists as to the relationship of exotic plants with biodiversity\\u000a and native plant communities. A better understanding

Kirk W. Davies

243

Frequency distribution and assessment of genetic diversity of novel endophyte Alternaria alternata accessions isolated from Pongamia pinnata L.  

PubMed

Thepresent study discusses the frequency distribution and genetic diversity of novel fungal endopyte Alternaria alternata within the Pongammia pinnata plant samples. A total of ten plant samples of Pongammia pinnata, Pierre. (Karanja) were collected from specific locations of Sanganer region of Rajasthan for the isolation of fungal endophytes. Of these, maximum frequency of Alternaria alternata (22.29%) were recorded which are morphologically similar but ecologically variant. Efficacy of randomly amplified polymorphic DNA (RAPD), were assessed in seventeen individuals of the primers was GCC 180 where as 10 bands were generated by GCC 181. The similarity coefficient matrix generated for the primers was subjected to algorithm UPGMA (Unweighted Pair Group Method Analysis) and clusters were generated using NTSYS 2.02 pc program. To stabilize the level of relatedness among the seventeen ecologically variant Alternaria alternata accessions, the dendrogram was constructed, which showed that all the isolates were diversified endophytically with in the plant Pongamia pinnata. PMID:24502162

Tiwari, Kartikeya

2013-10-01

244

The effect of shelterwood logging on the diversity of plant species in a beech ( Fagus crenata) forest in Japan  

Microsoft Academic Search

To clarify the effect of shelterwood logging on the diversity of plant species in a beech (Fagus crenata) forest in central Japan, we compared the species composition and the organization of vascular plant communities in stands that were managed 10 years ago with those in primary stands. There were no significant differences between the stands in the species diversity (H?,

Takuo Nagaike; Tomohiko Kamitani; Tohru Nakashizuka

1999-01-01

245

Effects of human population, area, and time on non-native plant and fish diversity in the United States  

Microsoft Academic Search

Non-native species diversity of plants and fishes in the contiguous 48 United States is analyzed to measure the influence of human population size, time of modern settlement, area and native species diversity. Besides exotic (from outside USA) plants, four types of non-native fishes are examined: established exotic fishes, reported exotic fishes, US fishes not native to a state, and native

Michael L. McKinney

2001-01-01

246

Growth and Diversity in Doctoral Education: Assessing the Australian Experience  

ERIC Educational Resources Information Center

The major growth of doctoral education in recent decades has attracted attention from policy makers and researchers. In this article we explore the growth of doctoral education in Australia, its impact on diversity in respect of the doctoral population, shifts in disciplinary strengths, institutional concentration and award programs. We conclude…

Pearson, Margot; Evans, Terry; Macauley, Peter

2008-01-01

247

Molecular Techniques in the Assessment of Botanical Diversity  

Microsoft Academic Search

A variety of different molecular techniques can be used for the study of botanical diversity. Restriction fragment length polymorphism (RFLP), arbitrary primed DNA, amplified fragment length polymorphism (AFLP), variable number of tandem repeats (VNTR), sequence-tagged simple sequence repeats (SSRs) and polymerase chain reaction (PCR) sequencing are briefly reviewed here. These techniques differ in the way that they resolve genetic differences,

ANGELA KARP; OLE SEBERG; MARCELLO BUIATTI

1996-01-01

248

Genetic and functional diversity among root-associated psychrotrophic Pseudomonad's isolated from the Himalayan plants.  

PubMed

Out of 534 psychrotrophic bacteria, 12 bacteria were selected on the basis of plant growth promoting activities at 4 °C and identified as Pseudomonas genus. These strains showed high level of genetic polymorphisms based on RAPD and rep-PCR fingerprinting. This genetic variability revealed that isolates belonging to same species were as high as the variability among different species. Further inoculation of these Pseudomonas strains significantly improves root/shoot biomass and nutrients uptake of lentil plant as compared to non-bacterized control after 40 days of seed showing. Agglomerative hierarchical clustering analysis of pot assay results revealed that genetically diverse strains showing the same prototype in functional parameter and representing diverse blueprint of plant growth promoting attributes. Results of present findings explain the huge beneficial microbial resources from root zone of hilly crops of Himalayan region that could be effectively exploited as bio-inoculums for cold climatic condition. PMID:23861148

Bisht, Shekhar Chandra; Mishra, Pankaj Kumar; Joshi, Gopal Kishna

2013-09-01

249

Plant Diversity in the Human Diet: Weak Phylogenetic Signal Indicates Breadth  

NSDL National Science Digital Library

Worldwide, humans have access to a greater range of food plants than does any other species. Examination of phylogenetic patterns in plants consumed by animals has recently uncovered important ecological processes. The same techniques, however, have not been applied to our own species. Here we show that although humans tend to eat more species in certain families (e.g., Rosaceae) and fewer in others (e.g., Orchidaceae), the proportion of edible species in most families is similar to random expectations. Phylogenetic patterning in angiosperm edibility is also weak. We argue that the remarkable breadth of the human diet is the result of humans' huge geographic range, diverse food-collection methods, and ability to process normally inedible items. Humans are thus generalist feeders in the broadest sense. Cross-cultural analyses of diversity in the plant diet of humans could represent a fascinating new field of research linking ecology, anthropology, history, and sociology.

Proche& #351 (Stellenbosch University; )

2008-02-01

250

Nuclear power plant performance assessment pertaining to plant aging in France and the United States  

E-print Network

The effect of aging on nuclear power plant performance has come under increased scrutiny in recent years. The approaches used to make an assessment of this effect strongly influence the economics of nuclear power plant ...

Guyer, Brittany (Brittany Leigh)

2013-01-01

251

Assessing phenotypic, biochemical, and molecular diversity in coriander ( Coriandrum sativum L.) germplasm  

Microsoft Academic Search

Our goals for this research were to elucidate phenotypic and biochemical diversity in coriander (Coriandrum sativum L.) populations maintained at the North Central Regional Plant Introduction Station in Ames, IA, and examine relationships\\u000a between amplified fragment length polymorphism (AFLP) markers and patterns of phenotypic and biochemical diversity. Phenotypic\\u000a and biochemical traits were evaluated, and analyses of variance and mean comparisons

Pedro A. López; Mark P. Widrlechner; Philipp W. Simon; Satish Rai; Terri D. Boylston; Terry A. Isbell; Theodore B. Bailey; Candice A. Gardner; Lester A. Wilson

2008-01-01

252

ASSESSMENT OF TOKAMAK PLASMA OPERATION MODES AS FUSION POWER PLANTS  

E-print Network

ASSESSMENT OF TOKAMAK PLASMA OPERATION MODES AS FUSION POWER PLANTS: THE STARLITE STUDY Farrokh plants. The research also has aimed at identifying both the trade-offs that lead to the optimal regime of operation for a tokamak power plant and the critical plasma physics and technology issues. During

California at San Diego, University of

253

Growth and diversity in doctoral education: assessing the Australian experience  

Microsoft Academic Search

The major growth of doctoral education in recent decades has attracted attention from policy makers and researchers. In this\\u000a article we explore the growth of doctoral education in Australia, its impact on diversity in respect of the doctoral population,\\u000a shifts in disciplinary strengths, institutional concentration and award programs. We conclude that there has been both change\\u000a and continuity in the

Margot Pearson; Terry Evans; Peter Macauley

2008-01-01

254

Assessment of genetic diversity in Azadirachta indica using AFLP markers  

Microsoft Academic Search

Genetic diversity was estimated in 37 neem accessions from different eco-geographic regions of India and four exotic lines\\u000a from Thailand using AFLP markers. Seven AFLP selective primer combinations generated a total of 422 amplification products.\\u000a The average number of scorable fragments was 60 per experiment, and a high degree (69.8%) of polymorphism was obtained per\\u000a assay with values ranging from

A. Singh; M. S. Negi; J. Rajagopal; S. Bhatia; U. K. Tomar; P. S. Srivastava; M. Lakshmikumaran

1999-01-01

255

Bottom-up effects of host-plant species diversity and top-down effects of ants interactively increase plant performance.  

PubMed

While plant diversity is well known to increase primary productivity, whether these bottom-up effects are enhanced by reciprocal top-down effects from the third trophic level is unknown. We studied whether pine tree species diversity, aphid-tending ants and their interaction determined plant performance and arthropod community structure. Plant diversity had a positive effect on aphids, but only in the presence of mutualistic ants, leading to a threefold greater number of both groups in the tri-specific cultures than in monocultures. Plant diversity increased ant abundance not only by increasing aphid number, but also by increasing ant recruitment per aphid. The positive effect of diversity on ants in turn cascaded down to increase plant performance; diversity increased plant growth (but not biomass), and this effect was stronger in the presence of ants. Consequently, bottom-up effects of diversity within the same genus and guild of plants, and top-down effects from the third trophic level (predatory ants), interactively increased plant performance. PMID:22951745

Moreira, Xoaquín; Mooney, Kailen A; Zas, Rafael; Sampedro, Luis

2012-11-01

256

Interactive effects of landscape history and current management on dispersal trait diversity in grassland plant communities  

PubMed Central

Plant communities and their ecosystem functions are expected to be more resilient to future habitat fragmentation and deterioration if the species comprising the communities have a wide range of dispersal and persistence strategies. However, the extent to which the diversity of dispersal and persistence traits in plant communities is determined by the current and historical characteristics of sites and their surrounding landscape has yet to be explored. Using quantitative information on long-distance seed dispersal potential by wind and animals (dispersal in space) and on species' persistence/longevity (dispersal in time), we (i) compared levels of dispersal and persistence trait diversity (functional richness, FRic, and functional divergence, FDiv) in seminatural grassland plant communities with those expected by chance, and (ii) quantified the extent to which trait diversity was explained by current and historical landscape structure and local management history – taking into account spatial and phylogenetic autocorrel. Null model analysis revealed that more grassland communities than expected had a level of trait diversity that was lower or higher than predicted, given the level of species richness. Both the range (FRic) and divergence (FDiv) of dispersal and persistence trait values increased with grassland age. FDiv was mainly explained by the interaction between current grazing intensity and the amount of grassland habitat in the surrounding landscape in 1938. Synthesis. The study suggests that the variability of dispersal and persistence traits in grassland plant communities is driven by deterministic assembly processes, with both history and current management (and their interactions), playing a major role as determinants of trait diversity. While a long continuity of grazing management is likely to have promoted the diversity of dispersal and persistence traits in present-day grasslands, communities in sites that are well grazed at the present day, and were also surrounded by large amounts of grassland in the past, showed the highest diversity of dispersal and persistence strategies. Our results indicate that the historical context of a site within a landscape will influence the extent to which current grazing management is able to maintain a diversity of dispersal and persistence strategies and buffer communities (and their associated functions) against continuing habitat fragmentation. PMID:25506086

Purschke, Oliver; Sykes, Martin T; Poschlod, Peter; Michalski, Stefan G; Römermann, Christine; Durka, Walter; Kühn, Ingolf; Prentice, Honor C

2014-01-01

257

Portfolios for Prior Learning Assessment: Caught between Diversity and Standardization  

ERIC Educational Resources Information Center

In recent years, procedures have been established in Flanders for "Prior Learning Assessment" (PLA) outside the formal learning circuit, of which the portfolio is a regular component. In order to maximize the possibilities of acknowledgement of prior learning assessment, the Flemish government is looking for a set of common criteria and principles…

Sweygers, Annelies; Soetewey, Kim; Meeus, Wil; Struyf, Elke; Pieters, Bert

2009-01-01

258

Does Land-Use Intensification Decrease Plant Phylogenetic Diversity in Local Grasslands?  

PubMed Central

Phylogenetic diversity (PD) has been successfully used as a complement to classical measures of biological diversity such as species richness or functional diversity. By considering the phylogenetic history of species, PD broadly summarizes the trait space within a community. This covers amongst others complex physiological or biochemical traits that are often not considered in estimates of functional diversity, but may be important for the understanding of community assembly and the relationship between diversity and ecosystem functions. In this study we analyzed the relationship between PD of plant communities and land-use intensification in 150 local grassland plots in three regions in Germany. Specifically we asked whether PD decreases with land-use intensification and if so, whether the relationship is robust across different regions. Overall, we found that species richness decreased along land-use gradients the results however differed for common and rare species assemblages. PD only weakly decreased with increasing land-use intensity. The strength of the relationship thereby varied among regions and PD metrics used. From our results we suggest that there is no general relationship between PD and land-use intensification probably due to lack of phylogenetic conservatism in land-use sensitive traits. Nevertheless, we suggest that depending on specific regional idiosyncrasies the consideration of PD as a complement to other measures of diversity can be useful. PMID:25061934

Egorov, Eugen; Prati, Daniel; Durka, Walter; Michalski, Stefan; Fischer, Markus; Schmitt, Barbara; Blaser, Stefan; Brändle, Martin

2014-01-01

259

[Effect zone of forest road on plant species diversity in Great Hing 'an Mountains].  

PubMed

Forest road has far-reaching effects on plant species diversity across varying scales, and the estimation of its effect distance and effect zone is a key issue to integrate the road effect and ecological processes in forest area. In this paper, ten transects, 2 m wide and extending 50 m from varying grade roads including main road, main line for wood transportation, and secondary line for wood transportation in Huzhong forest area of Great Hing' an Mountains were set. The plant composition was investigated in twenty-five 2 m x 2 m plots of each transect. The road-effect distance on plant species diversity identified by moving window analysis in terms of the important value of each plot. The results showed that in study area, the effect distance reached up to 20-34 m, regardless of the roads grade. The plant species diversity of shrub stratum and herb stratum within the effect zone was greater than that in adjacent habitat, with the Shannon-Weiner index increased by 21% and 60%, respectively. The response of shrub stratum to the road effect was more stable than herb stratum, but no significant change was observed in tree stratum. Chamaenerion angustifolium was the indicative species of road-effect zone communities. Based on the estimation of road-effect distance, the road area in Huzhong Forestry Bureau and Great Hing' an Mountains occupied about 0.10%, and its effect zone on vegetation occupied 1.79% and 1.53%, respectively. PMID:20707089

Li, Yue-hui; Hu, Yuan-man; Chang, Yu; Li, Xiu-zhen; Bu, Ren-cang; Hu, Chang-he; Wang, Chun-lin

2010-05-01

260

The effects of plant diversity on nitrous oxide emissions in hydroponic microcosms  

NASA Astrophysics Data System (ADS)

Previous studies have shown that plant diversity can improve the wastewater purification efficiency of constructed wetlands (CWs), but its effect on the nitrous oxide (N2O) emission in CWs has been unknown. To investigate the effect of plant diversity on the N2O emission, we established four plant species richness levels (each level containing 1, 2, 3 and 4 species, respectively) by using 96 hydroponic microcosms. Results showed that plant species richness enhanced the N2O emission, ranging from 27.1 to 115.4 ?g N2O m-2 d-1, and improved nitrate removal (P < 0.001). The presence of Phalaris arundinacea within a given plant community increased the N2O emission (P < 0.001). The presence of Rumex japonicas had no influence on the N2O emissions (P > 0.05), but improved nitrogen removal (P < 0.001). Hence, our study highlights the importance of both plant species richness and species identity in mediating the N2O emission and nitrogen removal in CWs.

Sun, Hongying; Zhang, Chongbang; Song, Changchun; Chang, Scott X.; Gu, Baojing; Chen, Zhengxin; Peng, Changhui; Chang, Jie; Ge, Ying

2013-10-01

261

How do soil texture, plant community composition and earthworms affected the infiltration rate in a grassland plant diversity experiment depending on season?  

NASA Astrophysics Data System (ADS)

Background and aims: In this study we analyzed the influences of plant community characteristics, soil texture and earthworm presence on infiltration rates on a managed grassland plant diversity experiment assessing the role of biotic and abiotic factors on soil hydrology. Methods: We measured infiltration using a hood infiltrometer in subplots with ambient and reduced earthworm density (earthworm extraction) nested in plots of different plant species richness (1, 4, and 16), plant functional group number and composition (1 to 4; legumes, grasses, small herbs, tall herbs) in early summer (June) and autumn (September, October) 2011. Results: The presence of certain plant functional groups such as grasses and legumes influenced infiltration rates and this effect enhanced during the growing season. Infiltration was significantly higher in plots containing legumes than in plots without, and it was significantly lower in the presence of grasses than in their absence. In early summer, earthworm presence and biomass increased the infiltration rates, independently of plant species richness. In October, plant species richness only affected infiltration rates in reduced earthworm plots. At the end of the growing season earthworm populations were negatively influenced by grasses and positively by legumes. In September, infiltration rates were positive related to the proportion of finer grains. The correlation disappears when removing all plots containing legumes from the sample. For all measurements the infiltration rates decreases from early summer to autumn at the matric potentials at pressure zero and -0.02 m, but not for smaller macropores at matric potentials -0.04 and -0.06m. Conclusions: Considering infiltration rates as ecosystem function, this function will largely depend on the ecosystem composition and season, not on biodiversity per se. Our results indicate that biotic factors are of overriding influence for shaping infiltration rates mainly for larger macropores, and should be taken into account in hydrological applications.

Fischer, Christine; Britta, Merkel; Nico, Eisenhauer; Christiane, Roscher; Sabine, Attinger; Stefan, Scheu; Anke, Hildebrandt

2013-04-01

262

Genetic Structure, Diversity and Long Term Viability of a Medicinal Plant, Nothapodytes nimmoniana Graham. (Icacinaceae), in Protected and Non-Protected Areas in the Western Ghats Biodiversity Hotspot  

PubMed Central

Background and Question The harvesting of medicinal plants from wild sources is escalating in many parts of the world, compromising the long-term survival of natural populations of medicinally important plants and sustainability of sources of raw material to meet pharmaceutical industry needs. Although protected areas are considered to play a central role in conservation of plant genetic resources, the effectiveness of protected areas for maintaining medicinal plant populations subject to intense harvesting pressure remain largely unknown. We conducted genetic and demographic studies of Nothapodytes nimmoniana Graham, one of the extensively harvested medicinal plant species in the Western Ghats biodiversity hotspot, India to assess the effectiveness of protected areas in long-term maintenance of economically important plant species. Methodology/Principal Findings The analysis of adults and seedlings of N. nimmoniana in four protected and four non-protected areas using 7 nuclear microsatellite loci revealed that populations that are distributed within protected areas are subject to lower levels of harvesting and maintain higher genetic diversity (He?=?0.816, Ho?=?0.607, A?=?18.857) than populations in adjoining non-protected areas (He?=?0.781, Ho?=?0.511, A?=?15.571). Furthermore, seedlings in protected areas had significantly higher observed heterozygosity (Ho?=?0.630) and private alleles as compared to seedlings in adjoining non-protected areas (Ho?=?0.426). Most populations revealed signatures of recent genetic bottleneck. The prediction of long-term maintenance of genetic diversity using BOTTLESIM indicated that current population sizes of the species are not sufficient to maintain 90% of present genetic diversity for next 100 years. Conclusions/Significance Overall, these results highlight the need for establishing more protected areas encompassing a large number of adult plants in the Western Ghats to conserve genetic diversity of economically and medicinally important plant species. PMID:25493426

Shivaprakash, K. Nagaraju; Ramesha, B. Thimmappa; Uma Shaanker, Ramanan; Dayanandan, Selvadurai; Ravikanth, Gudasalamani

2014-01-01

263

Assessment of genetic diversity among selected raspberry cultivars  

Technology Transfer Automated Retrieval System (TEKTRAN)

Genetic markers, Random Amplification of Polymorphic DNA (RAPD), were developed for screening raspberry for cold/heat tolerance. Growing raspberries in southern United States is a challenging task as they are high chill-loving plants. Cultivation of raspberry in Florida is significantly hampered du...

264

Natural Products from Plant-associated Microorganisms: Distribution, Structural Diversity, Bioactivity, and Implications of Their Occurrence?  

PubMed Central

A growing body of evidence suggests that plant-associated microorganisms, especially endophytic and rhizosphere bacteria and fungi, represent a huge and largely untapped resource of natural products with chemical structures that have been optimized by evolution for biological and ecological relevance. A diverse array of bioactive small molecule natural products has been encountered in these microorganisms. The structures of over 230 metabolites isolated and characterized from over 70 plant-associated microbial strains during the past four years are presented with information on their hosts, culture conditions, and biological activities. Some significant biological and ecological implications of their occurrence are also reviewed. PMID:16562864

Gunatilaka, A. A. Leslie

2012-01-01

265

Local Plant Diversity Patterns and Evolutionary History at the Regional Scale  

Microsoft Academic Search

The effect of evolutionary history on local-scale diversity patterns has often been suggested, but not shown. I explored whether widely described local-scale relationships between plant species richness and soil pH are related to evolutionary history. I expected positive relationships to occur between richness and pH if the pool of species that is suited for high pH soil is larger than

Meelis Partel

2002-01-01

266

Effect of ploughing on plant species abundance and diversity in the northwestern coastal desert of Egypt  

Microsoft Academic Search

This study focuses on the effect of ploughing on plant abundance,vegetation cover, species richness, and taxonomic diversity during the growingseasons (winter and spring) of 1992 and 2000 in the habitat of inland plateau(natural habitat), 21 km south of Mersa-Matrouh (Egypt).Ninety-five species belonging to 27 families were recorded. High percentages oflife-forms and a large number of species were recorded in ploughed

Sania K. Hammouda; Selim Z. Heneidy

2003-01-01

267

An explanation for conflicting records of Triassic–Jurassic plant diversity  

PubMed Central

Macrofossils (mostly leaves) and sporomorphs (pollen and spores) preserve conflicting records of plant biodiversity during the end-Permian (P-Tr), Triassic–Jurassic (Tr-J), and end-Cretaceous (K-T) mass extinctions. Estimates of diversity loss based on macrofossils are typically much higher than estimates of diversity loss based on sporomorphs. Macrofossils from the Tr-J of East Greenland indicate that standing species richness declined by as much as 85% in the Late Triassic, whereas sporomorph records from the same region, and from elsewhere in Europe, reveal little evidence of such catastrophic diversity loss. To understand this major discrepancy, we have used a new high-resolution dataset of sporomorph assemblages from Astartekløft, East Greenland, to directly compare the macrofossil and sporomorph records of Tr-J plant biodiversity. Our results show that sporomorph assemblages from the Tr-J boundary interval are 10–12% less taxonomically diverse than sporomorph assemblages from the Late Triassic, and that vegetation composition changed rapidly in the boundary interval as a result of emigration and/or extirpation of taxa rather than immigration and/or origination of taxa. An analysis of the representation of different plant groups in the macrofossil and sporomorph records at Astartekløft reveals that reproductively specialized plants, including cycads, bennettites and the seed-fern Lepidopteris are almost absent from the sporomorph record. These results provide a means of reconciling the macrofossil and sporomorph records of Tr-J vegetation change, and may help to understand vegetation change during the P-Tr and K-T mass extinctions and around the Paleocene–Eocene Thermal Maximum. PMID:20713737

Mander, Luke; Kürschner, Wolfram M.; McElwain, Jennifer C.

2010-01-01

268

Incorporating biodiversity into rangeland health: Plant species richness and diversity in great plains grasslands  

USGS Publications Warehouse

Indicators of rangeland health generally do not include a measure of biodiversity. Increasing attention to maintaining biodiversity in rangelands suggests that this omission should be reconsidered, and plant species richness and diversity are two metrics that may be useful and appropriate. Ideally, their response to a variety of anthropogenic and natural drivers in the ecosystem of interest would be clearly understood, thereby providing a means to diagnose the cause of decline in an ecosystem. Conceptual ecological models based on ecological principles and hypotheses provide a framework for this understanding, but these models must be supported by empirical evidence if they are to be used for decision making. To that end, we synthesize results from published studies regarding the responses of plant species richness and diversity to drivers that are of management concern in Great Plains grasslands, one of North America's most imperiled ecosystems. In the published literature, moderate grazing generally has a positive effect on these metrics in tallgrass prairie and a neutral to negative effect in shortgrass prairie. The largest published effects on richness and diversity were caused by moderate grazing in tallgrass prairies and nitrogen fertilization in shortgrass prairies. Although weather is often cited as the reason for considerable annual fluctuations in richness and diversity, little information about the responses of these metrics to weather is available. Responses of the two metrics often diverged, reflecting differences in their sensitivity to different types of changes in the plant community. Although sufficient information has not yet been published for these metrics to meet all the criteria of a good indicator in Great Plains Grasslands, augmenting current methods of evaluating rangeland health with a measure of plant species richness would reduce these shortcomings and provide information critical to managing for biodiversity. ?? Society for Range Management.

Symstad, A.J.; Jonas, J.L.

2011-01-01

269

Diverse chalcone synthase superfamily enzymes from the most primitive vascular plant, Psilotum nudum  

Microsoft Academic Search

Psilotum nudum Griseb is a pteridophyte and belongs to the single family (Psilotaceae) of the division, Psilophyta. Being the only living species of a once populated division, P. nudum is the most primitive vascular plant. Chalcone synthase (CHS; EC 2.3.1.74) superfamily enzymes are responsible for biosyntheses of diverse secondary metabolites, including flavonoids and stilbenes. Using a reverse transcription-polymerase chain reaction

Yasuyo Yamazaki; Dae-Yeon Suh; Worapan Sitthithaworn; Kazuhiko Ishiguro; Yukie Kobayashi; Masaaki Shibuya; Yutaka Ebizuka; Ushio Sankawa

2001-01-01

270

Fungal diversity in the rhizosphere of endemic plant species of Tenerife (Canary Islands): relationship to vegetation zones and environmental factors  

Microsoft Academic Search

Knowledge about fungal diversity scaling relationships relative to that of plants is important to understand ecosystem functioning. Tenerife Island, a natural laboratory to study terrestrial biodiversity, is represented by six different vegetation zones characterized by specific abiotic conditions and plant communities with a high proportion of endemic plants. Little is known about the biodiversity of associated fungi. To understand the

Christin Zachow; Christian Berg; Henry Müller; Remo Meincke; Monika Komon-Zelazowska; Irina S Druzhinina; Christian P Kubicek; Gabriele Berg

2009-01-01

271

Assessing genetic diversity and its changes of bread wheat in Qinghai Province, China, using agronomic traits and microsatellite markers  

Microsoft Academic Search

Little is known about the diversity of wheat in Qinghai Province, China. Agronomic traits and microsatellite markers were used to survey genetic diversity and its change with time in 66 wheat cultivars registered from 1957 to 2009 in Qinghai Province. The average values of plant height, ear length, spikelets per ear, effective spikelets per ear, effective tillers per plant, internode

Hong-qin Li; Huai-gang Zhang; Bao-long Liu; Deng-cai Liu; Bo Zhang

2012-01-01

272

An index of plant community integrity: development of the methodology for assessing prairie wetland plant communities  

Microsoft Academic Search

We developed an Index of Plant Community Integrity (IPCI) for quantitatively assessing the quality of seasonal wetland plant communities. In 1998 and 1999, we sampled the plant communities of 46 seasonal wetlands in the Prairie Pothole Region (PPR) of central North Dakota, USA. We selected wetlands that represented a range of disturbance from well-managed native rangeland to heavily disturbed cropland.

Edward S. DeKeyser; Donald R. Kirby; Michael J. Ell

2003-01-01

273

Diversity of fungi associated with hair roots of ericaceous plants is affected by land use.  

PubMed

Culture-independent molecular studies have provided new insights into the diversity of fungi associating with ericaceous plant roots. However, there is little understanding of the distribution of these fungi across landscapes, or the effects of environmental heterogeneity on ericoid mycorrhizal (ERM) fungal diversity and distribution. Terminal-restriction fragment length polymorphism and selective sequence analyses of the internal transcribed spacer regions of rDNA were used to infer fungal diversity of bait Vaccinium macrocarpon grown in soils from nine peatland sites in Ireland, representing three different land uses (bog, rough grazing and forest plantation) and the fungal communities of field-collected Calluna vulgaris for five of these nine sites. A diverse range of potential ERM fungi were found, and the sampling approach significantly affected the diversity of the fungal community. Despite significant site groupings of the fungal communities associated with V. macrocarpon and C. vulgaris, fungal communities were significantly dissimilar between sites with different land uses. Soil nitrogen content significantly explained 52% of the variation in the V. macrocarpon fungal communities. Evidence suggests that environmental heterogeneity has a role in shaping ERM fungal community composition at the landscape scale. PMID:24741702

Hazard, Christina; Gosling, Paul; Mitchell, Derek T; Doohan, Fiona M; Bending, Gary D

2014-03-01

274

Self-Assessment and Dialogue as Tools for Appreciating Diversity  

ERIC Educational Resources Information Center

As social work educators continue to examine methods and techniques to provide meaningful knowledge about racism and discrimination, the role of self-assessment and dialogue should also be explored. This teaching note presents a tool for students and educators to use in considering literature discrimination and increasing awareness of…

O'Neal, Gwenelle S.

2012-01-01

275

Genomic and genetic analyses of diversity and plant interactions of Pseudomonas fluorescens  

PubMed Central

Background Pseudomonas fluorescens are common soil bacteria that can improve plant health through nutrient cycling, pathogen antagonism and induction of plant defenses. The genome sequences of strains SBW25 and Pf0-1 were determined and compared to each other and with P. fluorescens Pf-5. A functional genomic in vivo expression technology (IVET) screen provided insight into genes used by P. fluorescens in its natural environment and an improved understanding of the ecological significance of diversity within this species. Results Comparisons of three P. fluorescens genomes (SBW25, Pf0-1, Pf-5) revealed considerable divergence: 61% of genes are shared, the majority located near the replication origin. Phylogenetic and average amino acid identity analyses showed a low overall relationship. A functional screen of SBW25 defined 125 plant-induced genes including a range of functions specific to the plant environment. Orthologues of 83 of these exist in Pf0-1 and Pf-5, with 73 shared by both strains. The P. fluorescens genomes carry numerous complex repetitive DNA sequences, some resembling Miniature Inverted-repeat Transposable Elements (MITEs). In SBW25, repeat density and distribution revealed 'repeat deserts' lacking repeats, covering approximately 40% of the genome. Conclusions P. fluorescens genomes are highly diverse. Strain-specific regions around the replication terminus suggest genome compartmentalization. The genomic heterogeneity among the three strains is reminiscent of a species complex rather than a single species. That 42% of plant-inducible genes were not shared by all strains reinforces this conclusion and shows that ecological success requires specialized and core functions. The diversity also indicates the significant size of genetic information within the Pseudomonas pan genome. PMID:19432983

Silby, Mark W; Cerdeño-Tárraga, Ana M; Vernikos, Georgios S; Giddens, Stephen R; Jackson, Robert W; Preston, Gail M; Zhang, Xue-Xian; Moon, Christina D; Gehrig, Stefanie M; Godfrey, Scott AC; Knight, Christopher G; Malone, Jacob G; Robinson, Zena; Spiers, Andrew J; Harris, Simon; Challis, Gregory L; Yaxley, Alice M; Harris, David; Seeger, Kathy; Murphy, Lee; Rutter, Simon; Squares, Rob; Quail, Michael A; Saunders, Elizabeth; Mavromatis, Konstantinos; Brettin, Thomas S; Bentley, Stephen D; Hothersall, Joanne; Stephens, Elton; Thomas, Christopher M; Parkhill, Julian; Levy, Stuart B; Rainey, Paul B; Thomson, Nicholas R

2009-01-01

276

Differences in wetland nitrogen cycling between the invasive grass Microstegium vimineum and a diverse plant community.  

PubMed

Wetlands are valuable for buffering waterways from excess nitrogen, yet these habitats are often dominated by invasive plant species. There is little understanding as to how various invasive species alter ecosystem nitrogen cycling, especially if one invasive overtakes an entire community of plants. Microstegium vimineum is a nonnative annual grass from Asia that is dominating riparian wetlands in the southeastern United States. To evaluate M. vimineum impacts on the N cycle, we used six paired plots, one invaded by M. vimineum and the other carefully weeded of M. vimineum; removal allowed the establishment of a diverse plant community consisting of Polygonum, Juncus, and Carex species. In the paired plots, we estimated (1) N uptake and accumulation in vegetation biomass, (2) rates of decomposition and N release from plant detritus, (3) mineral soil N mineralization and nitrification, (4) root zone redox potential, and (5) soil water concentrations of inorganic N. The M. vimineum community accumulated approximately half the annual N biomass of the diverse community, 5.04 vs. 9.36 g N x m(-2) x yr(-1), respectively (P = 0.05). Decomposition and release of N from M. vimineum detritus was much less than in the diverse community, 1.19 vs. 5.24 g N x m(-2) x yr(-1). Significantly higher inorganic soil N persisted beneath M. vimineum during the dormant season, although rates of soil N mineralization estimated by in situ incubations were relatively similar in all plots. Microstegium vimineum invasion thus appears to greatly diminish within-ecosystem circulation of N through the understory plants of these wetlands, whereas invasion effects on ecosystem N losses may derive more from enhanced denitrification (due to lower redox potential under M. vimineum plots) than due to leaching. Microstegium vimineum's dominance and yet slower internal cycling of N are counterintuitive to conventional thinking that ecosystems with high N contain vegetation that quickly uptake and release N. PMID:20437951

DeMeester, Julie E; DeB Richter, Daniel

2010-04-01

277

Functional and genetic diversity of mycorrhizal fungi from single plants of Caladenia formosa (Orchidaceae)  

PubMed Central

Background and Aims Mycorrhizal associations are essential to the plant kingdom. The largest flowering plant family, the Orchidaceae, relies on mycorrhizal fungi for germination, growth and survival. Evidence suggests varying degrees of fungal-host specificity based on a single fungal isolate from a single plant. This paper shows for the first time the diversity of endophytes colonizing in a single plant over consecutive years and the functional significance of this diversity. Methods Stem-collars of Caladenia formosa were collected in different seasons and years. Mycorrhizal fungi isolated were tested for their efficacy to induce leafing and genetically determined using ITS-RFLP and sequencing. Results Multiple mycorrhizal fungi were repeatedly isolated from a single collar that displayed varying effectiveness in germination percentages and adult leaf length. Additional factors contributed to the isolation of effective mycorrhizal fungi; fungal collection season, year of collection and individual isolates. Surface sterilization only improved the number of isolated mycorrhizal fungi. Dual inoculation did not increase germination. All 59 mycorrhizal fungi effective in germinating seed belonged to one clearly defined ITS (internal transcribed spacer) clade and clustered close to Sebacina vermifera (79–89 % homology). Isolates resulting in the greatest germination were not necessarily those resulting in the greatest survival and growth 1 year after germination. Conclusion Single orchid plants contained multiple mycorrhizal fungal strains of one species that had diverse functional differences. These results suggest that our current knowledge of fungal–host specificity may be incomplete due to experimental and analytical limitations. It also suggests that the long-term effectiveness of a mycorrhizal fungus or fungi could only be found by germination and longer-term growth tests rather than genetically. PMID:19561011

Huynh, Tien T.; Thomson, Richard; Mclean, Cassandra B.; Lawrie, Ann C.

2009-01-01

278

Environmental assessment of plant protection strategies using scenarios for pig feed production.  

PubMed

Two scenarios for future pig meat production were constructed. The first was a "business as usual" scenario, where the pig feed was based on domestic grain and imported soy-meal, and no efforts were made to reduce pesticide use. The second scenario had a strong environmental focus, and both peas and rapeseed were grown at pig-farm level to produce grain and protein feed. Preventive measures, such as a more diverse crop rotation and mechanical weed control, were combined to reduce pesticide use. The two scenarios were environmentally assessed by Life Cycle Assessment (LCA) and a pesticide risk indicator model (PRI-Farm). The results showed environmentally sound possibilities to reduce pesticide dependency and risks by using altered plant protection strategies in pig-feed production. Organizing on-farm feed production so that protein feed crops are integrated with grain crops contributes to a more diverse crop rotation. PMID:16092277

Cederberg, Christel; Wivstad, Maria; Bergkvist, Peter; Mattsson, Berit; Ivarsson, Kjell

2005-06-01

279

Life-cycle assessment of wastewater treatment plants  

E-print Network

This thesis presents a general model for the carbon footprints analysis of wastewater treatment plants (WWTPs), using a life cycle assessment (LCA) approach. In previous research, the issue of global warming is often related ...

Dong, Bo, M. Eng. Massachusetts Institute of Technology

2012-01-01

280

How Do Earthworms, Soil Texture and Plant Composition Affect Infiltration along an Experimental Plant Diversity Gradient in Grassland?  

PubMed Central

Background Infiltration is a key process in determining the water balance, but so far effects of earthworms, soil texture, plant species diversity and their interaction on infiltration capacity have not been studied. Methodology/Principal Findings We measured infiltration capacity in subplots with ambient and reduced earthworm density nested in plots of different plant species (1, 4, and 16 species) and plant functional group richness and composition (1 to 4 groups; legumes, grasses, small herbs, tall herbs). In summer, earthworm presence significantly increased infiltration, whereas in fall effects of grasses and legumes on infiltration were due to plant-mediated changes in earthworm biomass. Effects of grasses and legumes on infiltration even reversed effects of texture. We propose two pathways: (i) direct, probably by modifying the pore spectrum and (ii) indirect, by enhancing or suppressing earthworm biomass, which in turn influenced infiltration capacity due to change in burrowing activity of earthworms. Conclusions/Significance Overall, the results suggest that spatial and temporal variations in soil hydraulic properties can be explained by biotic processes, especially the presence of certain plant functional groups affecting earthworm biomass, while soil texture had no significant effect. Therefore biotic parameters should be taken into account in hydrological applications. PMID:24918943

Fischer, Christine; Roscher, Christiane; Jensen, Britta; Eisenhauer, Nico; Baade, Jussi; Attinger, Sabine; Scheu, Stefan; Weisser, Wolfgang W.; Schumacher, Jens; Hildebrandt, Anke

2014-01-01

281

Biochemical survey of the polar head of plant glycosylinositolphosphoceramides unravels broad diversity.  

PubMed

Although Glycosyl-Inositol-Phospho-Ceramides (GIPCs) are the main sphingolipids of plant tissues, they remain poorly characterized in term of structures. This lack of information, notably with regard to polar heads, currently hampers the understanding of GIPC functions in biological systems. This situation prompted us to undertake a large scale-analysis of plant GIPCs: 23 plant species chosen in various phylogenetic groups were surveyed for their total GIPC content. GIPCs were extracted and their polar heads were characterized by negative ion MALDI and ESI mass spectrometry. Our data shed light on an unexpected broad diversity of GIPC distributions within Plantae, and the occurrence of yet-unreported GIPC structures in green and red algae. In monocots, GIPCs with three saccharides were apparently found to be major, whereas a series with two saccharides was dominant in Eudicots within a few notable exceptions. In plant cell cultures, GIPC polar heads appeared to bear a higher number of glycan units than in the tissue from which they originate. Perspectives are discussed in term of GIPC metabolism diversity and function of these lipids. PMID:23993446

Cacas, Jean-Luc; Buré, Corinne; Furt, Fabienne; Maalouf, Jean-Paul; Badoc, Alain; Cluzet, Stéphanie; Schmitter, Jean-Marie; Antajan, Elvire; Mongrand, Sébastien

2013-12-01

282

AM Fungal Diversity in Selected Medicinal Plants of Kanyakumari District, Tamil Nadu, India.  

PubMed

The association of Arbuscular Mycorrhizal Fungi (AMF) with three medicinally important plants viz., Eclipta prostrata, Indigofera aspalathoides, I. tinctoria collected from three different localities of Kanyakumari District, South India was examined. The study reports the colonization percentage, diversity and species richness of different AM fungi in the rhizosphere of the three medicinal plants and discusses the impact of soil physicochemical characteristics such as soil texture, pH and available macro- and micro nutrient content on AM fungal communities. A total 21 AM fungal species were identified in field conditions of the three plants from three sites. AM fungal species richness, colorization percentage and Shannon index were found to be high in the two Indigofera sp. growing in the hilly areas of Kanyakumari District and were low in E. prostrata collected from the damp regions in the foothills of the three study sites. Five species registered 100% frequency in all the study sites of the three medicinally important plants with Glomus as the dominant genera. The study states that the mean colonization and diversity patterns were dependant on edaphic factors and type of vegetation. PMID:22754000

Sundar, S K; Palavesam, A; Parthipan, B

2011-07-01

283

Coastal plants : chemical sensitivities and risk assessments  

EPA Science Inventory

The ability of plant-dominated ecosystems to improve water quality and provide habitat for biodiversity are important ecological services. These services are impacted by natural and anthropogenic stressors which includes contaminant toxicity. Scientific information describing the...

284

Variations in AOC and microbial diversity in an advanced water treatment plant  

NASA Astrophysics Data System (ADS)

SummaryThe objective of this study was to evaluate the variations in assimilable organic carbon (AOC) and microbial diversities in an advanced water treatment plant. The efficiency of biofiltration on AOC removal using anthracite and granular activated carbon (GAC) as the media was also evaluated through a pilot-scale column experiment. Effects of hydrological factors (seasonal effects and river flow) on AOC concentrations in raw water samples and hydraulic retention time (HRT) of biofiltration on AOC treatment were also evaluated. Results show that AOC concentrations in raw water and clear water of the plant were about 138 and 27 ?g acetate-C/L, respectively. Higher AOC concentrations were observed in wet seasons probably due to the resuspension of organic-contained sediments and discharges of non-point source (NPS) pollutants from the upper catchment. This reveals that seasonal effect played an important role in the variations in influent AOC concentrations. Approximately 82% and 70% of AOC removal efficiencies were observed in GAC and anthracite columns, respectively. Results from column experiment reveal that the applied treatment processes in the plant and biofiltration system were able to remove AOC effectively. Microbial colonization on GAC and anthracite were detected via the observation of scanning electron microscopic (SEM) images. Results of polymerase chain reaction (PCR), denaturing gradient gel electrophoresis (DGGE), and nucleotide sequence analysis reveal significant decrease in microbial diversities after the ozonation process. Higher HRT caused higher microbial contact time, and thus, more microbial colonies and higher microbial diversity were observed in the latter part of the biofilters. Some of the dominant microbial species in the biofiltration columns belonged to the beta- proteobacterium, which might contribute to the AOC degradation. Results of this study provide us insight into the variations in AOC and microbial diversity in the advanced water treatment processes.

Yang, B. M.; Liu, J. K.; Chien, C. C.; Surampalli, R. Y.; Kao, C. M.

2011-10-01

285

Reciprocal effects of host plant and natural enemy diversity on herbivore suppression: an empirical study of a model tritrophic system  

E-print Network

food web in which we manipulated the diversity of host plant species (Medicago sativa, Trifolium pratense and Vicia faba) and natural enemy species (Harmonia axyridis, Coleomegilla maculata and Nabis sp

Stachowicz, Jay

286

Development and Initial Psychometric Assessment of the Plant Attitude Questionnaire  

ERIC Educational Resources Information Center

Plants are integral parts of ecosystems which determine life on Earth. People's attitudes toward them are however, largely overlooked. Here we present initial psychometric assessment of self-constructed Plant Attitude Scale (PAS) that was administered to a sample of 310 Slovakian students living in rural areas aged 10-15 years. The final version…

Fancovicova, Jana; Prokop, Pavol

2010-01-01

287

ENVIRONMENTAL ASSESSMENT OF COKE BY-PRODUCT RECOVERY PLANTS  

EPA Science Inventory

The report gives results of an initial screening study, initiating a multimedia environmental assessment of coke by-product recovery plants in the U.S. The study included both the gathering and analysis of existing data and sampling and analysis at one plant based on EPA's Indust...

288

AQUATIC PLANT COMMUNITIES FOR IMPACT MONITORING AND ASSESSMENT  

EPA Science Inventory

The studies revewed here suggest that both structural and functional assessments of aquatic plant communities are valuable tools in the determination of environmental impacts and water quality. I am not suggesting that aquatic plants be used in lieu of macronivertebrates or fish ...

289

SPECTRAL SENSING FOR PLANT STRESS ASSESSMENT – A REVIEW  

Technology Transfer Automated Retrieval System (TEKTRAN)

Assessment of nitrogen and chlorophyll content from crop leaves can help growers adjust N fertilizer rates to meet the demands of the crop. Numerous researchers have presented their studies about spectral signature of plant leaves to characterize the plant features. However, interrelational review a...

290

Marine Macroalgal Diversity Assessment of Saba Bank, Netherlands Antilles  

PubMed Central

Background Located in the Dutch Windward Islands, Saba Bank is a flat-topped seamount (20–45 m deep in the shallower regions). The primary goals of the survey were to improve knowledge of biodiversity for one of the world's most significant, but little-known, seamounts and to increase basic data and analyses to promote the development of an improved management plan. Methodology/Principal Findings Our team of three divers used scuba to collect algal samples to depths of 50 m at 17 dive sites. Over 360 macrophyte specimens (12 putative new species) were collected, more than 1,000 photographs were taken in truly exceptional habitats, and three astonishing new seaweed community types were discovered. These included: (1) “Field of Greens” (N 17°30.620?, W 63°27.707?) dominated by green seaweeds as well as some filamentous reds, (2) “Brown Town” (N 17°28.027?, W 63°14.944?) dominated by large brown algae, and (3) “Seaweed City” (N 17°26.485?, W 63°16.850?) with a diversity of spectacular fleshy red algae. Conclusions/Significance Dives to 30 m in the more two-dimensional interior habitats revealed particularly robust specimens of algae typical of shallower seagrass beds, but here in the total absence of any seagrasses (seagrasses generally do not grow below 20 m). Our preliminary estimate of the number of total seaweed species on Saba Bank ranges from a minimum of 150 to 200. Few filamentous and thin sheet forms indicative of stressed or physically disturbed environments were observed. A more precise number still awaits further microscopic and molecular examinations in the laboratory. The expedition, while intensive, has only scratched the surface of this unique submerged seamount/atoll. PMID:20505757

Littler, Mark M.; Littler, Diane S.; Brooks, Barrett L.

2010-01-01

291

Microbail diversity in soil: selection of microbial populations by plant and soil type and implications for disease suppressiveness  

Microsoft Academic Search

An increasing interest has emerged with respect to the importance of microbial diversity in soil habitats. The extent of the diversity of microorganisms in soil is seen to be critical to the maintenance of soil health and quality, as a wide range of microorganisms is involved in important soil functions. This review focuses on recent data relating how plant type,

P. V. Garbeva; J. A. Van Veen; Elsas Van J. D

2004-01-01

292

The effects of grassland degradation on plant diversity, primary productivity, and soil fertility in the alpine region of Asia's headwaters.  

PubMed

A 3-year survey was conducted to explore the relationships among plant composition, productivity, and soil fertility characterizing four different degradation stages of an alpine meadow in the source region of the Yangtze and Yellow Rivers, China. Results showed that plant species diversity, productivity, and soil fertility of the top 30-cm soil layer significantly declined with degradation stages of alpine meadow over the study period. The productivity of forbs significantly increased with degradation stages, and the soil potassium stock was not affected by grassland degradation. The vegetation composition gradually shifted from perennial graminoids (grasses and sedges) to annual forbs along the degradation gradient. The abrupt change of response in plant diversity, plant productivity, and soil nutrients was demonstrated after heavy grassland degradation. Moreover, degradation can indicate plant species diversity and productivity through changing soil fertility. However, the clear relationships are difficult to establish. In conclusion, degradation influenced ecosystem function and services, such as plant species diversity, productivity, and soil carbon and nitrogen stocks. Additionally, both plant species diversity and soil nutrients were important predictors in different degradation stages of alpine meadows. To this end, heavy degradation grade was shown to cause shift of plant community in alpine meadow, which provided an important basis for sustaining ecosystem function, manipulating the vegetation composition of the area and restoring the degraded alpine grassland. PMID:25023744

Wang, Xuexia; Dong, Shikui; Yang, Bing; Li, Yuanyuan; Su, Xukun

2014-10-01

293

Risk management tools and the case study Brassica napus: evaluating possible effects of genetically modified plants on soil microbial diversity.  

PubMed

The cultivation of GMPs in Europe raises many questions about the environmental risks, in particular about their ecological impact on non-target organisms and on soil properties. The aim of a multidisciplinary group engaged in a LIFE+project (MAN-GMP-ITA) was to validate and improve an existing environmental risk assessment (ERA) methodology on GMPs within the European legislative framework on GMOs. Given the impossibility of evaluating GMO impact directly, as GMPs are banned in Italy, GMPs have not been used at any stage of the project. The project thus specifically focused on the conditions for the implementation of ERA in different areas of Italy, with an emphasis on some sensitive and protected areas located in the North, Centre, and South of the country, in order to lay the necessary baseline for evaluating the possible effects of a GMP on soil communities. Our sub-group carried out soil analyses in order to obtain soil health and fertility indicators to be used as baselines in the ERA model. Using various methods of chemical, biochemical, functional and genetic analysis, our study assessed the changes in diversity and functionality of bacterial populations, and arbuscular mycorrhizal fungi. The results show that plant identity and growth, soil characteristics, and field site climatic parameters are key factors in contributing to variation in microbial community structure and diversity, thus validating our methodological approach. Our project has come to the conclusion that the uneven composition and biological-agronomical quality of soils need to be taken into consideration in a risk analysis within the framework of ERA for the release of genetically modified plants. PMID:25014185

Canfora, Loredana; Sbrana, Cristiana; Avio, Luciano; Felici, Barbara; Scatà, Maria Carmela; Neri, Ulderico; Benedetti, Anna

2014-09-15

294

78 FR 44924 - Monsanto Co.; Availability of Plant Pest Risk Assessment, Environmental Assessment, Preliminary...  

Federal Register 2010, 2011, 2012, 2013

...petition to the Animal and Plant Health Inspection Service...canola is unlikely to pose a plant pest risk and, therefore...and effects on organic crop production. APHIS has evaluated the issues...impact (FONSI), and its plant pest risk assessment...

2013-07-25

295

Congruence and Diversity of Butterfly-Host Plant Associations at Higher Taxonomic Levels  

PubMed Central

We aggregated data on butterfly-host plant associations from existing sources in order to address the following questions: (1) is there a general correlation between host diversity and butterfly species richness?, (2) has the evolution of host plant use followed consistent patterns across butterfly lineages?, (3) what is the common ancestral host plant for all butterfly lineages? The compilation included 44,148 records from 5,152 butterfly species (28.6% of worldwide species of Papilionoidea) and 1,193 genera (66.3%). The overwhelming majority of butterflies use angiosperms as host plants. Fabales is used by most species (1,007 spp.) from all seven butterfly families and most subfamilies, Poales is the second most frequently used order, but is mostly restricted to two species-rich subfamilies: Hesperiinae (56.5% of all Hesperiidae), and Satyrinae (42.6% of all Nymphalidae). We found a significant and strong correlation between host plant diversity and butterfly species richness. A global test for congruence (Parafit test) was sensitive to uncertainty in the butterfly cladogram, and suggests a mixed system with congruent associations between Papilionidae and magnoliids, Hesperiidae and monocots, and the remaining subfamilies with the eudicots (fabids and malvids), but also numerous random associations. The congruent associations are also recovered as the most probable ancestral states in each node using maximum likelihood methods. The shift from basal groups to eudicots appears to be more likely than the other way around, with the only exception being a Satyrine-clade within the Nymphalidae that feed on monocots. Our analysis contributes to the visualization of the complex pattern of interactions at superfamily level and provides a context to discuss the timing of changes in host plant utilization that might have promoted diversification in some butterfly lineages. PMID:23717448

Ferrer-Paris, José R.; Sánchez-Mercado, Ada; Viloria, Ángel L.; Donaldson, John

2013-01-01

296

Assessment of the microbial diversity at the surface of Livarot cheese using culture-1 dependent and independent approaches2  

E-print Network

1 Assessment of the microbial diversity at the surface of Livarot cheese using culture-1 dependent-37" DOI : 10.1016/j.ijfoodmicro.2009.04.020 #12;2 ABSTRACT11 12 The microbial diversity of the surface the cheese microbial diversity21 with class-level and specific rRNA-targeted probes for bacteria and yeasts

Boyer, Edmond

297

Beta Diversity of Plant-Pollinator Networks and the Spatial Turnover of Pairwise Interactions  

PubMed Central

Interactions between species form complex networks that vary across space and time. Even without spatial or temporal constraints mutualistic pairwise interactions may vary, or rewire, across space but this variability is not well understood. Here, we quantify the beta diversity of species and interactions and test factors influencing the probability of turnover of pairwise interactions across space. We ask: 1) whether beta diversity of plants, pollinators, and interactions follow a similar trend across space, and 2) which interaction properties and site characteristics are related to the probability of turnover of pairwise interactions. Geographical distance was positively correlated with plant and interaction beta diversity. We find that locally frequent interactions are more consistent across space and that local flower abundance is important for the realization of pairwise interactions. While the identity of pairwise interactions is highly variable across space, some species-pairs form interactions that are locally frequent and spatially consistent. Such interactions represent cornerstones of interacting communities and deserve special attention from ecologists and conservation planners alike. PMID:25384058

Carstensen, Daniel W.; Sabatino, Malena; Trøjelsgaard, Kristian; Morellato, Leonor Patricia C.

2014-01-01

298

Linking invasions and biogeography: isolation differentially affects exotic and native plant diversity.  

PubMed

The role of native species diversity in providing biotic resistance to invasion remains controversial, with evidence supporting both negative and positive relationships that are often scale dependent. Across larger spatial scales, positive relationships suggest that exotic and native species respond similarly to factors other than diversity. In the case of island habitats, such factors may include island size and isolation from the mainland. However, previous island studies exploring this issue examined only a few islands or islands separated by extreme distances. In this study, we surveyed exotic and native plant diversity on 25 islands separated by <15 km in Boston Harbor. Exotic and native species richness were positively correlated. Consistent with island biogeography theory, species richness of both groups was positively related to area and negatively related to isolation. However, the isolation effect was significantly stronger for native species. This differential effect of isolation on native species translated into exotic species representing a higher proportion of all plant species on more distant islands. The community similarity of inner harbor islands vs. outer harbor islands was greater for exotic species, indicating that isolation had a weaker influence on individual exotic species. These results contrast with recent work focusing on similarities between exotic and native species and highlight the importance of studies that use an island biogeographic approach to better understand those factors influencing the ecology of invasive species. PMID:19449678

Long, Jeremy D; Trussell, Geoffrey C; Elliman, Ted

2009-04-01

299

Elevated CO2 and plant species diversity interact to slow root decomposition  

SciTech Connect

Changes in plant species diversity can result in synergistic increases in decomposition rates, while elevated atmospheric CO2 can slow the decomposition rates; yet it remains unclear how diversity and changes in atmospheric CO2 may interact to alter root decomposition. To investigate how elevated CO2 interacts with changes in root-litter diversity to alter decomposition rates, we conducted a 120-day laboratory incubation. Roots from three species (Trifolium repens, Lespedeza cuneata, and Festuca pratense) grown under ambient or elevated CO2 were incubated individually or in combination in soils that were exposed to ambient or elevated CO2 for five years. Our experiment resulted in two main findings: (1) Roots from T. repens and L. cuneata, both nitrogen (N) fixers, grown under elevated CO2 treatments had significantly slower decomposition rates than similar roots grown under ambient CO2 treatments; but the decomposition rate of F. pratense roots (a non-N-fixing species) was similar regardless of CO2 treatment. (2) Roots of the three species grown under ambient CO2 and decomposed in combination with each other had faster decomposition rates than when they were decomposed as single species. However, roots of the three species grown under elevated CO2 had similar decomposition rates when they were incubated alone or in combination with other species. These data suggest that if elevated CO2 reduces the root decomposition rate of even a few species in the community, it may slow root decomposition of the entire plant community.

De Graaff, Marie-Anne [ORNL; Schadt, Christopher Warren [ORNL; Rula, Kelly L [ORNL; Six, Johan W U A [University of California, Davis; Schweitzer, Jennifer A [ORNL; Classen, Aimee T [University of Tennessee, Knoxville (UTK)

2011-01-01

300

Environmental risk assessment for plant pests: a procedure to evaluate their impacts on ecosystem services.  

PubMed

The current methods to assess the environmental impacts of plant pests differ in their approaches and there is a lack of the standardized procedures necessary to provide accurate and consistent results, demonstrating the complexity of developing a commonly accepted scheme for this purpose. By including both the structural and functional components of the environment threatened by invasive alien species (IAS), in particular plant pests, we propose an environmental risk assessment scheme that addresses this complexity. Structural components are investigated by evaluating the impacts of the plant pest on genetic, species and landscape diversity. Functional components are evaluated by estimating how plant pests modify ecosystem services in order to determine the extent to which an IAS changes the functional traits that influence ecosystem services. A scenario study at a defined spatial and temporal resolution is then used to explore how an IAS, as an exogenous driving force, may trigger modifications in the target environment. The method presented here provides a standardized approach to generate comparable and reproducible results for environmental risk assessment as a component of Pest Risk Analysis. The method enables the assessment of overall environmental risk which integrates the impacts on different components of the environment and their probabilities of occurrence. The application of the proposed scheme is illustrated by evaluating the environmental impacts of the invasive citrus long-horn beetle, Anoplophora chinensis. PMID:24051446

Gilioli, G; Schrader, G; Baker, R H A; Ceglarska, E; Kertész, V K; Lövei, G; Navajas, M; Rossi, V; Tramontini, S; van Lenteren, J C

2014-01-15

301

Testing successional hypotheses of stability, heterogeneity, and diversity in pitcher-plant inquiline communities.  

PubMed

Succession is a foundation concept in ecology that describes changes in species composition through time, yet many successional patterns have not been thoroughly investigated. We highlight three hypotheses about succession that are often not clearly stated or tested: (1) individual communities become more stable over time, (2) replicate communities become more similar over time, and (3) diversity peaks at mid-succession. Testing general patterns of succession requires estimates of variation in trajectories within and among replicate communities. We followed replicate aquatic communities found within leaves of purple pitcher plants (Sarracenia purpurea) to test these three hypotheses. We found that stability of individual communities initially decreased, but then increased in older communities. Predation was highest in younger leaves but then declined, while competition was likely strongest in older leaves, as resources declined through time. Higher levels of predation and competition corresponded with periods of higher stability. As predicted, heterogeneity among communities decreased with age, suggesting that communities became more similar over time. Changes in diversity depended on trophic level. The diversity of bacteria slightly declined over time, but the diversity of consumers of bacteria increased linearly and strongly throughout succession. We suggest that studies need to focus on the variety of environmental drivers of succession, which are likely to vary through time and across habitats. PMID:22430372

Miller, Thomas E; terHorst, Casey P

2012-09-01

302

Genetic roadmap of the Arctic: plant dispersal highways, traffic barriers and capitals of diversity.  

PubMed

We provide the first comparative multispecies analysis of spatial genetic structure and diversity in the circumpolar Arctic using a common strategy for sampling and genetic analyses. We aimed to identify and explain potential general patterns of genetic discontinuity/connectivity and diversity, and to compare our findings with previously published hypotheses. We collected and analyzed 7707 samples of 17 widespread arctic-alpine plant species for amplified fragment length polymorphisms (AFLPs). Genetic structure, diversity and distinctiveness were analyzed for each species, and extrapolated to cover the geographic range of each species. The resulting maps were overlaid to produce metamaps. The Arctic and Atlantic Oceans, the Greenlandic ice cap, the Urals, and lowland areas between southern mountain ranges and the Arctic were the strongest barriers against gene flow. Diversity was highest in Beringia and gradually decreased into formerly glaciated areas. The highest degrees of distinctiveness were observed in Siberia. We conclude that large-scale general patterns exist in the Arctic, shaped by the Pleistocene glaciations combined with long-standing physical barriers against gene flow. Beringia served as both refugium and source for interglacial (re)colonization, whereas areas further west in Siberia served as refugia, but less as sources for (re)colonization. PMID:23869846

Eidesen, Pernille Bronken; Ehrich, Dorothee; Bakkestuen, Vegar; Alsos, Inger Greve; Gilg, Oliver; Taberlet, Pierre; Brochmann, Christian

2013-11-01

303

UNPALATABLE PLANTS PROTECT NEIGHBORS FROM GRAZING AND INCREASE PLANT COMMUNITY DIVERSITY  

Microsoft Academic Search

2 Institute of Botany of the Georgian Academy of Sciences, 1 Kojori Road, 380007, Tbilisi, Georgia Abstract. Tasty plants can be protected from herbivores by unpalatable neighbors. We used experimental exclosures, removal of unpalatable species, and transplants of palatable and unpalatable species in subalpine meadows of the Caucasus Mountains of Georgia to study the effects of two unpalatable species on

Ragan M. Callaway; David Kikodze; Marina Chiboshvili; Liana Khetsuriani

2005-01-01

304

Desert Farming Benefits from Microbial Potential in Arid Soils and Promotes Diversity and Plant Health  

PubMed Central

Background To convert deserts into arable, green landscapes is a global vision, and desert farming is a strong growing area of agriculture world-wide. However, its effect on diversity of soil microbial communities, which are responsible for important ecosystem services like plant health, is still not known. Methodology/Principal Findings We studied the impact of long-term agriculture on desert soil in one of the most prominent examples for organic desert farming in Sekem (Egypt). Using a polyphasic methodological approach to analyse microbial communities in soil as well as associated with cultivated plants, drastic effects caused by 30 years of agriculture were detected. Analysing bacterial fingerprints, we found statistically significant differences between agricultural and native desert soil of about 60%. A pyrosequencing-based analysis of the 16S rRNA gene regions showed higher diversity in agricultural than in desert soil (Shannon diversity indices: 11.21/7.90), and displayed structural differences. The proportion of Firmicutes in field soil was significantly higher (37%) than in the desert (11%). Bacillus and Paenibacillus play the key role: they represented 96% of the antagonists towards phytopathogens, and identical 16S rRNA sequences in the amplicon library and for isolates were detected. The proportion of antagonistic strains was doubled in field in comparison to desert soil (21.6%/12.4%); disease-suppressive bacteria were especially enriched in plant roots. On the opposite, several extremophilic bacterial groups, e.g., Acidimicrobium, Rubellimicrobium and Deinococcus-Thermus, disappeared from soil after agricultural use. The N-fixing Herbaspirillum group only occurred in desert soil. Soil bacterial communities were strongly driven by the a-biotic factors water supply and pH. Conclusions/Significance After long-term farming, a drastic shift in the bacterial communities in desert soil was observed. Bacterial communities in agricultural soil showed a higher diversity and a better ecosystem function for plant health but a loss of extremophilic bacteria. Interestingly, we detected that indigenous desert microorganisms promoted plant health in desert agro-ecosystems. PMID:21912695

Köberl, Martina; Müller, Henry; Ramadan, Elshahat M.; Berg, Gabriele

2011-01-01

305

Assessing genetic diversity of protected coho salmon ( Oncorhynchus kisutch ) populations in California  

Microsoft Academic Search

California coho salmon (Oncorhynchus kisutch) are under legal protection owing to significant declines in abundance over the last decades. Previously, California coho salmon were characterized as having low genetic diversity and weak population subdivision, attributable potentially to homogenization by out-of-basin hatchery releases. Here, di- versity at seven highly polymorphic microsatellite DNA markers is assessed within and among 32 collections of

Katherine A. Bucklin; Michael A. Banks; Dennis Hedgecock

2007-01-01

306

Sugarcane microsatellites for the assessment of genetic diversity in sugarcane germplasm  

Technology Transfer Automated Retrieval System (TEKTRAN)

The ability of microsatellite or simple sequence repeat (SSR) markers to determine the genetic diversity between Saccharum (S. officinarum, S. spontaneum, S. sinense), Old World Erianthus Michx. sect. Ripidium, North American E. giganteus (S. giganteum), Sorghum and Miscanthus was assessed. Six SSR ...

307

Assessing genetic diversity of wheat ( Triticum aestivum L.) germplasm using microsatellite markers  

Microsoft Academic Search

A set of 24 wheat microsatellite markers, representing at least one marker from each chromosome, was used for the assessment of genetic diversity in 998 accessions of hexaploid bread wheat (Triticum aestivum L.) which originated from 68 countries of five continents. A total of 470 alleles were detected with an average allele number of 18.1 per locus. The highest number

X. Q. Huang; A. Börner; M. S. Röder; M. W. Ganal

2002-01-01

308

Technical Assistance Document for Assessment and Evaluation of Preschool Children Who Are Culturally and Linguistically Diverse.  

ERIC Educational Resources Information Center

This manual presents New Mexico state guidelines for the assessment and evaluation of preschool children who are culturally and linguistically diverse, and focuses on the principles of parent participation and nondiscriminatory evaluation as defined in the Individuals with Disabilities Education Act and the New Mexico Administrative Codes. A…

Flores, Jeff; Lopez, Eric J.; De Leon, Jozi

309

Convergence or Divergence: Alignment of Standards, Assessment, and Issues of Diversity.  

ERIC Educational Resources Information Center

In this report, teacher educators scrutinize the relationships between the standards and assessment movement in education and the United States' increasingly multicultural population. The papers include: "Foreword" (Jacqueline Jordan Irvine); (1) "Diversity and Standards: Defining the Issues" (Norvella P. Carter); (2) "Accountability and…

Carter, Norvella, Ed.

310

Genetic Diversity of Lablab (L. purpureus) Germplasm Assessed by SSR Markers  

Technology Transfer Automated Retrieval System (TEKTRAN)

The genetic diversity of the USDA Lablab purpureus germplasm collection is unknown and was assessed by using polymorphic simple sequence repeat (SSR) markers derived from Medicago, soybean and cowpea. Phylogenetic analysis partitioned 47 representative accessions into two main clades (wild clade pr...

311

Assessing the Crossdisciplinarity of Technology-Enhanced Learning with Science Overlay Maps and Diversity Measures  

ERIC Educational Resources Information Center

This paper deals with the assessment of the crossdisciplinarity of technology-enhanced learning (TEL). Based on a general discussion of the concept interdisciplinarity and a summary of the discussion in the field, two empirical methods from scientometrics are introduced and applied. Science overlay maps and the Rao-Stirling diversity index are…

Kalz, Marco; Specht, Marcus

2014-01-01

312

Phylogenetic placement of diverse amoebae inferred from multigene analyses and assessment of clade stability within  

E-print Network

Phylogenetic placement of diverse amoebae inferred from multigene analyses and assessment of clade relationships within the `Amoebozoa'. Ã? 2007 Elsevier Inc. All rights reserved. Keywords: Amoeba; Sarcodina; Multigene analysis; SSU-rDNA; Unicellular eukaryote; Supergroups 1. Introduction The term amoeba is used

Katz, Laura

313

Involving Families in Education: Using Diverse Teaching and Assessment Strategies To Prepare Teachers for This Role.  

ERIC Educational Resources Information Center

This paper summarizes three presentations on the diverse teaching and assessment strategies used in a course designed to prepare preservice teachers for involving families and the community in the education of children. The course is required for early childhood and elementary teacher education majors at the University of Memphis (Tennessee). The…

Morris, Vivian Gunn; And Others

314

Diversity and functionality of arbuscular mycorrhizal fungi in three plant communities in semiarid Grasslands National Park, Canada.  

PubMed

Septate endophytes proliferating in the roots of grasslands' plants shed doubts on the importance of arbuscular mycorrhizal (AM) symbioses in dry soils. The functionality and diversity of the AM symbioses formed in four replicates of three adjacent plant communities (agricultural, native, and restored) in Grasslands National Park, Canada were assessed in periods of moisture sufficiency and deficiency typical of early and late summer in the region. The community structure of AM fungi, as determined by polymerase chain reaction-denaturing gradient gel electrophoresis, varied with sampling time and plant community. Soil properties other than soil moisture did not change significantly with sampling time. The DNA sequences dominating AM extraradical networks in dry soil apparently belonged to rare taxa unreported in GenBank. DNA sequences of Glomus viscosum, Glomus mosseae, and Glomus hoi were dominant under conditions of moisture sufficiency. In total, nine different AM fungal sequences were found suggesting a role for the AM symbioses in semiarid areas. Significant positive linear relationships between plant P and N concentrations and active extraradical AM fungal biomass, estimated by the abundance of the phospholipid fatty acid marker 16:1 omega 5, existed under conditions of moisture sufficiency, but not under dry conditions. Active extraradical AM fungal biomass had significantly positive linear relationship with the abundance of two early season grasses, Agropyron cristatum (L.) Gaertn. and Koeleria gracilis Pers., but no relationship was found under dry conditions. The AM symbioses formed under conditions of moisture sufficiency typical of early summer at this location appear to be important for the nutrition of grassland plant communities, but no evidence of mutualism was found under the dry conditions of late summer. PMID:20082070

Yang, Chao; Hamel, Chantal; Schellenberg, Michael P; Perez, Juan C; Berbara, Ricardo L

2010-05-01

315

Diversity  

NSDL National Science Digital Library

Look at the following resources to find information about diversity. Use your information to complete the assignment for your class. CIVIL RIGHTS Civil Rights Era Civil Rights Timeline JIM CROW LAWS AND SEGREGATION The Rise and Fall of Jim Crow Jim Crow and Segregation MARTIN LUTHER KING Dr. Martin Luther King, Jr. Biography Dr. Martin Luther King: I Have a Dream ROSA PARKS Rosa Parks: The Woman Who Changed a Nation Rosa Parks Biography EMMETT TILL The Murder of Emmett Till About African American History: The Biography of Emmett Till THE LITTLE ROCK 9 Little Rock 9 The 1957-1958 School Year School Integration in Little Rock, Arkansas MONTGOMERY BUS BOYCOTT Montgomery Bus Boycott They Changed the World: The Story of the Montgomery Bus Boycott Montgomery Bus Boycott FREEDOM RIDES Freedom Rides SNCC: Freedom Rides WOMEN'S RIGHTS Women s Rights Movement in the US--Timeline Women s Rights: National Historic Park History of the Equal Rights Amendment JAPANESE INTERNMENT Topaz Museum Japanese Relocation Photographs TRAIL OF TEARS Trail of Tears Trail of Tears Era HOLOCAUST Holocaust Encyclopedia The History Place: Holocaust Timeline Holocaust History Project ...

Albion Middle School Library--Mrs. Bates

2007-01-25

316

Metallography in life assessment of power plants  

Microsoft Academic Search

This report discusses the application of metallographic techniques in evaluating power plant components for integrity, continued service, and estimation of remaining safe life. Some of the pitfalls that may arise and the limitations to the methods of evaluation are discussed, and several specific cases are presented where metallography has been used to evaluate failures and to provide recommendations concerning future

Heloísa Cunha Furtado; Iain Le May

1996-01-01

317

SENSITVE PLANT SPECIES AND NOXIOUS WEED ASSESSMENT  

E-print Network

This report summarizes vegetation survey results for the proposed Boulder Bay Resort in Crystal Bay, Lake Tahoe, Nevada. The proposed project is located on private land, including the existing Tahoe Biltmore and the old Tahoe Mariner site. The survey addressed special interest, proposed, endangered, threatened, and sensitive plant species as well as noxious and invasive species.

unknown authors

2009-01-01

318

Diversity and regulation of plant Ca2+ pumps: insights from expression in yeast  

NASA Technical Reports Server (NTRS)

The spatial and temporal regulation of calcium concentration in plant cells depends on the coordinate activities of channels and active transporters located on different organelles and membranes. Several Ca2+ pumps have been identified and characterized by functional expression of plant genes in a yeast mutant (K616). This expression system has opened the way to a genetic and biochemical characterization of the regulatory and catalytic features of diverse Ca2+ pumps. Plant Ca(2+)-ATPases fall into two major types: AtECA1 represents one of four or more members of the type IIA (ER-type) Ca(2+)-ATPases in Arabidopsis, and AtACA2 is one of seven or more members of the type IIB (PM-type) Ca(2+)-ATPases that are regulated by a novel amino terminal domain. Type IIB pumps are widely distributed on membranes, including the PM (plasma membrane), vacuole, and ER (endoplasmic reticulum). The regulatory domain serves multiple functions, including autoinhibition, calmodulin binding, and sites for modification by phosphorylation. This domain, however, is considerably diverse among several type IIB ATPases, suggesting that the pumps are differentially regulated. Understanding of Ca2+ transporters at the molecular level is providing insights into their roles in signaling networks and in regulating fundamental processes of cell biology.

Sze, H.; Liang, F.; Hwang, I.; Curran, A. C.; Harper, J. F.; Evans, M. L. (Principal Investigator)

2000-01-01

319

A keystone predator controls bacterial diversity in the pitcher-plant (Sarracenia purpurea) microecosystem.  

PubMed

The community of organisms inhabiting the water-filled leaves of the carnivorous pitcher-plant Sarracenia purpurea includes arthropods, protozoa and bacteria, and serves as a model system for studies of food web dynamics. Despite the wealth of data collected by ecologists and zoologists on this food web, very little is known about the bacterial assemblage in this microecosystem. We used terminal restriction fragment length polymorphism (T-RFLP) analysis to quantify bacterial diversity within the pitchers as a function of pitcher size, pH of the pitcher fluid and the presence of the keystone predator in this food web, larvae of the pitcher-plant mosquito Wyeomyia smithii. Results were analysed at two spatial scales: within a single bog and across three isolated bogs. Pitchers were sterile before they opened and composition of the bacterial assemblage was more variable between different bogs than within bogs. Measures of bacterial richness and diversity were greater in the presence of W. smithii and increased with increasing pitcher size. Our results suggest that fundamental ecological concepts derived from macroscopic food webs can also be used to predict the bacterial assemblages in pitcher plants. PMID:18479443

Peterson, Celeste N; Day, Stephanie; Wolfe, Benjamin E; Ellison, Aaron M; Kolter, Roberto; Pringle, Anne

2008-09-01

320

Assessing ant seed predation in threatened plants: a case study  

NASA Astrophysics Data System (ADS)

Erodium paularense is a threatened plant species that is subject to seed predation by the granivorous ant Messor capitatus. In this paper we assessed the intensity and pattern of ant seed predation and looked for possible adaptive strategies at the seed and plant levels to cope with this predation. Seed predation was estimated in 1997 and 1998 at the population level by comparing total seed production and ant consumption, assessed by counting seed hulls in refuse piles. According to this method, ant seed predation ranged between 18% and 28%. A more detailed and direct assessment conducted in 1997 raised this estimate to 43%. In this assessment spatial and temporal patterns of seed predation by ants were studied by mapping all nest entrances in the studied area and marking the mature fruits of 109 reproductive plants with a specific colour code throughout the seed dispersal period. Intact fruit coats were later recovered from the refuse piles, and their mother plants and time of dispersal were identified. Seeds dispersed at the end of the dispersal period had a greater probability of escaping from ant seed predation. Similarly, in plants with late dispersal a greater percentage of seeds escaped from ant predation. Optimum dispersal time coincided with the maximum activity of granivorous ants because, at this time, ants focused their harvest on other plant species of the community. It was also observed that within-individual seed dispersal asynchrony minimised seed predation. From a conservation perspective, results show that the granivorous ant-plant interaction cannot be assessed in isolation and that the intensity of its effects basically depends on the seed dispersal pattern of the other members of the plant community. Furthermore, this threat must be assessed by considering the overall situation of the target population. Thus, in E. paularense, the strong limitation of safe-sites for seedling establishment reduces the importance of seed predation.

Albert, María José; Escudero, Adrián; Iriondo, José María

2005-11-01

321

Organic Farming and Landscape Structure: Effects on Insect-Pollinated Plant Diversity in Intensively Managed Grasslands  

PubMed Central

Parallel declines in insect-pollinated plants and their pollinators have been reported as a result of agricultural intensification. Intensive arable plant communities have previously been shown to contain higher proportions of self-pollinated plants compared to natural or semi-natural plant communities. Though intensive grasslands are widespread, it is not known whether they show similar patterns to arable systems nor whether local and/or landscape factors are influential. We investigated plant community composition in 10 pairs of organic and conventional dairy farms across Ireland in relation to the local and landscape context. Relationships between plant groups and local factors (farming system, position in field and soil parameters) and landscape factors (e.g. landscape complexity) were investigated. The percentage cover of unimproved grassland was used as an inverse predictor of landscape complexity, as it was negatively correlated with habitat-type diversity. Intensive grasslands (organic and conventional) contained more insect-pollinated forbs than non-insect pollinated forbs. Organic field centres contained more insect-pollinated forbs than conventional field centres. Insect-pollinated forb richness in field edges (but not field centres) increased with increasing landscape complexity (% unimproved grassland) within 1, 3, 4 and 5km radii around sites, whereas non-insect pollinated forb richness was unrelated to landscape complexity. Pollination systems within intensive grassland communities may be different from those in arable systems. Our results indicate that organic management increases plant richness in field centres, but that landscape complexity exerts strong influences in both organic and conventional field edges. Insect-pollinated forb richness, unlike that for non-insect pollinated forbs, showed positive relationships to landscape complexity reflecting what has been documented for bees and other pollinators. The insect-pollinated forbs, their pollinators and landscape context are clearly linked. This needs to be taken into account when managing and conserving insect-pollinated plant and pollinator communities. PMID:22666450

Power, Eileen F.; Kelly, Daniel L.; Stout, Jane C.

2012-01-01

322

Plant-animal diversity relationships in a rocky intertidal system depend on invertebrate body size and algal cover.  

PubMed

Considerable research has examined the influence of herbivores on the maintenance of plant diversity, but fewer studies have examined the reciprocal effect of plant diversity on the animals that use the plant community for food and shelter, particularly in marine systems. Several mechanisms could underlie such effects. Animal diversity and abundance could be increased by complementary use of different plants by different animals, or by an indirect effect of plant diversity on plant production that results in more total plant biomass in high plant-diversity communities. Alternatively, plant species identity could play a dominant role leading to sampling effects or no effect of diversity at all. We conducted a six-year field manipulation of the richness of rocky shore seaweeds in northern California and measured the effects of algal richness and identity on the invertebrate community, from meiofauna to macrofauna. We found that diverse algal communities hosted more species of both large and small invertebrates than the average algal monoculture but that the mechanisms underlying this pattern differed substantially for organisms of different size. More species of macrofauna occurred in the polycultures than in any of the monocultures, likely due to the greater total cover of algae produced in polycultures. Rare and common macrofaunal taxa responded to host plant species richness in opposite ways, with more occurrences of rare taxa and lower abundance of very common taxa in the polycultures. In contrast, meiofaunal richness in polycultures was no different than that of monocultures of finely branched species, leading to strong effects of algal identity. Our findings are similar to those from terrestrial systems in that the effects of plant diversity we observed were most related to the greater amount of habitat in polycultures as a result of overyielding in algal biomass. However, our findings differ from those in terrestrial systems in that the primary mechanisms for both richness and identity effects appear related to the value of plants as shelter from harsh abiotic conditions or predation rather than food, and in that animal body size altered the mechanisms underlying diversity effects. PMID:25000762

Best, Rebecca J; Chaudoin, Ambre L; Bracken, Matthew E S; Graham, Michael H; Stachowicz, John J

2014-05-01

323

Plant diversity effects on leaching of nitrate, ammonium, and dissolved organic nitrogen from an experimental grassland  

NASA Astrophysics Data System (ADS)

Leaching of nitrogen (N) from soil represents a resource loss and, in particular leaching of nitrate, can threaten drinking water quality. As plant diversity leads to a more exhaustive resource use, we investigated the effects of plant species richness, functional group richness, and the presence of specific functional groups on nitrate, ammonium, dissolved organic N (DON), and total dissolved N (TDN) leaching from an experimental grassland in the first 4 years after conversion from fertilized arable land to unfertilized grassland. The experiment is located in Jena, Germany, and consists of 82 plots with 1, 2, 4, 8, 16, or 60 plant species and 1-4 functional groups (legumes, grasses, non-leguminous tall herbs, non-leguminous small herbs). Nitrate, ammonium, and TDN concentrations in soil solution in the 0-0.3 m soil layer were measured every second week during 4 years on 62 plots and DON concentrations were calculated as difference between TDN and inorganic N. Missing concentrations in soil solution were estimated using a Bayesian statistical model. Downward water fluxes (DF) per plot from the 0-0.3 m soil layer were simulated in weekly resolution with a water balance model in connection with a Bayesian model for simulating missing soil water content measurements. To obtain annual nitrate, ammonium, and DON leaching from the 0-0.3 m soil layer per plot, we multiplied the respective concentrations in soil solution with DF and aggregated the data to annual sums. TDN leaching resulted from summation of nitrate, ammonium, and DON leaching. DON leaching contributed most to TDN leaching, particularly in plots without legumes. Dissolved inorganic N leaching in this grassland was dominated by nitrate. The amount of annual ammonium leaching was small and little influenced by plant diversity. Species richness affected DON leaching only in the fourth and last investigated year, possibly because of a delayed soil biota effect that increased microbial transformation of organic N to inorganic N in species-rich mixtures or because of complementary resource use of amino-acid DON of species-rich mixtures. Nitrate and TDN leaching generally decreased with increasing species richness likely because of more exhaustive resource use of more diverse plant mixtures. Functional group richness did not have a significant effect on nitrate, ammonium, DON, and TDN leaching. Legumes increased and grasses decreased nitrate, DON, and TDN leaching because of their N-fixing ability and their extensive rooting system, respectively. TDN leaching was highest in the first year after conversion from arable to grassland which can be related to former fertilization. Quantitative differences in nitrate leaching between plant diversity treatments were also highest in the first year after conversion. However, the percentage reduction of nitrate leaching by species richness, the presence of grasses, or the presence of small herbs increased with time since land-use change possibly because of a strengthening of diversity effects with time. We conclude that especially shortly after land-use change from fertilized arable land to unfertilized grassland, N leaching, in particular nitrate leaching, can be reduced considerably if highly diverse mixtures without legumes are established.

Leimer, Sophia; Oelmann, Yvonne; Wirth, Christian; Wilcke, Wolfgang

2014-05-01

324

Plant communities and plant diversity in softwater lakes of northern Europe  

Microsoft Academic Search

Numbered in hundreds of thousands, and ranging from <1ha in area to Europe’s largest lake (Lake Ladoga), North European softwater lakes (lime-deficient waterbodies, ranging from low-nutrient, low pH to meso-eutrophic, circumneutral pH) support an important plant component of the biodiversity resources of Europe. Within this region (comprising the British Isles, Scandinavia, and the North European Plain from Brittany to the

K. J. Murphy

2002-01-01

325

Multiscale sampling of plant diversity: Effects of minimum mapping unit size  

USGS Publications Warehouse

Only a small portion of any landscape can be sampled for vascular plant diversity because of constraints of cost (salaries, travel time between sites, etc.). Often, the investigator decides to reduce the cost of creating a vegetation map by increasing the minimum mapping unit (MMU), and/or by reducing the number of vegetation classes to be considered. Questions arise about what information is sacrificed when map resolution is decreased. We compared plant diversity patterns from vegetation maps made with 100-ha, 50-ha, 2-ha, and 0.02-ha MMUs in a 754-ha study area in Rocky Mountain National Park, Colorado, United States, using four 0.025-ha and 21 0.1-ha multiscale vegetation plots. We developed and tested species-log(area) curves, correcting the curves for within-vegetation type heterogeneity with Jaccard's coefficients. Total species richness in the study area was estimated from vegetation maps at each resolution (MMU), based on the corrected species-area curves, total area of the vegetation type, and species overlap among vegetation types. With the 0.02-ha MMU, six vegetation types were recovered, resulting in an estimated 552 species (95% CI = 520-583 species) in the 754-ha study area (330 plant species were observed in the 25 plots). With the 2-ha MMU, five vegetation types were recognized, resulting in an estimated 473 species for the study area. With the 50-ha MMU, 439 plant species were estimated for the four vegetation types recognized in the study area. With the 100-ha MMU, only three vegetation types were recognized, resulting in an estimated 341 plant species for the study area. Locally rare species and keystone ecosystems (areas of high or unique plant diversity) were missed at the 2-ha, 50-ha, and 100-ha scales. To evaluate the effects of minimum mapping unit size requires: (1) an initial stratification of homogeneous, heterogeneous, and rare habitat types; and (2) an evaluation of within-type and between-type heterogeneity generated by environmental gradients and other factors. We suggest that at least some portions of vegetation maps created at a coarser level of resolution be validated at a higher level of resolution.

Stohlgren, T.J.; Chong, G.W.; Kalkhan, M.A.; Schell, L.D.

1997-01-01

326

Applications of DNA barcoding to fish landings: authentication and diversity assessment  

PubMed Central

Abstract DNA barcoding methodologies are being increasingly applied not only for scientific purposes but also for diverse real-life uses. Fisheries assessment is a potential niche for DNA barcoding, which serves for species authentication and may also be used for estimating within-population genetic diversity of exploited fish. Analysis of single-sequence barcodes has been proposed as a shortcut for measuring diversity in addition to the original purpose of species identification. Here we explore the relative utility of different mitochondrial sequences (12S rDNA, COI, cyt b, and D-Loop) for application as barcodes in fisheries sciences, using as case studies two marine and two freshwater catches of contrasting diversity levels. Ambiguous catch identification from COI and cyt b was observed. In some cases this could be attributed to duplicated names in databases, but in others it could be due to mitochondrial introgression between closely related species that may obscure species assignation from mtDNA. This last problem could be solved using a combination of mitochondrial and nuclear genes. We suggest to simultaneously analyze one conserved and one more polymorphic gene to identify species and assess diversity in fish catches. PMID:24453550

Ardura, Alba; Planes, Serge; Garcia-Vazquez, Eva

2013-01-01

327

Isolated populations of a rare alpine plant show high genetic diversity and considerable population differentiation  

PubMed Central

Background and Aims Gene flow and genetic variability within and among alpine plant populations can be greatly influenced by the steep environmental gradients and heterogeneous topography of alpine landscapes. In this study, the effects are examined of natural isolation of alpine habitats on genetic diversity and geographic structure in populations of C. thyrsoides, a rare and isolated European Alpine monocarpic perennial with limited seed dispersal capacity. Methods Molecular diversity was analysed for 736 individuals from 32 populations in the Swiss Alps and adjacent Jura mountains using five polymorphic microsatellite loci. Pollen flow was estimated using pollen grain-sized fluorescent powder. In addition, individual-based Bayesian approaches were applied to examine population structure. Key Results High within-population genetic diversity (HE = 0·76) and a relatively low inbreeding coefficient (FIS = 0·022) were found. Genetic differentiation among populations measured with a standardized measure was considerable (G?ST = 0·53). A significant isolation-by-distance relationship was found (r = 0·62, P < 0·001) and a significant geographic sub-structure, coinciding with proposed postglacial migration patterns. Altitudinal location and size of populations did not influence molecular variation. Direct measures of pollen flow revealed that insect-mediated pollen dispersal was restricted to short distances within a population. Conclusions The natural isolation of suitable habitats for C. thyrsoides restricts gene flow among the populations as expected for a monocarpic species with very limited seed dispersal capacities. The observed high within-population genetic diversity in this rare monocarpic perennial is best explained by its outcrossing behaviour, long-lived individuals and overlapping generations. Despite the high within-population genetic diversity, the considerable genetic differentiation and the clear western–eastern differentiation in this species merits consideration in future conservation efforts. PMID:19797423

Ægisdóttir, Hafdís Hanna; Kuss, Patrick; Stöcklin, Jürg

2009-01-01

328

Diversity patterns of selected Andean plant groups correspond to topography and habitat dynamics, not orogeny  

PubMed Central

The tropical Andes are a hotspot of biodiversity, but detailed altitudinal and latitudinal distribution patterns of species are poorly understood. We compare the distribution and diversity patterns of four Andean plant groups on the basis of georeferenced specimen data: the genus Nasa (Loasaceae), the two South American sections of Ribes (sect. Parilla and sect. Andina, Grossulariaceae), and the American clade of Urtica (Urticaceae). In the tropical Andes, these often grow together, especially in (naturally or anthropogenically) disturbed or secondary vegetation at middle to upper elevations. The climatic niches of the tropical groups studied here are relatively similar in temperature and temperature seasonality, but do differ in moisture seasonality. The Amotape–Huancabamba Zone (AHZ) between 3 and 8° S shows a clear diversity peak of overall species richness as well as for narrowly endemic species across the groups studied. For Nasa, we also show a particular diversity of growth forms in the AHZ. This can be interpreted as proxy for a high diversity of ecological niches based on high spatial habitat heterogeneity in this zone. Latitudinal ranges are generally larger toward the margins of overall range of the group. Species number and number of endemic species of our taxa peak at elevations of 2,500–3,500 m in the tropical Andes. Altitudinal diversity patterns correspond well with the altitudinal distribution of slope inclination. We hypothesize that the likelihood and frequency of landslides at steeper slopes translate into temporal habitat heterogeneity. The frequency of landslides may be causally connected to diversification especially for the numerous early colonizing taxa, such as Urtica and annual species of Nasa. In contrast to earlier hypotheses, uplift history is not reflected in the pattern here retrieved, since the AHZ is the area of the most recent Andean uplift. Similarly, a barrier effect of the low-lying Huancabamba depression is not retrieved in our data. PMID:25346750

Mutke, Jens; Jacobs, Rana; Meyers, Katharina; Henning, Tilo; Weigend, Maximilian

2014-01-01

329

Diversity patterns of selected Andean plant groups correspond to topography and habitat dynamics, not orogeny.  

PubMed

The tropical Andes are a hotspot of biodiversity, but detailed altitudinal and latitudinal distribution patterns of species are poorly understood. We compare the distribution and diversity patterns of four Andean plant groups on the basis of georeferenced specimen data: the genus Nasa (Loasaceae), the two South American sections of Ribes (sect. Parilla and sect. Andina, Grossulariaceae), and the American clade of Urtica (Urticaceae). In the tropical Andes, these often grow together, especially in (naturally or anthropogenically) disturbed or secondary vegetation at middle to upper elevations. The climatic niches of the tropical groups studied here are relatively similar in temperature and temperature seasonality, but do differ in moisture seasonality. The Amotape-Huancabamba Zone (AHZ) between 3 and 8° S shows a clear diversity peak of overall species richness as well as for narrowly endemic species across the groups studied. For Nasa, we also show a particular diversity of growth forms in the AHZ. This can be interpreted as proxy for a high diversity of ecological niches based on high spatial habitat heterogeneity in this zone. Latitudinal ranges are generally larger toward the margins of overall range of the group. Species number and number of endemic species of our taxa peak at elevations of 2,500-3,500 m in the tropical Andes. Altitudinal diversity patterns correspond well with the altitudinal distribution of slope inclination. We hypothesize that the likelihood and frequency of landslides at steeper slopes translate into temporal habitat heterogeneity. The frequency of landslides may be causally connected to diversification especially for the numerous early colonizing taxa, such as Urtica and annual species of Nasa. In contrast to earlier hypotheses, uplift history is not reflected in the pattern here retrieved, since the AHZ is the area of the most recent Andean uplift. Similarly, a barrier effect of the low-lying Huancabamba depression is not retrieved in our data. PMID:25346750

Mutke, Jens; Jacobs, Rana; Meyers, Katharina; Henning, Tilo; Weigend, Maximilian

2014-01-01

330

Consequences of plant-chemical diversity for domestic goat food preference in Mediterranean forests  

NASA Astrophysics Data System (ADS)

The domestic goat, a major herbivore in the Mediterranean basin, has demonstrated a strong ability to adapt its feeding behaviour to the chemical characteristics of food, selecting plants according to their nutritive quality. In this study, we determine some chemical characteristics related to plant nutritional quality and its variability among and within five tree species, these being the main components of the mountain forests of SE Spain, with the aim of determining their influence on food selection by this generalist herbivore. We analyse nitrogen, total phenols, condensed tannins and fibre concentration as an indicator of the nutritive value of the different trees. To determine the preference by the domestic goat, we performed two types of feeding-choice assays, where goats had to select between different species or between branches of the same species but from trees of different nutritional quality. The analysis of the plant nutritional quality showed significant differences in the chemical characteristics between species, and a high variability within species. However, when faced with different tree species, the domestic goat selected some of them but showed striking individual differences between goats. When selecting between trees of the same species, the goats showed no differential selection. This limited effect of chemical plant characteristics, together with the variability in foraging behaviour, resulted in a widespread consumption of diverse plant species, which can potentially modulate the effect of the goat on vegetation composition, and open the way for the conservation of traditional livestock grazing on natural protected areas.

Baraza, Elena; Hódar, José A.; Zamora, Regino

2009-01-01

331

Genetic diversity and symbiotic compatibility among rhizobial strains and Desmodium incanum and Lotus spp. plants  

PubMed Central

This work aimed to evaluate the symbiotic compatibility and nodulation efficiency of rhizobia isolated from Desmodium incanum, Lotus corniculatus, L. subbiflorus, L. uliginosus and L. glaber plants by cross-inoculation. Twelve reference strains and 21 native isolates of rhizobia were genetically analyzed by the BOX-PCR technique, which showed a high genetic diversity among the rhizobia studied. The isolates were also characterized based on their production of indolic compounds and siderophores, as well as on their tolerance to salinity. Fifteen of the 33 rhizobia analyzed were able to produce indolic compounds, whereas 13 produced siderophores. All the tested rhizobia were sensitive to high salinity, although some were able to grow in solutions of up to 2% NaCl. Most of the native rhizobia isolated from L. uliginosus were able to induce nodulation in all plant species studied. In a greenhouse experiment using both D. incanum and L. corniculatus plants, the rhizobia isolate UFRGS Lu2 promoted the greatest plant growth. The results demonstrate that there are native rhizobia in the soils of southern Brazil that have low host specificity and are able to induce nodulation and form active nodules in several plant species. PMID:25071405

Granada, Camille E.; Strochein, Marcos; Vargas, Luciano K.; Bruxel, Manuela; de Sá, Enilson Luiz Saccol; Passaglia, Luciane M.P.

2014-01-01

332

S-allele diversity in a natural population of Physalis crassifolia (Solanaceae) (ground cherry) assessed by RT-PCR  

Microsoft Academic Search

Allelic diversity at the self-incompatibility (S-) locus in the ground cherry, Physalis crassifolia (Solanaceae), was surveyed in a natural population occurring in Deep Canyon, CA, using a molecular assay to determine the genotype of individual plants. A total of 28 different S-alleles were identified and sequenced from a sample of 22 plants. All plants examined were heterozygous, as expected under

Adam D Richman; Marcy K Uyenoyama; Joshua R Kohn

1996-01-01

333

Genetic and functional diversity of soil microbial communities associated to grapevine plants and wine quality  

NASA Astrophysics Data System (ADS)

Despite the economic importance of vineyards in Italy, the wine sector is facing severe challenges from increased global competition and climate changes. The quality of the grape at harvest has a strong direct impact on wine final quality and the strong relationship between wine composition, aroma, taste, and soil properties has been outlined in the "Terroir concept". However, information on the impact of soil microbial communities on soil functions, grapevine plants, and wine quality is generally lacking. In the current study, soils from two close sites in Central Tuscany (BRO11 and BRO12) cultivated with the same grapevine cultivar Sangiovese, but with contrasting wine quality, were examined. Although the BRO12 site provided a better wine quality than the BRO11, the two soils showed similar physical, chemical, and hydrological properties. Also soil humidity, as determined by FDR (Frequency Domain Reflectometry) sensors, indicated a similar water availability in the first 75 cm during a three years trial (2000-2010). Interestingly, the mean three years value of the ratio between the two stable carbon isotopes 13C/12C, measured in the alcohol of the wines, was significantly higher in BRO12 than in BRO11 (-28,3‰ and -24,4‰, respectively), indicating the presence of a relatively higher water stress in the BRO11 soil. Functional GeoChip microarray analyses revealed higher presence of Actinobacteria in the BRO12 than in the BRO11 soil, where the alfa-Proteobacteria were more abundant. Furthermore, a consistent difference in genes involved in S cycling, with a significant overrepresentation of sulphur-oxidation genes in BRO11 and increased levels of sulphate reduction genes BRO12 was detected. These results are consistent with the high content of sulphates and the abundance of Firmicutes such as Sulfobacillus thermosulfidooxidans in the BRO11 soil. Therefore, the different microbiology of the two soils could be related to the different redox conditions of the two soils. The structure of soil microbial communities was assessed using 16S and 18S rRNA genes pyrosequencing and the determination of some soil microbial properties such as microbial respiration, microbial C-biomass were also determined. The role of both genetic and functional diversity of soil bacterial community on grape physiology and wine quality will be discussed.

Mocali, Stefano; Fabiani, Arturo; Kuramae, Eiko; de Hollander, Mattias; Kowalchuk, George A.; Vignozzi, Nadia; Valboa, Giuseppe; Costantini, Edoardo

2013-04-01

334

Factors affecting plant diversity during post-fire recovery and succession of mediterranean-climate shrublands in California, USA  

USGS Publications Warehouse

Plant community diversity, measured as species richness, is typically highest in the early post-fire years in California shrublands. However, this generalization is overly simplistic and the present study demonstrates that diversity is determined by a complex of temporal and spatial effects. Ninety sites distributed across southern California were studied for 5 years after a series of fires. Characteristics of the disturbance event, in this case fire severity, can alter post-fire diversity, both decreasing and increasing diversity, depending on life form. Spatial variability in resource availability is an important factor explaining patterns of diversity, and there is a complex interaction between landscape features and life form. Temporal variability in resource availability affects diversity, and the diversity peak in the immediate post-fire year (or two) appears to be driven by factors different from subsequent diversity peaks. Early post-fire diversity is influenced by life-history specialization, illustrated by species that spend the bulk of their life cycle as a dormant seed bank, which is then triggered to germinate by fire. Resource fluctuations, precipitation in particular, may be associated with subsequent post-fire diversity peaks. These later peaks in diversity comprise a flora that is compositionally different from the immediate post-fire flora, and their presence may be due to mass effects from population expansion of local populations in adjacent burned areas. ?? 2005 Blackwell Publishing Ltd.

Keeley, J.E.; Fotheringham, C.J.; Baer-Keeley, M.

2005-01-01

335

Comparative genomics of plant-associated Pseudomonas spp.: Insights into diversity and inheritance of traits involved in multitrophic interactions  

Technology Transfer Automated Retrieval System (TEKTRAN)

We provide here a comparative genome analysis of the Pseudomonas fluorescens group, including seven new genomic sequences for plant-associated strains. These strains exhibit a diverse spectrum of traits involved in biological control and other multitrophic interactions with plants, microbes, and ins...

336

The impact of livestock grazing on plant diversity: an analysis across dryland ecosystems and scales in southern Africa.  

PubMed

A general understanding of grazing effects on plant diversity in drylands is still missing, despite an extensive theoretical background. Cross-biome syntheses are hindered by the fact that the outcomes of disturbance studies are strongly affected by the choice of diversity measures, and the spatial and temporal scales of measurements. The aim of this study is to overcome these weaknesses by applying a wide range of diversity measures to a data set derived from identical sampling in three distinct ecosystems. We analyzed three fence-line contrasts (heavier vs. lighter grazing intensity), representing different degrees of aridity (from arid to semiarid) and precipitation regimes (summer rain vs. winter rain) in southern Africa. We tested the impact of grazing intensity on multiple aspects of plant diversity (species and functional group level, richness and evenness components, alpha and beta diversity, and composition) at two spatial scales, and for both 5-yr means and interannual variability. Heavier grazing reduced total plant cover and substantially altered the species and functional composition at all sites. However, a significant decrease in species alpha diversity was detected at only one of the three sites. By contrast, alpha diversity of plant functional groups responded consistently across ecosystems and scales, with a significant decrease at heavier grazing intensity. The cover-based measures of functional group diversity responded more sensitively and more consistently than functional group richness. Beta diversity of species and functional types increased under heavier grazing, showing that at larger scales, the heterogeneity of the community composition and the functional structure were increased. Heavier grazing mostly increased interannual variability of alpha diversity, while effects on beta diversity and cover were inconsistent. Our results suggest that species diversity alone may not adequately reflect the shifts in vegetation structure that occur in response to increased grazing intensity in the dryland biomes of southern Africa. Compositional and structural changes of the vegetation are better reflected by trait-based diversity measures. In particular, measures of plant functional diversity that include evenness represent a promising tool to detect and quantify disturbance effects on ecosystems. PMID:25154106

Hanke, Wiebke; Böhner, Jürgen; Dreber, Niels; Jürgens, Norbert; Schmiedel, Ute; Wesuls, Dirk; Dengler, Jürgen

2014-07-01

337

Functional diversity of 2-oxoglutarate/Fe(II)-dependent dioxygenases in plant metabolism  

PubMed Central

Oxidative enzymes catalyze many different reactions in plant metabolism. Among this suite of enzymes are the 2-oxoglutarate/Fe(II)-dependent dioxygenases (2-ODDs). Cytochromes P450 (CYPs) as often considered the most versatile oxidative enzymes in nature, but the diversity and complexity of reactions catalyzed by 2-ODDs is superior to the CYPs. The list of oxidative reactions catalyzed by 2-ODDs includes hydroxylations, demethylations, desaturations, ring closure, ring cleavage, epimerization, rearrangement, halogenation, and demethylenation. Furthermore, recent work, including the discovery of 2-ODDs involved in epigenetic regulation, and others catalyzing several characteristic steps in specialized metabolic pathways, support the argument that 2-ODDs are among the most versatile and important oxidizing biological catalysts. In this review, we survey and summarize the pertinent literature with a focus on several key reactions catalyzed by 2-ODDs, and discuss the significance and impact of these enzymes in plant metabolism. PMID:25346740

Farrow, Scott C.; Facchini, Peter J.

2014-01-01

338

Environmental Determinants of Woody Plant Diversity at a Regional Scale in China  

PubMed Central

Understanding what drives the geographic variation of species richness across the globe is a fundamental goal of ecology and biogeography. Environmental variables have been considered as drivers of global diversity patterns but there is no consensus among ecologists on what environmental variables are primary drivers of the geographic variation of species richness. Here, I examine the relationship of woody plant species richness at a regional scale in China with sixteen environmental variables representing energy availability, water availability, energy-water balance, seasonality, and habitat heterogeneity. I found that temperature seasonality is the best predictor of woody species richness in China. Other important environmental variables include annual precipitation, mean temperature of the coldest month, and potential evapotranspiration. The best model explains 85% of the variation in woody plant species richness at the regional scale in China. PMID:24086642

Qian, Hong

2013-01-01

339

Phylogenetic diversity of dominant bacterial and archaeal communities in plant-microbial fuel cells using rice plants.  

PubMed

In this study, the phylogenetic diversities of bacterial and archaeal communities in a plantmicrobial fuel cell (P-MFC) were investigated together with the environmental parameters, affecting its performance by using rice as a model plant. The beneficial effect of the plant appeared only during a certain period of the rice-growing season, at which point the maximum power density was approximately 3-fold higher with rice plants. The temperature, electrical conductivity (EC), and pH in the cathodic and anodic compartments changed considerably during the rice-growing season, and a higher temperature, reduced difference in pH between the cathodic and anodic compartments, and higher EC were advantageous to the performance of the P-MFC. A 16S rRNA pyrosequencing analysis showed that the 16S rRNAs of Deltaproteobacteria and those of Gammaproteobacteria were enriched on the anodes and the cathodes, respectively, when the electrical circuit was connected. At the species level, the operational taxonomic units (OTUs) related to Rhizobiales, Geobacter, Myxococcus, Deferrisoma, and Desulfobulbus were enriched on the anodes, while an OTU related to Acidiferrobacter thiooxydans occupied the highest proportion on the cathodes and occurred only when the circuit was connected. Furthermore, the connection of the electrical circuit decreased the abundance of 16S rRNAs of acetotrophic methanogens and increased that of hydrogenotrophic methanogens. The control of these physicochemical and microbiological factors is expected to be able to improve the performance of P-MFCs. PMID:25189409

Ahn, Jae-Hyung; Jeong, Woo-Suk; Choi, Min-Young; Kim, Byung-Yong; Song, Jaekyeong; Weon, Hang-Yeon

2014-12-28

340

Impacts of recent cultivation on genetic diversity pattern of a medicinal plant, Scutellaria baicalensis (Lamiaceae)  

PubMed Central

Background Cultivation of medicinal plants is not only a means for meeting current and future demands for large volume production of plant-based drug and herbal remedies, but also a means of relieving harvest pressure on wild populations. Scutellaria baicalensis Georgi (Huang-qin or Chinese skullcap) is a very important medicinal plant in China. Over the past several decades, wild resource of this species has suffered rapid declines and large-scale cultivation was initiated to meet the increasing demand for its root. However, the genetic impacts of recent cultivation on S. baicalensis have never been evaluated. In this study, the genetic diversity and genetic structure of 28 wild and 22 cultivated populations were estimated using three polymorphic chloroplast fragments. The objectives of this study are to provide baseline data for preserving genetic resource of S. baicalensis and to evaluate the genetic impacts of recent cultivation on medicinal plants, which may be instructive to future cultivation projects of traditional Chinese medicinal plants. Results Thirty-two haplotypes of S. baicalensis (HapA-Y and Hap1-7) were identified when three chloroplast spacers were combined. These haplotypes constituted a shallow gene tree without obvious clusters for cultivated populations, suggesting multiple origins of cultivated S. baicalensis. Cultivated populations (hT = 0.832) maintained comparable genetic variation with wild populations (hT = 0.888), indicating a slight genetic bottleneck due to multiple origins of cultivation. However, a substantial amount of rare alleles (10 out of 25 haplotypes within wild populations) lost during the course of S. baicalensis cultivation. The genetic differentiation for cultivated group (GST = 0.220) was significantly lower than that of wild group (GST = 0.701). Isolation by distance analysis showed that the effect of geographical isolation on genetic structure was significant in wild populations (r = 0.4346, P < 0.0010), but not in cultivated populations (r = 0.0599, P = 0.2710). These genetic distribution patterns suggest that a transient cultivation history and the extensive seed change among different geographical areas during the course of S. baicalensis cultivation. Conclusions Although cultivated S. baicalensis maintains comparable genetic diversity relative to wild populations, recent cultivation has still imposed profound impacts on genetic diversity patterns of the cultivated S. baicalensis populations, i.e., the loss of rare alleles and homogenization of cultivated populations. This study suggests that conservation-by-cultivation is an effective means for protecting genetic resources of S. baicalensis, however, the wild resources still need to be protected in situ and the evolutionary consequences of extensive seed exchange mediated by human being should be monitored carefully. PMID:20429879

2010-01-01

341

Evaluating methods for isolating total RNA and predicting the success of sequencing phylogenetically diverse plant transcriptomes.  

PubMed

Next-generation sequencing plays a central role in the characterization and quantification of transcriptomes. Although numerous metrics are purported to quantify the quality of RNA, there have been no large-scale empirical evaluations of the major determinants of sequencing success. We used a combination of existing and newly developed methods to isolate total RNA from 1115 samples from 695 plant species in 324 families, which represents >900 million years of phylogenetic diversity from green algae through flowering plants, including many plants of economic importance. We then sequenced 629 of these samples on Illumina GAIIx and HiSeq platforms and performed a large comparative analysis to identify predictors of RNA quality and the diversity of putative genes (scaffolds) expressed within samples. Tissue types (e.g., leaf vs. flower) varied in RNA quality, sequencing depth and the number of scaffolds. Tissue age also influenced RNA quality but not the number of scaffolds ? 1000 bp. Overall, 36% of the variation in the number of scaffolds was explained by metrics of RNA integrity (RIN score), RNA purity (OD 260/230), sequencing platform (GAIIx vs HiSeq) and the amount of total RNA used for sequencing. However, our results show that the most commonly used measures of RNA quality (e.g., RIN) are weak predictors of the number of scaffolds because Illumina sequencing is robust to variation in RNA quality. These results provide novel insight into the methods that are most important in isolating high quality RNA for sequencing and assembling plant transcriptomes. The methods and recommendations provided here could increase the efficiency and decrease the cost of RNA sequencing for individual labs and genome centers. PMID:23185583

Johnson, Marc T J; Carpenter, Eric J; Tian, Zhijian; Bruskiewich, Richard; Burris, Jason N; Carrigan, Charlotte T; Chase, Mark W; Clarke, Neil D; Covshoff, Sarah; Depamphilis, Claude W; Edger, Patrick P; Goh, Falicia; Graham, Sean; Greiner, Stephan; Hibberd, Julian M; Jordon-Thaden, Ingrid; Kutchan, Toni M; Leebens-Mack, James; Melkonian, Michael; Miles, Nicholas; Myburg, Henrietta; Patterson, Jordan; Pires, J Chris; Ralph, Paula; Rolf, Megan; Sage, Rowan F; Soltis, Douglas; Soltis, Pamela; Stevenson, Dennis; Stewart, C Neal; Surek, Barbara; Thomsen, Christina J M; Villarreal, Juan Carlos; Wu, Xiaolei; Zhang, Yong; Deyholos, Michael K; Wong, Gane Ka-Shu

2012-01-01

342

ASSESSING OFF-TARGET IMPACTS OF HERBICIDE DRIFT ON NATIVE PLANTS - IMPLICATIONS FOR PLANT COMMUNITIES AND WILDLIFE  

EPA Science Inventory

The off target movement of herbicidess onto nontarget vegetation can affect native plants, plant communities and ecosystems. Within the agroecosystem, plants provide the basis for food and shelter for wildlife. The risk assessment process to determine potential pesticide impacts...

343

Diversity of endophytic bacterial populations and their interaction with Xylella fastidiosa in citrus plants.  

PubMed

Citrus variegated chlorosis (CVC) is caused by Xylella fastidiosa, a phytopathogenic bacterium that can infect all Citrus sinensis cultivars. The endophytic bacterial communities of healthy, resistant, and CVC-affected citrus plants were studied by using cultivation as well as cultivation-independent techniques. The endophytic communities were assessed in surface-disinfected citrus branches by plating and denaturing gradient gel electrophoresis (DGGE). Dominant isolates were characterized by fatty-acid methyl ester analysis as Bacillus pumilus, Curtobacterium flaccumfaciens, Enterobacter cloacae, Methylobacterium spp. (including Methylobacterium extorquens, M. fujisawaense, M. mesophilicum, M. radiotolerans, and M. zatmanii), Nocardia sp., Pantoea agglomerans, and Xanthomonas campestris. We observed a relationship between CVC symptoms and the frequency of isolation of species of Methylobacterium, the genus that we most frequently isolated from symptomatic plants. In contrast, we isolated C. flaccumfaciens significantly more frequently from asymptomatic plants than from those with symptoms of CVC while P. agglomerans was frequently isolated from tangerine (Citrus reticulata) and sweet-orange (C. sinensis) plants, irrespective of whether the plants were symptomatic or asymptomatic or showed symptoms of CVC. DGGE analysis of 16S rRNA gene fragments amplified from total plant DNA resulted in several bands that matched those from the bacterial isolates, indicating that DGGE profiles can be used to detect some endophytic bacteria of citrus plants. However, some bands had no match with any isolate, suggesting the occurrence of other, nonculturable or as yet uncultured, endophytic bacteria. A specific band with a high G+C ratio was observed only in asymptomatic plants. The higher frequency of C. flaccumfaciens in asymptomatic plants suggests a role for this organism in the resistance of plants to CVC. PMID:12324338

Araújo, Welington L; Marcon, Joelma; Maccheroni, Walter; Van Elsas, Jan Dirk; Van Vuurde, Jim W L; Azevedo, João Lúcio

2002-10-01

344

Diversity of Endophytic Bacterial Populations and Their Interaction with Xylella fastidiosa in Citrus Plants  

PubMed Central

Citrus variegated chlorosis (CVC) is caused by Xylella fastidiosa, a phytopathogenic bacterium that can infect all Citrus sinensis cultivars. The endophytic bacterial communities of healthy, resistant, and CVC-affected citrus plants were studied by using cultivation as well as cultivation-independent techniques. The endophytic communities were assessed in surface-disinfected citrus branches by plating and denaturing gradient gel electrophoresis (DGGE). Dominant isolates were characterized by fatty-acid methyl ester analysis as Bacillus pumilus, Curtobacterium flaccumfaciens, Enterobacter cloacae, Methylobacterium spp. (including Methylobacterium extorquens, M. fujisawaense, M. mesophilicum, M. radiotolerans, and M. zatmanii), Nocardia sp., Pantoea agglomerans, and Xanthomonas campestris. We observed a relationship between CVC symptoms and the frequency of isolation of species of Methylobacterium, the genus that we most frequently isolated from symptomatic plants. In contrast, we isolated C. flaccumfaciens significantly more frequently from asymptomatic plants than from those with symptoms of CVC while P. agglomerans was frequently isolated from tangerine (Citrus reticulata) and sweet-orange (C. sinensis) plants, irrespective of whether the plants were symptomatic or asymptomatic or showed symptoms of CVC. DGGE analysis of 16S rRNA gene fragments amplified from total plant DNA resulted in several bands that matched those from the bacterial isolates, indicating that DGGE profiles can be used to detect some endophytic bacteria of citrus plants. However, some bands had no match with any isolate, suggesting the occurrence of other, nonculturable or as yet uncultured, endophytic bacteria. A specific band with a high G+C ratio was observed only in asymptomatic plants. The higher frequency of C. flaccumfaciens in asymptomatic plants suggests a role for this organism in the resistance of plants to CVC. PMID:12324338

Araújo, Welington L.; Marcon, Joelma; Maccheroni, Walter; van Elsas, Jan Dirk; van Vuurde, Jim W. L.; Azevedo, João Lúcio

2002-01-01

345

Plant characterization of Roundup Ready 2 Yield(®) soybean, MON 89788, for use in ecological risk assessment.  

PubMed

During the development of a genetically modified (GM) crop product, extensive phenotypic and agronomic data are collected to characterize the plant in comparison to a conventional control with a similar genetic background. The data are evaluated for potential differences resulting from the genetic modification process or the GM trait, and the differences-if any-are subsequently considered in the context of contributing to the pest potential of the GM crop. Ultimately, these study results and those of other studies are used in an ecological risk assessment of the GM crop. In the studies reported here, seed germination, vegetative and reproductive growth, and pollen morphology of Roundup Ready 2 Yield(®) soybean, MON 89788, were compared to those of A3244, a conventional control soybean variety with the same genetic background. Any statistically significant differences were considered in the context of the genetic variation known to occur in soybean and were evaluated as indicators of an effect of the genetic modification process and assessed for impact on plant pest (weed) characteristics and adverse ecological impact (ecological risk). The results of these studies revealed no effects attributable to the genetic modification process or to the GM trait in the plant that would result in increased pest potential or adverse ecological impact of MON 89788 compared with A3244. These results and the associated risk assessments obtained from diverse geographic and environmental conditions in the United States and Argentina can be used by regulators in other countries to inform various assessments of ecological risk. PMID:25248506

Horak, Michael J; Rosenbaum, Eric W; Kendrick, Daniel L; Sammons, Bernard; Phillips, Samuel L; Nickson, Thomas E; Dobert, Raymond C; Perez, Tim

2014-09-24

346

The roles of community biomass and species pools in the regulation of plant diversity  

USGS Publications Warehouse

Considerable debate has developed over the importance of community biomass and species pools in the regulation of community diversity. Attempts to explain patterns of plant diversity as a function of community biomass or productivity have been only partially successful and in general, have explained only a fraction of the observed variation in diversity. At the same time studies that have focused on the importance of species pools have led some to conclude that diversity is primarily regulated in the short term by the size of the species pool rather than by biotic interactions. In this paper, I explore how community biomass and species pools may work in combination to regulate diversity in herbaceous plant communities. To address this problem, I employ a simple model in which the dynamics of species richness are a function of aboveground community biomass and environmentally controlled gradients in species pools. Model results lead to two main predictions about the role of biomass regulation: (1) Seasonal dynamics of richness will tend to follow a regular oscillation, with richness rising to peak values during the early to middle portion of the growing season and then declining during the latter part of the season. (2.) Seasonal dieback of aboveground tissues facilitates the long-term maintenance of high levels of richness in the community. The persistence of aboveground tissues and accumulation of litter are especially important in limiting the number of species through the suppression of recruitment. Model results also lead to two main predictions about the role of species pools: (1) The height and position of peak richness relative to community biomass will be influenced by the rate at which the species pool increases as available soil resources increase. (2) Variations in nonresource environmental factors (e.g. soil pH or soil salinity) have the potential to regulate species pools in a way that is uncorrelated with aboveground biomass. Under extreme conditions, such nonresource effects can create a unimodal envelope of biomass-richness values. Available evidence from the literature provides partial support for these predictions, though additional data are needed to provide more convincing tests.

Grace, J.B.

2001-01-01

347

Assessment of Genetic Diversity, Relationships and Structure among Korean Native Cattle Breeds Using Microsatellite Markers  

PubMed Central

Four Korean native cattle (KNC) breeds—Hanwoo, Chikso, Heugu, and Jeju black—are entered in the Domestic Animal Diversity Information System of the United Nations Food and Agriculture Organization (FAO). The objective of this study was to assess the genetic diversity, phylogenetic relationships and population structure of these KNC breeds (n = 120) and exotic breeds (Holstein and Charolais, n = 56). Thirty microsatellite loci recommended by the International Society for Animal Genetics/FAO were genotyped. These genotypes were used to determine the allele frequencies, allelic richness, heterozygosity and polymorphism information content per locus and breed. Genetic diversity was lower in Heugu and Jeju black breeds. Phylogenetic analysis, Factorial Correspondence Analysis and genetic clustering grouped each breed in its own cluster, which supported the genetic uniqueness of the KNC breeds. These results will be useful for conservation and management of KNC breeds as animal genetic resources. PMID:25358313

Suh, Sangwon; Kim, Young-Sin; Cho, Chang-Yeon; Byun, Mi-Jeong; Choi, Seong-Bok; Ko, Yeoung-Gyu; Lee, Chang Woo; Jung, Kyoung-Sub; Bae, Kyoung Hun; Kim, Jae-Hwan

2014-01-01

348

Diverse Lifestyles and Strategies of Plant Pathogenesis Encoded in the Genomes of Eighteen Dothideomycetes Fungi  

SciTech Connect

The class Dothideomycetes is one of the largest groups of fungi with a high level of ecological diversity including many plant pathogens infecting a broad range of hosts. Here, we compare genome features of 18 members of this class, including 6 necrotrophs, 9 (hemi)biotrophs and 3 saprotrophs, to analyze genome structure, evolution, and the diverse strategies of pathogenesis. The Dothideomycetes most likely evolved from a common ancestor more than 280 million years ago. The 18 genome sequences differ dramatically in size due to variation in repetitive content, but show much less variation in number of (core) genes. Gene order appears to have been rearranged mostly within chromosomal boundaries by multiple inversions, in extant genomes frequently demarcated by adjacent simple repeats. Several Dothideomycetes contain one or more gene-poor, transposable element (TE)-rich putatively dispensable chromosomes of unknown function. The 18 Dothideomycetes offer an extensive catalogue of genes involved in cellulose degradation, proteolysis, secondary metabolism, and cysteine-rich small secreted proteins. Ancestors of the two major orders of plant pathogens in the Dothideomycetes, the Capnodiales and Pleosporales, may have had different modes of pathogenesis, with the former having fewer of these genes than the latter. Many of these genes are enriched in proximity to transposable elements, suggesting faster evolution because of the effects of repeat induced point (RIP) mutations. A syntenic block of genes, including oxidoreductases, is conserved in most Dothideomycetes and upregulated during infection in L. maculans, suggesting a possible function in response to oxidative stress.

Ohm, Robin A.; Feau, Nicolas; Henrissat, Bernard; Schoch, Conrad L.; Horwitz, Benjamin A.; Barry, Kerrie W.; Condon, Bradford J.; Copeland, Alex C.; Dhillon, Braham; Glaser, Fabian; Hesse, Cedar N.; Kosti, Idit; LaButti, Kurt; Lindquist, Erika A.; Lucas, Susan; Salamov, Asaf A.; Bradshaw, Rosie E.; Ciuffetti, Lynda; Hamelin, Richard C.; Kema, Gert H. J.; Lawrence, Christopher; Scott, James A.; Spatafora, Joseph W.; Turgeon, B. Gillian; Wit, Pierre J. G. M. de; Zhong, Shaobin; Goodwin, Stephen B.; Grigoriev, Igor V.

2012-02-29

349

Diverse Lifestyles and Strategies of Plant Pathogenesis Encoded in the Genomes of Eighteen Dothideomycetes Fungi  

PubMed Central

The class Dothideomycetes is one of the largest groups of fungi with a high level of ecological diversity including many plant pathogens infecting a broad range of hosts. Here, we compare genome features of 18 members of this class, including 6 necrotrophs, 9 (hemi)biotrophs and 3 saprotrophs, to analyze genome structure, evolution, and the diverse strategies of pathogenesis. The Dothideomycetes most likely evolved from a common ancestor more than 280 million years ago. The 18 genome sequences differ dramatically in size due to variation in repetitive content, but show much less variation in number of (core) genes. Gene order appears to have been rearranged mostly within chromosomal boundaries by multiple inversions, in extant genomes frequently demarcated by adjacent simple repeats. Several Dothideomycetes contain one or more gene-poor, transposable element (TE)-rich putatively dispensable chromosomes of unknown function. The 18 Dothideomycetes offer an extensive catalogue of genes involved in cellulose degradation, proteolysis, secondary metabolism, and cysteine-rich small secreted proteins. Ancestors of the two major orders of plant pathogens in the Dothideomycetes, the Capnodiales and Pleosporales, may have had different modes of pathogenesis, with the former having fewer of these genes than the latter. Many of these genes are enriched in proximity to transposable elements, suggesting faster evolution because of the effects of repeat induced point (RIP) mutations. A syntenic block of genes, including oxidoreductases, is conserved in most Dothideomycetes and upregulated during infection in L. maculans, suggesting a possible function in response to oxidative stress. PMID:23236275

Ohm, Robin A.; Feau, Nicolas; Henrissat, Bernard; Schoch, Conrad L.; Horwitz, Benjamin A.; Barry, Kerrie W.; Condon, Bradford J.; Copeland, Alex C.; Dhillon, Braham; Glaser, Fabian; Hesse, Cedar N.; Kosti, Idit; LaButti, Kurt; Lindquist, Erika A.; Lucas, Susan; Salamov, Asaf A.; Bradshaw, Rosie E.; Ciuffetti, Lynda; Hamelin, Richard C.; Kema, Gert H. J.; Lawrence, Christopher; Scott, James A.; Spatafora, Joseph W.; Turgeon, B. Gillian; de Wit, Pierre J. G. M.; Zhong, Shaobin; Goodwin, Stephen B.; Grigoriev, Igor V.

2012-01-01

350

Diversity and Taxonomy of Endophytic Xylariaceous Fungi from Medicinal Plants of Dendrobium (Orchidaceae)  

PubMed Central

Dendrobium spp. are traditional Chinese medicinal plants, and the main effective ingredients (polysaccharides and alkaloids) have pharmacologic effects on gastritis infection, cancer, and anti-aging. Previously, we confirmed endophytic xylariaceous fungi as the dominant fungi in several Dendrobium species of tropical regions from China. In the present study, the diversity, taxonomy, and distribution of culturable endophytic xylariaceous fungi associated with seven medicinal species of Dendrobium (Orchidaceae) were investigated. Among the 961 endophytes newly isolated, 217 xylariaceous fungi (morphotaxa) were identified using morphological and molecular methods. The phylogenetic tree constructed using nuclear ribosomal internal transcribed spacer (ITS), large subunit of ribosomal DNA (LSU), and beta-tubulin sequences divided these anamorphic xylariaceous isolates into at least 18 operational taxonomic units (OTUs). The diversity of the endophytic xylariaceous fungi in these seven Dendrobium species was estimated using Shannon and evenness indices, with the results indicating that the dominant Xylariaceae taxa in each Dendrobium species were greatly different, though common xylariaceous fungi were found in several Dendrobium species. These findings implied that different host plants in the same habitats exhibit a preference and selectivity for their fungal partners. Using culture-dependent approaches, these xylariaceous isolates may be important sources for the future screening of new natural products and drug discovery. PMID:23472167

Chen, Juan; Zhang, Li-Chun; Xing, Yong-Mei; Wang, Yun-Qiang; Xing, Xiao-Ke; Zhang, Da-Wei; Liang, Han-Qiao; Guo, Shun-Xing

2013-01-01

351

Communities of different plant diversity respond similarly to drought stress: experimental evidence from field non-weeded and greenhouse conditions  

NASA Astrophysics Data System (ADS)

Accelerating rate of species loss has prompted researchers to study the role of species diversity in processes that control ecosystem functioning. Although negative impact of species loss has been documented, the evidence concerning its impact on ecosystem stability is still limited. Here, we studied the effects of declining species and functional diversity on plant community responses to drought in the field (open to weed colonization) and greenhouse conditions. Both species and functional diversity positively affected the average yields of field communities. However, this pattern was similar in both drought-stressed and control plots. No effect of diversity on community resistance, biomass recovery after drought and resilience was found because drought reduced biomass production similarly at each level of diversity by approximately 30 %. The use of dissimilarity (characterized by Euclidean distance) revealed higher variation under changing environments (drought-stressed vs. control) in more diverse communities compared to less species-rich assemblages. In the greenhouse experiment, the effect of species diversity affected community resistance, indicating that more diverse communities suffered more from drought than species-poor ones. We conclude that our study did not support the insurance hypothesis (stability properties of a community should increase with species richness) because species diversity had an equivocal effect on ecosystem resistance and resilience in an environment held under non-weeded practice, regardless of the positive relationship between sown species diversity and community biomass production. More species-rich communities were less resistant against drought-stressed conditions than species-poor ones grown in greenhouse conditions.

Lanta, Vojt?ch; Doležal, Ji?í; Zemková, Lenka; Lepš, Jan

2012-06-01

352

78 FR 66892 - BASF Plant Science LP; Availability of Plant Pest Risk Assessment and Environmental Assessment...  

Federal Register 2010, 2011, 2012, 2013

...Organisms and Products Altered or Produced Through Genetic Engineering Which Are Plant Pests or Which There Is Reason to...organisms and products altered or produced through genetic engineering that are plant pests or that there is reason...

2013-11-07

353

Pinellas Plant final action plan: environmental, safety and health assessment of Pinellas Plant, Largo, Florida  

SciTech Connect

This document contains responses and planned actions and their estimated costs for addressing the findings presented in the Tiger Team Environment, Safety, and Health Compliance Assessment of the Pinellas Plant. The assessment presented 170 findings in three general categories: environment, safety and health, and management and organization.

Not Available

1990-12-03

354

Transcript profiles of the cytokinin response regulator gene family in Populus imply diverse roles in plant development.  

PubMed

Cytokinins are plant hormones that influence diverse processes of growth and development. In this study the cytokinin response regulators (RRs) were identified, annotated and characterized at the transcript level in Populus balsamifera ssp. trichocarpa genotype Nisqually 1. The Populus genome was searched for genes that exhibit high sequence identity across their receiver domains. Gene structure was determined by prediction software and, where possible, corroborated by publicly available expressed sequence tags (ESTs). Thirty-three genes belonging to the cytokinin RR gene family were identified in Populus: 11 type As, 11 type Bs and 11 pseudo-RRs. Developmental and cytokinin-responsive expression of the Populus RRs was assessed by whole-genome microarrays and semiquantitative reverse transcription polymerase chain reaction (RT-PCR). Populus RR type As and type Bs appear to be preferentially expressed in nodes, while pseudo-RRs are preferentially expressed in mature leaves. Seven type As and three type Bs were rapidly induced by exogenous cytokinin. Organ-preferred expression patterns suggest possible roles for type As and Bs in development and for pseudo-RRs in integration of environmental signals with plant function. PMID:17944821

Ramírez-Carvajal, Gustavo A; Morse, Alison M; Davis, John M

2008-01-01

355

Diverse evolutionary mechanisms shape the type III effector virulence factor repertoire in the plant pathogen Pseudomonas syringae.  

PubMed Central

Many gram-negative pathogenic bacteria directly translocate effector proteins into eukaryotic host cells via type III delivery systems. Type III effector proteins are determinants of virulence on susceptible plant hosts; they are also the proteins that trigger specific disease resistance in resistant plant hosts. Evolution of type III effectors is dominated by competing forces: the likely requirement for conservation of virulence function, the avoidance of host defenses, and possible adaptation to new hosts. To understand the evolutionary history of type III effectors in Pseudomonas syringae, we searched for homologs to 44 known or candidate P. syringae type III effectors and two effector chaperones. We examined 24 gene families for distribution among bacterial species, amino acid sequence diversity, and features indicative of horizontal transfer. We assessed the role of diversifying and purifying selection in the evolution of these gene families. While some P. syringae type III effectors were acquired recently, others have evolved predominantly by descent. The majority of codons in most of these genes were subjected to purifying selection, suggesting selective pressure to maintain presumed virulence function. However, members of 7 families had domains subject to diversifying selection. PMID:15280247

Rohmer, Laurence; Guttman, David S; Dangl, Jeffery L

2004-01-01

356

CRITICAL EXAMINATION OF CANDIDATES' DIVERSITY COMPETENCE: RIGOROUS AND SYSTEMATIC ASSESSMENT OF CANDIDATES' EFFICACY TO TEACH DIVERSE STUDENT POPULATIONS  

Microsoft Academic Search

The National Center for Educational Statistics (NCES, 2010) continues to report substantial underachievement of diverse student populations in the nation's schools. After decades of focus on diversity and multicultural education, with integrating field and clinical practice, candidates continue to graduate without adequate knowledge, skills and dispositions to teach diverse students. The National Council of Accreditation of Teacher Education (NCATE) requires

Beatrice Hope Benton-Borghi; Young Mi Chang

2012-01-01

357

Draft environmental assessment: Ocean Thermal Energy Conversion (OTEC) Pilot Plants  

SciTech Connect

This Environmental Assessment (EA) has been prepared, in accordance with the National Environmental Policy Act of 1969, for the deployment and operation of a commercial 40-Megawatt (MW) Ocean Thermal Energy Conversion (OTEC) Pilot Plant (hereafter called the Pilot Plant). A description of the proposed action is presented, and a generic environment typical of the candidate Pilot Plant siting regions is described. An assessment of the potential environmental impacts associated with the proposed action is given, and the risk of credible accidents and mitigating measures to reduce these risks are considered. The Federal and State plans and policies the proposed action will encompass are described. Alternatives to the proposed action are presented. Appendix A presents the navigation and environmental information contained in the US Coast Pilot for each of the candidate sites; Appendix B provides a brief description of the methods and calculations used in the EA. It is concluded that environmental disturbances associated with Pilot Plant activities could potentially cause significant environmental impacts; however, the magnitude of these potential impacts cannot presently be assessed, due to insufficient engineering and environmental information. A site- and design-specific OTEC Pilot Plant Environmental Impact Statement (EIS) is required to resolve the potentially significant environmental effects associated with Pilot Plant deployment and operation. (WHK)

Sullivan, S.M.; Sands, M.D.; Donat, J.R.; Jepsen, P.; Smookler, M.; Villa, J.F.

1981-02-01

358

Plant-Wide Energy Efficiency Assessment at the Arizona Portland Cement Plant in Rillito, Arizona  

SciTech Connect

A Department of Energy Plant-wide Assessment was undertaken by Arizona Portland Cement (APC) beginning in May 2005. The assessment was performed at APC’s cement production facility in Rillito, Arizona. The assessment included a compressed air evaluation along with a detailed process audit of plant operations and equipment. The purpose of this Energy Survey was to identify a series of energy cost savings opportunities at the Plant, and provide preliminary cost and savings estimates for the work. The assessment was successful in identifying projects that could provide annual savings of over $2.7 million at an estimated capital cost of $4.3 million. If implemented, these projects could amount to a savings of over 4.9 million kWh/yr and 384,420 MMBtu/year.

Stephen J. Coppinger, P.E.; Bruce Colburn, Ph.D., P.E., CEM

2007-05-17

359

Lean manufacturing performance in China: assessment of 65 manufacturing plants  

Microsoft Academic Search

Purpose – The purpose of this paper is to investigate the adaptation of lean production and assess its current state of practice in selected plants in electronics, telecommunication, wireless, computer, food\\/beverage, garment, pharmaceutical, chemical, petroleum, printing, A\\/C and heating, and a few others in China. Design\\/methodology\\/approach – An assessment tool is used to evaluate actual manufacturing practice related to key

Shahram Taj

2008-01-01

360

The Arabidopsis synaptotagmin SYTA regulates the cell-to-cell movement of diverse plant viruses.  

PubMed

Synaptotagmins are a large gene family in animals that have been extensively characterized due to their role as calcium sensors to regulate synaptic vesicle exocytosis and endocytosis in neurons, and dense core vesicle exocytosis for hormone secretion from neuroendocrine cells. Thought to be exclusive to animals, synaptotagmins have recently been characterized in Arabidopsis thaliana, in which they comprise a five gene family. Using infectivity and leaf-based functional assays, we have shown that Arabidopsis SYTA regulates endocytosis and marks an endosomal vesicle recycling pathway to regulate movement protein-mediated trafficking of the Begomovirus Cabbage leaf curl virus (CaLCuV) and the Tobamovirus Tobacco mosaic virus (TMV) through plasmodesmata (Lewis and Lazarowitz, 2010). To determine whether SYTA has a central role in regulating the cell-to-cell trafficking of a wider range of diverse plant viruses, we extended our studies here to examine the role of SYTA in the cell-to-cell movement of additional plant viruses that employ different modes of movement, namely the Potyvirus Turnip mosaic virus (TuMV), the Caulimovirus Cauliflower mosaic virus (CaMV) and the Tobamovirus Turnip vein clearing virus (TVCV), which in contrast to TMV does efficiently infect Arabidopsis. We found that both TuMV and TVCV systemic infection, and the cell-to-cell trafficking of the their movement proteins, were delayed in the Arabidopsis Col-0 syta-1 knockdown mutant. In contrast, CaMV systemic infection was not inhibited in syta-1. Our studies show that SYTA is a key regulator of plant virus intercellular movement, being necessary for the ability of diverse cell-to-cell movement proteins encoded by Begomoviruses (CaLCuV MP), Tobamoviruses (TVCV and TMV 30K protein) and Potyviruses (TuMV P3N-PIPO) to alter PD and thereby mediate virus cell-to-cell spread. PMID:25414709

Uchiyama, Asako; Shimada-Beltran, Harumi; Levy, Amit; Zheng, Judy Y; Javia, Parth A; Lazarowitz, Sondra G

2014-01-01

361

Distributional patterns of species diversity of main plant communities along altitudinal gradient in secondary forest region, Guandi Mountain, China  

Microsoft Academic Search

Fourteen plots were chosen along with the altitude of 1600–2600 m in Guandi Mountain, Shanxi Province, China to investigate\\u000a all the trees in the plots, and the species diversity indexes were calculated for analyzing the effects of altitudinal gradient\\u000a on plant species diversity. The results showed that the order of dominant species from low altitude to high altitude is as

Jun-feng Gao; Yun-xiang Zhang

2006-01-01

362

The Importance of Tropical Rain Forest Fragments to the Conservation of Plant Species Diversity in Los Tuxtlas, Mexico  

Microsoft Academic Search

Of what value are forest fragments to the conservation of the tropical rain forest diversity for a landscape? We compared\\u000a the changes in composition, diversity, and plant structure of 15 small (1–76 ha) relatively unprotected forest fragments with\\u000a those of a large (700 ha) well protected fragment (LWPF) in Los Tuxtlas, Mexico. The trees, shrubs, lianas, palms, and herbs\\u000a with dbh???2.5 cm were

Víctor Arroyo-Rodríguez; Salvador Mandujano

2006-01-01

363

Diversity and evolution of a trait mediating ant–plant interactions: insights from extrafloral nectaries in Senna (Leguminosae)  

PubMed Central

Background and Aims Plants display a wide range of traits that allow them to use animals for vital tasks. To attract and reward aggressive ants that protect developing leaves and flowers from consumers, many plants bear extrafloral nectaries (EFNs). EFNs are exceptionally diverse in morphology and locations on a plant. In this study the evolution of EFN diversity is explored by focusing on the legume genus Senna, in which EFNs underwent remarkable morphological diversification and occur in over 80 % of the approx. 350 species. Methods EFN diversity in location, morphology and plant ontogeny was characterized in wild and cultivated plants, using scanning electron microscopy and microtome sectioning. From these data EFN evolution was reconstructed in a phylogenetic framework comprising 83 Senna species. Key Results Two distinct kinds of EFNs exist in two unrelated clades within Senna. ‘Individualized’ EFNs (iEFNs), located on the compound leaves and sometimes at the base of pedicels, display a conspicuous, gland-like nectary structure, are highly diverse in shape and characterize the species-rich EFN clade. Previously overlooked ‘non-individualized’ EFNs (non-iEFNs) embedded within stipules, bracts, and sepals are cryptic and may represent a new synapomorphy for clade II. Leaves bear EFNs consistently throughout plant ontogeny. In one species, however, early seedlings develop iEFNs between the first pair of leaflets, but later leaves produce them at the leaf base. This ontogenetic shift reflects our inferred diversification history of iEFN location: ancestral leaves bore EFNs between the first pair of leaflets, while leaves derived from them bore EFNs either between multiple pairs of leaflets or at the leaf base. Conclusions EFNs are more diverse than previously thought. EFN-bearing plant parts provide different opportunities for EFN presentation (i.e. location) and individualization (i.e. morphology), with implications for EFN morphological evolution, EFN–ant protective mutualisms and the evolutionary role of EFNs in plant diversification. PMID:23104672

Marazzi, Brigitte; Conti, Elena; Sanderson, Michael J.; McMahon, Michelle M.; Bronstein, Judith L.

2013-01-01

364

Floristic Diversity and Distribution Pattern of Plant Communities along Altitudinal Gradient in Sangla Valley, Northwest Himalaya  

PubMed Central

Himalayas are globally important biodiversity hotspots and are facing rapid loss in floristic diversity and changing pattern of vegetation due to various biotic and abiotic factors. This has necessitated the qualitative and quantitative assessment of vegetation here. The present study was conducted in Sangla Valley of northwest Himalaya aiming to assess the structure of vegetation and its trend in the valley along the altitudinal gradient. In the forest and alpine zones of the valley, 15 communities were recorded. Study revealed 320 species belonging to 199 genera and 75 families. Asteraceae, Rosaceae, Apiaceae, and Ranunculaceae were dominant. Among genera, Artemisia followed by Polygonum, Saussurea, Berberis, and Thalictrum were dominant. Tree and shrub's density ranged from 205 to 600 and from 105 to 1030 individual per hectare, respectively, whereas herbs ranged from 22.08 to 78.95 individual/m2. Nearly 182 species were native to the Himalaya. Maximum altitudinal distribution of few selected climate sensitive species was found to be highest in northeast and north aspects. This study gives an insight into the floristic diversity and community structure of the fragile Sangla Valley which was hitherto not available. PMID:25383363

Rana, J. C.; Devi, Usha; Randhawa, S. S.; Kumar, Rajesh

2014-01-01

365

Floristic diversity and distribution pattern of plant communities along altitudinal gradient in Sangla Valley, Northwest Himalaya.  

PubMed

Himalayas are globally important biodiversity hotspots and are facing rapid loss in floristic diversity and changing pattern of vegetation due to various biotic and abiotic factors. This has necessitated the qualitative and quantitative assessment of vegetation here. The present study was conducted in Sangla Valley of northwest Himalaya aiming to assess the structure of vegetation and its trend in the valley along the altitudinal gradient. In the forest and alpine zones of the valley, 15 communities were recorded. Study revealed 320 species belonging to 199 genera and 75 families. Asteraceae, Rosaceae, Apiaceae, and Ranunculaceae were dominant. Among genera, Artemisia followed by Polygonum, Saussurea, Berberis, and Thalictrum were dominant. Tree and shrub's density ranged from 205 to 600 and from 105 to 1030 individual per hectare, respectively, whereas herbs ranged from 22.08 to 78.95 individual/m(2). Nearly 182 species were native to the Himalaya. Maximum altitudinal distribution of few selected climate sensitive species was found to be highest in northeast and north aspects. This study gives an insight into the floristic diversity and community structure of the fragile Sangla Valley which was hitherto not available. PMID:25383363

Sharma, Pankaj; Rana, J C; Devi, Usha; Randhawa, S S; Kumar, Rajesh

2014-01-01

366

An Assessment of Urea-Formaldehyde Fertilizer on the Diversity of Bacterial Communities in Onion and Sugar Beet  

PubMed Central

The impact of a urea-formaldehyde (UF) fertilizer on bacterial diversity in onion bulbs and main roots of sugar beet were examined using a 16S rRNA gene clone library. The UF fertilizer markedly increased bacterial diversity in both plants. The results of principal coordinates analysis (PCoA) revealed that nearly 30% of the variance observed in bacterial diversity in both the onion and sugar beet was attributed to the fertilization conditions and also that the community structures in both plants shifted unidirectionally in response to the UF fertilizer. PMID:24882062

Ikeda, Seishi; Suzuki, Keijiro; Kawahara, Makoto; Noshiro, Masao; Takahashi, Naokazu

2014-01-01

367

Imprinting in plants as a mechanism to generate seed phenotypic diversity  

PubMed Central

Normal plant development requires epigenetic regulation to enforce changes in developmental fate. Genomic imprinting is a type of epigenetic regulation in which identical alleles of genes are expressed in a parent-of-origin dependent manner. Deep sequencing of transcriptomes has identified hundreds of imprinted genes with scarce evidence for the developmental importance of individual imprinted loci. Imprinting is regulated through global DNA demethylation in the central cell prior to fertilization and directed repression of individual loci with the Polycomb Repressive Complex 2 (PRC2). There is significant evidence for transposable elements and repeat sequences near genes acting as cis-elements to determine imprinting status of a gene, implying that imprinted gene expression patterns may evolve randomly and at high frequency. Detailed genetic analysis of a few imprinted loci suggests an imprinted pattern of gene expression is often dispensable for seed development. Few genes show conserved imprinted expression within or between plant species. These data are not fully explained by current models for the evolution of imprinting in plant seeds. We suggest that imprinting may have evolved to provide a mechanism for rapid neofunctionalization of genes during seed development to increase phenotypic diversity of seeds. PMID:25674092

Bai, Fang; Settles, A. M.

2015-01-01

368

Compositional stability and diversity of vascular plant communities following logging disturbance in Appalachian forests.  

PubMed

Human-caused changes in disturbance regimes and introductions of nonnative species have the potential to result in widespread, directional changes in forest community structure. The degree that plant community composition persists or changes following disturbances depends on the balance between local extirpation and colonization by new species, including nonnatives. In this study, we examined species losses and gains, and entry of native vs. exotic species to determine how oak forests in the Appalachian Mountains might shift in species composition following a gradient of pulse disturbances (timber harvesting). We asked (1) how compositional stability of the plant community (resistance and resilience) was influenced by disturbance intensity, (2) whether community responses were driven by extirpation or colonization of species, and (3) how disturbance intensity influenced total and functional group diversity, including the nonnative proportion of the flora through time. We collected data at three spatial scales and three times, including just before, one year post-disturbance, and 10 years post-disturbance. Resistance was estimated using community distance measures between pre- and one year post-disturbance, and resilience using community distance between pre- and 10-year post-disturbance conditions. The number of colonizing and extirpated species between sampling times was analyzed for all species combined and for six functional groups. Resistance and resilience decreased with increasing timber-harvesting disturbance; compositional stability was lower in the most disturbed plots, which was driven by colonization, but not extirpation, of species. Colonization of species also led to increases in diversity after disturbance that was typically maintained after 10 years following disturbance. Most of the community-level responses were driven by post-disturbance colonization of native forbs and graminoids. The nonnative proportion of plant species tended to increase following disturbance, especially at large spatial scales in the most disturbed treatments, but tended to decrease through time following disturbance due to canopy development. The results of this study are consistent with the theory that resources released by disturbance have strong influences on species colonization and community composition. The effects of management activities tested in this study, which span a gradient of timber-harvesting disturbance, shift species composition largely via an increase in species colonization and diversity. PMID:22611850

Belote, R Travis; Jones, Robert H; Wieboldt, Thomas F

2012-03-01

369

Assessing Plants for Phytoremediation of Arsenic-Contaminated Soils  

E-print Network

24 Assessing Plants for Phytoremediation of Arsenic-Contaminated Soils Nandita Singh and Lena Q. Ma. Phytoremediation is potentially a cost-effective and environmentally benign method of extracting pollutants from soils. Key Words: Arsenic (As); hyperaccumulation; phytoremediation; Pteris vittata. 1. Introduction

Ma, Lena

370

Turbocharged PFBC Power Plant Technical and Economic Assessments  

E-print Network

TURBOCHARGED PFBC POWER PLANT TECHNICAL AND ECONOMIC ASSESSMENTS DELBERT M. LEPPKE Senior Technical Manager Fluor Daniel Chicago, Illinois Fluidized bed combustion (FBC) boilers are receiving considerable attention by the utility... form. Although the most attention is directed toward atmospheric fluidized bed combustion (AFBC) because of its simplicity, AFBC does not offer substantial improvement in operating economy over pulverized coal systems. Steam conditions...

Leppke, D.

371

Natural phenomena risk assessment at Rocky Flats Plant  

SciTech Connect

A realistic approach is currently being used at the Rocky Flats Plant to assess the risks of natural phenomena events. The methodology addresses frequency of occurrence estimates, damage stress on the facility and vital equipment, material-at-risk, release fractions and source terms, leakpath, dispersion and dosimetric models, risk curves, and an uncertainty analysis. 28 refs.

Foppe, T.L.

1985-01-01

372

Cross-Scale Analysis of the Region Effect on Vascular Plant Species Diversity in Southern and Northern European Mountain Ranges  

PubMed Central

Background The divergent glacial histories of southern and northern Europe affect present-day species diversity at coarse-grained scales in these two regions, but do these effects also penetrate to the more fine-grained scales of local communities? Methodology/Principal Findings We carried out a cross-scale analysis to address this question for vascular plants in two mountain regions, the Alps in southern Europe and the Scandes in northern Europe, using environmentally paired vegetation plots in the two regions (n?=?403 in each region) to quantify four diversity components: (i) total number of species occurring in a region (total ?-diversity), (ii) number of species that could occur in a target plot after environmental filtering (habitat-specific ?-diversity), (iii) pair-wise species compositional turnover between plots (plot-to-plot ?-diversity) and (iv) number of species present per plot (plot ?-diversity). We found strong region effects on total ?-diversity, habitat-specific ?-diversity and plot-to-plot ?-diversity, with a greater diversity in the Alps even towards distances smaller than 50 m between plots. In contrast, there was a slightly greater plot ?-diversity in the Scandes, but with a tendency towards contrasting region effects on high and low soil-acidity plots. Conclusions/Significance We conclude that there are strong regional differences between coarse-grained (landscape- to regional-scale) diversity components of the flora in the Alps and the Scandes mountain ranges, but that these differences do not necessarily penetrate to the finest-grained (plot-scale) diversity component, at least not on acidic soils. Our findings are consistent with the contrasting regional Quaternary histories, but we also consider alternative explanatory models. Notably, ecological sorting and habitat connectivity may play a role in the unexpected limited or reversed region effect on plot ?-diversity, and may also affect the larger-scale diversity components. For instance, plot connectivity and/or selection for high dispersal ability may increase plot ?-diversity and compensate for low total ?-diversity. PMID:21203521

Lenoir, Jonathan; Gégout, Jean-Claude; Guisan, Antoine; Vittoz, Pascal; Wohlgemuth, Thomas; Zimmermann, Niklaus E.; Dullinger, Stefan; Pauli, Harald; Willner, Wolfgang; Grytnes, John-Arvid; Virtanen, Risto; Svenning, Jens-Christian

2010-01-01

373

Forest Ecology and Management 155 ?2002) 291±302 Plant species diversity on logged versus burned sites in central Alaska  

E-print Network

Natural ®res and logging are two of the main disturbances affecting upland boreal forest in Alaska. The objectives of this study were to determine whether logged sites differ from burned sites in ?1) overall plant species richness, ?2) successional trajectories, and ?3) species diversity at particular stand structural development stages. We compared plant species diversity on sites burned in natural ®res to sites that were logged and not subsequently burned in central Alaska. We sampled 12 logged and 12 burned former upland white spruce ?Picea glauca ?Moench) Voss) forests in four stand development stages representing

Daniel C. Rees; Glenn Patrick Juday

374

Tiger Team Assessment of the Pantex Plant, Amarillo, Texas  

SciTech Connect

This document contains the findings and associated root causes identified during the Tiger Team Assessment of the Department of Energy's (DOE) Pantex Plant in Amarillo, Texas. This assessment was conducted by the Department's Office of Environment, Safety and Health between October 2 and 31, 1989. The scope of the assessment of the Pantex Plant covered all areas of environment, safety and health (ES H) activities, including compliance with federal, state, and local regulations, requirements, permits, agreements, orders and consent decrees, and DOE ES H Orders. The assessment also included an evaluation of the adequacy of DOE and site contractor ES H management programs. The draft findings were submitted to the Office of Defense Programs, the Albuquerque Operations Office, the Amarillo Area Office, and regulatory agencies at the conclusion of the on-site assessment activities for review and comment on technical accuracy. Final modifications and any other appropriate changes have been incorporated in the final report. The Tiger Team Assessment of the Pantex Plant is part of the larger Tiger Team Assessment program which will encompass over 100 DOE operating facilities. The assessment program is part of a 10-point initiative announced by Secretary of Energy James D. Watkins on June 27, 1989, to strengthen environmental protection and waste management activities in the Department. The results of the program will provide the Secretary with information on the compliance status of DOE facilities with regard to ES H requirements, root causes for noncompliance, adequacy of DOE and site contractor ES H management programs, and DOE-wide ES H compliance trends.

Not Available

1990-02-01

375

Phylogenetic, microbiological, and glycoside hydrolase diversities within the extremely thermophilic, plant biomass-degrading genus Caldicellulosiruptor.  

PubMed

Phylogenetic, microbiological, and comparative genomic analyses were used to examine the diversity among members of the genus Caldicellulosiruptor, with an eye toward the capacity of these extremely thermophilic bacteria to degrade the complex carbohydrate content of plant biomass. Seven species from this genus (C. saccharolyticus, C. bescii, C. hydrothermalis, C. owensensis, C. kronotskyensis, C. lactoaceticus, and C. kristjanssonii) were compared on the basis of 16S rRNA gene phylogeny and cross-species DNA-DNA hybridization to a whole-genome C. saccharolyticus oligonucleotide microarray, revealing that C. saccharolyticus was the most divergent within this group. Growth physiology of the seven Caldicellulosiruptor species on a range of carbohydrates showed that, while all could be cultivated on acid-pretreated switchgrass, only C. saccharolyticus, C. bescii, C. kronotskyensis, and C. lactoaceticus were capable of hydrolyzing Whatman no. 1 filter paper. Two-dimensional gel electrophoresis of the secretomes from cells grown on microcrystalline cellulose revealed that the cellulolytic species also had diverse secretome fingerprints. The C. saccharolyticus secretome contained a prominent S-layer protein that appears in the cellulolytic Caldicellulosiruptor species, suggesting a possible role in cell-substrate interactions. Growth physiology also correlated with glycoside hydrolase (GH) and carbohydrate-binding module (CBM) inventories for the seven bacteria, as deduced from draft genome sequence information. These inventories indicated that the absence of a single GH and CBM family was responsible for diminished cellulolytic capacity. Overall, the genus Caldicellulosiruptor appears to contain more genomic and physiological diversity than previously reported, and this argues for continued efforts to isolate new members from high-temperature terrestrial biotopes. PMID:20971878

Blumer-Schuette, Sara E; Lewis, Derrick L; Kelly, Robert M

2010-12-01

376

Phylogenetic, Microbiological, and Glycoside Hydrolase Diversities within the Extremely Thermophilic, Plant Biomass-Degrading Genus Caldicellulosiruptor?  

PubMed Central

Phylogenetic, microbiological, and comparative genomic analyses were used to examine the diversity among members of the genus Caldicellulosiruptor, with an eye toward the capacity of these extremely thermophilic bacteria to degrade the complex carbohydrate content of plant biomass. Seven species from this genus (C. saccharolyticus, C. bescii, C. hydrothermalis, C. owensensis, C. kronotskyensis, C. lactoaceticus, and C. kristjanssonii) were compared on the basis of 16S rRNA gene phylogeny and cross-species DNA-DNA hybridization to a whole-genome C. saccharolyticus oligonucleotide microarray, revealing that C. saccharolyticus was the most divergent within this group. Growth physiology of the seven Caldicellulosiruptor species on a range of carbohydrates showed that, while all could be cultivated on acid-pretreated switchgrass, only C. saccharolyticus, C. bescii, C. kronotskyensis, and C. lactoaceticus were capable of hydrolyzing Whatman no. 1 filter paper. Two-dimensional gel electrophoresis of the secretomes from cells grown on microcrystalline cellulose revealed that the cellulolytic species also had diverse secretome fingerprints. The C. saccharolyticus secretome contained a prominent S-layer protein that appears in the cellulolytic Caldicellulosiruptor species, suggesting a possible role in cell-substrate interactions. Growth physiology also correlated with glycoside hydrolase (GH) and carbohydrate-binding module (CBM) inventories for the seven bacteria, as deduced from draft genome sequence information. These inventories indicated that the absence of a single GH and CBM family was responsible for diminished cellulolytic capacity. Overall, the genus Caldicellulosiruptor appears to contain more genomic and physiological diversity than previously reported, and this argues for continued efforts to isolate new members from high-temperature terrestrial biotopes. PMID:20971878

Blumer-Schuette, Sara E.; Lewis, Derrick L.; Kelly, Robert M.

2010-01-01

377

Diversity and physiological properties of root endophytic actinobacteria in native herbaceous plants of Korea.  

PubMed

Endophytic actinobacterial diversity in the native herbaceous plant species of Korea was analyzed using a culture-based approach. Sixty one actinobacterial strains were isolated, and assigned to 15 genera based on 16S rRNA gene analysis. The members of the genus Streptomyces comprised 45.9% of the total isolates, followed by Micromonospora (18.8%), Rhodococcus (6.6%), Microbispora (4.9%), and Micrococcus (4.9%). Other minor constituents included members of Microbacterium, Streptacidiphilus, Arthrobacter, Dietzia, Kitasatospora, Herbiconiux, Mycobacterium, Nocardia, Rathayibacter, and Tsukamurella. Among the isolates, 65.6% exhibited at least one hydrolytic enzyme activity out of four, and 45.9% exhibited antagonistic activity against at least one fungal pathogen out of five, thus demonstrating that endophytic actinobacteria can be an important source of bioactive compounds. Notably, most strains of Streptomyces proved active for both enzymatic and antagonistic activities. PMID:22367937

Kim, Tae-Ui; Cho, Sung-Heun; Han, Ji-Hye; Shin, Young Min; Lee, Hyang Burm; Kim, Seung Bum

2012-02-01

378

Membrane bioreactor wastewater treatment plants reveal diverse yeast and protist communities of potential significance in biofouling.  

PubMed

The yeast community was studied in a municipal full-scale membrane bioreactor wastewater treatment plant (MBR-WWTP). The unexpectedly high diversity of yeasts indicated that the activated sludge formed a suitable environment for them to proliferate, with cellular concentrations of 2.2 ± 0.8?×?10(3) CFU ml(-1). Sixteen species of seven genera were present in the biological reactor, with Ascomycetes being the most prevalent group (93%). Most isolates were able to grow in a synthetic wastewater medium, adhere to polyethylene surfaces, and develop biofilms of variable complexity. The relationship between yeast populations and the protists in the MBR-WWTP was also studied, revealing that some protist species preyed on and ingested yeasts. These results suggest that yeast populations may play a role in the food web of a WWTP and, to some extent, contribute to membrane biofouling in MBR systems. PMID:25588128

Liébana, Raquel; Arregui, Lucía; Belda, Ignacio; Gamella, Luis; Santos, Antonio; Marquina, Domingo; Serrano, Susana

2015-01-01

379

Hydroperiod and plant diversity in the wet meadow zone of glaciated prairie wetlands  

SciTech Connect

Stewart and Kantrud`s (1971) widely used wetland classification system does not recognize the large differences in hydroperiod and species diversity that often occur in the same vegetation zone in wetlands of different water permanence class (temporary, seasonal, semi-permanent). Research in eastern South Dakota wetlands in 1994 indicated that annual range in surface water/groundwater elevation within a zone varied inversely with permanence. For example, within the wet meadow zone, average annual water elevation range was 124 cm in temporary wetlands, 65 cm in seasonal wetlands, and 15 cm in semi-permanent wetlands. The number of dominant plants in this zone was strongly and positively correlated to the amount of annual fluctuation in water elevation, from an average of 5 species in the relatively stable, semi-permanent wetlands to 14 species in the ephemeral, temporary wetlands. These results have application to research in wetland restoration and climate change.

Boettcher, S.E.; Johnson, W.C. [South Dakota State Univ., Brookings, SD (United States)

1995-06-01

380

Novel Symbiotic Protoplasts Formed by Endophytic Fungi Explain Their Hidden Existence, Lifestyle Switching, and Diversity within the Plant Kingdom  

PubMed Central

Diverse fungi live all or part of their life cycle inside plants as asymptomatic endophytes. While endophytic fungi are increasingly recognized as significant components of plant fitness, it is unclear how they interact with plant cells; why they occur throughout the fungal kingdom; and why they are associated with most fungal lifestyles. Here we evaluate the diversity of endophytic fungi that are able to form novel protoplasts called mycosomes. We found that mycosomes cultured from plants and phylogenetically diverse endophytic fungi have common morphological characteristics, express similar developmental patterns, and can revert back to the free-living walled state. Observed with electron microscopy, mycosome ontogeny within Aureobasidium pullulans may involve two organelles: double membrane-bounded promycosome organelles (PMOs) that form mycosomes, and multivesicular bodies that may form plastid-infecting vesicles. Cultured mycosomes also contain a double membrane-bounded organelle, which may be homologous to the A. pullulans PMO. The mycosome PMO is often expressed as a vacuole-like organelle, which alternatively may contain a lipoid body or a starch grain. Mycosome reversion to walled cells occurs within the PMO, and by budding from lipid or starch-containing mycosomes. Mycosomes discovered in chicken egg yolk provided a plant-independent source for analysis: they formed typical protoplast stages, contained fungal ITS sequences and reverted to walled cells, suggesting mycosome symbiosis with animals as well as plants. Our results suggest that diverse endophytic fungi express a novel protoplast phase that can explain their hidden existence, lifestyle switching, and diversity within the plant kingdom. Importantly, our findings outline “what, where, when and how”, opening the way for cell and organelle-specific tests using in situ DNA hybridization and fluorescent labels. We discuss developmental, ecological and evolutionary contexts that provide a robust framework for continued tests of the mycosome phase hypothesis. PMID:24777121

Atsatt, Peter R.; Whiteside, Matthew D.

2014-01-01

381

Genetic diversity of high-elevation populations of an endangered medicinal plant.  

PubMed

Intraspecific genetic variation in natural populations governs their potential to overcome challenging ecological and environmental conditions. In addition, knowledge of this variation is critical for the conservation and management of endangered plant taxa. Found in the Himalayas, Podophyllum hexandrum is an endangered high-elevation plant species that has great medicinal importance. Here we report on the genetic diversity analysis of 24 P. hexandrum populations (209 individuals), representing the whole of the Indian Himalayas. In the present study, seven amplified fragment length polymorphism (AFLP) primer pairs generated 1677 fragments, of which 866 were found to be polymorphic. Neighbour joining clustering, principal coordinate analysis and STRUCTURE analysis clustered 209 individuals from 24 populations of the Indian Himalayan mountains into two major groups with a significant amount of gene flow (Nm = 2.13) and moderate genetic differentiation Fst(0.196), G'st(0.20). This suggests that, regardless of geographical location, all of the populations from the Indian Himalayas are intermixed and are composed broadly of two types of genetic populations. High variance partitioned within populations (80 %) suggests that most of the diversity is restricted to the within-population level. These results suggest two possibilities about the ancient population structure of P. hexandrum: either all of the populations in the geographical region of the Indian Himalayas are remnants of a once-widespread ancient population, or they originated from two types of genetic populations, which coexisted a long time ago, but subsequently separated as a result of long-distance dispersal and natural selection. High variance partitioned within the populations indicates that these populations have evolved in response to their respective environments over time, but low levels of heterozygosity suggest the presence of historical population bottlenecks. PMID:25416728

Nag, Akshay; Ahuja, Paramvir Singh; Sharma, Ram Kumar

2014-01-01

382

Prescription Opioid Abuse and Diversion in an Urban Community: The Results of an Ultra- Rapid Assessment  

PubMed Central

Objective Prescription drug diversion is a topic about which comparatively little is known, and systematic information garnered from prescription drug abusers and dealers on the specific mechanisms of diversion is extremely limited. Design A pilot ultra-rapid assessment was carried out in Wilmington, Delaware, during December 2006 to better understand the scope and dynamics of prescription drug abuse and diversion. This involved focus groups with prescription drug abusers, and key informant interviews with police, regulatory officials, prescription drug dealers, and pill brokers. Results The primary sources of prescription drugs on the street were the elderly, pain patients, and doctor shoppers, as well as pill brokers and dealers who work with all of the former. The popularity of prescription drugs in the street market was rooted in the abusers’ perceptions of these drugs as: 1) less stigmatizing; 2) less dangerous; and, 3) less subject to legal consequences than illicit drugs. For many, the abuse of prescription opioids also appeared to serve as a gateway to heroin use. Conclusion The diversion of prescription opioids might be reduced through physician education focusing on: 1) recognizing that a patient is misusing and/or diverting prescribed medications; 2) considering a patient’s risk for opioid misuse before initiating opioid therapy; and, 3) understanding the variation in the abuse potential of different opioid medications currently on the market. Patient education also appears appropriate in the areas of safeguarding medications, disposal of unused medications, and understanding the consequences of manipulating physicians and selling their medications. PMID:19416440

Inciardi, James A.; Surratt, Hilary L.; Cicero, Theodore J.; Beard, Ronald A.

2009-01-01

383

Direct Anthelmintic Effects of Condensed Tannins from Diverse Plant Sources against Ascaris suum  

PubMed Central

Ascaris suum is one of the most prevalent nematode parasites in pigs and causes significant economic losses, and also serves as a good model for A. lumbricoides, the large roundworm of humans that is ubiquitous in developing countries and causes malnutrition, stunted growth and compromises immunity to other pathogens. New treatment options for Ascaris infections are urgently needed, to reduce reliance on the limited number of synthetic anthelmintic drugs. In areas where Ascaris infections are common, ethno-pharmacological practices such as treatment with natural plant extracts are still widely employed. However, scientific validation of these practices and identification of the active compounds are lacking, although observed effects are often ascribed to plant secondary metabolites such as tannins. Here, we extracted, purified and characterised a wide range of condensed tannins from diverse plant sources and investigated anthelmintic effects against A. suum in vitro. We show that condensed tannins can have potent, direct anthelmintic effects against A. suum, as evidenced by reduced migratory ability of newly hatched third-stage larvae and reduced motility and survival of fourth-stage larvae recovered from pigs. Transmission electron microscopy showed that CT caused significant damage to the cuticle and digestive tissues of the larvae. Furthermore, we provide evidence that the strength of the anthelmintic effect is related to the polymer size of the tannin molecule. Moreover, the identity of the monomeric structural units of tannin polymers may also have an influence as gallocatechin and epigallocatechin monomers exerted significant anthelmintic activity whereas catechin and epicatechin monomers did not. Therefore, our results clearly document direct anthelmintic effects of condensed tannins against Ascaris and encourage further in vivo investigation to determine optimal strategies for the use of these plant compounds for the prevention and/or treatment of ascariosis. PMID:24810761

Williams, Andrew R.; Fryganas, Christos; Ramsay, Aina; Mueller-Harvey, Irene; Thamsborg, Stig M.

2014-01-01

384

Diversity of bacteria nesting the plant cover of north Sinai deserts, Egypt  

PubMed Central

North Sinai deserts were surveyed for the predominant plant cover and for the culturable bacteria nesting their roots and shoots. Among 43 plant species reported, 13 are perennial (e.g. Fagonia spp., Pancratium spp.) and 30 annuals (e.g. Bromus spp., Erodium spp.). Eleven species possessed rhizo-sheath, e.g. Cyperus capitatus, Panicum turgidum and Trisetaria koelerioides. Microbiological analyses demonstrated: the great diversity and richness of associated culturable bacteria, in particular nitrogen-fixing bacteria (diazotrophs); the majority of bacterial residents were of true and/or putative diazotrophic nature; the bacterial populations followed an increasing density gradient towards the root surfaces; sizeable populations were able to reside inside the root (endorhizosphere) and shoot (endophyllosphere) tissues. Three hundred bacterial isolates were secured from studied spheres. The majority of nitrogen-fixing bacilli isolates belonged to Bacillus megaterium,Bacillus pumilus, Bacillus polymexa,Bacillus macerans,Bacillus circulans and Bacillus licheniformis. The family Enterobacteriaceae represented by Enterobacter agglomerans,Enterobacter sackazakii, Enterobacter cloacae, Serratia adorifera,Serratia liquefaciens and Klebsiella oxytoca. The non-Enterobacteriaceae population was rich in Pantoae spp., Agrobacterium rdiobacter, Pseudomonas vesicularis, Pseudomonas putida, Stenotrophomonas maltophilia, Ochrobactrum anthropi, Sphingomonas paucimobilis and Chrysemonas luteola.Gluconacetobacter diazotrophicus were reported inside root and shoot tissues of a number of tested plants. The dense bacterial populations reported speak well to the very possible significant role played by the endophytic bacterial populations in the survival, in respect of nutrition and health, of existing plants. Such groups of diazotrophs are good candidates, as bio-preparates, to support the growth of future field crops grown in deserts of north Sinai and irrigated by the water of El-Salam canal.

Hanna, Amira L.; Youssef, Hanan H.; Amer, Wafaa M.; Monib, Mohammed; Fayez, Mohammed; Hegazi, Nabil A.

2012-01-01

385

Abscisic acid has a key role in modulating diverse plant-pathogen interactions.  

PubMed

We isolated an activation-tagged Arabidopsis (Arabidopsis thaliana) line, constitutive disease susceptibility2-1D (cds2-1D), that showed enhanced bacterial growth when challenged with various Pseudomonas syringae strains. Systemic acquired resistance and systemic PATHOGENESIS-RELATED GENE1 induction were also compromised in cds2-1D. The T-DNA insertion adjacent to NINE-CIS-EPOXYCAROTENOID DIOXYGENASE5 (NCED5), one of six genes encoding the abscisic acid (ABA) biosynthetic enzyme NCED, caused a massive increase in transcript level and enhanced ABA levels >2-fold. Overexpression of NCED genes recreated the enhanced disease susceptibility phenotype. NCED2, NCED3, and NCED5 were induced, and ABA accumulated strongly following compatible P. syringae infection. The ABA biosynthetic mutant aba3-1 showed reduced susceptibility to virulent P. syringae, and ABA, whether through exogenous application or endogenous accumulation in response to mild water stress, resulted in increased bacterial growth following challenge with virulent P. syringae, indicating that ABA suppresses resistance to P. syringae. Likewise ABA accumulation also compromised resistance to the biotrophic oomycete Hyaloperonospora arabidopsis, whereas resistance to the fungus Alternaria brassicicola was enhanced in cds2-1D plants and compromised in aba3-1 plants, indicating that ABA promotes resistance to this necrotroph. Comparison of the accumulation of salicylic acid and jasmonic acid in the wild type, cds2-1D, and aba3-1 plants challenged with P. syringae showed that ABA promotes jasmonic acid accumulation and exhibits a complex antagonistic relationship with salicylic acid. Our findings provide genetic evidence that the abiotic stress signal ABA also has profound roles in modulating diverse plant-pathogen interactions mediated at least in part by cross talk with the jasmonic acid and salicylic acid biotic stress signal pathways. PMID:19571312

Fan, Jun; Hill, Lionel; Crooks, Casey; Doerner, Peter; Lamb, Chris

2009-08-01

386

Biophysical methods for assessing plant responses to nanoparticle exposure.  

PubMed

As nanotechnology rapidly emerges into a new industry-driven by its enormous potential to revolutionize electronics, materials, and medicine-exposure of living species to discharged nanoparticles has become inevitable. Despite the increased effort on elucidating the environmental impact of nanotechnology, literature on higher plants exposure to nanoparticles remains scarce and often contradictory. Here we present our biophysical methodologies for the study of carbon nanoparticle uptake by Allium cepa cells and rice plants. We address the three essential aspects for such studies: identification of carbon nanoparticles in the plant species, quantification of nanotransport and aggregation in the plant compartments, and evaluation of plant responses to nanoparticle exposure on the cellular and organism level. Considering the close connection between plant and mammalian species in ecological systems especially in the food chain, we draw a direct comparison on the uptake of carbon nanoparticles in plant and mammalian cells. In addition to the above studies, we present methods for assessing the effects of quantum dot adsorption on algal photosynthesis. PMID:22975977

Ratnikova, Tatsiana A; Chen, Ran; Bhattacharya, Priyanka; Ke, Pu Chun

2012-01-01

387

Quantifying the importance of plant functional diversity for ecosystem functioning and resilience under scenarios of climate change (Invited)  

NASA Astrophysics Data System (ADS)

Dynamic Global Vegetation Models (DGVMs) typically employ only a small set of Plant Functional Types (PFTs) to represent the vast diversity of observed vegetation forms and functioning. There is growing evidence, however, that this abstraction may not adequately represent the observed variation in plant functional traits, which is thought to play an important role for many ecosystem functions and for ecosystem resilience to environmental change. The geographic distribution of PFTs in these models is also often based on empirical relationships between present-day climate and vegetation patterns. Projections of future climate change, however, point toward the possibility of novel regional climates, which could lead to no-analog vegetation compositions incompatible with the PFT paradigm. Here, we present results from the Jena Diversity-DGVM (JeDi-DGVM), a novel traits-based vegetation model, which simulates a large number of hypothetical plant growth strategies constrained by functional tradeoffs, thereby allowing for a more flexible temporal and spatial representation of the terrestrial biosphere. We run two sets of model experiments forced with the latest bias-corrected climate change scenarios from several different global climate models. In the first set, we simulate a diverse biosphere using a large number of plant growth strategies, allowing the modelled ecosystems to adapt through emergent changes in ecosystem composition. We then aggregate the surviving growth strategies from the first set of diverse simulations to a small number of biome-averaged growth strategies, recreating something akin to PFTs. We use this smaller set of PFT-like growth strategies to represent a sparse or low-diversity biosphere in the second set of model experiments. We quantify the importance of functional diversity by comparing key metrics of ecosystem functioning across the two sets of simulations. The results reveal the implications of using the common PFT vegetation modelling paradigm versus a more diverse approach and may help to quantify the value of biodiversity conservation efforts.

Pavlick, R.; Drewry, D.; Kleidon, A.

2013-12-01

388

New chloroplast microsatellite markers suitable for assessing genetic diversity of Lolium perenne and other related grass species  

PubMed Central

Background and Aims Lolium perenne (perennial ryegrass) is the most important forage grass species of temperate regions. We have previously released the chloroplast genome sequence of L. perenne ‘Cashel’. Here nine chloroplast microsatellite markers are published, which were designed based on knowledge about genetically variable regions within the L. perenne chloroplast genome. These markers were successfully used for characterizing the genetic diversity in Lolium and different grass species. Methods Chloroplast genomes of 14 Poaceae taxa were screened for mononucleotide microsatellite repeat regions and primers designed for their amplification from nine loci. The potential of these markers to assess genetic diversity was evaluated on a set of 16 Irish and 15 European L. perenne ecotypes, nine L. perenne cultivars, other Lolium taxa and other grass species. Key Results All analysed Poaceae chloroplast genomes contained more than 200 mononucleotide repeats (chloroplast simple sequence repeats, cpSSRs) of at least 7 bp in length, concentrated mainly in the large single copy region of the genome. Nucleotide composition varied considerably among subfamilies (with Pooideae biased towards poly A repeats). The nine new markers distinguish L. perenne from all non-Lolium taxa. TeaCpSSR28 was able to distinguish between all Lolium species and Lolium multiflorum due to an elongation of an A8 mononucleotide repeat in L. multiflorum. TeaCpSSR31 detected a considerable degree of microsatellite length variation and single nucleotide polymorphism. TeaCpSSR27 revealed variation within some L. perenne accessions due to a 44-bp indel and was hence readily detected by simple agarose gel electrophoresis. Smaller insertion/deletion events or single nucleotide polymorphisms detected by these new markers could be visualized by polyacrylamide gel electrophoresis or DNA sequencing, respectively. Conclusions The new markers are a valuable tool for plant breeding companies, seed testing agencies and the wider scientific community due to their ability to monitor genetic diversity within breeding pools, to trace maternal inheritance and to distinguish closely related species. PMID:22419761

Diekmann, Kerstin; Hodkinson, Trevor R.; Barth, Susanne

2012-01-01

389

Proteome Profiling for Assessing Diversity: Analysis of Individual Heads of Drosophila melanogaster Using LC-Ion Mobility-MS  

E-print Network

Proteome Profiling for Assessing Diversity: Analysis of Individual Heads of Drosophila melanogaster splicing,6-8 DNA recombination,9,10 transcription start sites,11,12 RNA editing,13,14 polyadenylation,15

Clemmer, David E.

390

Affinity Purification of the Arabidopsis 26 S Proteasome Reveals a Diverse Array of Plant Proteolytic Complexes*  

PubMed Central

Selective proteolysis in plants is largely mediated by the ubiquitin (Ub)/proteasome system in which substrates, marked by the covalent attachment of Ub, are degraded by the 26 S proteasome. The 26 S proteasome is composed of two subparticles, the 20 S core protease (CP) that compartmentalizes the protease active sites and the 19 S regulatory particle that recognizes and translocates appropriate substrates into the CP lumen for breakdown. Here, we describe an affinity method to rapidly purify epitope-tagged 26 S proteasomes intact from Arabidopsis thaliana. In-depth mass spectrometric analyses of preparations generated from young seedlings confirmed that the 2.5-MDa CP-regulatory particle complex is actually a heterogeneous set of particles assembled with paralogous pairs for most subunits. A number of these subunits are modified post-translationally by proteolytic processing, acetylation, and/or ubiquitylation. Several proteasome-associated proteins were also identified that likely assist in complex assembly and regulation. In addition, we detected a particle consisting of the CP capped by the single subunit PA200 activator that may be involved in Ub-independent protein breakdown. Taken together, it appears that a diverse and highly dynamic population of proteasomes is assembled in plants, which may expand the target specificity and functions of intracellular proteolysis. PMID:20516081

Book, Adam J.; Gladman, Nicholas P.; Lee, Sang-Sook; Scalf, Mark; Smith, Lloyd M.; Vierstra, Richard D.

2010-01-01

391

Medicinal parasitic plants on diverse hosts with their usages and barcodes.  

PubMed

Medicinal properties of parasitic plants were investigated by means of ethnobotanical study in some areas of northeastern Thailand. Important traditional usages are: Scurrula atropurpurea nourishes blood, Dendrophthoe pentandra decreases high blood pressure, and Helixanthera parasitica treats liver disease. Their systematics were also determined. The research is based on findings obtained from 100 parasite-host pairs. Of these, eight parasitic species were recorded; they are members of two families, viz. family Loranthaceae, namely D. lanosa, D. pentandra, H. parasitica, Macrosolen brandisianus, M. cochinchinensis and S. atropurpurea, and family Viscaceae, namely Viscum articulatum and V. ovalifolium. In addition, each parasitic species is found on diverse hosts, indicating non-host-parasitic specificity. Species-specific tagging of all species studied was carried out using the rbcL and psbA-trnH chloroplast regions. These tag sequences are submitted to GenBank databases under accession numbers JN687563-JN687578. Genetic distances calculated from nucleotide variations in a couple of species of each genus, Dendrophthoe, Macrosolen, and Viscum, were 0.032, 0.067 and 0.036 in the rbcL region, and 0.269, 0.073 and 0.264 in the psbA-trnH spacer region, respectively. These variations will be used for further identification of incomplete plant parts or other forms such as capsule, powder, dried or chopped pieces. PMID:22864809

Kwanda, Nantiya; Noikotr, Kowit; Sudmoon, Runglawan; Tanee, Tawatchai; Chaveerach, Arunrat

2013-07-01

392

A Continent of Plant Defense Peptide Diversity: Cyclotides in Australian Hybanthus (Violaceae)W?  

PubMed Central

Cyclotides are plant-derived miniproteins that have the unusual features of a head-to-tail cyclized peptide backbone and a knotted arrangement of disulfide bonds. It had been postulated that they might be an especially large family of host defense agents, but this had not yet been tested by field data on cyclotide variation in wild plant populations. In this study, we sampled Australian Hybanthus (Violaceae) to gain an insight into the level of variation within populations, within species, and between species. A wealth of cyclotide diversity was discovered: at least 246 new cyclotides are present in the 11 species sampled, and 26 novel sequences were characterized. A new approach to the discovery of cyclotide sequences was developed based on the identification of a conserved sequence within a signal sequence in cyclotide precursors. The number of cyclotides in the Violaceae is now estimated to be >9000. Cyclotide physicochemical profiles were shown to be a useful taxonomic feature that reflected species and their morphological relationships. The novel sequences provided substantial insight into the tolerance of the cystine knot framework in cyclotides to amino acid substitutions and will facilitate protein engineering applications of this framework. PMID:16199617

Simonsen, Shane M.; Sando, Lillian; Ireland, David C.; Colgrave, Michelle L.; Bharathi, Rekha; Göransson, Ulf; Craik, David J.

2005-01-01

393

Tiger Team Assessment of the Paducah Gaseous Diffusion Plant  

SciTech Connect

This document contains findings and concerns identified during the Tiger Team Assessment of the Department of Energy's (DOE) Paducah Gaseous Diffusion Plant (PGDP) in Paducah, Kentucky. The assessment was directed by the Department's Office of Environment, Safety and Health (ES H) and was conducted from June 18 to July 20, 1990. The PGDP Tiger Team Assessment is comprehensive in scope. It covers the Environmental, Safety and Health (including OSHA Compliance), and Management areas and determines the site's compliance with applicable federal (including DOE), state, and local regulations and requirements. The objective of the assessment program is to provide the Secretary with information on the current ES H compliance status of DOE facilities, root causation for noncompliance, adequacy of DOE and site contractor ES H management programs, response actions to address the identified problem areas, and DOE-wide ES H compliance trends and root causes.

Not Available

1990-07-01

394

Tiger Team Assessment of the Paducah Gaseous Diffusion Plant  

SciTech Connect

This document contains findings and concerns identified during the Tiger Team Assessment of the Department of Energy's (DOE's) Paducah Gaseous Diffusion Plant (PGDP) in Paducah, Kentucky. The assessment was directed by the Department's Office of Environment, Safety and Health (ES H) and was conducted from June 18 to July 20, 1990. The PGDP Tiger Team Assessment is comprehensive in scope. It covers the Environmental, Safety and Health (including OSHA Compliance), and Management areas and determines the site's compliance with applicable federal (including DOE), state, and local regulations and requirements. The objective of the assessment program is to provide the Secretary with information on the current ES H compliance status of DOE facilities, root causation for noncompliance, adequacy of DOE and site contractor ES H management programs, response actions to address the identified problem areas, and DOE-wide ES H compliance trends and root causes. This volume contains appendices.

Not Available

1990-07-01

395

Phenotypic and RAPD diversity among 80 germplasm accessions of the medicinal plant isabgol (Plantago ovata, Plantaginaceae).  

PubMed

Plantago ovata, popularly known as isabgol, has great commercial and medicinal importance due to thin rosy white membranous seed husk. Isabgol seeds and husks have emollient, demulcent and laxative properties. We used both biometric and molecular techniques to assess the genetic variability and relatedness of 80 germplasm accessions of Plantago spp (P. ovata, P. lanceolata, and P. major) collected both from India and abroad. The range of D2 values (2.01-4890.73) indicated a very high degree of divergence among the accessions. Based on the degree of divergence, 80 accessions/genotypes were grouped into seven clusters. Thirty-six accessions were analyzed through RAPD profiling for similarity and genetic distances, using 20 random primers. Intraspecific differences in all three species were smaller [range for P. ovata (2-17%), P. lanceolata (3-15%), P. major (2-11%)] than interspecific diversity. These highly divergent lines could be used to produce superior hybrids. PMID:19876869

Singh, N; Lal, R K; Shasany, A K

2009-01-01

396

Utilizing common-garden and genetic diversity structure analysis to determine strategies for releasing wildland plant germplasm for rangeland revegetation  

Technology Transfer Automated Retrieval System (TEKTRAN)

Semi-arid rangelands in the western North America face many challenges due to invasive weedy species, wildfires, and past mismanagement. A diversity of plant species are needed to effectively revegetate degraded rangelands in this expansive area. Legumes native to western North America are of inte...

397

Plant species diversity and soil quality in harvested and grazed boreal aspen stands of northeastern British Columbia  

Microsoft Academic Search

Understory vegetation in aspen (Populus tremuloides Michx.) stands produces up to 50% of all forage on Crown land for domestic livestock grazing in the Peace River area of British Columbia (BC), Canada. The objective of this study was to determine the effects of clearcut harvesting and long-term cattle grazing on plant species diversity and soil quality in aspen cutblocks located

M Krzic; R. F Newman; K Broersma

2003-01-01

398

Transcript Profiles of the Cytokinin Response Regulator Gene Family in Populus Imply Diverse Roles in Plant Development  

Microsoft Academic Search

• Cytokinins are plant hormones that influence diverse processes of growth and development. In this study the cytokinin response regulators (RRs) were identified, annotated and characterized at the transcript level in Populus balsamifera ssp. trichocarpa genotype Nisqually 1. • The Populus genome was searched for genes that exhibit high sequence identity across their receiver domains. Gene structure was determined by

Gustavo A. Ramírez-Carvajal; Alison M. Morse; John M. Davis

2008-01-01

399

Field Study of Plant Diversity: Extending the Whole-Class Knowledge Base through Open-Ended Learning  

ERIC Educational Resources Information Center

Students following a pre-Certificate year in biology (the preliminary year of a 4-year BSc programme) learnt about plant diversity through integrated field and classroom studies carried out in an afforested area of north-east England. The students identified, listed and made interpretive drawings of their own choice of the specimens they had…

Goulder, Raymond; Scott, Graham W.

2009-01-01

400

Plant diversity effects on soil food webs are stronger than those of elevated CO2 and N deposition  

E-print Network

in a long-term grassland experiment Nico Eisenhauera,b,1 , Tomasz Dobiesc , Simone Cesarza , Sarah E richness, atmospheric CO2, and N deposition--in a grassland experiment in Minnesota. Plant diversity this gap in understanding by examining the understudied responses of soil food webs and functions to a long

Minnesota, University of

401

Preliminary assessment of arbuscular mycorrhizal fungal diversity and community structure in an urban ecosystem.  

PubMed

Arbuscular mycorrhizal fungal (AMF) species richness, composition, spore density and diversity indices were evaluated in the Phoenix metropolitan area, Arizona, USA at 20 sampling sites selected to represent the four predominant land-use types found in the greater urban area: urban-residential, urban non-residential, agriculture and desert. AMF spores were extracted and identified from soil samples and from trap cultures established using soil collected at each site. Data were analyzed according to land use, land-use history, soil chemistry and vegetation characteristics at each site. Current agricultural sites were associated with decreased spore densities and historically agricultural sites with decreased species richness. Overall species composition was similar to that previously reported for the Sonoran desert, but composition at each sampling site was influenced by the vegetation from which samples were collected. Sites with the highest degrees of similarity in AMF species composition were also similar to each other in native plants or land use. Conversely, sites with the lowest similarity in AMF composition were those from which the majority of samples were collected from non-mycorrhizal plants, predominately ectomycorrhizal plants or bare soil. Spores of Glomus microggregatum were most abundant in urban sites, while those of G. eburneum were most abundant in desert and agricultural sites. Further studies are needed to determine the functional implications of shifts in AMF communities in urban ecosystems, including effects on plant primary productivity. PMID:12748839

Cousins, Jamaica R; Hope, Diane; Gries, Corinna; Stutz, Jean C

2003-12-01

402

Diversity and population structure of sewage derived microorganisms in wastewater treatment plant influent  

PubMed Central

The release of untreated sewage introduces non-indigenous microbial populations of uncertain composition into surface waters. We used massively parallel 454 sequencing of hypervariable regions in rRNA genes to profile microbial communities from eight untreated sewage influent samples of two wastewater treatment plants (WWTP) in metropolitan Milwaukee. The sewage profiles included a discernable human fecal signature made up of several taxonomic groups including multiple Bifidobacteriaceae, Coriobacteriaceae, Bacteroidaceae, Lachnospiraceae, and Ruminococcaceae genera. The fecal signature made up a small fraction of the taxa present in sewage but the relative abundance of these sequence tags mirrored the population structures of human fecal samples. These genera were much more prevalent in the sewage influent than standard indicators species. High-abundance sequences from taxonomic groups within the Beta- and Gammaproteobacteria dominated the sewage samples but occurred at very low levels in fecal and surface water samples, suggesting that these organisms proliferate within the sewer system. Samples from Jones Island (JI – servicing residential plus a combined sewer system) and South Shore (SS – servicing a residential area) WWTPs had very consistent community profiles, with greater similarity between WWTPs on a given collection day than the same plant collected on different days. Rainfall increased influent flows at SS and JI WWTPs, and this corresponded to greater diversity in the community at both plants. Overall, the sewer system appears to be a defined environment with both infiltration of rainwater and stormwater inputs modulating community composition. Microbial sewage communities represent a combination of inputs from human fecal microbes and enrichment of specific microbes from the environment to form a unique population structure. PMID:19840106

McLellan, S.L.; Huse, S.M.; Mueller-Spitz, S.R.; Andreishcheva, E.N.; Sogin, M.L.

2009-01-01

403

Metabarcoding vs. morphological identification to assess diatom diversity in environmental studies.  

PubMed

Diatoms are frequently used for water quality assessments; however, identification to species level is difficult, time-consuming and needs in-depth knowledge of the organisms under investigation, as nonhomoplastic species-specific morphological characters are scarce. We here investigate how identification methods based on DNA (metabarcoding using NGS platforms) perform in comparison to morphological diatom identification and propose a workflow to optimize diatom fresh water quality assessments. Diatom diversity at seven different sites along the course of the river system Odra and Lusatian Neisse from the source to the mouth is analysed with DNA and morphological methods, which are compared. The NGS technology almost always leads to a higher number of identified taxa (270 via NGS vs. 103 by light microscopy LM), whose presence could subsequently be verified by LM. The sequence-based approach allows for a much more graduated insight into the taxonomic diversity of the environmental samples. Taxa retrieval varies considerably throughout the river system, depending on species occurrences and the taxonomic depth of the reference databases. Mostly rare taxa from oligotrophic parts of the river systems are less well represented in the reference database used. A workflow for DNA-based NGS diatom identification is presented. 28 000 diatom sequences were evaluated. Our findings provide evidence that metabarcoding of diatoms via NGS sequencing of the V4 region (18S) has a great potential for water quality assessments and could complement and maybe even improve the identification via light microscopy. PMID:25270047

Zimmermann, Jonas; Glöckner, Gernot; Jahn, Regine; Enke, Neela; Gemeinholzer, Birgit

2014-09-30

404

Assessing the diversity of arbuscular mycorrhizal fungi in semiarid shrublands dominated by Artemisia tridentata ssp. wyomingensis.  

PubMed

Variation in the abiotic environment and host plant preferences can affect the composition of arbuscular mycorrhizal (AMF) assemblages. This study analyzed the AMF taxa present in soil and seedlings of Artemisia tridentata ssp. wyomingensis collected from sagebrush steppe communities in southwestern Idaho, USA. Our aims were to determine the AMF diversity within and among these communities and the extent to which preferential AMF-plant associations develop during seedling establishment. Mycorrhizae were identified using molecular methods following DNA extraction from field and pot culture samples. The extracted DNA was amplified using Glomeromycota specific primers, and identification of AMF was based on phylogenetic analysis of sequences from the large subunit-D2 rDNA region. The phylogenetic analyses revealed seven phylotypes, two within the Claroideoglomeraceae and five within the Glomeraceae. Four phylotypes clustered with known species including Claroideoglomus claroideum, Rhizophagus irregularis, Glomus microaggregatum, and Funneliformis mosseae. The other three phylotypes were similar to several published sequences not included in the phylogenetic analysis, but all of these were from uncultured and unnamed glomeromycetes. Pairwise distance analysis revealed some phylotypes with high genetic variation. The most diverse was the phylotype that included R. irregularis, which contained sequences showing pairwise differences up to 12 %. Most of the diversity in AMF sequences occurred within sites. The smaller genetic differentiation detected among sites was correlated with differences in soil texture. In addition, multiplication in pot cultures led to differentiation of AMF communities. Comparison of sequences obtained from the soil with those from A. tridentata roots revealed no significant differences between the AMF present in these samples. Overall, the sites sampled were dominated by cosmopolitan AMF taxa, and young seedlings of A. tridentata ssp. wyomingensis were colonized in relation to the abundance of these taxa in the soil. PMID:24249492

Carter, Keith A; Smith, James F; White, Merlin M; Serpe, Marcelo D

2014-05-01