Arabidopsis thaliana - Myzus persicae interaction: shaping the understanding of plant defense against phloem-feeding aphids

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Joe eLouis

2013-07-01

Full Text Available The phloem provides a unique niche for several organisms. Aphids are a large group of Hemipteran insects that utilize stylets present in their mouthparts to pierce sieve elements and drink large volumes of phloem sap. In addition, many aphids also vector viral diseases. Myzus persicae, commonly known as the green peach aphid (GPA, is an important pest of a large variety of plants that includes Arabidopsis thaliana. This review summarizes recent studies that have exploited the compatible interaction between Arabidopsis and GPA to understand the molecular and physiological mechanisms utilized by plants to control aphid infestation, as well as genes and mechanisms that contribute to susceptibility. In addition, recent efforts to identify aphid-delivered elicitors of plant defenses and novel aphid salivary components that facilitate infestation are also discussed.

A Spatially Explicit Dual-Isotope Approach to Map Regions of Plant-Plant Interaction after Exotic Plant Invasion.

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Christine Hellmann

Full Text Available Understanding interactions between native and invasive plant species in field settings and quantifying the impact of invaders in heterogeneous native ecosystems requires resolving the spatial scale on which these processes take place. Therefore, functional tracers are needed that enable resolving the alterations induced by exotic plant invasion in contrast to natural variation in a spatially explicit way. 15N isoscapes, i.e., spatially referenced representations of stable nitrogen isotopic signatures, have recently provided such a tracer. However, different processes, e.g. water, nitrogen or carbon cycles, may be affected at different spatial scales. Thus multi-isotope studies, by using different functional tracers, can potentially return a more integrated picture of invader impact. This is particularly true when isoscapes are submitted to statistical methods suitable to find homogeneous subgroups in multivariate data such as cluster analysis. Here, we used model-based clustering of spatially explicit foliar δ15N and δ13C isoscapes together with N concentration of a native indicator species, Corema album, to map regions of influence in a Portuguese dune ecosystem invaded by the N2-fixing Acacia longifolia. Cluster analysis identified regions with pronounced alterations in N budget and water use efficiency in the native species, with a more than twofold increase in foliar N, and δ13C and δ15N enrichment of up to 2‰ and 8‰ closer to the invader, respectively. Furthermore, clusters of multiple functional tracers indicated a spatial shift from facilitation through N addition in the proximity of the invader to competition for resources other than N in close contact. Finding homogeneous subgroups in multi-isotope data by means of model-based cluster analysis provided an effective tool for detecting spatial structure in processes affecting plant physiology and performance. The proposed method can give an objective measure of the spatial extent

Microbial genome-enabled insights into plant-microorganism interactions.

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Guttman, David S; McHardy, Alice C; Schulze-Lefert, Paul

2014-12-01

Advances in genome-based studies on plant-associated microorganisms have transformed our understanding of many plant pathogens and are beginning to greatly widen our knowledge of plant interactions with mutualistic and commensal microorganisms. Pathogenomics has revealed how pathogenic microorganisms adapt to particular hosts, subvert innate immune responses and change host range, as well as how new pathogen species emerge. Similarly, culture-independent community profiling methods, coupled with metagenomic and metatranscriptomic studies, have provided the first insights into the emerging field of research on plant-associated microbial communities. Together, these approaches have the potential to bridge the gap between plant microbial ecology and plant pathology, which have traditionally been two distinct research fields.

Trichoderma-plant-pathogen interactions: advances in genetics of biological control.

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Mukherjee, Mala; Mukherjee, Prasun K; Horwitz, Benjamin A; Zachow, Christin; Berg, Gabriele; Zeilinger, Susanne

2012-12-01

Trichoderma spp. are widely used in agriculture as biofungicides. Induction of plant defense and mycoparasitism (killing of one fungus by another) are considered to be the most important mechanisms of Trichoderma-mediated biological control. Understanding these mechanisms at the molecular level would help in developing strains with superior biocontrol properties. In this article, we review our current understanding of the genetics of interactions of Trichoderma with plants and plant pathogens.

Methylobacterium-plant interaction genes regulated by plant exudate and quorum sensing molecules

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Manuella Nóbrega Dourado

2013-12-01

Full Text Available Bacteria from the genus Methylobacterium interact symbiotically (endophytically and epiphytically with different plant species. These interactions can promote plant growth or induce systemic resistance, increasing plant fitness. The plant colonization is guided by molecular communication between bacteria-bacteria and bacteria-plants, where the bacteria recognize specific exuded compounds by other bacteria (e.g. homoserine molecules and/or by the plant roots (e.g. flavonoids, ethanol and methanol, respectively. In this context, the aim of this study was to evaluate the effect of quorum sensing molecules (N-acyl-homoserine lactones and plant exudates (including ethanol in the expression of a series of bacterial genes involved in Methylobacterium-plant interaction. The selected genes are related to bacterial metabolism (mxaF, adaptation to stressful environment (crtI, phoU and sss, to interactions with plant metabolism compounds (acdS and pathogenicity (patatin and phoU. Under in vitro conditions, our results showed the differential expression of some important genes related to metabolism, stress and pathogenesis, thereby AHL molecules up-regulate all tested genes, except phoU, while plant exudates induce only mxaF gene expression. In the presence of plant exudates there is a lower bacterial density (due the endophytic and epiphytic colonization, which produce less AHL, leading to down regulation of genes when compared to the control. Therefore, bacterial density, more than plant exudate, influences the expression of genes related to plant-bacteria interaction.

Understanding plant-to-plant interactions for soil resources in multilayered Iberian dehesas

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Moreno, G.; Rolo, V.; Cubera, E.; López-Díaz, L.

2009-04-01

Iberian dehesa is usually defined as two-layered silvopastoral system, where native grasses cohabit with a scattered widely-space tree layer. In the last two decades, an intense debate has been developed on the sustainability of this simplified type of dehesa. While some authors argue that that the forest cycle has been disrupted in most dehesas, where the lack of regeneration is an inherent problem to their exploitation, other authors have showed that dehesa degradation is easily reversible if certain abandonment is periodically exerted. The coexistence of two-layered plots with multilayered plots (encroached open woodlands) and mono-layered plots (either closed forest or mono-pasture/monocrops) has been a common feature of dehesas, as result of a systematic combination of agricultural, pastoral, and forestry uses. Different structures of vegetation depend on land use, giving a mosaic at both estate and landscape scales. These mosaic-type systems allow finding several scenarios of plant-to-plant interactions, mostly at belowground level. A key issue for sustainable management of oak woodland is to understand the complexity of the plant-to-plant relationships and their consequences in the ecosystem functioning in terms of productivity and stability. The competitive abilities of component systems are modified by the environment conditions. Dehesas, as most savanna systems, exhibit a low rainfall with high variability within and between years as well as a high evaporative demand during the summer. Indeed, water availability is one of the major ecological factors influencing either natural savannas or man-made open woodlands. Although most of the available studies have focused different aspects of the mature tree-grass interactions, we also present here some recent results on tree-tree, tree-shrub, shrub-seedling and seedling-grass interactions, explained mostly in terms of competition for soil water and nutrients. Trees can modify the soil and microclimate

Evolutionary Ecology of Multitrophic Interactions between Plants, Insect Herbivores and Entomopathogens.

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Shikano, Ikkei

2017-06-01

Plants play an important role in the interactions between insect herbivores and their pathogens. Since the seminal review by Cory and Hoover (2006) on plant-mediated effects on insect-pathogen interactions, considerable progress has been made in understanding the complexity of these tritrophic interactions. Increasing interest in the areas of nutritional and ecological immunology over the last decade have revealed that plant primary and secondary metabolites can influence the outcomes of insect-pathogen interactions by altering insect immune functioning and physical barriers to pathogen entry. Some insects use plant secondary chemicals and nutrients to prevent infections (prophylactic medication) and medicate to limit the severity of infections (therapeutic medication). Recent findings suggest that there may be selectable plant traits that enhance entomopathogen efficacy, suggesting that entomopathogens could potentially impose selection pressure on plant traits that improve both pathogen and plant fitness. Moreover, plants in nature are inhabited by diverse communities of microbes, in addition to entomopathogens, some of which can trigger immune responses in insect herbivores. Plants are also shared by numerous other herbivorous arthropods with different modes of feeding that can trigger different defensive responses in plants. Some insect symbionts and gut microbes can degrade ingested defensive phytochemicals and be orally secreted onto wounded plant tissue during herbivory to alter plant defenses. Since non-entomopathogenic microbes and other arthropods are likely to influence the outcomes of plant-insect-entomopathogen interactions, I discuss a need to consider these multitrophic interactions within the greater web of species interactions.

Towards an Enhanced Understanding of Plant-Microbiome Interactions to Improve Phytoremediation: Engineering the Metaorganism

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Sofie eThijs

2016-03-01

Full Text Available Phytoremediation is a promising technology to clean-up contaminated soils based on the synergistic actions of plants and microorganisms. However, to become a widely accepted, and predictable remediation alternative, a deeper understanding of the plant-microbe interactions is needed. A number of studies link the success of phytoremediation to the plant-associated microbiome functioning, though whether the microbiome can exist in alternative, functional states for soil remediation, is incompletely understood. Moreover, current approaches that target the plant host, and environment separately to improve phytoremediation, potentially overlook microbial functions and properties that are part of the multiscale complexity of the plant-environment wherein biodegradation takes place. In contrast, in situ studies of phytoremediation research at the metaorganism level (host and microbiome together are lacking. Here, we discuss a competition-driven model, based on recent evidence from the metagenomics level, and hypotheses generated by microbial community ecology, to explain the establishment of a catabolic rhizosphere microbiome in a contaminated soil. There is evidence to ground that if the host provides the right level and mix of resources (exudates over which the microbes can compete, then a competitive catabolic and plant-growth promoting (PGP microbiome can be selected for as long as it provides a competitive superiority in the niche. The competition-driven model indicates four strategies to interfere with the microbiome. Specifically, the rhizosphere microbiome community can be shifted using treatments that alter the host, resources, environment, and that take advantage of prioritization in inoculation. Our model and suggestions, considering the metaorganism in its natural context, would allow to gain further knowledge on the plant-microbial functions, and facilitate translation to more effective, and predictable phytotechnologies.

The impact of whole-plant instruction of preservice teachers' understanding of plant science principles

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Hypolite, Christine Collins

The purpose of this research was to determine how an inquiry-based, whole-plant instructional strategy would affect preservice elementary teachers' understanding of plant science principles. This study probed: what preservice teachers know about plant biology concepts before and after instruction, their views of the interrelatedness of plant parts and the environment, how growing a plant affects preservice teachers' understanding, and which types of activity-rich plant themes studies, if any, affect preservice elementary teachers' understandings. The participants in the study were enrolled in two elementary science methods class sections at a state university. Each group was administered a preinstructional test at the beginning of the study. The treatment group participated in inquiry-based activities related to the Principles of Plant Biology (American Society of Plant Biologists, 2001), while the comparison group studied those same concepts through traditional instructional methods. A focus group was formed from the treatment group to participate in co-concept mapping sessions. The participants' understandings were assessed through artifacts from activities, a comparison of pre- and postinstructional tests, and the concept maps generated by the focus group. Results of the research indicated that the whole-plant, inquiry-based instructional strategy can be applied to teach preservice elementary teachers plant biology while modeling the human constructivist approach. The results further indicated that this approach enhanced their understanding of plant science content knowledge, as well as pedagogical knowledge. The results also showed that a whole-plant approach to teaching plant science concepts is an instructional strategy that is feasible for the elementary school. The theoretical framework for this study was Human Constructivist learning theory (Mintzes & Wandersee, 1998). The content knowledge and instructional strategy was informed by the Principles of Plant

Mirid (Hemiptera: Heteroptera) specialists of sticky plants: adaptations, interactions, and ecological implications.

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Wheeler, Alfred G; Krimmel, Billy A

2015-01-07

Sticky plants-those having glandular trichomes (hairs) that produce adhesive, viscous exudates-can impede the movement of, and entrap, generalist insects. Disparate arthropod groups have adapted to these widespread and taxonomically diverse plants, yet their interactions with glandular hosts rarely are incorporated into broad ecological theory. Ecologists and entomologists might be unaware of even well-documented examples of insects that are sticky-plant specialists. The hemipteran family Miridae (more specifically, the omnivorous Dicyphini: Dicyphina) is the best-known group of arthropods that specializes on sticky plants. In the first synthesis of relationships with glandular plants for any insect family, we review mirid interactions with sticky hosts, including their adaptations (behavioral, morphological, and physiological) and mutualisms with carnivorous plants, and the ecological and agricultural implications of mirid-sticky plant systems. We propose that mirid research applies generally to tritrophic interactions on trichome-defended plants, enhances an understanding of insect-plant interactions, and provides information useful in managing crop pests.

Recent developments in systems biology and metabolic engineering of plant microbe interactions

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Vishal Kumar

2016-09-01

Full Text Available Microorganisms play a crucial role in the sustainability of the various ecosystems. The characterization of various interactions between microorganisms and other biotic factors is a necessary footstep to understand the association and functions of microbial communities. Among the different microbial interactions in an ecosystem, plant-microbe interaction plays an important role to balance the ecosystem. The present review explores plant microbe interactions using gene editing and system biology tools towards the comprehension in improvement of plant traits. Further, system biology tools like FBA, OptKnock and constrain based modeling helps in understanding such interactions as a whole. In addition, various gene editing tools have been summarized and a strategy has been hypothesized for the development of disease free plants. Furthermore, we have tried to summarize the predictions through data retrieved from various types of sources such as high throughput sequencing data (e.g. single nucleotide polymorphism (SNP detection, RNA-seq, proteomics and metabolic models have been reconstructed from such sequences for species communities. It is well known fact that systems biology approaches and modeling of biological networks will enable us to learn the insight of such network and will also help further in understanding these interactions.

Arsenic-phosphorus interactions in the soil-plant-microbe system: Dynamics of uptake, suppression and toxicity to plants.

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Anawar, Hossain M; Rengel, Zed; Damon, Paul; Tibbett, Mark

2018-02-01

High arsenic (As) concentrations in the soil, water and plant systems can pose a direct health risk to humans and ecosystems. Phosphate (Pi) ions strongly influence As availability in soil, its uptake and toxicity to plants. Better understanding of As(V)-Pi interactions in soils and plants will facilitate a potential remediation strategy for As contaminated soils, reducing As uptake by crop plants and toxicity to human populations via manipulation of soil Pi content. However, the As(V)-Pi interactions in soil-plant systems are complex, leading to contradictory findings among different studies. Therefore, this review investigates the role of soil type, soil properties, minerals, Pi levels in soil and plant, Pi transporters, mycorrhizal association and microbial activities on As-Pi interactions in soils and hydroponics, and uptake by plants, elucidate the key mechanisms, identify key knowledge gaps and recommend new research directions. Although Pi suppresses As uptake by plants in hydroponic systems, in soils it could either increase or decrease As availability and toxicity to plants depending on the soil types, properties and charge characteristics. In soil, As(V) availability is typically increased by the addition of Pi. At the root surface, the Pi transport system has high affinity for Pi over As(V). However, Pi concentration in plant influences the As transport from roots to shoots. Mycorrhizal association may reduce As uptake via a physiological shift to the mycorrhizal uptake pathway, which has a greater affinity for Pi over As(V) than the root epidermal uptake pathway. Copyright © 2017 Elsevier Ltd. All rights reserved.

Plant-pathogen interactions: what microarray tells about it?

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Lodha, T D; Basak, J

2012-01-01

Plant defense responses are mediated by elementary regulatory proteins that affect expression of thousands of genes. Over the last decade, microarray technology has played a key role in deciphering the underlying networks of gene regulation in plants that lead to a wide variety of defence responses. Microarray is an important tool to quantify and profile the expression of thousands of genes simultaneously, with two main aims: (1) gene discovery and (2) global expression profiling. Several microarray technologies are currently in use; most include a glass slide platform with spotted cDNA or oligonucleotides. Till date, microarray technology has been used in the identification of regulatory genes, end-point defence genes, to understand the signal transduction processes underlying disease resistance and its intimate links to other physiological pathways. Microarray technology can be used for in-depth, simultaneous profiling of host/pathogen genes as the disease progresses from infection to resistance/susceptibility at different developmental stages of the host, which can be done in different environments, for clearer understanding of the processes involved. A thorough knowledge of plant disease resistance using successful combination of microarray and other high throughput techniques, as well as biochemical, genetic, and cell biological experiments is needed for practical application to secure and stabilize yield of many crop plants. This review starts with a brief introduction to microarray technology, followed by the basics of plant-pathogen interaction, the use of DNA microarrays over the last decade to unravel the mysteries of plant-pathogen interaction, and ends with the future prospects of this technology.

Recent advances in plant-herbivore interactions [version 1; referees: 2 approved

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Deron E. Burkepile

2017-02-01

Full Text Available Plant-herbivore interactions shape community dynamics across marine, freshwater, and terrestrial habitats. From amphipods to elephants and from algae to trees, plant-herbivore relationships are the crucial link generating animal biomass (and human societies from mere sunlight. These interactions are, thus, pivotal to understanding the ecology and evolution of virtually any ecosystem. Here, we briefly highlight recent advances in four areas of plant-herbivore interactions: (1 plant defense theory, (2 herbivore diversity and ecosystem function, (3 predation risk aversion and herbivory, and (4 how a changing climate impacts plant-herbivore interactions. Recent advances in plant defense theory, for example, highlight how plant life history and defense traits affect and are affected by multiple drivers, including enemy pressure, resource availability, and the local plant neighborhood, resulting in trait-mediated feedback loops linking trophic interactions with ecosystem nutrient dynamics. Similarly, although the positive effect of consumer diversity on ecosystem function has long been recognized, recent advances using DNA barcoding to elucidate diet, and Global Positioning System/remote sensing to determine habitat selection and impact, have shown that herbivore communities are probably even more functionally diverse than currently realized. Moreover, although most diversity-function studies continue to emphasize plant diversity, herbivore diversity may have even stronger impacts on ecosystem multifunctionality. Recent studies also highlight the role of risk in plant-herbivore interactions, and risk-driven trophic cascades have emerged as landscape-scale patterns in a variety of ecosystems. Perhaps not surprisingly, many plant-herbivore interactions are currently being altered by climate change, which affects plant growth rates and resource allocation, expression of chemical defenses, plant phenology, and herbivore metabolism and behavior. Finally

Nitrilase enzymes and their role in plant-microbe interactions.

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Howden, Andrew J M; Preston, Gail M

2009-07-01

Nitrilase enzymes (nitrilases) catalyse the hydrolysis of nitrile compounds to the corresponding carboxylic acid and ammonia, and have a wide range of industrial and biotechnological applications, including the synthesis of industrially important carboxylic acids and bioremediation of cyanide and toxic nitriles. Nitrilases are produced by a wide range of organisms, including plants, bacteria and fungi, but despite their biotechnological importance, the role of these enzymes in living organisms is relatively underexplored. Current research suggests that nitrilases play important roles in a range of biological processes. In the context of plant-microbe interactions they may have roles in hormone synthesis, nutrient assimilation and detoxification of exogenous and endogenous nitriles. Nitrilases are produced by both plant pathogenic and plant growth-promoting microorganisms, and their activities may have a significant impact on the outcome of plant-microbe interactions. In this paper we review current knowledge of the role of nitriles and nitrilases in plants and plant-associated microorganisms, and discuss how greater understanding of the natural functions of nitrilases could be applied to benefit both industry and agriculture. © 2009 The Authors. Journal compilation © 2009 Society for Applied Microbiology and Blackwell Publishing Ltd.

Mathematical models for plant-herbivore interactions

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Feng, Zhilan; DeAngelis, Donald L.

2017-01-01

Mathematical Models of Plant-Herbivore Interactions addresses mathematical models in the study of practical questions in ecology, particularly factors that affect herbivory, including plant defense, herbivore natural enemies, and adaptive herbivory, as well as the effects of these on plant community dynamics. The result of extensive research on the use of mathematical modeling to investigate the effects of plant defenses on plant-herbivore dynamics, this book describes a toxin-determined functional response model (TDFRM) that helps explains field observations of these interactions. This book is intended for graduate students and researchers interested in mathematical biology and ecology.

The role of plant-microbiome interactions in weed establishment and control.

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Trognitz, Friederike; Hackl, Evelyn; Widhalm, Siegrid; Sessitsch, Angela

2016-10-01

The soil microbiome plays an important role in the establishment of weeds and invasive plants. They associate with microorganisms supporting their growth and health. Weed management strategies, like tillage and herbicide treatments, to control weeds generally alter soil structure going alongside with changes in the microbial community. Once a weed population establishes in the field, the plants build up a close relationship with the available microorganisms. Seeds or vegetative organs overwinter in soil and select early in the season their own microbiome before crop plants start to vegetate. Weed and crop plants compete for light, nutrition and water, but may differently interact with soil microorganisms. The development of new sequencing technologies for analyzing soil microbiomes has opened up the possibility for in depth analysis of the interaction between 'undesired' plants and crop plants under different management systems. These findings will help us to understand the functions of microorganisms involved in crop productivity and plant health, weed establishment and weed prevention. Exploitation of the knowledge offers the possibility to search for new biocontrol methods against weeds based on soil and plant-associated microorganisms. This review discusses the recent advances in understanding the functions of microbial communities for weed/invasive plant establishment and shows new ways to use plant-associated microorganisms to control weeds and invasive plants in different land management systems. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Plant diversity increases spatio?temporal niche complementarity in plant?pollinator interactions

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Venjakob, Christine; Klein, Alexandra?Maria; Ebeling, Anne; Tscharntke, Teja; Scherber, Christoph

2016-01-01

Ongoing biodiversity decline impairs ecosystem processes, including pollination. Flower visitation, an important indicator of pollination services, is influenced by plant species richness. However, the spatio-temporal responses of different pollinator groups to plant species richness have not yet been analyzed experimentally. Here, we used an experimental plant species richness gradient to analyze plant-pollinator interactions with an unprecedented spatio-temporal resolution. We observed four...

Omnivore-herbivore interactions: thrips and whiteflies compete via the shared host plant.

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Pappas, Maria L; Tavlaki, Georgia; Triantafyllou, Anneta; Broufas, George

2018-03-05

Phytophagy is a common feature among pure herbivorous insects and omnivores that utilise both plant and prey as food resources; nevertheless, experimental evidence for factors affecting their interactions is restricted to intraguild predation and predator-mediated competition. We herein focused on plant-mediated effects that could result from plant defence activation or quality alteration and compared the performance of an omnivore, the western flower thrips Frankliniella occidentalis, and a pure herbivore, the greenhouse whitefly Trialeurodes vaporariorum, on cucumber plants previously infested with either species. Furthermore, we recorded their behavioural responses when given a choice among infested and clean plants. Whiteflies laid less eggs on plants previously exposed to thrips but more on whitefly-infested plants. Thrips survival was negatively affected on whitefly-infested than on thrips-infested or clean plants. Notably, whiteflies developed significantly faster on plants infested with conspecifics. In accordance, whiteflies avoided thrips-infested plants and preferred whitefly-infested over clean plants. Thrips showed no preference for either infested or clean plants. Our study is a first report on the role of plant-mediated effects in shaping omnivore-herbivore interactions. Considering the factors driving such interactions we will likely better understand the ecology of the more complex relationships among plants and pest organisms.

Plant traits related to nitrogen uptake influence plant-microbe competition.

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Moreau, Delphine; Pivato, Barbara; Bru, David; Busset, Hugues; Deau, Florence; Faivre, Céline; Matejicek, Annick; Strbik, Florence; Philippot, Laurent; Mougel, Christophe

2015-08-01

Plant species are important drivers of soil microbial communities. However, how plant functional traits are shaping these communities has received less attention though linking plant and microbial traits is crucial for better understanding plant-microbe interactions. Our objective was to determine how plant-microbe interactions were affected by plant traits. Specifically we analyzed how interactions between plant species and microbes involved in nitrogen cycling were affected by plant traits related to 'nitrogen nutrition in interaction with soil nitrogen availability. Eleven plant species, selected along an oligotrophic-nitrophilic gradient, were grown individually in a nitrogen-poor soil with two levels of nitrate availability. Plant traits for both carbon and nitrogen nutrition were measured and the genetic structure and abundance of rhizosphere. microbial communities, in particular the ammonia oxidizer and nitrate reducer guilds, were analyzed. The structure of the bacterial community in the rhizosphere differed significantly between plant species and these differences depended on nitrogen availability. The results suggest that the rate of nitrogen uptake per unit of root biomass and per day is a key plant trait, explaining why the effect of nitrogen availability on the structure of the bacterial community depends on the plant species. We also showed that the abundance of nitrate reducing bacteria always decreased with increasing nitrogen uptake per unit of root biomass per day, indicating that there was competition for nitrate between plants and nitrate reducing bacteria. This study demonstrates that nitrate-reducing microorganisms may be adversely affected by plants with a high nitrogen uptake rate. Our work puts forward the role of traits related to nitrogen in plant-microbe interactions, whereas carbon is commonly considered as the main driver. It also suggests that plant traits related to ecophysiological processes, such as nitrogen uptake rates, are more

The promise of genomics in the study of plant-pollinator interactions

Science.gov (United States)

2013-01-01

Flowers exist in exceedingly complex fitness landscapes, in which subtle variation in each trait can affect the pollinators, herbivores and pleiotropically linked traits in other plant tissues. A whole-genome approach to flower evolution will help our understanding of plant-pollinator interactions. PMID:23796166

Plant physiology meets phytopathology: plant primary metabolism and plant-pathogen interactions.

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Berger, Susanne; Sinha, Alok K; Roitsch, Thomas

2007-01-01

Phytopathogen infection leads to changes in secondary metabolism based on the induction of defence programmes as well as to changes in primary metabolism which affect growth and development of the plant. Therefore, pathogen attack causes crop yield losses even in interactions which do not end up with disease or death of the plant. While the regulation of defence responses has been intensively studied for decades, less is known about the effects of pathogen infection on primary metabolism. Recently, interest in this research area has been growing, and aspects of photosynthesis, assimilate partitioning, and source-sink regulation in different types of plant-pathogen interactions have been investigated. Similarly, phytopathological studies take into consideration the physiological status of the infected tissues to elucidate the fine-tuned infection mechanisms. The aim of this review is to give a summary of recent advances in the mutual interrelation between primary metabolism and pathogen infection, as well as to indicate current developments in non-invasive techniques and important strategies of combining modern molecular and physiological techniques with phytopathology for future investigations.

Plant-soil feedbacks and the coexistence of competing plants

NARCIS (Netherlands)

Revilla Rimbach, Tomas; Veen, G. F. (Ciska); Eppinga, Maarten B.; Weissing, Franz J.

Plant-soil feedbacks can have important implications for the interactions among plants. Understanding these effects is a major challenge since it is inherently difficult to measure and manipulate highly diverse soil communities. Mathematical models may advance this understanding by making the

Ecology and evolution of plant-pollinator interactions.

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Mitchell, Randall J; Irwin, Rebecca E; Flanagan, Rebecca J; Karron, Jeffrey D

2009-06-01

Some of the most exciting advances in pollination biology have resulted from interdisciplinary research combining ecological and evolutionary perspectives. For example, these two approaches have been essential for understanding the functional ecology of floral traits, the dynamics of pollen transport, competition for pollinator services, and patterns of specialization and generalization in plant-pollinator interactions. However, as research in these and other areas has progressed, many pollination biologists have become more specialized in their research interests, focusing their attention on either evolutionary or ecological questions. We believe that the continuing vigour of a synthetic and interdisciplinary field like pollination biology depends on renewed connections between ecological and evolutionary approaches. In this Viewpoint paper we highlight the application of ecological and evolutionary approaches to two themes in pollination biology: (1) links between pollinator behaviour and plant mating systems, and (2) generalization and specialization in pollination systems. We also describe how mathematical models and synthetic analyses have broadened our understanding of pollination biology, especially in human-modified landscapes. We conclude with several suggestions that we hope will stimulate future research. This Viewpoint also serves as the introduction to this Special Issue on the Ecology and Evolution of Plant-Pollinator Interactions. These papers provide inspiring examples of the synergy between evolutionary and ecological approaches, and offer glimpses of great accomplishments yet to come.

Plant-insect interactions under bacterial influence: ecological implications and underlying mechanisms.

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Sugio, Akiko; Dubreuil, Géraldine; Giron, David; Simon, Jean-Christophe

2015-02-01

Plants and insects have been co-existing for more than 400 million years, leading to intimate and complex relationships. Throughout their own evolutionary history, plants and insects have also established intricate and very diverse relationships with microbial associates. Studies in recent years have revealed plant- or insect-associated microbes to be instrumental in plant-insect interactions, with important implications for plant defences and plant utilization by insects. Microbial communities associated with plants are rich in diversity, and their structure greatly differs between below- and above-ground levels. Microbial communities associated with insect herbivores generally present a lower diversity and can reside in different body parts of their hosts including bacteriocytes, haemolymph, gut, and salivary glands. Acquisition of microbial communities by vertical or horizontal transmission and possible genetic exchanges through lateral transfer could strongly impact on the host insect or plant fitness by conferring adaptations to new habitats. Recent developments in sequencing technologies and molecular tools have dramatically enhanced opportunities to characterize the microbial diversity associated with plants and insects and have unveiled some of the mechanisms by which symbionts modulate plant-insect interactions. Here, we focus on the diversity and ecological consequences of bacterial communities associated with plants and herbivorous insects. We also highlight the known mechanisms by which these microbes interfere with plant-insect interactions. Revealing such mechanisms in model systems under controlled environments but also in more natural ecological settings will help us to understand the evolution of complex multitrophic interactions in which plants, herbivorous insects, and micro-organisms are inserted. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions

Parasitic plants of the genus Cuscuta and their interaction with susceptible and resistant host plants

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Bettina eKaiser

2015-02-01

Full Text Available By comparison with plant-microbe interaction, little is known about the interaction of parasitic plants with their hosts. Plants of the genus Cuscuta belong to the family of Cuscutaceae and comprise about 200 species, all of which live as stem holoparasites on other plants. Cuscuta spp. possess no roots nor fully expanded leaves and the vegetative portion appears to be a stem only. The parasite winds around plants and penetrates the host stems via haustoria, forming direct connections to the vascular bundles of their hosts to withdraw water, carbohydrates and other solutes. Besides susceptible hosts, a few plants exist that exhibit an active resistance against infestation by Cuscuta spp. For example, cultivated tomato (Solanum lycopersicum fends off Cuscuta reflexa by means of a hypersensitive-type response occurring in the early penetration phase. This report on the plant-plant dialogue between Cuscuta spp. and its host plants focuses on the incompatible interaction of Cuscuta reflexa with tomato.

Parasitic plants of the genus Cuscuta and their interaction with susceptible and resistant host plants.

Science.gov (United States)

Kaiser, Bettina; Vogg, Gerd; Fürst, Ursula B; Albert, Markus

2015-01-01

By comparison with plant-microbe interaction, little is known about the interaction of parasitic plants with their hosts. Plants of the genus Cuscuta belong to the family of Cuscutaceae and comprise about 200 species, all of which live as stem holoparasites on other plants. Cuscuta spp. possess no roots nor fully expanded leaves and the vegetative portion appears to be a stem only. The parasite winds around plants and penetrates the host stems via haustoria, forming direct connections to the vascular bundles of their hosts to withdraw water, carbohydrates, and other solutes. Besides susceptible hosts, a few plants exist that exhibit an active resistance against infestation by Cuscuta spp. For example, cultivated tomato (Solanum lycopersicum) fends off Cuscuta reflexa by means of a hypersensitive-type response occurring in the early penetration phase. This report on the plant-plant dialog between Cuscuta spp. and its host plants focuses on the incompatible interaction of C. reflexa with tomato.

Transcription Factor Functional Protein-Protein Interactions in Plant Defense Responses

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Murilo S. Alves

2014-03-01

Full Text Available Responses to biotic stress in plants lead to dramatic reprogramming of gene expression, favoring stress responses at the expense of normal cellular functions. Transcription factors are master regulators of gene expression at the transcriptional level, and controlling the activity of these factors alters the transcriptome of the plant, leading to metabolic and phenotypic changes in response to stress. The functional analysis of interactions between transcription factors and other proteins is very important for elucidating the role of these transcriptional regulators in different signaling cascades. In this review, we present an overview of protein-protein interactions for the six major families of transcription factors involved in plant defense: basic leucine zipper containing domain proteins (bZIP, amino-acid sequence WRKYGQK (WRKY, myelocytomatosis related proteins (MYC, myeloblastosis related proteins (MYB, APETALA2/ ETHYLENE-RESPONSIVE ELEMENT BINDING FACTORS (AP2/EREBP and no apical meristem (NAM, Arabidopsis transcription activation factor (ATAF, and cup-shaped cotyledon (CUC (NAC. We describe the interaction partners of these transcription factors as molecular responses during pathogen attack and the key components of signal transduction pathways that take place during plant defense responses. These interactions determine the activation or repression of response pathways and are crucial to understanding the regulatory networks that modulate plant defense responses.

Plant-plant competition outcomes are modulated by plant effects on the soil bacterial community.

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Hortal, S; Lozano, Y M; Bastida, F; Armas, C; Moreno, J L; Garcia, C; Pugnaire, F I

2017-12-19

Competition is a key process that determines plant community structure and dynamics, often mediated by nutrients and water availability. However, the role of soil microorganisms on plant competition, and the links between above- and belowground processes, are not well understood. Here we show that the effects of interspecific plant competition on plant performance are mediated by feedbacks between plants and soil bacterial communities. Each plant species selects a singular community of soil microorganisms in its rhizosphere with a specific species composition, abundance and activity. When two plant species interact, the resulting soil bacterial community matches that of the most competitive plant species, suggesting strong competitive interactions between soil bacterial communities as well. We propose a novel mechanism by which changes in belowground bacterial communities promoted by the most competitive plant species influence plant performance and competition outcome. These findings emphasise the strong links between plant and soil communities, paving the way to a better understanding of plant community dynamics and the effects of soil bacterial communities on ecosystem functioning and services.

Life in the dark: Roots and how they regulate plant-soil interactions

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Wu, Y.; Chou, C.; Peruzzo, L.; Riley, W. J.; Hao, Z.; Petrov, P.; Newman, G. A.; Versteeg, R.; Blancaflor, E.; Ma, X.; Dafflon, B.; Brodie, E.; Hubbard, S. S.

2017-12-01

Roots play a key role in regulating interactions between soil and plants, an important biosphere process critical for soil development and health, global food security, carbon sequestration, and the cycling of elements (water, carbon, nutrients, and environmental contaminants). However, their underground location has hindered studies of plant roots and the role they play in regulating plant-soil interactions. Technological limitations for root phenotyping and the lack of an integrated approach capable of linking root development, its environmental adaptation/modification with subsequent impact on plant health and productivity are major challenges faced by scientists as they seek to understand the plant's hidden half. To overcome these challenges, we combine novel experimental methods with numerical simulations, and conduct controlled studies to explore the dynamic growth of crop roots. We ask how roots adapt to and change the soil environment and their subsequent impacts on plant health and productivity. Specifically, our efforts are focused on (1) developing novel geophysical approaches for non-invasive plant root and rhizosphere characterization; (2) correlating root developments with key canopy traits indicative of plant health and productivity; (3) developing numerical algorithms for novel geophysical root signal processing; (4) establishing plant growth models to explore root-soil interactions and above and below ground traits co-variabilities; and (5) exploring how root development modifies rhizosphere physical, hydrological, and geochemical environments for adaptation and survival. Our preliminary results highlight the potential of using electro-geophysical methods to quantifying key rhizosphere traits, the capability of the ecosys model for mechanistic plant growth simulation and traits correlation exploration, and the combination of multi-physics and numerical approach for a systematic understanding of root growth dynamics, impacts on soil physicochemical

Climate change driven plant-metal-microbe interactions.

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Rajkumar, Mani; Prasad, Majeti Narasimha Vara; Swaminathan, Sandhya; Freitas, Helena

2013-03-01

Various biotic and abiotic stress factors affect the growth and productivity of crop plants. Particularly, the climatic and/or heavy metal stress influence various processes including growth, physiology, biochemistry, and yield of crops. Climatic changes particularly the elevated atmospheric CO₂ enhance the biomass production and metal accumulation in plants and help plants to support greater microbial populations and/or protect the microorganisms against the impacts of heavy metals. Besides, the indirect effects of climatic change (e.g., changes in the function and structure of plant roots and diversity and activity of rhizosphere microbes) would lead to altered metal bioavailability in soils and concomitantly affect plant growth. However, the effects of warming, drought or combined climatic stress on plant growth and metal accumulation vary substantially across physico-chemico-biological properties of the environment (e.g., soil pH, heavy metal type and its bio-available concentrations, microbial diversity, and interactive effects of climatic factors) and plant used. Overall, direct and/or indirect effects of climate change on heavy metal mobility in soils may further hinder the ability of plants to adapt and make them more susceptible to stress. Here, we review and discuss how the climatic parameters including atmospheric CO₂, temperature and drought influence the plant-metal interaction in polluted soils. Other aspects including the effects of climate change and heavy metals on plant-microbe interaction, heavy metal phytoremediation and safety of food and feed are also discussed. This review shows that predicting how plant-metal interaction responds to altering climatic change is critical to select suitable crop plants that would be able to produce more yields and tolerate multi-stress conditions without accumulating toxic heavy metals for future food security. Copyright © 2012 Elsevier Ltd. All rights reserved.

Volatile chemical interaction between undamaged plants

OpenAIRE

Glinwood, Robert

2010-01-01

This chapter discusses whether plant chemical communication is a mechanism by which plant genetic diversity can affect the natural enemies of herbivores. Plant genetic diversity influences natural enemies, and these insects use volatile chemical cues to locate suitable habitats. However, the importance of chemical communication for these interactions has not been considered. In this chapter, the latest research on chemical communication between undamaged plants is reviewed. ...

Plastic potential: how the phenotypes and adaptations of pathogens are influenced by microbial interactions within plants.

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O'Keeffe, Kayleigh R; Carbone, Ignazio; Jones, Corbin D; Mitchell, Charles E

2017-08-01

Predicting the effects of plant-associated microbes on emergence, spread, and evolution of plant pathogens demands an understanding of how pathogens respond to these microbes at two levels of biological organization: that of an individual pathogen and that of a pathogen population across multiple individual plants. We first examine the plastic responses of individual plant pathogens to microbes within a shared host, as seen through changes in pathogen growth and multiplication. We then explore the limited understanding of how within-plant microbial interactions affect pathogen populations and discuss the need to incorporate population-level observations with population genomic techniques. Finally, we suggest that integrating across levels will further our understanding of the ecological and evolutionary impacts of within-plant microbial interactions on pathogens. Copyright © 2017 Elsevier Ltd. All rights reserved.

Functional plant types drive plant interactions in a Mediterranean mountain range

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Petr eMacek

2016-05-01

Full Text Available Shrubs have both positive (facilitation and negative (competition effects on understory plants, the net interaction effect being modulated by abiotic conditions. Overall shrubs influence to great extent the structure of plant communities where they have significant presence. Interactions in a plant community are quite diverse but little is known about their variability and effects at community level. Here we checked the effects of co-occurring shrub species from different functional groups on a focal understory species, determining mechanisms driving interaction outcome, and tested whether effects measured on the focal species were a proxy for effects measured at the community level. Growth, physiological, and reproductive traits of Euphorbia nicaeensis, our focal species, were recorded on individuals growing in association with four dominant shrub species and in adjacent open areas. We also recorded community composition and environmental conditions in each microhabitat.Shrubs provided environmental conditions for plant growth, which contrasted with open areas, including moister soil, greater N content, higher air temperatures, and lower radiation. Shrub-associated individuals showed lower reproductive effort and greater allocation to growth, while most physiological traits remained unaffected. Euphorbia individuals were bigger and had more leaf N under N-fixing than under non-fixing species. Soil moisture was also higher under N-fixing shrubs; therefore soil conditions in the understory may counter reduced light conditions.There was a significant effect of species identity and functional types in the outcome of plant interactions with consistent effects at individual and community levels. The contrasting allocation strategies to reproduction and growth in Euphorbia plants, either associated or not with shrubs, showed high phenotypic plasticity and evidence its ability to cope with contrasting environmental conditions.

Plant-Microbiota Interactions as a Driver of the Mineral Turnover in the Rhizosphere.

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Alegria Terrazas, R; Giles, C; Paterson, E; Robertson-Albertyn, S; Cesco, S; Mimmo, T; Pii, Y; Bulgarelli, D

2016-01-01

A major challenge facing agriculture in the 21st century is the need to increase the productivity of cultivated land while reducing the environmentally harmful consequences of mineral fertilization. The microorganisms thriving in association and interacting with plant roots, the plant microbiota, represent a potential resource of plant probiotic function, capable of conjugating crop productivity with sustainable management in agroecosystems. However, a limited knowledge of the organismal interactions occurring at the root-soil interface is currently hampering the development and use of beneficial plant-microbiota interactions in agriculture. Therefore, a comprehensive understanding of the recruitment cues of the plant microbiota and the molecular basis of nutrient turnover in the rhizosphere will be required to move toward efficient and sustainable crop nutrition. In this chapter, we will discuss recent insights into plant-microbiota interactions at the root-soil interface, illustrate the processes driving mineral dynamics in soil, and propose experimental avenues to further integrate the metabolic potential of the plant microbiota into crop management and breeding strategies for sustainable agricultural production. Copyright © 2016 Elsevier Inc. All rights reserved.

Root profile in Multi-layered Dehesas: an approach to plant-to-plant Interaction

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Rolo, V.; Moreno, G.

2009-04-01

Assessing plant-to-plant relationship is a key issue in agroforestry systems. Due to the sessile feature of plants most of these interactions take place within a restricted space, so characterizing the zone where the plant alters its environment is important to find overlapping areas where the facilitation or competition could occur. Main part of plan-to-plant interactions in the dehesa are located at belowground level, thus the main limited resources in Mediterranean ecosystems are soil nutrient and water. Hence a better knowledge of rooting plant profile can be useful to understand the functioning of the dehesa. The Iberian dehesa has always been considered as a silvopastoral system where, at least, two strata of vegetation coexist: native grasses and trees. However the dehesa is also a diverse system where cropland and encroached territories have been systematically combined, more or less periodically, with native pasture in order to obtain agricultural, pastoral and forestry outputs. These multipurpose mosaic-type systems generate several scenarios where the plant influence zone may be overlapped and the interaction, competition or facilitation, between plants can play an important role in the ecosystem functioning in terms of productivity and stability. In the present study our aim was to characterize the rooting profile of multi-layered dehesas in order to understand the competitive, and/or facilitative, relationships within the different plant strata. The root profile of Quercus ilex subsp. ballota, Cistus ladanifer, Retama spaherocarpa and natural grasses was studied. So 48 trenches, up to 2 meters deep, were excavated in 4 different environments: (i) grass; (ii) tree-grass; (iii) tree-shrub and (iv) tree-shrub-grass (12 trenches in each environment). The study was carried out in 4 dehesas, 2 encroached with C. ladanifer and 2 with R. spaherocarpa. In every trench soil samples were taken each 20 cm. Subsequently, all samples were sieved using different mesh

Plant-aphid interactions: molecular and ecological perspectives.

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Goggin, Fiona L

2007-08-01

Many aphids are major agricultural pests because of their unparalleled reproductive capacity and their ability to manipulate host plant physiology. Aphid population growth and its impact on plant fitness are strongly influenced by interactions with other organisms, including plant pathogens, endophytes, aphid endosymbionts, predators, parasitoids, ants, and other herbivores. Numerous molecular and genomic resources have recently been developed to identify sources of aphid resistance in plants, as well as potentially novel targets for control in aphids. Moreover, the same model systems that are used to explore direct molecular interactions between plants and aphids can be utilized to study the ecological context in which they occur.

Plant host finding by parasitic plants: a new perspective on plant to plant communication.

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Mescher, Mark C; Runyon, Justin B; De Moraes, Consuelo M

2006-11-01

Plants release airborne chemicals that can convey ecologically relevant information to other organisms. These plant volatiles are known to mediate a large array of, often complex, interactions between plants and insects. It has been suggested that plant volatiles may have similar importance in mediating interactions among plant species, but there are few well-documented examples of plant-to-plant communication via volatiles, and the ecological significance of such interactions has been much debated. To date, nearly all studies of volatile-mediated interactions among plant species have focused on the reception of herbivore-induced volatiles by neighboring plants. We recently documented volatile effects in another system, demonstrating that the parasitic plant Cuscuta pentagona uses volatile cues to locate its hosts. This finding may broaden the discussion regarding plant-to-plant communication, and suggests that new classes of volatile-meditated interactions among plant species await discovery.

Understanding plant defence responses against herbivore attacks: an essential first step towards the development of sustainable resistance against pests.

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Santamaria, M Estrella; Martínez, Manuel; Cambra, Inés; Grbic, Vojislava; Diaz, Isabel

2013-08-01

Plant-herbivore relationships are complex interactions encompassing elaborate networks of molecules, signals and strategies used to overcome defences developed by each other. Herbivores use multiple feeding strategies to obtain nutrients from host plants. In turn, plants respond by triggering defence mechanisms to inhibit, block or modify the metabolism of the pest. As part of these defences, herbivore-challenged plants emit volatiles to attract natural enemies and warn neighbouring plants of the imminent threat. In response, herbivores develop a variety of strategies to suppress plant-induced protection. Our understanding of the plant-herbivore interphase is limited, although recent molecular approaches have revealed the participation of a battery of genes, proteins and volatile metabolites in attack-defence processes. This review describes the intricate and dynamic defence systems governing plant-herbivore interactions by examining the diverse strategies plants employ to deny phytophagous arthropods the ability to breach newly developed mechanisms of plant resistance. A cornerstone of this understanding is the use of transgenic tools to unravel the complex networks that control these interactions.

Communicative interactions involving plants: information, evolution, and ecology.

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Mescher, Mark C; Pearse, Ian S

2016-08-01

The role of information obtained via sensory cues and signals in mediating the interactions of organisms with their biotic and abiotic environments has been a major focus of work on sensory and behavioral ecology. Information-mediated interactions also have important implications for broader ecological patterns emerging at the community and ecosystem levels that are only now beginning to be explored. Given the extent to which plants dominate the sensory landscapes of terrestrial ecosystems, information-mediated interactions involving plants should be a major focus of efforts to elucidate these broader patterns. Here we explore how such efforts might be enhanced by a clear understanding of information itself-a central and potentially unifying concept in biology that has nevertheless been the subject of considerable confusion-and of its relationship to adaptive evolution and ecology. We suggest that information-mediated interactions should be a key focus of efforts to more fully integrate evolutionary biology and ecology. Copyright © 2016 Elsevier Ltd. All rights reserved.

Species interactions and plant polyploidy.

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Segraves, Kari A; Anneberg, Thomas J

2016-07-01

Polyploidy is a common mode of speciation that can have far-reaching consequences for plant ecology and evolution. Because polyploidy can induce an array of phenotypic changes, there can be cascading effects on interactions with other species. These interactions, in turn, can have reciprocal effects on polyploid plants, potentially impacting their establishment and persistence. Although there is a wealth of information on the genetic and phenotypic effects of polyploidy, the study of species interactions in polyploid plants remains a comparatively young field. Here we reviewed the available evidence for how polyploidy may impact many types of species interactions that range from mutualism to antagonism. Specifically, we focused on three main questions: (1) Does polyploidy directly cause the formation of novel interactions not experienced by diploids, or does it create an opportunity for natural selection to then form novel interactions? (2) Does polyploidy cause consistent, predictable changes in species interactions vs. the evolution of idiosyncratic differences? (3) Does polyploidy lead to greater evolvability in species interactions? From the scarce evidence available, we found that novel interactions are rare but that polyploidy can induce changes in pollinator, herbivore, and pathogen interactions. Although further tests are needed, it is likely that selection following whole-genome duplication is important in all types of species interaction and that there are circumstances in which polyploidy can enhance the evolvability of interactions with other species. © 2016 Botanical Society of America.

Ant aggression and evolutionary stability in plant-ant and plant-pollinator mutualistic interactions.

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Oña, L; Lachmann, M

2011-03-01

Mutualistic partners derive a benefit from their interaction, but this benefit can come at a cost. This is the case for plant-ant and plant-pollinator mutualistic associations. In exchange for protection from herbivores provided by the resident ants, plants supply various kinds of resources or nests to the ants. Most ant-myrmecophyte mutualisms are horizontally transmitted, and therefore, partners share an interest in growth but not in reproduction. This lack of alignment in fitness interests between plants and ants drives a conflict between them: ants can attack pollinators that cross-fertilize the host plants. Using a mathematical model, we define a threshold in ant aggressiveness determining pollinator survival or elimination on the host plant. In our model we observed that, all else being equal, facultative interactions result in pollinator extinction for lower levels of ant aggressiveness than obligatory interactions. We propose that the capacity to discriminate pollinators from herbivores should not often evolve in ants, and when it does it will be when the plants exhibit limited dispersal in an environment that is not seed saturated so that each seed produced can effectively generate a new offspring or if ants acquire an extra benefit from pollination (e.g. if ants eat fruit). We suggest specific mutualism examples where these hypotheses can be tested empirically. © 2010 The Authors. Journal of Evolutionary Biology © 2010 European Society For Evolutionary Biology.

Plant-Mediated Systemic Interactions Between Pathogens, Parasitic Nematodes, and Herbivores Above- and Belowground

NARCIS (Netherlands)

Biere, A.; Goverse, A.

2016-01-01

Plants are important mediators of interactions between aboveground (AG) and belowground (BG) pathogens, arthropod herbivores, and nematodes (phytophages). We highlight recent progress in our understanding of within- and cross-compartment plant responses to these groups of phytophages in terms of

Plant-mediated systemic interactions between pathogens, parasitic nematodes, and herbivores above- and belowground

NARCIS (Netherlands)

Biere, A.; Goverse, Aska

2016-01-01

Plants are important mediators of interactions between aboveground (AG) and belowground (BG) pathogens, arthropod herbivores, and nematodes (phytophages). We highlight recent progress in our understanding of within and cross-compartment plant responses to these groups of phytophages in terms of

Generalist Bee Species on Brazilian Bee-Plant Interaction Networks

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Astrid de Matos Peixoto Kleinert

2012-01-01

Full Text Available Determining bee and plant interactions has an important role on understanding general biology of bee species as well as the potential pollinating relationship between them. Bee surveys have been conducted in Brazil since the end of the 1960s. Most of them applied standardized methods and had identified the plant species where the bees were collected. To analyze the most generalist bees on Brazilian surveys, we built a matrix of bee-plant interactions. We estimated the most generalist bees determining the three bee species of each surveyed locality that presented the highest number of interactions. We found 47 localities and 39 species of bees. Most of them belong to Apidae (31 species and Halictidae (6 families and to Meliponini (14 and Xylocopini (6 tribes. However, most of the surveys presented Apis mellifera and/or Trigona spinipes as the most generalist species. Apis mellifera is an exotic bee species and Trigona spinipes, a native species, is also widespread and presents broad diet breath and high number of individuals per colony.

Plant response to biotic stress: Is there a common epigenetic response during plant-pathogenic and symbiotic interactions?

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Zogli, Prince; Libault, Marc

2017-10-01

Plants constantly interact with pathogenic and symbiotic microorganisms. Recent studies have revealed several regulatory mechanisms controlling these interactions. Among them, the plant defense system is activated not only in response to pathogenic, but also in response to symbiotic microbes. Interestingly, shortly after symbiotic microbial recognition, the plant defense system is suppressed to promote plant infection by symbionts. Research studies have demonstrated the influence of the plant epigenome in modulating both pathogenic and symbiotic plant-microbe interactions, thereby influencing plant survival, adaptation and evolution of the plant response to microbial infections. It is however unclear if plant pathogenic and symbiotic responses share similar epigenomic profiles or if epigenomic changes differentially regulate plant-microbe symbiosis and pathogenesis. In this mini-review, we provide an update of the current knowledge of epigenomic control on plant immune responses and symbiosis, with a special attention being paid to knowledge gap and potential strategies to fill-in the missing links. Copyright © 2017 Elsevier B.V. All rights reserved.

Volatile communication in plant-aphid interactions.

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de Vos, Martin; Jander, Georg

2010-08-01

Volatile communication plays an important role in mediating the interactions between plants, aphids, and other organisms in the environment. In response to aphid infestation, many plants initiate indirect defenses through the release of volatiles that attract ladybugs, parasitoid wasps, and other aphid-consuming predators. Aphid-induced volatile release in the model plant Arabidopsis thaliana requires the jasmonate signaling pathway. Volatile release is also induced by infection with aphid-transmitted viruses. Consistent with mathematical models of optimal transmission, viruses that are acquired rapidly by aphids induce volatile release to attract migratory aphids, but discourage long-term aphid feeding. Although the ecology of these interactions is well-studied, further research is needed to identify the molecular basis of aphid-induced and virus-induced changes in plant volatile release. Copyright 2010 Elsevier Ltd. All rights reserved.

Plant-microbe and plant-insect interactions meet common grounds

NARCIS (Netherlands)

Schenk, P.; McGrath, K.C.; Lorito, M.; Pieterse, C.M.J.

2008-01-01

Plant–microbe and plant–insect interactions are of global importance for agriculture and of high interest to many plant scientists, microbiologists and entomologists. Traditionally, plant–microbe and plant–insect interactions have been looked at as two separate issues, but in recent years it has

Plant Host Finding by Parasitic Plants: A New Perspective on Plant to Plant Communication

OpenAIRE

Mescher, Mark C; Runyon, Justin B; De Moraes, Consuelo M

2006-01-01

Plants release airborne chemicals that can convey ecologically relevant information to other organisms. These plant volatiles are known to mediate a large array of, often complex, interactions between plants and insects. It has been suggested that plant volatiles may have similar importance in mediating interactions among plant species, but there are few well-documented examples of plant-to-plant communication via volatiles, and the ecological significance of such interactions has been much d...

Two-way plant mediated interactions between root-associated microbes and insects: from ecology to mechanisms

Directory of Open Access Journals (Sweden)

Nurmi ePangesti

2013-10-01

Full Text Available Plants are members of complex communities and function as a link between above- and below-ground organisms. Associations between plants and soil-borne microbes commonly occur and have often been found beneficial for plant fitness. Root-associated microbes may trigger physiological changes in the host plant that influence interactions between plants and aboveground insects at several trophic levels. Aboveground, plants are under continuous attack by insect herbivores and mount multiple responses that also have systemic effects on belowground microbes. Until recently, both ecological and mechanistic studies have mostly focused on exploring these below- and above-ground interactions using simplified systems involving both single microbe and herbivore species, which is far from the naturally occurring interactions. Increasing the complexity of the systems studied is required to increase our understanding of microbe - plant - insect interactions and to gain more benefit from the use of non-pathogenic microbes in agriculture. In this review, we explore how colonization by either single non-pathogenic microbe species or a community of such microbes belowground affects plant growth and defense and how this affects the interactions of plants with aboveground insects at different trophic levels. Moreover, we review how plant responses to foliar herbivory by insects belonging to different feeding guilds affect interactions of plants with non-pathogenic soil-borne microbes. The role of phytohormones in coordinating plant growth, plant defenses against foliar herbivores while simultaneously establishing associations with non-pathogenic soil microbes is discussed.

Three-way interaction among plants, bacteria, and coleopteran insects.

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Wielkopolan, Beata; Obrępalska-Stęplowska, Aleksandra

2016-08-01

Coleoptera, the largest and the most diverse Insecta order, is characterized by multiple adaptations to plant feeding. Insect-associated microorganisms can be important mediators and modulators of interactions between insects and plants. Interactions between plants and insects are highly complex and involve multiple factors. There are various defense mechanisms initiated by plants upon attack by herbivorous insects, including the development of morphological structures and the synthesis of toxic secondary metabolites and volatiles. In turn, herbivores have adapted to feeding on plants and further sophisticated adaptations to overcome plant responses may continue to evolve. Herbivorous insects may detoxify toxic phytocompounds, sequester poisonous plant factors, and alter their own overall gene expression pattern. Moreover, insects are associated with microbes, which not only considerably affect insects, but can also modify plant defense responses to the benefit of their host. Plants are also frequently associated with endophytes, which may act as bioinsecticides. Therefore, it is very important to consider the factors influencing the interaction between plants and insects. Herbivorous insects cause considerable damage to global crop production. Coleoptera is the largest and the most diverse order in the class Insecta. In this review, various aspects of the interactions among insects, microbes, and plants are described with a focus on coleopteran species, their bacterial symbionts, and their plant hosts to demonstrate that many factors contribute to the success of coleopteran herbivory.

Microbial brokers of insect-plant interactions revisited.

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Douglas, Angela E

2013-07-01

Recent advances in sequencing methods have transformed the field of microbial ecology, making it possible to determine the composition and functional capabilities of uncultured microorganisms. These technologies have been instrumental in the recognition that resident microorganisms can have profound effects on the phenotype and fitness of their animal hosts by modulating the animal signaling networks that regulate growth, development, behavior, etc. Against this backdrop, this review assesses the impact of microorganisms on insect-plant interactions, in the context of the hypothesis that microorganisms are biochemical brokers of plant utilization by insects. There is now overwhelming evidence for a microbial role in insect utilization of certain plant diets with an extremely low or unbalanced nutrient content. Specifically, microorganisms enable insect utilization of plant sap by synthesizing essential amino acids. They also can broker insect utilization of plant products of extremely high lignocellulose content, by enzymatic breakdown of complex plant polysaccharides, nitrogen fixation, and sterol synthesis. However, the experimental evidence for microbial-mediated detoxification of plant allelochemicals is limited. The significance of microorganisms as brokers of plant utilization by insects is predicted to vary, possibly widely, as a result of potentially complex interactions between the composition of the microbiota and the diet and insect developmental age or genotype. For every insect species feeding on plant material, the role of resident microbiota as biochemical brokers of plant utilization is a testable hypothesis.

A pharm-ecological perspective of terrestrial and aquatic plant-herbivore interactions.

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Forbey, Jennifer Sorensen; Dearing, M Denise; Gross, Elisabeth M; Orians, Colin M; Sotka, Erik E; Foley, William J

2013-04-01

We describe some recent themes in the nutritional and chemical ecology of herbivores and the importance of a broad pharmacological view of plant nutrients and chemical defenses that we integrate as "Pharm-ecology". The central role that dose, concentration, and response to plant components (nutrients and secondary metabolites) play in herbivore foraging behavior argues for broader application of approaches derived from pharmacology to both terrestrial and aquatic plant-herbivore systems. We describe how concepts of pharmacokinetics and pharmacodynamics are used to better understand the foraging phenotype of herbivores relative to nutrient and secondary metabolites in food. Implementing these concepts into the field remains a challenge, but new modeling approaches that emphasize tradeoffs and the properties of individual animals show promise. Throughout, we highlight similarities and differences between the historic and future applications of pharm-ecological concepts in understanding the ecology and evolution of terrestrial and aquatic interactions between herbivores and plants. We offer several pharm-ecology related questions and hypotheses that could strengthen our understanding of the nutritional and chemical factors that modulate foraging behavior of herbivores across terrestrial and aquatic systems.

Fires can benefit plants by disrupting antagonistic interactions.

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García, Y; Castellanos, M C; Pausas, J G

2016-12-01

Fire has a key role in the ecology and evolution of many ecosystems, yet its effects on plant-insect interactions are poorly understood. Because interacting species are likely to respond to fire differently, disruptions of the interactions are expected. We hypothesized that plants that regenerate after fire can benefit through the disruption of their antagonistic interactions. We expected stronger effects on interactions with specialist predators than with generalists. We studied two interactions between two Mediterranean plants (Ulex parviflorus, Asphodelus ramosus) and their specialist seed predators after large wildfires. In A. ramosus we also studied the generalist herbivores. We sampled the interactions in burned and adjacent unburned areas during 2 years by estimating seed predation, number of herbivores and fruit set. To assess the effect of the distance to unburned vegetation we sampled plots at two distance classes from the fire perimeter. Even 3 years after the fires, Ulex plants experienced lower seed damage by specialists in burned sites. The presence of herbivores on Asphodelus decreased in burned locations, and the variability in their presence was significantly related to fruit set. Generalist herbivores were unaffected. We show that plants can benefit from fire through the disruption of their antagonistic interactions with specialist seed predators for at least a few years. In environments with a long fire history, this effect might be one additional mechanism underlying the success of fire-adapted plants.

Catechin-metal interactions as a mechanism for conditional allelopathy by the invasive plant, Centaurea maculosa

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Jarrod L. Pollock; Ragan M. Callaway; Giles C. Thelen; William E. Holben

2009-01-01

Considering variation, or conditionality, in the ways that plants compete for resources, facilitate or indirectly interact with each other has been crucial for understanding the relative importance of these interactions in the organization of plant communities (Tilman 1985; Wilson & Keddy 1986; Kitzberger, Steinaker & Veblen 2000; Levine 2000; Brooker...

Secondary metabolites in fungus-plant interactions

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Pusztahelyi, Tünde; Holb, Imre J.; Pócsi, István

2015-01-01

Fungi and plants are rich sources of thousands of secondary metabolites. The genetically coded possibilities for secondary metabolite production, the stimuli of the production, and the special phytotoxins basically determine the microscopic fungi-host plant interactions and the pathogenic lifestyle of fungi. The review introduces plant secondary metabolites usually with antifungal effect as well as the importance of signaling molecules in induced systemic resistance and systemic acquired resistance processes. The review also concerns the mimicking of plant effector molecules like auxins, gibberellins and abscisic acid by fungal secondary metabolites that modulate plant growth or even can subvert the plant defense responses such as programmed cell death to gain nutrients for fungal growth and colonization. It also looks through the special secondary metabolite production and host selective toxins of some significant fungal pathogens and the plant response in form of phytoalexin production. New results coming from genome and transcriptional analyses in context of selected fungal pathogens and their hosts are also discussed. PMID:26300892

A conceptual framework for studying the strength of plant-animal mutualistic interactions.

Science.gov (United States)

Vázquez, Diego P; Ramos-Jiliberto, Rodrigo; Urbani, Pasquinell; Valdovinos, Fernanda S

2015-04-01

The strength of species interactions influences strongly the structure and dynamics of ecological systems. Thus, quantifying such strength is crucial to understand how species interactions shape communities and ecosystems. Although the concepts and measurement of interaction strength in food webs have received much attention, there has been comparatively little progress in the context of mutualism. We propose a conceptual scheme for studying the strength of plant-animal mutualistic interactions. We first review the interaction strength concepts developed for food webs, and explore how these concepts have been applied to mutualistic interactions. We then outline and explain a conceptual framework for defining ecological effects in plant-animal mutualisms. We give recommendations for measuring interaction strength from data collected in field studies based on a proposed approach for the assessment of interaction strength in plant-animal mutualisms. This approach is conceptually integrative and methodologically feasible, as it focuses on two key variables usually measured in field studies: the frequency of interactions and the fitness components influenced by the interactions. © 2015 John Wiley & Sons Ltd/CNRS.

Macromolecule exchange in Cuscuta-host plant interactions.

Science.gov (United States)

Kim, Gunjune; Westwood, James H

2015-08-01

Cuscuta species (dodders) are parasitic plants that are able to grow on many different host plants and can be destructive to crops. The connections between Cuscuta and its hosts allow movement of not only water and small nutrients, but also macromolecules including mRNA, proteins and viruses. Recent studies show that RNAs move bidirectionally between hosts and parasites and involve a large number of different genes. Although the function of mobile mRNAs has not been demonstrated in this system, small RNAs are also transmitted and a silencing construct expressed in hosts is able to affect expression of the target gene in the parasite. High throughput sequencing of host-parasite associations has the potential to greatly accelerate understanding of this remarkable interaction. Copyright © 2015 Elsevier Ltd. All rights reserved.

Beneficial interactions between plants and soil microbes

DEFF Research Database (Denmark)

Ravnskov, S.

2012-01-01

with Arbuscular Mycorrhizal Fungi (AMF); thus the relation between root pathogens and most plants under field conditions is an interaction between AM and pathogens. The AM symbiosis has functionally been characterised as the reciprocal exchange of nutrients between the symbionts: the fungus is obligate biotrophic......The microbial community in the rhizosphere plays a key role in plant growth and -health, either directly by influencing plant nutrient uptake and by causing disease, or indirectly via microbial interactions in the rhizosphere. The majority of field grown crops (70-80 %) naturally form symbiosis...

A conserved pattern in plant-mediated interactions between herbivores

OpenAIRE

Lu Jing; Robert Christelle A. M.; Lou Yonggen; Erb Matthias

2016-01-01

Abstract Plant?mediated interactions between herbivores are important determinants of community structure and plant performance in natural and agricultural systems. Current research suggests that the outcome of the interactions is determined by herbivore and plant identity, which may result in stochastic patterns that impede adaptive evolution and agricultural exploitation. However, few studies have systemically investigated specificity versus general patterns in a given plant system by varyi...

Man-machine interaction in Canadian nuclear power plants

International Nuclear Information System (INIS)

Olmstead, R.A.

1994-01-01

The design of man-machine interaction in the CANDU plants has evolved considerably over several generations of plants, from the first Douglas Point plant through to the next generation of plants represented by new designs like CANDU 3. In the early plants, the control room configuration was based on designers' projections of control interface requirements. With succeeding generations of designs, there has been an evolution towards a more systematic consideration of human strengths and weaknesses, increasing attention to formal requirements definition, and incorporation of a larger base of operational experience. This paper describes the design of the man-machine interaction for third generation CANDU-3 control rooms for improved operator reliability and reduced costs. (author). 13 refs., 3 figs

The importance of aboveground–belowground interactions on the evolution and maintenance of variation in plant defense traits

Science.gov (United States)

van Geem, Moniek; Gols, Rieta; van Dam, Nicole M.; van der Putten, Wim H.; Fortuna, Taiadjana; Harvey, Jeffrey A.

2013-01-01

Over the past two decades a growing body of empirical research has shown that many ecological processes are mediated by a complex array of indirect interactions occurring between rhizosphere-inhabiting organisms and those found on aboveground plant parts. Aboveground–belowground studies have thus far focused on elucidating processes and underlying mechanisms that mediate the behavior and performance of invertebrates in opposite ecosystem compartments. Less is known about genetic variation in plant traits such as defense as that may be driven by above- and belowground trophic interactions. For instance, although our understanding of genetic variation in aboveground plant traits and its effects on community-level interactions is well developed, little is known about the importance of aboveground–belowground interactions in driving this variation. Plant traits may have evolved in response to selection pressures from above- and below-ground interactions from antagonists and mutualists. Here, we discuss gaps in our understanding of genetic variation in plant-related traits as they relate to aboveground and belowground multitrophic interactions. When metabolic resources are limiting, multiple attacks by antagonists in both domains may lead to trade-offs. In nature, these trade-offs may critically depend upon their effects on plant fitness. Natural enemies of herbivores may also influence selection for different traits via top–down control. At larger scales these interactions may generate evolutionary “hotspots” where the expression of various plant traits is the result of strong reciprocal selection via direct and indirect interactions. The role of abiotic factors in driving genetic variation in plant traits is also discussed. PMID:24348484

Chemical signaling involved in plant-microbe interactions.

Science.gov (United States)

Chagas, Fernanda Oliveira; Pessotti, Rita de Cassia; Caraballo-Rodríguez, Andrés Mauricio; Pupo, Mônica Tallarico

2018-03-05

Microorganisms are found everywhere, and they are closely associated with plants. Because the establishment of any plant-microbe association involves chemical communication, understanding crosstalk processes is fundamental to defining the type of relationship. Although several metabolites from plants and microbes have been fully characterized, their roles in the chemical interplay between these partners are not well understood in most cases, and they require further investigation. In this review, we describe different plant-microbe associations from colonization to microbial establishment processes in plants along with future prospects, including agricultural benefits.

Plant host finding by parasitic plants: A new perspective on plant to plant communication

Science.gov (United States)

Mark C. Mescher; Justin B. Runyon; Consuelo M. De Moraes

2006-01-01

Plants release airborne chemicals that can convey ecologically relevant information to other organisms. These plant volatiles are known to mediate a large array of, often complex, interactions between plants and insects. It has been suggested that plant volatiles may have similar importance in mediating interactions among plant species, but there are few well-...

Nitrogen signalling in plant interactions with associative and endophytic diazotrophic bacteria.

Science.gov (United States)

Carvalho, T L G; Balsemão-Pires, E; Saraiva, R M; Ferreira, P C G; Hemerly, A S

2014-10-01

Some beneficial plant-interacting bacteria can biologically fix N2 to plant-available ammonium. Biological nitrogen fixation (BNF) is an important source of nitrogen (N) input in agriculture and represents a promising substitute for chemical N fertilizers. Diazotrophic bacteria have the ability to develop different types of root associations with different plant species. Among the highest rates of BNF are those measured in legumes nodulated by endosymbionts, an already very well documented model of plant-diazotrophic bacterial association. However, it has also been shown that economically important crops, especially monocots, can obtain a substantial part of their N needs from BNF by interacting with associative and endophytic diazotrophic bacteria, that either live near the root surface or endophytically colonize intercellular spaces and vascular tissues of host plants. One of the best reported outcomes of this association is the promotion of plant growth by direct and indirect mechanisms. Besides fixing N, these bacteria can also produce plant growth hormones, and some species are reported to improve nutrient uptake and increase plant tolerance against biotic and abiotic stresses. Thus, this particular type of plant-bacteria association consists of a natural beneficial system to be explored; however, the regulatory mechanisms involved are still not clear. Plant N status might act as a key signal, regulating and integrating various metabolic processes that occur during association with diazotrophic bacteria. This review will focus on the recent progress in understanding plant association with associative and endophytic diazotrophic bacteria, particularly on the knowledge of the N networks involved in BNF and in the promotion of plant growth. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Chemical ecology of insect-plant interactions: ecological significance of plant secondary metabolites.

Science.gov (United States)

Nishida, Ritsuo

2014-01-01

Plants produce a diverse array of secondary metabolites as chemical barriers against herbivores. Many phytophagous insects are highly adapted to these allelochemicals and use such unique substances as the specific host-finding cues, defensive substances of their own, and even as sex pheromones or their precursors by selectively sensing, incorporating, and/or processing these phytochemicals. Insects also serve as pollinators often effectively guided by specific floral fragrances. This review demonstrates the ecological significance of such plant secondary metabolites in the highly diverse interactions between insects and plants.

UNDERSTANDING PLANT-SOIL RELATIONSHIPS USING CONTROLLED ENVIRONMENT FACILITIES

Science.gov (United States)

Although soil is a component of terrestrial ecosystems, it is comprised of a complex web of interacting organisms, and therefore, can be considered itself as an ecosystem. Soil microflora and fauna derive energy from plants and plant residues and serve important functions in mai...

Water use, productivity and interactions among desert plants

Energy Technology Data Exchange (ETDEWEB)

Ehleringer, J.R.

1992-11-17

Productivity, stability, and competitive interactions among ecosystem components within aridlands are key processes related directly to water in deserts. This project assumes that integrated aspects of plant metabolism provide insight into the structure and function of plant communities and ecosystems. While it is difficult to extrapolate from instantaneous physiological observations to higher scales, such as whole plant performance or to the interactions between plants as components of ecosystems, several key aspects of plant metabolism are scalable. Analyses of stable isotopic composition in plant tissues at natural abundance levels provide a useful tool that can provide insight into the consequences of physiological processes over temporal and spatial scales. Some plant processes continuously fractionate among light and heavy stable isotopic forms of an element; over time this results in integrated measures of plant metabolism. For example, carbon isotope fractionation during photosynthesis results in leaf carbon isotopic composition that is a measure of the set-point for photosynthetic metabolism and of water-use efficiency. Thus it provides information on the temporal scaling of a key physiological process.

Antagonistic interactions between plant competition and insect herbivory.

Science.gov (United States)

Schädler, Martin; Brandl, Roland; Haase, Josephine

2007-06-01

Interspecific competition between plants and herbivory by specialized insects can have synergistic effects on the growth and performance of the attacked host plant. We tested the hypothesis that competition between plants may also negatively affect the performance of herbivores as well as their top-down effect on the host plant. In such a case, the combined effects of competition and herbivory may be less than expected from a simple multiplicative response. In other words, competition and herbivory may interact antagonistically. In a greenhouse experiment, Poa annua was grown in the presence or absence of a competitor (either Plantago lanceolata or Trifolium repens), as well as with or without a Poa-specialist aphid herbivore. Both competition and herbivory negatively affected Poa growth. Competition also reduced aphid density on Poa. This effect could in part be explained by changes in the biomass and the nitrogen content of Poa shoots. In treatments with competitors, reduced aphid densities alleviated the negative effect of herbivory on above- and belowground Poa biomass. Hence, we were able to demonstrate an antagonistic interaction between plant-plant interspecific competition and herbivory. However, response indices suggested that antagonistic interactions between competition and herbivory were contingent on the identity of the competitor. We found the antagonistic effect only in treatments with T. repens as the competitor. We conclude that both competitor identity and the herbivore's ability to respond with changes in its density or activity to plant competition affect the magnitude and direction (synergistic vs. antagonistic) of the interaction between competition and herbivory on plant growth.

Evolutionary adaptation in three-way interactions between plants, microbes and arthropods

OpenAIRE

Biere, A.; Tack, A.J.M.

2013-01-01

Evolutionary adaptations in interactions between plants, microbes and arthropods are generally studied in interactions that involve only two of these groups, that is, plants and microbes, plants and arthropods or arthropods and microbes. We review the accumulating evidence from a wide variety of systems, including plant- and arthropod-associated microbes, and symbionts as well as antagonists, that selection and adaptation in seemingly two-way interactions between plants and microbes, plants a...

Climate impacts on bird and plant communities from altered animal-plant interactions

Science.gov (United States)

Martin, Thomas E.; Maron, John L.

2012-01-01

The contribution of climate change to declining populations of organisms remains a question of outstanding concern. Much attention to declining populations has focused on how changing climate drives phenological mismatches between animals and their food. Effects of climate on plant communities may provide an alternative, but particularly powerful, influence on animal populations because plants provide their habitats. Here, we show that abundances of deciduous trees and associated songbirds have declined with decreasing snowfall over 22 years of study in montane Arizona, USA. We experimentally tested the hypothesis that declining snowfall indirectly influences plants and associated birds by allowing greater over-winter herbivory by elk (Cervus canadensis). We excluded elk from one of two paired snowmelt drainages (10 ha per drainage), and replicated this paired experiment across three distant canyons. Over six years, we reversed multi-decade declines in plant and bird populations by experimentally inhibiting heavy winter herbivory associated with declining snowfall. Moreover, predation rates on songbird nests decreased in exclosures, despite higher abundances of nest predators, demonstrating the over-riding importance of habitat quality to avian recruitment. Thus, our results suggest that climate impacts on plant–animal interactions can have forceful ramifying effects on plants, birds, and ecological interactions.

Negative Plant-Soil Feedback and Positive Species Interaction in a Herbaceous Plant Community

NARCIS (Netherlands)

Bonanomi, G.; Rietkerk, M.; Dekker, S.C.; Mazzoleni, S.

2005-01-01

Increasing evidence shows that facilitative interaction and negative plant¿soil feedback are driving factors of plant population dynamics and community processes. We studied the intensity and the relative impact of negative feedback on clonal growth and seed germination of Scirpus holoschoenus, a

Effects of plant diversity on primary production and species interactions in brackish water angiosperm communities

DEFF Research Database (Denmark)

Salo, Tiina; Gustafsson, Camilla; Boström, Christoffer

2009-01-01

Research on plant biodiversity and ecosystem functioning has mainly focused on terrestrial ecosystems, and our understanding of how plant species diversity and interactions affect processes in marine ecosystems is still limited. To investigate if plant species richness and composition influence...... plant productivity in brackish water angiosperm communities, a 14 wk field experiment was conducted. Using a replacement design with a standardized initial aboveground biomass, shoots of Zostera marina, Potamogeton filiformis and P. perfoliatus were planted on a shallow, sandy bottom in replicated...

Plant neighbour identity matters to belowground interactions under controlled conditions.

Science.gov (United States)

Armas, Cristina; Pugnaire, Francisco Ignacio

2011-01-01

Root competition is an almost ubiquitous feature of plant communities with profound effects on their structure and composition. Far beyond the traditional view that plants interact mainly through resource depletion (exploitation competition), roots are known to be able to interact with their environment using a large variety of mechanisms that may inhibit or enhance access of other roots to the resource or affect plant growth (contest interactions). However, an extensive analysis on how these contest root interactions may affect species interaction abilities is almost lacking. In a common garden experiment with ten perennial plant species we forced pairs of plants of the same or different species to overlap their roots and analyzed how belowground contest interactions affected plant performance, biomass allocation patterns, and competitive abilities under abundant resource supply. Our results showed that net interaction outcome ranged from negative to positive, affecting total plant mass and allocation patterns. A species could be a strong competitor against one species, weaker against another one, and even facilitator to a third species. This leads to sets of species where competitive hierarchies may be clear but also to groups where such rankings are not, suggesting that intransitive root interactions may be crucial for species coexistence. The outcome of belowground contest interactions is strongly dependent on neighbours' identity. In natural plant communities this conditional outcome may hypothetically help species to interact in non-hierarchical and intransitive networks, which in turn might promote coexistence.

A perspective on plant origin radiolabeled compounds, their biological affinities and interaction between plant extracts with radiopharmaceuticals

International Nuclear Information System (INIS)

Zumrut Biber Muftuler, F.; Ayfer Yurt Kilcar; Perihan Unak

2015-01-01

Plant origin products having anticancer properties come into prominence due to widespread of cancer. There is significant increase on the usage of plant origin products and their purification to investigate the potential use at the treatment and diagnosis. Plant origin radiolabeled compounds have been attracting more scientific attention since the achievement of earlier researches. Furthermore, plant extracts are consumed quite a lot with unknown side effects of their contents. Researchers focus on investigation of their interactions with radiopharmaceuticals. Current review is carried out to evaluate the contribution of plant extracts for the development of new plant origin radiolabeled ( 125 / 131 I, 99m Tc) compounds for imaging and/or therapy and to investigate the interaction of plant extracts with radiopharmaceuticals. (author)

Water use, productivity and interactions among desert plants

Energy Technology Data Exchange (ETDEWEB)

Ehleringer, J.R.

1992-11-17

Water plays a central role affecting all aspects of the dynamics in aridland ecosystems. Productivity, stability, and competitive interactions among ecosystem components within aridlands are key processes related directly to water in deserts. The ecological studies in this project revolve around one fundamental premise: that integrated aspects of plant metabolism provide insight into the structure and function of plant communities and ecosystems. While it is difficult to extrapolate from instantaneous physiological observations to higher scales, such as whole plant performance or to interactions between plants as components of ecosystems, several key aspects of plant metabolism are scalable. Analyses of stable isotopic composition in plant tissues at natural abundance levels provide a useful tool that can provide insight into the consequences of physiological processes over temporal and spatial scales. Some plant processes continuously fractionate among light and heavy stable isotopic forms of an element; over time this results in integrated measures of plant metabolism. For example, carbon isotope fractionation during photosynthesis results in leaf carbon isotopic composition that is a measure of the set-point for photosynthetic metabolism and of water-use efficiency. Thus it provides information on the temporal scaling of a key physiological process. In contrast, hydrogen is not fractionated during water uptake through the root. Soil water availability in shallow, deep, and/or groundwater layers vary spatially; therefore hydrogen isotope ratios of xylem sap provide a direct measure of the water source currently used by a plant. The longer-term record of carbon and hydrogen isotope ratios is recorded annually in xylem tissues (tree rings). The research in this project addresses variation in stable isotopic composition of aridland plants and its consequences for plant performance and community-level interactions.

Understanding plant cell-wall remodelling during the symbiotic interaction between Tuber melanosporum and Corylus avellana using a carbohydrate microarray.

Science.gov (United States)

Sillo, Fabiano; Fangel, Jonatan U; Henrissat, Bernard; Faccio, Antonella; Bonfante, Paola; Martin, Francis; Willats, William G T; Balestrini, Raffaella

2016-08-01

A combined approach, using a carbohydrate microarray as a support for genomic data, has revealed subtle plant cell-wall remodelling during Tuber melanosporum and Corylus avellana interaction. Cell walls are involved, to a great extent, in mediating plant-microbe interactions. An important feature of these interactions concerns changes in the cell-wall composition during interaction with other organisms. In ectomycorrhizae, plant and fungal cell walls come into direct contact, and represent the interface between the two partners. However, very little information is available on the re-arrangement that could occur within the plant and fungal cell walls during ectomycorrhizal symbiosis. Taking advantage of the Comprehensive Microarray Polymer Profiling (CoMPP) technology, the current study has had the aim of monitoring the changes that take place in the plant cell wall in Corylus avellana roots during colonization by the ascomycetous ectomycorrhizal fungus T. melanosporum. Additionally, genes encoding putative plant cell-wall degrading enzymes (PCWDEs) have been identified in the T. melanosporum genome, and RT-qPCRs have been performed to verify the expression of selected genes in fully developed C. avellana/T. melanosporum ectomycorrhizae. A localized degradation of pectin seems to occur during fungal colonization, in agreement with the growth of the ectomycorrhizal fungus through the middle lamella and with the fungal gene expression of genes acting on these polysaccharides.

How plants cope with biotic interactions

NARCIS (Netherlands)

Van Dam, N.M.

2009-01-01

In their natural environment, plants interact with many different organisms. The nature of these interactions may range from positive, for example interactions with pollinators, to negative, such as interactions with pathogens and herbivores. In this special issue, the contributors provide several

Plant odour plumes as mediators of plant-insect interactions.

Science.gov (United States)

Beyaert, Ivo; Hilker, Monika

2014-02-01

Insect olfactory orientation along odour plumes has been studied intensively with respect to pheromonal communication, whereas little knowledge is available on how plant odour plumes (POPs) affect olfactory searching by an insect for its host plants. The primary objective of this review is to examine the role of POPs in the attraction of insects. First, we consider parameters of an odour source and the environment which determine the size, shape and structure of an odour plume, and we apply that knowledge to POPs. Second, we compare characteristics of insect pheromonal plumes and POPs. We propose a 'POP concept' for the olfactory orientation of insects to plants. We suggest that: (i) an insect recognises a POP by means of plant volatile components that are encountered in concentrations higher than a threshold detection limit and that occur in a qualitative and quantitative blend indicating a resource; (ii) perception of the fine structure of a POP enables an insect to distinguish a POP from an unspecific odorous background and other interfering plumes; and (iii) an insect can follow several POPs to their sources, and may leave the track of one POP and switch to another one if this conveys a signal with higher reliability or indicates a more suitable resource. The POP concept proposed here may be a useful tool for research in olfactory-mediated plant-insect interactions. © 2013 The Authors. Biological Reviews © 2013 Cambridge Philosophical Society.

Herbivore-induced plant volatiles and tritrophic interactions across spatial scales.

Science.gov (United States)

Aartsma, Yavanna; Bianchi, Felix J J A; van der Werf, Wopke; Poelman, Erik H; Dicke, Marcel

2017-12-01

Herbivore-induced plant volatiles (HIPVs) are an important cue used in herbivore location by carnivorous arthropods such as parasitoids. The effects of plant volatiles on parasitoids have been well characterised at small spatial scales, but little research has been done on their effects at larger spatial scales. The spatial matrix of volatiles ('volatile mosaic') within which parasitoids locate their hosts is dynamic and heterogeneous. It is shaped by the spatial pattern of HIPV-emitting plants, the concentration, chemical composition and breakdown of the emitted HIPV blends, and by environmental factors such as wind, turbulence and vegetation that affect transport and mixing of odour plumes. The volatile mosaic may be exploited differentially by different parasitoid species, in relation to species traits such as sensory ability to perceive volatiles and the physical ability to move towards the source. Understanding how HIPVs influence parasitoids at larger spatial scales is crucial for our understanding of tritrophic interactions and sustainable pest management in agriculture. However, there is a large gap in our knowledge on how volatiles influence the process of host location by parasitoids at the landscape scale. Future studies should bridge the gap between the chemical and behavioural ecology of tritrophic interactions and landscape ecology. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

Calcium Signalling in Plant Biotic Interactions

Directory of Open Access Journals (Sweden)

Didier Aldon

2018-02-01

Full Text Available Calcium (Ca2+ is a universal second messenger involved in various cellular processes, leading to plant development and to biotic and abiotic stress responses. Intracellular variation in free Ca2+ concentration is among the earliest events following the plant perception of environmental change. These Ca2+ variations differ in their spatio-temporal properties according to the nature, strength and duration of the stimulus. However, their conversion into biological responses requires Ca2+ sensors for decoding and relaying. The occurrence in plants of calmodulin (CaM but also of other sets of plant-specific Ca2+ sensors such as calmodulin-like proteins (CMLs, Ca2+-dependent protein kinases (CDPKs and calcineurin B-like proteins (CBLs indicate that plants possess specific tools and machineries to convert Ca2+ signals into appropriate responses. Here, we focus on recent progress made in monitoring the generation of Ca2+ signals at the whole plant or cell level and their long distance propagation during biotic interactions. The contribution of CaM/CMLs and CDPKs in plant immune responses mounted against bacteria, fungi, viruses and insects are also presented.

Understanding Plant Nitrogen Metabolism through Metabolomics and Computational Approaches

Directory of Open Access Journals (Sweden)

Perrin H. Beatty

2016-10-01

Full Text Available A comprehensive understanding of plant metabolism could provide a direct mechanism for improving nitrogen use efficiency (NUE in crops. One of the major barriers to achieving this outcome is our poor understanding of the complex metabolic networks, physiological factors, and signaling mechanisms that affect NUE in agricultural settings. However, an exciting collection of computational and experimental approaches has begun to elucidate whole-plant nitrogen usage and provides an avenue for connecting nitrogen-related phenotypes to genes. Herein, we describe how metabolomics, computational models of metabolism, and flux balance analysis have been harnessed to advance our understanding of plant nitrogen metabolism. We introduce a model describing the complex flow of nitrogen through crops in a real-world agricultural setting and describe how experimental metabolomics data, such as isotope labeling rates and analyses of nutrient uptake, can be used to refine these models. In summary, the metabolomics/computational approach offers an exciting mechanism for understanding NUE that may ultimately lead to more effective crop management and engineered plants with higher yields.

Plant-pollinator interactions in a biodiverse meadow are rather stable and tight for 3 consecutive years.

Science.gov (United States)

Fang, Qiang; Huang, Shuangquan

2016-05-01

Plant-pollinator interactions can be highly variable across years in natural communities. Although variation in the species composition and its basic structure has been investigated to understand the dynamic nature of pollination networks, little is known about the temporal dynamic of interaction strength between the same plant and pollinator species in any natural community. Pollinator-mediated selection on the evolution of floral traits could be diminished if plant-pollinator interactions vary temporally. To quantify the temporal variation in plant-pollinator interactions and the interaction strength (observed visits), we compared weighted networks between plants and pollinators in a biodiverse alpine meadow in Shangri-La, southwest China for 3 consecutive years. Although plant-pollinator interactions were highly dynamic such that identical interactions only accounted for 10.7% of the total between pair years, the diversity of interactions was stable. These identical interactions contributed 41.2% of total visits and were similar in strength and weighted nestedness. For plant species, 72.6% of species were visited by identical pollinator species between pair years, accounting for over half of the total visits and three-quarters at the functional group level. More generalized pollinators contributed more connectiveness and were more central in networks across years. However, there was no similar or even opposite trend for plant species, which suggested that specialized plant species may also be central in pollinator networks. The variation in pollinator composition decreased as pollinator species numbers increased, suggesting that generalized plants experienced stable pollinator partition. The stable, tight interactions between generalized pollinators and specialized plants represent cornerstones of the studied community. © 2016 International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and John Wiley & Sons Australia, Ltd.

Influence of student-designed experiments with fast plants on their understanding of plants and of scientific inquiry

Science.gov (United States)

Akey, Ann Kosek

2000-10-01

This dissertation investigates the influence of student designed experiments with Fast Plants in an undergraduate agroecology course on the students' conceptual understanding of plant life cycles and on their procedural understanding of scientific experimentation. It also considers students' perspectives on the value of these experiences. Data sources included semi-structured interviews with students and the instructor, a written task, course evaluations, and observations of class meetings. Students came into the course having strong practical experience with plants from their agricultural backgrounds. Students did not always connect aspects of plant biology that they studied in class, particularly respiration and photosynthesis, to plant growth requirements. The instructor was able to bridge the gap between some practical knowledge and textbook knowledge with experiences other than the Fast Plant project. Most students held an incomplete picture of plant reproduction that was complicated by differences between agricultural and scientific vocabulary. There is need for teaching approaches that help students tie together their knowledge of plants into a cohesive framework. Experiences that help students draw on their background knowledge related to plants, and which give students the opportunity to examine and discuss their ideas, may help students make more meaningful connections. The Fast Plant project, a positive experience for most students, was seen by these undergraduate students as being more helpful in learning about scientific experimentation than about plants. The process of designing and carrying out their own experiments gave students insight into experimentation, provoked their curiosity, and resulted in a sense of ownership and accomplishment.

Does plant-Microbe interaction confer stress tolerance in plants: A review?

Science.gov (United States)

Kumar, Akhilesh; Verma, Jay Prakash

2018-03-01

The biotic and abiotic stresses are major constraints for crop yield, food quality and global food security. A number of parameters such as physiological, biochemical, molecular of plants are affected under stress condition. Since the use of inorganic fertilizers and pesticides in agriculture practices cause degradation of soil fertility and environmental pollutions. Hence it is necessary to develop safer and sustainable means for agriculture production. The application of plant growth promoting microbes (PGPM) and mycorrhizal fungi enhance plant growth, under such conditions. It offers an economically fascinating and ecologically sound ways for protecting plants against stress condition. PGPM may promote plant growth by regulating plant hormones, improve nutrition acquisition, siderophore production and enhance the antioxidant system. While acquired systemic resistance (ASR) and induced systemic resistance (ISR) effectively deal with biotic stress. Arbuscular mycorrhiza (AM) enhance the supply of nutrients and water during stress condition and increase tolerance to stress. This plant-microbe interaction is vital for sustainable agriculture and industrial purpose, because it depends on biological processes and replaces conventional agriculture practices. Therefore, microbes may play a key role as an ecological engineer to solve environmental stress problems. So, it is a feasible and potential technology in future to feed global population at available resources with reduced impact on environmental quality. In this review, we have attempted to explore about abiotic and biotic stress tolerant beneficial microorganisms and their modes of action to enhance the sustainable agricultural production. Copyright © 2017 Elsevier GmbH. All rights reserved.

Plant life history and above–belowground interactions

NARCIS (Netherlands)

Deyn, de Gerlinde

2017-01-01

The importance of above–belowground interactions for plant growth and community dynamics became clear in the last decades, whereas the numerous studies on plant life history improved our knowledge on eco-evolutionary dynamics. However, surprisingly few studies have linked both research fields

Interactive nuclear plant analyzer for VVER-440 reactor

International Nuclear Information System (INIS)

Shier, W.; Horak, W.; Kennett, R.

1992-05-01

This document discusses an interactive nuclear plant analyzer (NPA) which has been developed for a VVER-440, Model 213 reactor for use in the training of plant personnel, the development and verification of plant operating procedures, and in the analysis of various anticipated operational occurrences and accident scenarios. This NPA is operational on an IBM RISC-6000 workstation and utilizes the RELAP5/MOD2 computer code for the calculation of the VVER-440 reactor response to the interactive commands initiated by the NPA operator

Plant-plant interactions mediate the plastic and genotypic response of Plantago asiatica to CO

NARCIS (Netherlands)

Loon, Van Marloes P.; Rietkerk, Max; Dekker, Stefan C.; Hikosaka, Kouki; Ueda, Miki U.; Anten, Niels P.R.

2016-01-01

Background and Aims The rising atmospheric CO₂ concentration ([CO₂]) is a ubiquitous selective force that may strongly impact species distribution and vegetation functioning. Plant-plant interactions could mediate the trajectory of vegetation responses to elevated

Interactions between fluvial forces and vegetation size, density and morphology influence plant mortality during experimental floods

Science.gov (United States)

Stella, J. C.; Kui, L.; Manners, R.; Wilcox, A. C.; Lightbody, A.; Sklar, L. S.

2015-12-01

Introduction and methods Fluvial disturbance is a key driver of riparian vegetation dynamics in river corridors. Despite an increasing understanding of ecohydraulic interactions between plants and fluvial forces, the interactive influences of plant morphology and sediment supply on plant mortality, a key demographic factor, are largely unknown. To better understand these processes, we designed and conducted a series of flume experiments to: (1) quantify effects of plant traits that interact with flow and sediment transport on plant loss to scour during floods; and (2) predict plant dislodgement for different species across a range of plant sizes, patch densities, and sediment condition (equilibrium transport versus sediment deficit). We ran ten experimental floods in a 28 m long × 0.6 m wide × 0.71 m tall flume, using live, 1-3 year-old tamarisk and cottonwood seedlings with contrasting morphologies with varied combinations of size and density. Results and discussion Both sediment supply and plant traits (morphology and composition) have significant impacts on plant vulnerability during floods. Sediment deficit resulted in bed degradation and a 35% greater risk of plant loss compared to equilibrium sediment conditions. The probability of plant dislodgement in sparse patches was 4.5 times greater than in dense patches. Tamarisk plants and patches had greater frontal area, basal diameter and longer roots compared to cottonwood across all seedling heights. These traits, as well as its lower crown position reduced tamarisk's vulnerability to scour by 75%. Compared with cottonwood, tamarisk exhibits better resistance to floods, due to its greater root biomass and longer roots that stabilize soil, and its greater frontal area and lower crown that effectively trap sediment. These traits likely contribute to riverscape-scale changes in channel morphology that are evident where tamarisk has invaded native riparian communities, and explain the persistence of tamarisk

Data integration aids understanding of butterfly-host plant networks.

Science.gov (United States)

Muto-Fujita, Ai; Takemoto, Kazuhiro; Kanaya, Shigehiko; Nakazato, Takeru; Tokimatsu, Toshiaki; Matsumoto, Natsushi; Kono, Mayo; Chubachi, Yuko; Ozaki, Katsuhisa; Kotera, Masaaki

2017-03-06

Although host-plant selection is a central topic in ecology, its general underpinnings are poorly understood. Here, we performed a case study focusing on the publicly available data on Japanese butterflies. A combined statistical analysis of plant-herbivore relationships and taxonomy revealed that some butterfly subfamilies in different families feed on the same plant families, and the occurrence of this phenomenon more than just by chance, thus indicating the independent acquisition of adaptive phenotypes to the same hosts. We consequently integrated plant-herbivore and plant-compound relationship data and conducted a statistical analysis to identify compounds unique to host plants of specific butterfly families. Some of the identified plant compounds are known to attract certain butterfly groups while repelling others. The additional incorporation of insect-compound relationship data revealed potential metabolic processes that are related to host plant selection. Our results demonstrate that data integration enables the computational detection of compounds putatively involved in particular interspecies interactions and that further data enrichment and integration of genomic and transcriptomic data facilitates the unveiling of the molecular mechanisms involved in host plant selection.

Comparing human-Salmonella with plant-Salmonella protein-protein interaction predictions

Directory of Open Access Journals (Sweden)

Sylvia eSchleker

2015-01-01

Full Text Available Salmonellosis is the most frequent food-borne disease world-wide and can be transmitted to humans by a variety of routes, especially via animal and plant products. Salmonella bacteria are believed to use not only animal and human but also plant hosts despite their evolutionary distance. This raises the question if Salmonella employs similar mechanisms in infection of these diverse hosts. Given that most of our understanding comes from its interaction with human hosts, we investigate here to what degree knowledge of Salmonella-human interactions can be transferred to the Salmonella-plant system. Reviewed are recent publications on analysis and prediction of Salmonella-host interactomes. Putative protein-protein interactions (PPIs between Salmonella and its human and Arabidopsis hosts were retrieved utilizing purely interolog-based approaches in which predictions were inferred based on available sequence and domain information of known PPIs, and machine learning approaches that integrate a larger set of useful information from different sources. Transfer learning is an especially suitable machine learning technique to predict plant host targets from the knowledge of human host targets. A comparison of the prediction results with transcriptomic data shows a clear overlap between the host proteins predicted to be targeted by PPIs and their gene ontology enrichment in both host species and regulation of gene expression. In particular, the cellular processes Salmonella interferes with in plants and humans are catabolic processes. The details of how these processes are targeted, however, are quite different between the two organisms, as expected based on their evolutionary and habitat differences. Possible implications of this observation on evolution of host-pathogen communication are discussed.

Floral biology and the effects of plant-pollinator interaction on ...

African Journals Online (AJOL)

Reproductive biology and patterns of plant-pollinator interaction are fundamental to gene flow, diversity and evolutionary success of plants. Consequently, we examined the magnitude of insect-plant interaction based on the dynamics of breeding systems and floral biology and their effects on pollination intensity, fruit and ...

Interactions of Corbicula sp. with power plants

International Nuclear Information System (INIS)

Mattice, J.S.

1977-01-01

There are three perspectives with which to view the interaction of Corbicula and power plants: as a fouling agent; as an important part of the natural ecosystem; and as a potential species for use in waste heat aquaculture. The first two of these interactions are essentially negative in character, since they involve avoidance of impacts either of Corbicula on power plant operation or of power plant operation on Corbicula. Condenser fouling by these claims has been controlled by mechanical means or by continuous chlorination. Our data support the potential for using heated water to control fouling and a model for determining required thermal dosing is presented. Preliminary data also indicate potential for control by combining simultaneous short-term exposure to hot water and chlorine. The third of the interactions is essentially positive in character. The use of thermal effluents in Corbicula aquaculture systems is proposed

Influence of humic substances on plant-microbes interactions in the rhizosphere

Science.gov (United States)

Puglisi, Edoardo; Pascazio, Silvia; Spaccini, Riccardo; Crecchio, Carmine; Trevisan, Marco; Piccolo, Alessandro

2013-04-01

Humic substances are known to play a wide range of effects on the physiology of plant and microbes. This is of particular relevance in the rhizosphere of terrestrial environments, where the reciprocal interactions between plants roots, soil constituents and microorganisms strongly influence the plants acquisition of nutrients. Chemical advances are constantly improving our knowledge on humic substances: their supra-molecular architecture, as well as the moltitude of their chemical constituents, many of which are biologically active. An approach for linking the structure of humic substances with their biological activity in the rhizosphere is the use of rhizoboxes, which allow applying a treatment (e.g., an amendment with humic substances) in an upper soil-plant compartment and take measurements in a lower isolated rhizosphere compartment that can be sampled at desired distances from the rhizoplane. This approach can be adopted to assess the effects of several humic substances, as well as composted materials, on maize plants rhizodeposition of carbon, and in turn on the structure and activity of rhizosphere microbial communities. In order to gain a complete understanding of processes occurring in the complex soil-plant-microorganisms tripartite system, rhizobox experiments can be coupled with bacterial biosensors for the detection and quantification of bioavailable nutrients, chemical analyses of main rhizodeposits constituents, advanced chemical characterizations of humic substances, DNA-fingerprinting of microbial communities, and multivariate statistical approaches to manage the dataset produced and to infer general conclusions. By such an approach it was found that humic substances are significantly affecting the amount of carbon deposited by plant roots. This induction effect is more evident for substances with more hydrophobic and complex structure, thus supporting the scientific hypothesis of the "microbial loop model", which assumes that plants feed

Phytohormone mediation of interactions between herbivores and plant pathogens

NARCIS (Netherlands)

Lazebnik, J.; Frago, E.; Dicke, M.; Loon, van J.J.A.

2014-01-01

Induced plant defenses against either pathogens or herbivore attackers are regulated by phytohormones. These phytohormones are increasingly recognized as important mediators of interactions between organisms associated with plants. In this review, we discuss the role of plant defense hormones in

Plant-soil feedbacks and the coexistence of competing plants

NARCIS (Netherlands)

Revilla, T.A.; Veen, G.F.; Eppinga, M.B.; Weissing, F.J.

2013-01-01

Plant–soil feedbacks can have important implications for the interactions among plants. Understanding these effects is a major challenge since it is inherently difficult to measure and manipulate highly diverse soil communities. Mathematical models may advance this understanding by making the

Plant-soil feedbacks and the coexistence of competing plants

NARCIS (Netherlands)

Revilla, T.A.; Veen, G.F.; Eppinga, M.B.; Weissing, F.J.

Plant–soil feedbacks can have important implications for the interactions among plants. Understanding these effects is a major challenge since it is inherently difficult to measure and manipulate highly diverse soil communities. Mathematical models may advance this understanding by making the

Understanding and managing corrosion in nuclear power plants

International Nuclear Information System (INIS)

Johnson, A.B. Jr.; Jarrell, D.B.; Sinha, U.P.; Shah, V.N.

1991-03-01

The main theme of this paper is a concept: understanding and managing corrosion in nuclear power plants. The concept is not new--in various forms the concept has been applied throughout the development and maturing of nuclear technology. However, the concept has frequently not been well conceived and applied. Too often, understanding corrosion has been based on reaction rather than on anticipation. Regulatory and utility industry initiatives are creating a climate and framework for more effective application of the concept. This paper characterizes the framework and provides some illustrations of how the concept is being applied, drawing from work conducted under the Nuclear Plant Aging Research (NPAR) Program, sponsored by the Nuclear Regulatory Commission's (NRCs) Office of Research. Nuclear plants are becoming an increasingly important factor in the national electrical grid. Initiatives are currently underway to extend the operating licenses beyond the current 40-year period and to evaluate advanced reactor designs the feature higher safety factors. Corrosion has not caused a major nuclear accident, but numerous corrosion mechanisms, have degraded nuclear systems and components. New corrosion phenomena continue to appear, and occasionally corrosion phenomena cause reactor shutdowns. Effective application of understanding and managing corrosion is important to safe and economic operation of the nuclear plants and also to public perception of a soundly operated technology. 53 refs., 11 figs., 5 tabs

Emerging trends in molecular interactions between plants and the broad host range fungal pathogens Botrytis cinerea and Sclerotinia sclerotiorum

Directory of Open Access Journals (Sweden)

Malick eMbengue

2016-03-01

Full Text Available Fungal plant pathogens are major threats to food security worldwide. Sclerotinia sclerotiorum and Botrytis cinerea are closely related Ascomycete plant pathogens causing mold diseases on hundreds of plant species. There is no genetic source of complete plant resistance to these broad host range pathogens known to date. Instead, natural plant populations show a continuum of resistance levels controlled by multiple genes, a phenotype designated as quantitative disease resistance. Little is known about the molecular mechanisms controlling the interaction between plants and S. sclerotiorum and B. cinerea but significant advances were made on this topic in the last years. This minireview highlights a selection of nine themes that emerged in recent research reports on the molecular bases of plant-S. sclerotiorum and plant-B. cinerea interactions. On the fungal side, this includes progress on understanding the role of oxalic acid, on the study of fungal small secreted proteins. Next, we discuss the exchanges of small RNA between organisms and the control of cell death in plant and fungi during pathogenic interactions. Finally on the plant side, we highlight defense priming by mechanical signals, the characterization of plant Receptor-like proteins and the hormone abscisic acid in the response to B. cinerea and S. sclerotiorum , the role of plant general transcription machinery and plant small bioactive peptides. These represent nine trends we selected as remarkable in our understanding of fungal molecules causing disease and plant mechanisms associated with disease resistance to two devastating broad host range fungi.

Carbohydrate Microarrays in Plant Science

DEFF Research Database (Denmark)

Fangel, Jonatan Ulrik; Pedersen, H.L.; Vidal-Melgosa, S.

2012-01-01

Almost all plant cells are surrounded by glycan-rich cell walls, which form much of the plant body and collectively are the largest source of biomass on earth. Plants use polysaccharides for support, defense, signaling, cell adhesion, and as energy storage, and many plant glycans are also important...... industrially and nutritionally. Understanding the biological roles of plant glycans and the effective exploitation of their useful properties requires a detailed understanding of their structures, occurrence, and molecular interactions. Microarray technology has revolutionized the massively high...... for plant research and can be used to map glycan populations across large numbers of samples to screen antibodies, carbohydrate binding proteins, and carbohydrate binding modules and to investigate enzyme activities....

Plant functional diversity affects climate-vegetation interaction

Science.gov (United States)

Groner, Vivienne P.; Raddatz, Thomas; Reick, Christian H.; Claussen, Martin

2018-04-01

We present how variations in plant functional diversity affect climate-vegetation interaction towards the end of the African Humid Period (AHP) in coupled land-atmosphere simulations using the Max Planck Institute Earth system model (MPI-ESM). In experiments with AHP boundary conditions, the extent of the green Sahara varies considerably with changes in plant functional diversity. Differences in vegetation cover extent and plant functional type (PFT) composition translate into significantly different land surface parameters, water cycling, and surface energy budgets. These changes have not only regional consequences but considerably alter large-scale atmospheric circulation patterns and the position of the tropical rain belt. Towards the end of the AHP, simulations with the standard PFT set in MPI-ESM depict a gradual decrease of precipitation and vegetation cover over time, while simulations with modified PFT composition show either a sharp decline of both variables or an even slower retreat. Thus, not the quantitative but the qualitative PFT composition determines climate-vegetation interaction and the climate-vegetation system response to external forcing. The sensitivity of simulated system states to changes in PFT composition raises the question how realistically Earth system models can actually represent climate-vegetation interaction, considering the poor representation of plant diversity in the current generation of land surface models.

Parasitic nematode interactions with mammals and plants.

Science.gov (United States)

Jasmer, Douglas P; Goverse, Aska; Smant, Geert

2003-01-01

Parasitic nematodes that infect humans, animals, and plants cause serious diseases that are deleterious to human health and agricultural productivity. Chemical and biological control methods have reduced the impact of these parasites. However, surviving environmental stages lead to persistent reinfection of host species. In addition, development of resistance to nematicides and anthelmintics by these parasites and reduced availability of some nematicides, for environmental protection, pose significant obstacles for current and future prospects of effective parasite control. Due to marked differences in host species, research on animal and plant parasitic nematodes often proceeds independently. Despite the differences between animals and plants, basic cellular properties are shared among these host organisms. Some common properties may be important for mechanisms [homologous or convergent (homoplastic)] by which nematodes successfully infect these diverse hosts or by which animal and plant hosts resist infections by these pathogens. Here we compare host/parasite interactions between plant parasitic nematodes (PPN) and animal parasitic nematodes, with an emphasis on mammalian hosts (MPN). Similarities and differences are considered in the context of progress on molecular dissection of these interactions. A comprehensive coverage is not possible in the space allotted. Instead, an illustrative approach is used to establish examples that, it is hoped, exemplify the value of the comparative approach.

Understanding the holobiont: the interdependence of plants and their microbiome.

Science.gov (United States)

Sánchez-Cañizares, Carmen; Jorrín, Beatriz; Poole, Philip S; Tkacz, Andrzej

2017-08-01

The holobiont is composed by the plant and its microbiome. In a similar way to ecological systems of higher organisms, the holobiont shows interdependent and complex dynamics [1,2]. While plants originate from seeds, the microbiome has a multitude of sources. The assemblage of these communities depends on the interaction between the emerging seedling and its surrounding environment, with soil being the main source. These microbial communities are controlled by the plant through different strategies, such as the specific profile of root exudates and its immune system. Despite this control, the microbiome is still able to adapt and thrive. The molecular knowledge behind these interactions and microbial '-omic' technologies are developing to the point of enabling holobiont engineering. For a long time microorganisms were in the background of plant biology but new multidisciplinary approaches have led to an appreciation of the importance of the holobiont, where plants and microbes are interdependent. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

Ecosystem development in roadside grasslands: Biotic control, plant-soil interactions, and dispersal limitations

Science.gov (United States)

Garcia-Palacios, P.; Bowker, M.A.; Maestre, F.T.; Soliveres, S.; Valladares, F.; Papadopoulos, J.; Escudero, A.

2011-01-01

Roadside grasslands undergoing secondary succession are abundant, and represent ecologically meaningful examples of novel, human-created ecosystems. Interactions between plant and soil communities (hereafter plant-soil interactions) are of major importance in understanding the role of biotic control in ecosystem functioning, but little is known about these links in the context of ecosystem restoration and succession. The assessment of the key biotic communities and interactions driving ecosystem development will help practitioners to better allocate the limited resources devoted to roadside grassland restoration. We surveyed roadside grasslands from three successional stages (0-2, 7-9, and > 20 years) in two Mediterranean regions of Spain. Structural equation modeling was used to evaluate how interactions between plants, biological soil crusts (BSCs), and soil microbial functional diversity (soil microorganisms) affect indicators of ecosystem development and restoration: plant similarity to the reference ecosystem, erosion control, and soil C storage and N accumulation. Changes in plant community composition along the successional gradient exerted the strongest influence on these indicators. High BSC cover was associated with high soil stability, and high soil microbial functional diversity from late-successional stages was associated with high soil fertility. Contrary to our expectations, the indirect effects of plants, mediated by either BSCs or soil microorganisms, were very weak in both regions, suggesting a minor role for plant-soil interactions upon ecosystem development indicators over long periods. Our results suggest that natural vegetation dynamics effectively improved ecosystem development within a time frame of 20 years in the grasslands evaluated. They also indicate that this time could be shortened if management actions focus on: (1) maintaining wellconserved natural areas close to roadsides to enhance plant compositional changes towards late

Human-machine interaction in nuclear power plants

International Nuclear Information System (INIS)

Yoshikawa, Hidekazu

2005-01-01

Advanced nuclear power plants are generally large complex systems automated by computers. Whenever a rate plant emergency occurs the plant operators must cope with the emergency under severe mental stress without committing any fatal errors. Furthermore, the operators must train to improve and maintain their ability to cope with every conceivable situation, though it is almost impossible to be fully prepared for an infinite variety of situations. In view of the limited capability of operators in emergency situations, there has been a new approach to preventing the human error caused by improper human-machine interaction. The new approach has been triggered by the introduction of advanced information systems that help operators recognize and counteract plant emergencies. In this paper, the adverse effect of automation in human-machine systems is explained. The discussion then focuses on how to configure a joint human-machine system for ideal human-machine interaction. Finally, there is a new proposal on how to organize technologies that recognize the different states of such a joint human-machine system

Importance of earthworm-seed interactions for the composition and structure of plant communities: A review

Science.gov (United States)

Forey, Estelle; Barot, Sébastien; Decaëns, Thibaud; Langlois, Estelle; Laossi, Kam-Rigne; Margerie, Pierre; Scheu, Stefan; Eisenhauer, Nico

2011-11-01

Soil seed bank composition and dynamics are crucial elements for the understanding of plant population and community ecology. Earthworms are increasingly recognized as important dispersers and predators of seeds. Through direct and indirect effects they influence either positively or negatively the establishment and survival of seeds and seedlings. Seedling establishment is affected by a variety of earthworm-mediated mechanisms, such as selective seed ingestion and digestion, acceleration or deceleration of germination, and seed transport. Earthworm casts deposited on the soil surface and the entrance of earthworm burrows often contain viable seeds and constitute important regeneration niches for plant seedlings and therefore likely favour specific seed traits. However, the role of earthworms as seed dispersers, mediators of seed bank dynamics and seed predators has not been considered in concert. The overall effect of earthworms on plant communities remains little understood. Most knowledge is based on laboratory studies on temperate species and future work has to explore the biological significance of earthworm-seed interactions under more natural conditions. In this review we summarize the current knowledge on earthworm-seed interactions and discuss factors determining these interactions. We highlight that this interaction may be an underappreciated, yet major driving force for the dynamics of soil seed banks and plant communities which most likely have experienced co-evolutionary processes. Despite the experimental bias, we hypothesize that the knowledge gathered in the present review is of crucial relevance for restoration and conservation ecology. For instance, as earthworms emerge as successful and ubiquitous invaders in various ecosystems, the summarized information might serve as a basis for realistic estimations and modelling of consequences on native plant communities. We depict promising directions of future research and point to the need to consider

Physiological and molecular implications of plant polyamine metabolism during biotic interactions

Directory of Open Access Journals (Sweden)

Juan Francisco Jiménez Bremont

2014-03-01

Full Text Available During ontogeny, plants interact with a wide variety of microorganisms. The association with mutualistic microbes results in benefits for the plant. By contrast, pathogens may cause a remarkable impairment of plant growth and development. Both types of plant-microbe interactions provoke notable changes in the polyamine (PA metabolism of the host and/or the microbe, being each interaction a complex and dynamic process. It has been well documented that the levels of free and conjugated PAs undergo profound changes in plant tissues during the interaction with microorganisms. In general, this is correlated with a precise and coordinated regulation of PA biosynthetic and catabolic enzymes. Interestingly, some evidence suggests that the relative importance of these metabolic pathways may depend on the nature of the microorganism, a concept that stems from the fact that these amines mediate the activation of plant defense mechanisms. This effect is mediated mostly through PA oxidation, even though part of the response is activated by non-oxidized PAs. In the last years, a great deal of effort has been devoted to profile plant gene expression following microorganism recognition. In addition, the phenotypes of transgenic and mutant plants in PA metabolism genes have been assessed. In this review, we integrated the current knowledge on this field and analyze the possible roles of these amines during the interaction of plants with microbes.

Insect-plant interactions: new pathways to a better comprehension of ecological communities in Neotropical savannas.

Science.gov (United States)

Del-Claro, Kleber; Torezan-Silingardi, Helena M

2009-01-01

The causal mechanisms shaping and structuring ecological communities are among the most important themes in ecology. The study of insect-plant interactions in trophic nets is pointed out as basic to improve our knowledge on this issue. The cerrado tropical savanna, although extremely diverse, distributed in more than 20% of the Brazilian territory and filled up with rich examples of multitrophic interactions, is underexplored in terms of biodiversity interaction. Here, this ecosystem is suggested as valuable to the study of insect-plant interactions whose understanding can throw a new light at the ecological communities' theory. Three distinct systems: extrafloral nectary plants or trophobiont herbivores and the associated ant fauna; floral herbivores-predators-pollinators; and plants-forest engineers and associated fauna, will serve as examples to illustrate promising new pathways in cerrado. The aim of this brief text is to instigate young researchers, mainly entomologists, to initiate more elaborated field work, including experimental manipulations in multitrophic systems, to explore in an interactive way the structure that maintain preserved viable communities in the Neotropical savanna.

Ecosystem Fabrication (EcoFAB) Protocols for The Construction of Laboratory Ecosystems Designed to Study Plant-microbe Interactions.

Science.gov (United States)

Gao, Jian; Sasse, Joelle; Lewald, Kyle M; Zhalnina, Kateryna; Cornmesser, Lloyd T; Duncombe, Todd A; Yoshikuni, Yasuo; Vogel, John P; Firestone, Mary K; Northen, Trent R

2018-04-10

Beneficial plant-microbe interactions offer a sustainable biological solution with the potential to boost low-input food and bioenergy production. A better mechanistic understanding of these complex plant-microbe interactions will be crucial to improving plant production as well as performing basic ecological studies investigating plant-soil-microbe interactions. Here, a detailed description for ecosystem fabrication is presented, using widely available 3D printing technologies, to create controlled laboratory habitats (EcoFABs) for mechanistic studies of plant-microbe interactions within specific environmental conditions. Two sizes of EcoFABs are described that are suited for the investigation of microbial interactions with various plant species, including Arabidopsis thaliana, Brachypodium distachyon, and Panicum virgatum. These flow-through devices allow for controlled manipulation and sampling of root microbiomes, root chemistry as well as imaging of root morphology and microbial localization. This protocol includes the details for maintaining sterile conditions inside EcoFABs and mounting independent LED light systems onto EcoFABs. Detailed methods for addition of different forms of media, including soils, sand, and liquid growth media coupled to the characterization of these systems using imaging and metabolomics are described. Together, these systems enable dynamic and detailed investigation of plant and plant-microbial consortia including the manipulation of microbiome composition (including mutants), the monitoring of plant growth, root morphology, exudate composition, and microbial localization under controlled environmental conditions. We anticipate that these detailed protocols will serve as an important starting point for other researchers, ideally helping create standardized experimental systems for investigating plant-microbe interactions.

Plant-plant interactions mediate the plastic and genotypic response of Plantago asiatica to CO2: an experiment with plant populations from naturally high CO2 areas.

Science.gov (United States)

van Loon, Marloes P; Rietkerk, Max; Dekker, Stefan C; Hikosaka, Kouki; Ueda, Miki U; Anten, Niels P R

2016-06-01

The rising atmospheric CO2 concentration ([CO2]) is a ubiquitous selective force that may strongly impact species distribution and vegetation functioning. Plant-plant interactions could mediate the trajectory of vegetation responses to elevated [CO2], because some plants may benefit more from [CO2] elevation than others. The relative contribution of plastic (within the plant's lifetime) and genotypic (over several generations) responses to elevated [CO2] on plant performance was investigated and how these patterns are modified by plant-plant interactions was analysed. Plantago asiatica seeds originating from natural CO2 springs and from ambient [CO2] sites were grown in mono stands of each one of the two origins as well as mixtures of both origins. In total, 1944 plants were grown in [CO2]-controlled walk-in climate rooms, under a [CO2] of 270, 450 and 750 ppm. A model was used for upscaling from leaf to whole-plant photosynthesis and for quantifying the influence of plastic and genotypic responses. It was shown that changes in canopy photosynthesis, specific leaf area (SLA) and stomatal conductance in response to changes in growth [CO2] were mainly determined by plastic and not by genotypic responses. We further found that plants originating from high [CO2] habitats performed better in terms of whole-plant photosynthesis, biomass and leaf area, than those from ambient [CO2] habitats at elevated [CO2] only when both genotypes competed. Similarly, plants from ambient [CO2] habitats performed better at low [CO2], also only when both genotypes competed. No difference in performance was found in mono stands. The results indicate that natural selection under increasing [CO2] will be mainly driven by competitive interactions. This supports the notion that plant-plant interactions have an important influence on future vegetation functioning and species distribution. Furthermore, plant performance was mainly driven by plastic and not by genotypic responses to changes in

Evolutionary adaptation in three-way interactions between plants, microbes and arthropods

NARCIS (Netherlands)

Biere, A.; Tack, A.J.M.

2013-01-01

Evolutionary adaptations in interactions between plants, microbes and arthropods are generally studied in interactions that involve only two of these groups, that is, plants and microbes, plants and arthropods or arthropods and microbes. We review the accumulating evidence from a wide variety of

Aluminum–Nitrogen Interactions in the Soil–Plant System

Directory of Open Access Journals (Sweden)

Xue Q. Zhao

2018-06-01

Full Text Available Aluminum (Al is the most abundant metal in the Earth’s crust and is not an essential element for plant growth. In contrast, nitrogen (N is the most important mineral element for plant growth, but this non-metal is often present at low levels in soils, and plants are often N deficient. Aluminum toxicity is dominant in acid soils, and so plants growing in acid soils have to overcome both Al toxicity and N limitation. Because of low N-use efficiency, large amounts of N fertilizers are applied to crop fields to achieve high yields, leading to soil acidification and potential Al toxicity. Aluminum lowers plant N uptake and N-use efficiency because Al inhibits root growth. Although numerous studies have investigated the interactions between Al and N, a complete review of these studies was lacking. This review describes: (1 the link between plant Al tolerance and ammonium/nitrate (NH4+/NO3- preference; (2 the effects of NH4+/NO3- and pH on Al toxicity; (3 the effects of Al on soil N transformations; and (4 the effects of Al on NH4+/NO3- uptake and assimilation by plants. Acid soils are characterized chemically by a relatively high ratio of NH4+ to NO3- and high concentrations of toxic Al. Aluminum-tolerant plants generally prefer NH4+ as an N source, while Al-sensitive plants prefer NO3-. Compared with NO3-, NH4+ increases the solubilization of toxic Al into soil solutions, but NH4+ generally alleviates Al phytotoxicity under solution culture because the protons from NH4+ compete with Al3+ for adsorption sites on the root surface. Plant NO3- uptake and nitrate reductase activity are both inhibited by Al, while plant NH4+ uptake is inhibited to a smaller degree than NO3-. Together, the results of numerous studies indicate that there is a synergistic interaction between plant Al tolerance and NH4+ nutrition. This has important implications for the adaptation of plants to acid soils that are dominated chemically by toxic Al as well as NH4+. Finally, we

The relative importance of rapid evolution for plant-microbe interactions depends on ecological context.

Science.gov (United States)

Terhorst, Casey P; Lennon, Jay T; Lau, Jennifer A

2014-06-22

Evolution can occur on ecological time-scales, affecting community and ecosystem processes. However, the importance of evolutionary change relative to ecological processes remains largely unknown. Here, we analyse data from a long-term experiment in which we allowed plant populations to evolve for three generations in dry or wet soils and used a reciprocal transplant to compare the ecological effect of drought and the effect of plant evolutionary responses to drought on soil microbial communities and nutrient availability. Plants that evolved under drought tended to support higher bacterial and fungal richness, and increased fungal : bacterial ratios in the soil. Overall, the magnitudes of ecological and evolutionary effects on microbial communities were similar; however, the strength and direction of these effects depended on the context in which they were measured. For example, plants that evolved in dry environments increased bacterial abundance in dry contemporary environments, but decreased bacterial abundance in wet contemporary environments. Our results suggest that interactions between recent evolutionary history and ecological context affect both the direction and magnitude of plant effects on soil microbes. Consequently, an eco-evolutionary perspective is required to fully understand plant-microbe interactions.

Evolving ideas about genetics underlying insect virulence to plant resistance in rice-brown planthopper interactions.

Science.gov (United States)

Kobayashi, Tetsuya

2016-01-01

Many plant-parasite interactions that include major plant resistance genes have subsequently been shown to exhibit features of gene-for-gene interactions between plant Resistance genes and parasite Avirulence genes. The brown planthopper (BPH) Nilaparvata lugens is an important pest of rice (Oryza sativa). Historically, major Resistance genes have played an important role in agriculture. As is common in gene-for-gene interactions, evolution of BPH virulence compromises the effectiveness of singly-deployed resistance genes. It is therefore surprising that laboratory studies of BPH have supported the conclusion that virulence is conferred by changes in many genes rather than a change in a single gene, as is proposed by the gene-for-gene model. Here we review the behaviour, physiology and genetics of the BPH in the context of host plant resistance. A problem for genetic understanding has been the use of various insect populations that differ in frequencies of virulent genotypes. We show that the previously proposed polygenic inheritance of BPH virulence can be explained by the heterogeneity of parental populations. Genetic mapping of Avirulence genes indicates that virulence is a monogenic trait. These evolving concepts, which have brought the gene-for-gene model back into the picture, are accelerating our understanding of rice-BPH interactions at the molecular level. Copyright © 2015 Elsevier Ltd. All rights reserved.

Interactive nuclear plant analyzer for the VVER-440 reactor

International Nuclear Information System (INIS)

Shier, W.; Kennett, R.

1993-01-01

An interactive nuclear plant analyzer (NPA) has been developed for a VVER-440 model 213 reactor for use in the training of plant personnel, the development and verification of plant operating procedures, and in the analysis of various anticipated operational occurrences and accident scenarios. This NPA is operational on an IBM RISC-6000 workstation and utilizes the RELAP5/MOD2 computer code for the calculation of the VVER-440 reactor response to the interactive commands initiated by the NPA operator. Results of the interactive calculation can be through the user-defined, digital display of various plant parameters and through color changes that reflect changes in primary system fluid temperatures, fuel and clad temperatures, and the temperatures of other metal structures. In addition, changes in the status of various components and system can be initiated and/or displayed both numerically and graphically on the mask

Physiological effects of climate warming on flowering plants and insect pollinators and potential consequences for their interactions

Directory of Open Access Journals (Sweden)

Victoria L. SCAVEN, Nicole E. RAFFERTY

2013-06-01

Full Text Available Growing concern about the influence of climate change on flowering plants, pollinators, and the mutualistic interactions between them has led to a recent surge in research. Much of this research has addressed the consequences of warming for phenological and distributional shifts. In contrast, relatively little is known about the physiological responses of plants and insect pollinators to climate warming and, in particular, how these responses might affect plant-pollinator interactions. Here, we summarize the direct physiological effects of temperature on flowering plants and pollinating insects to highlight ways in which plant and pollinator responses could affect floral resources for pollinators, and pollination success for plants, respectively. We also consider the overall effects of these responses on plant-pollinator interaction networks. Plant responses to warming, which include altered flower, nectar, and pollen production, could modify floral resource availability and reproductive output of pollinating insects. Similarly, pollinator responses, such as altered foraging activity, body size, and life span, could affect patterns of pollen flow and pollination success of flowering plants. As a result, network structure could be altered as interactions are gained and lost, weakened and strengthened, even without the gain or loss of species or temporal overlap. Future research that addresses not only how plant and pollinator physiology are affected by warming but also how responses scale up to affect interactions and networks should allow us to better understand and predict the effects of climate change on this important ecosystem service [Current Zoolo­gy 59 (3: 418–426, 2013].

Interactions between aboveground herbivores and the mycorrhizal mutualists of plants.

Science.gov (United States)

Gehring, C A; Whitham, T G

1994-07-01

Plant growth, reproduction and survival can be affected both by mycorrhizal fungi and aboveground herbivores, but few studies have examined the interactive effects of these factors on plants. Most of the available data suggest that severe herbivory reduces root colonization by vesicular-arbuscular and ectomycorrhizal fungi. However, the reverse interaction has also been documented - mycorrhizal fungi deter herbivores and interact with fungal endophytes to influence herbivory. Although consistent patterns and mechanistic explanations are yet to emerge, it is likely that aboveground herbivore-mycorrhiza interactions have important implications for plant populations and communities. Copyright © 1994. Published by Elsevier Ltd.

Recent progress in plant nutrition research: cross-talk between nutrients, plant physiology and soil microorganisms.

Science.gov (United States)

Ohkama-Ohtsu, Naoko; Wasaki, Jun

2010-08-01

Mineral nutrients taken up from the soil become incorporated into a variety of important compounds with structural and physiological roles in plants. We summarize how plant nutrients are linked to many metabolic pathways, plant hormones and other biological processes. We also focus on nutrient uptake, describing plant-microbe interactions, plant exudates, root architecture, transporters and their applications. Plants need to survive in soils with mineral concentrations that vary widely. Describing the relationships between nutrients and biological processes will enable us to understand the molecular basis for signaling, physiological damage and responses to mineral stresses.

Allocation, stress tolerance and carbon transport in plants: how does phloem physiology affect plant ecology?

Science.gov (United States)

Savage, Jessica A; Clearwater, Michael J; Haines, Dustin F; Klein, Tamir; Mencuccini, Maurizio; Sevanto, Sanna; Turgeon, Robert; Zhang, Cankui

2016-04-01

Despite the crucial role of carbon transport in whole plant physiology and its impact on plant-environment interactions and ecosystem function, relatively little research has tried to examine how phloem physiology impacts plant ecology. In this review, we highlight several areas of active research where inquiry into phloem physiology has increased our understanding of whole plant function and ecological processes. We consider how xylem-phloem interactions impact plant drought tolerance and reproduction, how phloem transport influences carbon allocation in trees and carbon cycling in ecosystems and how phloem function mediates plant relations with insects, pests, microbes and symbiotes. We argue that in spite of challenges that exist in studying phloem physiology, it is critical that we consider the role of this dynamic vascular system when examining the relationship between plants and their biotic and abiotic environment. © 2015 John Wiley & Sons Ltd.

Water use, productivity and interactions among desert plants. Final report

Energy Technology Data Exchange (ETDEWEB)

Ehleringer, J.R.

1992-11-17

Productivity, stability, and competitive interactions among ecosystem components within aridlands are key processes related directly to water in deserts. This project assumes that integrated aspects of plant metabolism provide insight into the structure and function of plant communities and ecosystems. While it is difficult to extrapolate from instantaneous physiological observations to higher scales, such as whole plant performance or to the interactions between plants as components of ecosystems, several key aspects of plant metabolism are scalable. Analyses of stable isotopic composition in plant tissues at natural abundance levels provide a useful tool that can provide insight into the consequences of physiological processes over temporal and spatial scales. Some plant processes continuously fractionate among light and heavy stable isotopic forms of an element; over time this results in integrated measures of plant metabolism. For example, carbon isotope fractionation during photosynthesis results in leaf carbon isotopic composition that is a measure of the set-point for photosynthetic metabolism and of water-use efficiency. Thus it provides information on the temporal scaling of a key physiological process.

Data integration aids understanding of butterfly–host plant networks

Science.gov (United States)

Muto-Fujita, Ai; Takemoto, Kazuhiro; Kanaya, Shigehiko; Nakazato, Takeru; Tokimatsu, Toshiaki; Matsumoto, Natsushi; Kono, Mayo; Chubachi, Yuko; Ozaki, Katsuhisa; Kotera, Masaaki

2017-01-01

Although host-plant selection is a central topic in ecology, its general underpinnings are poorly understood. Here, we performed a case study focusing on the publicly available data on Japanese butterflies. A combined statistical analysis of plant–herbivore relationships and taxonomy revealed that some butterfly subfamilies in different families feed on the same plant families, and the occurrence of this phenomenon more than just by chance, thus indicating the independent acquisition of adaptive phenotypes to the same hosts. We consequently integrated plant–herbivore and plant–compound relationship data and conducted a statistical analysis to identify compounds unique to host plants of specific butterfly families. Some of the identified plant compounds are known to attract certain butterfly groups while repelling others. The additional incorporation of insect–compound relationship data revealed potential metabolic processes that are related to host plant selection. Our results demonstrate that data integration enables the computational detection of compounds putatively involved in particular interspecies interactions and that further data enrichment and integration of genomic and transcriptomic data facilitates the unveiling of the molecular mechanisms involved in host plant selection. PMID:28262809

Ecological turmoil in evolutionary dynamics of plant-insect interactions: defense to offence.

Science.gov (United States)

Mishra, Manasi; Lomate, Purushottam R; Joshi, Rakesh S; Punekar, Sachin A; Gupta, Vidya S; Giri, Ashok P

2015-10-01

Available history manifests contemporary diversity that exists in plant-insect interactions. A radical thinking is necessary for developing strategies that can co-opt natural insect-plant mutualism, ecology and environmental safety for crop protection since current agricultural practices can reduce species richness and evenness. The global environmental changes, such as increased temperature, CO₂ and ozone levels, biological invasions, land-use change and habitat fragmentation together play a significant role in re-shaping the plant-insect multi-trophic interactions. Diverse natural products need to be studied and explored for their biological functions as insect pest control agents. In order to assure the success of an integrated pest management strategy, human activities need to be harmonized to minimize the global climate changes. Plant-insect interaction is one of the most primitive and co-evolved associations, often influenced by surrounding changes. In this review, we account the persistence and evolution of plant-insect interactions, with particular focus on the effect of climate change and human interference on these interactions. Plants and insects have been maintaining their existence through a mutual service-resource relationship while defending themselves. We provide a comprehensive catalog of various defense strategies employed by the plants and/or insects. Furthermore, several important factors such as accelerated diversification, imbalance in the mutualism, and chemical arms race between plants and insects as indirect consequences of human practices are highlighted. Inappropriate implementation of several modern agricultural practices has resulted in (i) endangered mutualisms, (ii) pest status and resistance in insects and (iii) ecological instability. Moreover, altered environmental conditions eventually triggered the resetting of plant-insect interactions. Hence, multitrophic approaches that can harmonize human activities and minimize their

Role of glucosinolates in insect-plant relationships and multitrophic interactions

NARCIS (Netherlands)

Hopkins, R.J.; Dam, van N.M.; Loon, van J.J.A.

2009-01-01

Glucosinolates present classical examples of plant compounds affecting insect-plant interactions. They are found mainly in the family Brassicaceae, which includes several important crops. More than 120 different glucosinolates are known. The enzyme myrosinase, which is stored in specialized plant

Soil inoculation method determines the strength of plant-soil interactions

NARCIS (Netherlands)

Voorde, van de T.F.J.; Ruijten, M.; Putten, van der W.H.; Bezemer, T.M.

2012-01-01

There is increasing evidence that interactions between plants and biotic components of the soil influence plant productivity and plant community composition. Many plant–soil feedback experiments start from inoculating relatively small amounts of natural soil to sterilized bulk soil. These soil

Plant-soil feedbacks: role of plant functional group and plant traits

NARCIS (Netherlands)

Cortois, R.; Schröder-Georgi, T.; Weigelt, A.; van der Putten, W.H.; De Deyn, G.B.

2016-01-01

Plant-soil feedback (PSF), plant trait and functional group concepts advanced our understanding of plant community dynamics, but how they are interlinked is poorly known. To test how plant functional groups (FGs: graminoids, small herbs, tall herbs, legumes) and plant traits relate to PSF, we grew

Linking plant specialization to dependence in interactions for seed set in pollination networks.

Science.gov (United States)

Tur, Cristina; Castro-Urgal, Rocío; Traveset, Anna

2013-01-01

Studies on pollination networks have provided valuable information on the number, frequency, distribution and identity of interactions between plants and pollinators. However, little is still known on the functional effect of these interactions on plant reproductive success. Information on the extent to which plants depend on such interactions will help to make more realistic predictions of the potential impacts of disturbances on plant-pollinator networks. Plant functional dependence on pollinators (all interactions pooled) can be estimated by comparing seed set with and without pollinators (i.e. bagging flowers to exclude them). Our main goal in this study was thus to determine whether plant dependence on current insect interactions is related to plant specialization in a pollination network. We studied two networks from different communities, one in a coastal dune and one in a mountain. For ca. 30% of plant species in each community, we obtained the following specialization measures: (i) linkage level (number of interactions), (ii) diversity of interactions, and (iii) closeness centrality (a measure of how much a species is connected to other plants via shared pollinators). Phylogenetically controlled regression analyses revealed that, for the largest and most diverse coastal community, plants highly dependent on pollinators were the most generalists showing the highest number and diversity of interactions as well as occupying central positions in the network. The mountain community, by contrast, did not show such functional relationship, what might be attributable to their lower flower-resource heterogeneity and diversity of interactions. We conclude that plants with a wide array of pollinator interactions tend to be those that are more strongly dependent upon them for seed production and thus might be those more functionally vulnerable to the loss of network interaction, although these outcomes might be context-dependent.

Linking plant specialization to dependence in interactions for seed set in pollination networks.

Directory of Open Access Journals (Sweden)

Cristina Tur

Full Text Available Studies on pollination networks have provided valuable information on the number, frequency, distribution and identity of interactions between plants and pollinators. However, little is still known on the functional effect of these interactions on plant reproductive success. Information on the extent to which plants depend on such interactions will help to make more realistic predictions of the potential impacts of disturbances on plant-pollinator networks. Plant functional dependence on pollinators (all interactions pooled can be estimated by comparing seed set with and without pollinators (i.e. bagging flowers to exclude them. Our main goal in this study was thus to determine whether plant dependence on current insect interactions is related to plant specialization in a pollination network. We studied two networks from different communities, one in a coastal dune and one in a mountain. For ca. 30% of plant species in each community, we obtained the following specialization measures: (i linkage level (number of interactions, (ii diversity of interactions, and (iii closeness centrality (a measure of how much a species is connected to other plants via shared pollinators. Phylogenetically controlled regression analyses revealed that, for the largest and most diverse coastal community, plants highly dependent on pollinators were the most generalists showing the highest number and diversity of interactions as well as occupying central positions in the network. The mountain community, by contrast, did not show such functional relationship, what might be attributable to their lower flower-resource heterogeneity and diversity of interactions. We conclude that plants with a wide array of pollinator interactions tend to be those that are more strongly dependent upon them for seed production and thus might be those more functionally vulnerable to the loss of network interaction, although these outcomes might be context-dependent.

Effects of Soil Quality Enhancement on Pollinator-Plant Interactions

Directory of Open Access Journals (Sweden)

Yasmin J. Cardoza

2012-01-01

Full Text Available Both biotic and abiotic factors can affect soil quality, which can significantly impact plant growth, productivity, and resistance to pests. However, the effects of soil quality on the interactions of plants with beneficial arthropods, such as pollinators, have not been extensively examined. We studied the effects of vermicompost (earthworm compost, VC soil amendment on behavioral and physiological responses of pollinators to flowers and floral resources, using cucumbers, Cucumis sativus, as our model system. Results from experiments conducted over three field seasons demonstrated that, in at least two out of three years, VC amendment significantly increased visit length, while reducing the time to first discovery. Bumblebee (Bombus impatiens workers that fed on flowers from VC-amended plants had significantly larger and more active ovaries, a measure of nutritional quality. Pollen fractions of flowers from VC-grown plants had higher protein compared to those of plants grown in chemically fertilized potting soil. Nectar sugar content also tended to be higher in flowers from VC-grown plants, but differences were not statistically significant. In conclusion, soil quality enhancement, as achieved with VC amendment in this study, can significantly affect plant-pollinator interactions and directly influences pollinator nutrition and overall performance.

Plant-soil interactions promote co-occurrence of three nonnative woody shrubs.

Science.gov (United States)

Kuebbing, Sara E; Classen, Aimée T; Call, Jaime J; Henning, Jeremiah A; Simberloff, Daniel

2015-08-01

Ecosystems containing multiple nonnative plant species are common, but mechanisms promoting their co-occurrence are understudied. Plant-soil interactions contribute to the dominance of singleton species in nonnative ranges because many nonnatives experience stronger positive feedbacks relative to co-occurring natives. Plant-soil interactions could impede other nonnatives if an individual nonnative benefits from its soil community to a greater extent than its neighboring nonnatives, as is seen with natives. However, plant-soil interactions could promote nonnative co-occurrence if a nonnative accumulates beneficial soil mutualists that also assist other nonnatives. Here, we use greenhouse and field experiments to ask whether plant-soil interactions (1) promote the codominance of two common nonnative shrubs (Ligustrum sinense and Lonicera maackii) and (2) facilitate the invasion of a less-common nonnative shrub (Rhamnus davurica) in deciduous forests of the southeastern United States. In the greenhouse, we found that two of the nonnatives, L. maackii and R. davurica, performed better in soils conditioned by nonnative shrubs compared to uninvaded forest soils, which. suggests that positive feedbacks among co-occurring nonnative shrubs can promote continued invasion of a site. In both greenhouse and field experiments, we found consistent signals that the codominance of the nonnatives L. sinense and L. maackii may be at least partially explained by the increased growth of L. sinense in L. maackii soils. Overall, significant effects of plant-soil interactions on shrub performance indicate that plant-soil interactions can potentially structure the co-occurrence patterns of these nonnatives.

The interaction between strigolactones and other plant hormones in the regulation of plant development

Directory of Open Access Journals (Sweden)

Xi eCheng

2013-06-01

Full Text Available Plant hormones are small molecules derived from various metabolic pathways and are important regulators of plant development. The most recently discovered phytohormone class comprises the carotenoid-derived strigolactones (SLs. For a long time these compounds were only known to be secreted into the rhizosphere where they act as signalling compounds, but now we know they are also active as endogenous plant hormones and they have been in the spotlight ever since. The initial discovery that SLs are involved in the inhibition of axillary bud outgrowth, initiated a multitude of other studies showing that SLs also play a role in defining root architecture, secondary growth, hypocotyl elongation and seed germination, mostly in interaction with other hormones. Their coordinated action enables the plant to respond in an appropriate manner to environmental factors such as temperature, shading, day length and nutrient availability. Here, we will review the current knowledge on the crosstalk between SLs and other plant hormones – such as auxin, cytokinin, abscisic acid, ethylene and gibberellins - during different physiological processes. We will furthermore take a bird’s eye view of how this hormonal crosstalk enables plants to respond to their ever changing environments.

RNA mobility in parasitic plant – host interactions

Science.gov (United States)

Kim, Gunjune

2017-01-01

ABSTRACT The parasitic plant Cuscuta exchanges mRNAs with its hosts. Systemic mobility of mRNAs within plants is well documented, and has gained increasing attention as studies using grafted plant systems have revealed new aspects of mobile mRNA regulation and function. But parasitic plants take this phenomenon to a new level by forming seamless connections to a wide range of host species, and raising questions about how mRNAs might function after transfer to a different species. Cuscuta and other parasitic plant species also take siRNAs from their hosts, indicating that multiple types of RNA are capable of trans-specific movement. Parasitic plants are intriguing systems for studying RNA mobility, in part because such exchange opens new possibilities for control of parasitic weeds, but also because they provide a fresh perspective into understanding roles of RNAs in inter-organismal communication. PMID:28277936

Integrating plant-microbe interactions to understand soil C stabilization with the MIcrobial-MIneral Carbon Stabilization model (MIMICS)

Science.gov (United States)

Grandy, Stuart; Wieder, Will; Kallenbach, Cynthia; Tiemann, Lisa

2014-05-01

If soil organic matter is predominantly microbial biomass, plant inputs that build biomass should also increase SOM. This seems obvious, but the implications fundamentally change how we think about the relationships between plants, microbes and SOM. Plant residues that build microbial biomass are typically characterized by low C/N ratios and high lignin contents. However, plants with high lignin contents and high C/N ratios are believed to increase SOM, an entrenched idea that still strongly motivates agricultural soil management practices. Here we use a combination of meta-analysis with a new microbial-explicit soil biogeochemistry model to explore the relationships between plant litter chemistry, microbial communities, and SOM stabilization in different soil types. We use the MIcrobial-MIneral Carbon Stabilization (MIMICS) model, newly built upon the Community Land Model (CLM) platform, to enhance our understanding of biology in earth system processes. The turnover of litter and SOM in MIMICS are governed by the activity of r- and k-selected microbial groups and temperature sensitive Michaelis-Menten kinetics. Plant and microbial residues are stabilized short-term by chemical recalcitrance or long-term by physical protection. Fast-turnover litter inputs increase SOM by >10% depending on temperature in clay soils, and it's only in sandy soils devoid of physical protection mechanisms that recalcitrant inputs build SOM. These results challenge centuries of lay knowledge as well as conventional ideas of SOM formation, but are they realistic? To test this, we conducted a meta-analysis of the relationships between the chemistry of plant liter inputs and SOM concentrations. We find globally that the highest SOM concentrations are associated with plant inputs containing low C/N ratios. These results are confirmed by individual tracer studies pointing to greater stabilization of low C/N ratio inputs, particularly in clay soils. Our model and meta-analysis results suggest

Interaction of Plant Extracts with Central Nervous System Receptors

Directory of Open Access Journals (Sweden)

Kenneth Lundstrom

2017-02-01

Full Text Available Background: Plant extracts have been used in traditional medicine for the treatment of various maladies including neurological diseases. Several central nervous system receptors have been demonstrated to interact with plant extracts and components affecting the pharmacology and thereby potentially playing a role in human disease and treatment. For instance, extracts from Hypericum perforatum (St. John’s wort targeted several CNS receptors. Similarly, extracts from Piper nigrum, Stephania cambodica, and Styphnolobium japonicum exerted inhibition of agonist-induced activity of the human neurokinin-1 receptor. Methods: Different methods have been established for receptor binding and functional assays based on radioactive and fluorescence-labeled ligands in cell lines and primary cell cultures. Behavioral studies of the effect of plant extracts have been conducted in rodents. Plant extracts have further been subjected to mood and cognition studies in humans. Results: Mechanisms of action at molecular and cellular levels have been elucidated for medicinal plants in support of standardization of herbal products and identification of active extract compounds. In several studies, plant extracts demonstrated affinity to a number of CNS receptors in parallel indicating the complexity of this interaction. In vivo studies showed modifications of CNS receptor affinity and behavioral responses in animal models after treatment with medicinal herbs. Certain plant extracts demonstrated neuroprotection and enhanced cognitive performance, respectively, when evaluated in humans. Noteworthy, the penetration of plant extracts and their protective effect on the blood-brain-barrier are discussed. Conclusion: The affinity of plant extracts and their isolated compounds for CNS receptors indicates an important role for medicinal plants in the treatment of neurological disorders. Moreover, studies in animal and human models have confirmed a scientific basis for the

Genetics-based interactions among plants, pathogens, and herbivores define arthropod community structure.

Science.gov (United States)

Busby, Posy E; Lamit, Louis J; Keith, Arthur R; Newcombe, George; Gehring, Catherine A; Whitham, Thomas G; Dirzo, Rodolfo

2015-07-01

Plant resistance to pathogens or insect herbivores is common, but its potential for indirectly influencing plant-associated communities is poorly known. Here, we test whether pathogens' indirect effects on arthropod communities and herbivory depend on plant resistance to pathogens and/or herbivores, and address the overarching interacting foundation species hypothesis that genetics-based interactions among a few highly interactive species can structure a much larger community. In a manipulative field experiment using replicated genotypes of two Populus species and their interspecific hybrids, we found that genetic variation in plant resistance to both pathogens and insect herbivores modulated the strength of pathogens' indirect effects on arthropod communities and insect herbivory. First, due in part to the pathogens' differential impacts on leaf biomass among the two Populus species and the hybrids, the pathogen most strongly impacted arthropod community composition, richness, and abundance on the pathogen-susceptible tree species. Second, we found similar patterns comparing pathogen-susceptible and pathogen-resistant genotypes within species. Third, within a plant species, pathogens caused a fivefold greater reduction in herbivory on insect-herbivore-susceptible plant genotypes than on herbivore-resistant genotypes, demonstrating that the pathogen-herbivore interaction is genotype dependent. We conclude that interactions among plants, pathogens, and herbivores can structure multitrophic communities, supporting the interacting foundation species hypothesis. Because these interactions are genetically based, evolutionary changes in genetic resistance could result in ecological changes in associated communities, which may in turn feed back to affect plant fitness.

Uptake of nuclides by plants

International Nuclear Information System (INIS)

Greger, Maria

2004-04-01

This review on plant uptake of elements has been prepared to demonstrate how plants take up different elements. The work discusses the nutrient elements, as well as the general uptake and translocation in plants, both via roots and by foliar absorption. Knowledge of the uptake by the various elements within the periodic system is then reviewed. The work also discusses transfer factors (TF) as well as difficulties using TF to understand the uptake by plants. The review also focuses on species differences. Knowledge necessary to understand and calculate plant influence on radionuclide recirculation in the environment is discussed, in which the plant uptake of a specific nuclide and the fate of that nuclide in the plant must be understood. Plants themselves determine the uptake, the soil/sediment determines the availability of the nuclides and the nuclides themselves can interact with each other, which also influences the uptake. Consequently, it is not possible to predict the nuclide uptake in plants by only analysing the nuclide concentration of the soil/substrate

Uptake of nuclides by plants

Energy Technology Data Exchange (ETDEWEB)

Greger, Maria [Stockholm Univ. (Sweden). Dept. of Botany

2004-04-01

This review on plant uptake of elements has been prepared to demonstrate how plants take up different elements. The work discusses the nutrient elements, as well as the general uptake and translocation in plants, both via roots and by foliar absorption. Knowledge of the uptake by the various elements within the periodic system is then reviewed. The work also discusses transfer factors (TF) as well as difficulties using TF to understand the uptake by plants. The review also focuses on species differences. Knowledge necessary to understand and calculate plant influence on radionuclide recirculation in the environment is discussed, in which the plant uptake of a specific nuclide and the fate of that nuclide in the plant must be understood. Plants themselves determine the uptake, the soil/sediment determines the availability of the nuclides and the nuclides themselves can interact with each other, which also influences the uptake. Consequently, it is not possible to predict the nuclide uptake in plants by only analysing the nuclide concentration of the soil/substrate.

Plant interactions with multiple insect herbivores: from community to genes

NARCIS (Netherlands)

Stam, J.M.; Kroes, A.; Li, Y.; Gols, R.; Loon, van J.J.A.; Poelman, E.H.; Dicke, M.

2014-01-01

Every plant is a member of a complex insect community that consists of tens to hundreds of species that belong to different trophic levels. The dynamics of this community are critically influenced by the plant, which mediates interactions between community members that can occur on the plant

Coupling auto trophic in vitro plant cultivation system to scanning electron microscope to study plant-fungal interactions

Energy Technology Data Exchange (ETDEWEB)

Jaeger, N. de; Decock, C.; Declereck, S.; Providencia, I. E. de la

2010-07-01

The interactions of plants with pathogens and beneficial micro-organisms have been seldom compared on the same host and under strict controlled auto trophic in vitro culture conditions. Here, the life cycle of two plant beneficial (Glomus sp. MUCL 41833 and Trichoderma harzianum) and one plant pathogen (Rhizoctonia solani) fungi were described on potato (Solanum tuberosum) plantlets under auto trophic in vitro culture conditions using video camera imaging and the scanning electron microscope (SEM). (i) The colony developmental pattern of the extraradical mycelium within the substrate, (ii) the reproduction structures and (iii) the three-dimensional spatial arrangements of the fungal hyphae within the potato root cells were successfully visualized, monitored and described. The combination of the autotrophic in vitro culture system and SEM represent a powerful tool for improving our knowledge on the dynamics of plant-fungal interactions. (Author) 41 refs.

Plant-hummingbird interactions and temporal nectar availability in arestinga from Brazil

Directory of Open Access Journals (Sweden)

LORENA C.N. FONSECA

2015-12-01

Full Text Available ABSTRACT Hummingbirds are the most important and specialized group of pollinating birds in the Neotropics and their interactions with plants are key components to many communities. In the present study we identified the assemblage of plants visited by hummingbirds and investigated the temporal availability of floral resources in an area of restinga, sandy plain coastal vegetation associated with the Atlantic forest, in Southeastern Brazil. We recorded flower and nectar features, flowering phenology and interactions between plants and hummingbirds and estimated the amount of calories produced per hectare from June 2005 to August 2006. Ten plant species were visited by two hummingbirds,Amazilia fimbriata and Eupetomena macroura. Resource availability was highly variable among plant species and over time. Nectar volume and concentration per flower were similar to other Neotropical hummingbird-visited plant assemblages. The estimated nectar resource availability between months varied from 0.85 to 5.97 Kcal per hectare/day, demanding an area between one and 6.8 ha to support a single hummingbird. Our study reports an unusual tropical setting where almost all interactions between hummingbirds and plants were performed by a single hummingbird species,A. fimbriata. Hence, the variable nectar availability is probably influencing hummingbird movements, its foraging area, and consequently plant pollination.

A novel interaction between plant-beneficial rhizobacteria and roots: colonization induces corn resistance against the root herbivore Diabrotica speciosa.

Science.gov (United States)

Santos, Franciele; Peñaflor, Maria Fernanda G V; Paré, Paul W; Sanches, Patrícia A; Kamiya, Aline C; Tonelli, Mateus; Nardi, Cristiane; Bento, José Mauricio S

2014-01-01

A number of soil-borne microorganisms, such as mycorrhizal fungi and rhizobacteria, establish mutualistic interactions with plants, which can indirectly affect other organisms. Knowledge of the plant-mediated effects of mutualistic microorganisms is limited to aboveground insects, whereas there is little understanding of what role beneficial soil bacteria may play in plant defense against root herbivory. Here, we establish that colonization by the beneficial rhizobacterium Azospirillum brasilense affects the host selection and performance of the insect Diabrotica speciosa. Root larvae preferentially orient toward the roots of non-inoculated plants versus inoculated roots and gain less weight when feeding on inoculated plants. As inoculation by A. brasilense induces higher emissions of (E)-β-caryophyllene compared with non-inoculated plants, it is plausible that the non-preference of D. speciosa for inoculated plants is related to this sesquiterpene, which is well known to mediate belowground insect-plant interactions. To the best of our knowledge, this is the first study showing that a beneficial rhizobacterium inoculant indirectly alters belowground plant-insect interactions. The role of A. brasilense as part of an integrative pest management (IPM) program for the protection of corn against the South American corn rootworm, D. speciosa, is considered.

Developing microbe-plant interactions for applications in plant-growth promotion and disease control, production of useful compounds, remediation, and carbon sequestration

Energy Technology Data Exchange (ETDEWEB)

Wu, C.H.; Bernard, S.; Andersen, G.L.; Chen, W.

2009-03-01

Interactions between plants and microbes are an integral part of our terrestrial ecosystem. Microbe-plant interactions are being applied in many areas. In this review, we present recent reports of applications in the areas of plant-growth promotion, biocontrol, bioactive compound and biomaterial production, remediation and carbon sequestration. Challenges, limitations and future outlook for each field are discussed.

Plant-pollinator interactions in tropical monsoon forests in Southeast Asia.

Science.gov (United States)

Kato, Makoto; Kosaka, Yasuyuki; Kawakita, Atsushi; Okuyama, Yudai; Kobayashi, Chisato; Phimminith, Thavy; Thongphan, Daovorn

2008-11-01

Forests with different flora and vegetation types harbor different assemblages of flower visitors, and plant-pollinator interactions vary among forests. In monsoon-dominated East and Southeast Asia, there is a characteristic gradient in climate along latitude, creating a broad spectrum of forest types with potentially diverse pollinator communities. To detect a geographical pattern of plant-pollinator interactions, we investigated flowering phenology and pollinator assemblages in the least-studied forest type, i.e., tropical monsoon forest, in the Vientiane plain in Laos. Throughout the 5-year study, we observed 171 plant species blooming and detected flower visitors on 145 species. Flowering occurred throughout the year, although the number of flowering plant species peaked at the end of dry season. The dominant canopy trees, including Dipterocarpaceae, bloomed annually, in contrast to the supra-annual general flowering that occurs in Southeast Asian tropical rain forests. Among the 134 native plant species, 68 were pollinated by hymenopterans and others by lepidopterans, beetles, flies, or diverse insects. Among the observed bees, Xylocopa, megachilids, and honeybees mainly contributed to the pollination of canopy trees, whereas long-tongued Amegilla bees pollinated diverse perennials with long corolla tubes. This is the first community-level study of plant-pollinator interactions in an Asian tropical monsoon forest ecosystem.

Diverse role of CBL-interacting protein kinases in plant

Indian Academy of Sciences (India)

admin

Diverse role of CBL-interacting protein kinases in plant. Most of the extracellular and ... to their role in stress signalling. Their role in transport of plant hormone auxin and mechanism of action in stress response shed new light on diverse role of.

Functional plant types drive plant interactions in a Mediterranean mountain range

Czech Academy of Sciences Publication Activity Database

Macek, P.; Prieto, I.; Macková, Jana; Pistón, N.; Pugnaire, F.I.

2016-01-01

Roč. 7, May (2016), č. článku 662. ISSN 1664-462X R&D Projects: GA MŠk(CZ) EE2.3.30.0032 Institutional support: RVO:60077344 Keywords : biomass allocation * competition * facilitation * functional traits * plant interaction balance Subject RIV: EH - Ecology, Behaviour Impact factor: 4.298, year: 2016

Integrating Studies on Plant-Pollinator and Plant-Herbivore Interactions

NARCIS (Netherlands)

Lucas-Barbosa, Dani

2016-01-01

Research on herbivore-induced plant defence and research on pollination ecology have had a long history of separation. Plant reproduction of most angiosperm species is mediated by pollinators, and the effects of herbivore-induced plant defences on pollinator behaviour have been largely neglected.

Interaction of electromagnetic pulse with commercial nuclear-power-plant systems

Energy Technology Data Exchange (ETDEWEB)

Ericson, D.M. Jr.; Strawe, D.F.; Sandberg, S.J.; Jones, V.K.; Rensner, G.D.; Shoup, R.W.; Hanson, R.J.; Williams, C.B.

1983-02-01

This study examines the interaction of the electromagnetic pulse from a high altitude nuclear burst with commercial nuclear power plant systems. The potential vulnerability of systems required for safe shutdown of a specific nuclear power plant are explored. EMP signal coupling, induced plant response and component damage thresholds are established using techniques developed over several decades under Defense Nuclear Agency sponsorship. A limited test program was conducted to verify the coupling analysis technique as applied to a nuclear power plant. The results are extended, insofar as possible, to other nuclear plants.

Interaction of electromagnetic pulse with commercial nuclear-power-plant systems

International Nuclear Information System (INIS)

Ericson, D.M. Jr.; Strawe, D.F.; Sandberg, S.J.; Jones, V.K.; Rensner, G.D.; Shoup, R.W.; Hanson, R.J.; Williams, C.B.

1983-02-01

This study examines the interaction of the electromagnetic pulse from a high altitude nuclear burst with commercial nuclear power plant systems. The potential vulnerability of systems required for safe shutdown of a specific nuclear power plant are explored. EMP signal coupling, induced plant response and component damage thresholds are established using techniques developed over several decades under Defense Nuclear Agency sponsorship. A limited test program was conducted to verify the coupling analysis technique as applied to a nuclear power plant. The results are extended, insofar as possible, to other nuclear plants

Physiological and biochemical perspectives of non-salt tolerant plants during bacterial interaction against soil salinity.

Science.gov (United States)

Radhakrishnan, Ramalingam; Baek, Kwang Hyun

2017-07-01

Climatic changes on earth affect the soil quality of agricultural lands, especially by increasing salt deposition in soil, which results in soil salinity. Soil salinity is a major challenge to growth and reproduction among glycophytes (including all crop plants). Soil bacteria present in the rhizosphere and/or roots naturally protect plants from the adverse effects of soil salinity by reprogramming the stress-induced physiological changes in plants. Bacteria can enrich the soil with major nutrients (nitrogen, phosphorus, and potassium) in a form easily available to plants and prevent the transport of excess sodium to roots (exopolysaccharides secreted by bacteria bind with sodium ions) for maintaining ionic balance and water potential in cells. Salinity also affects plant growth regulators and suppresses seed germination and root and shoot growth. Bacterial secretion of indole-3-acetic acid and gibberellins compensates for the salt-induced hormonal decrease in plants, and bacterial 1-aminocyclopropane-1-carboxylate (ACC) deaminase synthesis decreases ethylene production to stimulate plant growth. Furthermore, bacteria modulate the redox state of salinity-affected plants by enhancing antioxidants and polyamines, which leads to increased photosynthetic efficiency. Bacteria-induced accumulation of compatible solutes in stressed plants regulates plant cellular activities and prevents salt stress damage. Plant-bacterial interaction reprograms the expression of salt stress-responsive genes and proteins in salinity-affected plants, resulting in a precise stress mitigation metabolism as a defense mechanism. Soil bacteria increase the fertility of soil and regulate the plant functions to prevent the salinity effects in glycophytes. This review explains the current understanding about the physiological changes induced in glycophytes during bacterial interaction to alleviate the adverse effects of soil salinity stress. Copyright © 2017 Elsevier Masson SAS. All rights

Thermography to explore plant-environment interactions.

Science.gov (United States)

Costa, J Miguel; Grant, Olga M; Chaves, M Manuela

2013-10-01

Stomatal regulation is a key determinant of plant photosynthesis and water relations, influencing plant survival, adaptation, and growth. Stomata sense the surrounding environment and respond rapidly to abiotic and biotic stresses. Stomatal conductance to water vapour (g s) and/or transpiration (E) are therefore valuable physiological parameters to be monitored in plant and agricultural sciences. However, leaf gas exchange measurements involve contact with leaves and often interfere with leaf functioning. Besides, they are time consuming and are limited by the sampling characteristics (e.g. sample size and/or the high number of samples required). Remote and rapid means to assess g s or E are thus particularly valuable for physiologists, agronomists, and ecologists. Transpiration influences the leaf energy balance and, consequently, leaf temperature (T leaf). As a result, thermal imaging makes it possible to estimate or quantify g s and E. Thermal imaging has been successfully used in a wide range of conditions and with diverse plant species. The technique can be applied at different scales (e.g. from single seedlings/leaves through whole trees or field crops to regions), providing great potential to study plant-environment interactions and specific phenomena such as abnormal stomatal closure, genotypic variation in stress tolerance, and the impact of different management strategies on crop water status. Nevertheless, environmental variability (e.g. in light intensity, temperature, relative humidity, wind speed) affects the accuracy of thermal imaging measurements. This review presents and discusses the advantages of thermal imaging applications to plant science, agriculture, and ecology, as well as its limitations and possible approaches to minimize them, by highlighting examples from previous and ongoing research.

Spatial heterogeneity of plant-soil feedback affects root interactions and interspecific competition.

Science.gov (United States)

Hendriks, Marloes; Ravenek, Janneke M; Smit-Tiekstra, Annemiek E; van der Paauw, Jan Willem; de Caluwe, Hannie; van der Putten, Wim H; de Kroon, Hans; Mommer, Liesje

2015-08-01

Plant-soil feedback is receiving increasing interest as a factor influencing plant competition and species coexistence in grasslands. However, we do not know how spatial distribution of plant-soil feedback affects plant below-ground interactions. We investigated the way in which spatial heterogeneity of soil biota affects competitive interactions in grassland plant species. We performed a pairwise competition experiment combined with heterogeneous distribution of soil biota using four grassland plant species and their soil biota. Patches were applied as quadrants of 'own' and 'foreign' soils from all plant species in all pairwise combinations. To evaluate interspecific root responses, species-specific root biomass was quantified using real-time PCR. All plant species suffered negative soil feedback, but strength was species-specific, reflected by a decrease in root growth in own compared with foreign soil. Reduction in root growth in own patches by the superior plant competitor provided opportunities for inferior competitors to increase root biomass in these patches. These patterns did not cascade into above-ground effects during our experiment. We show that root distributions can be determined by spatial heterogeneity of soil biota, affecting plant below-ground competitive interactions. Thus, spatial heterogeneity of soil biota may contribute to plant species coexistence in species-rich grasslands. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

Plant lectins: the ties that bind in root symbiosis and plant defense.

Science.gov (United States)

De Hoff, Peter L; Brill, Laurence M; Hirsch, Ann M

2009-07-01

Lectins are a diverse group of carbohydrate-binding proteins that are found within and associated with organisms from all kingdoms of life. Several different classes of plant lectins serve a diverse array of functions. The most prominent of these include participation in plant defense against predators and pathogens and involvement in symbiotic interactions between host plants and symbiotic microbes, including mycorrhizal fungi and nitrogen-fixing rhizobia. Extensive biological, biochemical, and molecular studies have shed light on the functions of plant lectins, and a plethora of uncharacterized lectin genes are being revealed at the genomic scale, suggesting unexplored and novel diversity in plant lectin structure and function. Integration of the results from these different types of research is beginning to yield a more detailed understanding of the function of lectins in symbiosis, defense, and plant biology in general.

How phytohormones shape interactions between plants and the soil-borne fungus Fusarium oxysporum

Directory of Open Access Journals (Sweden)

Xiaotang eDi

2016-02-01

Full Text Available Plants interact with a huge variety of soil microbes, ranging from pathogenic to mutualistic. The Fusarium oxysporum (Fo species complex consists of ubiquitous soil inhabiting fungi that can infect and cause disease in over 120 different plant species including tomato, banana, cotton and Arabidopsis. However, in many cases Fo colonization remains symptomless or even has beneficial effects on plant growth and/or stress tolerance. Also in pathogenic interactions a lengthy asymptomatic phase usually precedes disease development. All this indicates a sophisticated and fine-tuned interaction between Fo and its host. The molecular mechanisms underlying this balance are poorly understood. Plant hormone signaling networks emerge as key regulators of plant-microbe interactions in general. In this review we summarize the effects of the major phytohormones on the interaction between Fo and its diverse hosts. Generally, Salicylic Acid (SA signaling reduces plant susceptibility, whereas Jasmonic Acid (JA, Ethylene (ET, Abscisic Acid (ABA and auxin have complex effects, and are potentially hijacked by Fo for host manipulation. Finally, we discuss how plant hormones and Fo effectors balance the interaction from beneficial to pathogenic and vice versa.

Plant interactions with microbes and insects: from molecular mechanisms to ecology

NARCIS (Netherlands)

Pieterse, C.M.J.; Dicke, M.

2007-01-01

Plants are members of complex communities and interact both with antagonists and beneficial organisms. An important question in plant defense-signaling research is how plants integrate signals induced by pathogens, beneficial microbes and insects into the most appropriate adaptive response.

Intra-annual variation of arthropod–plant interactions and arthropod ...

African Journals Online (AJOL)

Arthropods are valuable biological indicators owing to strong relationships with primary producers. The supposition that arthropod–plant interactions are constant over seasons was tested using Mantel tests on correlations between these groups. A total of 78 plant species and 108 arthropod families were sampled monthly ...

Linking agricultural practices, mycorrhizal fungi, and traits mediating plant-insect interactions.

Science.gov (United States)

Barber, Nicholas A; Kiers, E Toby; Theis, Nina; Hazzard, Ruth V; Adler, Lynn S

2013-10-01

Agricultural management has profound effects on soil communities. Activities such as fertilizer inputs can modify the composition of arbuscular mycorrhizal fungi (AMF) communities, which form important symbioses with the roots of most crop plants. Intensive conventional agricultural management may select for less mutualistic AMF with reduced benefits to host plants compared to organic management, but these differences are poorly understood. AMF are generally evaluated based on their direct growth effects on plants. However, mycorrhizal colonization also may alter plant traits such as tissue nutrients, defensive chemistry, or floral traits, which mediate important plant-insect interactions like herbivory and pollination. To determine the effect of AMF from different farming practices on plant performance and traits that putatively mediate species interactions, we performed a greenhouse study by inoculating Cucumis sativus (cucumber, Cucurbitaceae) with AMF from conventional farms, organic farms, and a commercial AMF inoculum. We measured growth and a suite of plant traits hypothesized to be important predictors of herbivore resistance and pollinator attraction. Several leaf and root traits and flower production were significantly affected by AMF inoculum. Both conventional and organic AMF reduced leaf P content but increased Na content compared to control and commercial AMF. Leaf defenses were unaffected by AMF treatments, but conventional AMF increased root cucurbitacin C, the primary defensive chemical of C. sativus, compared to organic AMF. These effects may have important consequences for herbivore preference and population dynamics. AMF from both organic and conventional farms decreased flower production relative to commercial and control treatments, which may reduce pollinator attraction and plant reproduction. AMF from both farm types also reduced seed germination, but effects on plant growth were limited. Our results suggest that studies only considering AMF

A review of plant-pharmaceutical interactions: from uptake and effects in crop plants to phytoremediation in constructed wetlands

DEFF Research Database (Denmark)

Carvalho, Pedro N; Basto, M Clara P; Almeida, C Marisa R

2014-01-01

the potential impact of veterinary and human pharmaceuticals on arable land. However, plant uptake as well as phytotoxicity data are scarcely studied. Simultaneously, phytoremediation as a tool for pharmaceutical removal from soils, sediments and water is starting to be researched, with promising results....... This review gives an in-depth overview of the phytotoxicity of pharmaceuticals, their uptake and their removal by plants. The aim of the current work was to map the present knowledge concerning pharmaceutical interactions with plants in terms of uptake and the use of plant-based systems for phytoremediation...

A novel interaction between plant-beneficial rhizobacteria and roots: colonization induces corn resistance against the root herbivore Diabrotica speciosa.

Directory of Open Access Journals (Sweden)

Franciele Santos

Full Text Available A number of soil-borne microorganisms, such as mycorrhizal fungi and rhizobacteria, establish mutualistic interactions with plants, which can indirectly affect other organisms. Knowledge of the plant-mediated effects of mutualistic microorganisms is limited to aboveground insects, whereas there is little understanding of what role beneficial soil bacteria may play in plant defense against root herbivory. Here, we establish that colonization by the beneficial rhizobacterium Azospirillum brasilense affects the host selection and performance of the insect Diabrotica speciosa. Root larvae preferentially orient toward the roots of non-inoculated plants versus inoculated roots and gain less weight when feeding on inoculated plants. As inoculation by A. brasilense induces higher emissions of (E-β-caryophyllene compared with non-inoculated plants, it is plausible that the non-preference of D. speciosa for inoculated plants is related to this sesquiterpene, which is well known to mediate belowground insect-plant interactions. To the best of our knowledge, this is the first study showing that a beneficial rhizobacterium inoculant indirectly alters belowground plant-insect interactions. The role of A. brasilense as part of an integrative pest management (IPM program for the protection of corn against the South American corn rootworm, D. speciosa, is considered.

Molecular mechanisms of nematode-nematophagous microbe interactions: basis for biological control of plant-parasitic nematodes.

Science.gov (United States)

Li, Juan; Zou, Chenggang; Xu, Jianping; Ji, Xinglai; Niu, Xuemei; Yang, Jinkui; Huang, Xiaowei; Zhang, Ke-Qin

2015-01-01

Plant-parasitic nematodes cause significant damage to a broad range of vegetables and agricultural crops throughout the world. As the natural enemies of nematodes, nematophagous microorganisms offer a promising approach to control the nematode pests. Some of these microorganisms produce traps to capture and kill the worms from the outside. Others act as internal parasites to produce toxins and virulence factors to kill the nematodes from within. Understanding the molecular basis of microbe-nematode interactions provides crucial insights for developing effective biological control agents against plant-parasitic nematodes. Here, we review recent advances in our understanding of the interactions between nematodes and nematophagous microorganisms, with a focus on the molecular mechanisms by which nematophagous microorganisms infect nematodes and on the nematode defense against pathogenic attacks. We conclude by discussing several key areas for future research and development, including potential approaches to apply our recent understandings to develop effective biocontrol strategies.

Floral biology and the effects of plant-pollinator interaction on ...

African Journals Online (AJOL)

oyelana

2012-10-18

Oct 18, 2012 ... interaction on pollination intensity, fruit and seed set in. Solanum ... which plants offer rewards to flower visitors and they inadvertently ... fragmentation and extinction. Therefore, the ...... Plant resources of tropical Africa 2.

Involvement of lipid-protein complexes in plant-microorganism interactions

Directory of Open Access Journals (Sweden)

Blein Jean-Pierre

2002-01-01

Full Text Available Increasing concerns about the environmental impact of modern agricultural have prompted research for alternate practices to pesticide treatments, notably using plant defense mechanisms. Thus, isolation and characterization of plant defense elicitors have been the main step of studies in many groups. Moreover, in the global concept of interactions between organisms and their environment, a major concern is to discriminate recognition between exogenous and endogenous signals, notably during pathogenic or allergenic interactions involving small proteins, such as elicitins or lipid transfer proteins (LTPs. Elicitins and lipid transfer proteins (LTP are both able to load and transfer lipidic molecules and share some structural and functional properties. While elicitins are known as elicitors of plant defense mechanisms, the biological function of LTPs is still an enigma. They are ubiquitous plant proteins able to load and transfer hydrophobic molecules such as fatty acids or phospholipids. Among them, LTPs1 (type 1 lipid transfer proteins constitute a multigenic family of secreted plant lipid binding proteins that are constitutively expressed in specific tissues and/or induced in response to biotic and abiotic stress (for reviews [1-4]. Their biological function is still unknown, even if some data provide arguments for a role of these proteins in the assembly of extracellular hydrophobic polymers (i.e., cutin and suberin [2, 4] and/or in plant defense against fungal pathogens [1, 3]. Beside their involvement in plant defense, LTPs1 are also known to be pan-allergens of plant-derived foods [5]. Finally, the discovery of the sterol carrier-properties of elicitins has opened new perspectives dealing with the relationship between this function and the elicitor activity of these small cystein-rich proteins. Nevertheless, this elicitor activity is restrained to few plant species, and thus does not appear in accordance with a universal lipid transfer

Method and apparatus to image biological interactions in plants

Science.gov (United States)

Weisenberger, Andrew; Bonito, Gregory M.; Reid, Chantal D.; Smith, Mark Frederick

2015-12-22

A method to dynamically image the actual translocation of molecular compounds of interest in a plant root, root system, and rhizosphere without disturbing the root or the soil. The technique makes use of radioactive isotopes as tracers to label molecules of interest and to image their distribution in the plant and/or soil. The method allows for the study and imaging of various biological and biochemical interactions in the rhizosphere of a plant, including, but not limited to, mycorrhizal associations in such regions.

Plant interactions alter the predictions of metabolic scaling theory.

Directory of Open Access Journals (Sweden)

Yue Lin

Full Text Available Metabolic scaling theory (MST is an attempt to link physiological processes of individual organisms with macroecology. It predicts a power law relationship with an exponent of -4/3 between mean individual biomass and density during density-dependent mortality (self-thinning. Empirical tests have produced variable results, and the validity of MST is intensely debated. MST focuses on organisms' internal physiological mechanisms but we hypothesize that ecological interactions can be more important in determining plant mass-density relationships induced by density. We employ an individual-based model of plant stand development that includes three elements: a model of individual plant growth based on MST, different modes of local competition (size-symmetric vs. -asymmetric, and different resource levels. Our model is consistent with the observed variation in the slopes of self-thinning trajectories. Slopes were significantly shallower than -4/3 if competition was size-symmetric. We conclude that when the size of survivors is influenced by strong ecological interactions, these can override predictions of MST, whereas when surviving plants are less affected by interactions, individual-level metabolic processes can scale up to the population level. MST, like thermodynamics or biomechanics, sets limits within which organisms can live and function, but there may be stronger limits determined by ecological interactions. In such cases MST will not be predictive.

Pivoting from Arabidopsis to wheat to understand how agricultural plants integrate responses to biotic stress

Science.gov (United States)

Here we argue for a research initiative on gene-for-gene (g-f-g) interactions between wheat and its parasites. One aim is to begin a conversation between the disparate communities of plant pathology and entomology. Another is to understand how responses to biotic stress are integrated in an import...

Endophytic Actinobacteria and the Interaction of Micromonospora and Nitrogen Fixing Plants

Science.gov (United States)

Trujillo, Martha E.; Riesco, Raúl; Benito, Patricia; Carro, Lorena

2015-01-01

For a long time, it was believed that a healthy plant did not harbor any microorganisms within its tissues, as these were often considered detrimental for the plant. In the last three decades, the numbers of studies on plant microbe-interactions has led to a change in our view and we now know that many of these invisible partners are essential for the overall welfare of the plant. The application of Next Generation Sequencing techniques is a powerful tool that has permitted the detection and identification of microbial communities in healthy plants. Among the new plant microbe interactions recently reported several actinobacteria such as Micromonospora are included. Micromonospora is a Gram-positive bacterium with a wide geographical distribution; it can be found in the soil, mangrove sediments, and freshwater and marine ecosistems. In the last years our group has focused on the isolation of Micromonospora strains from nitrogen fixing nodules of both leguminous and actinorhizal plants and reported for the first time its wide distribution in nitrogen fixing nodules of both types of plants. These studies have shown how this microoganism had been largely overlooked in this niche due to its slow growth. Surprisingly, the genetic diversity of Micromonospora strains isolated from nodules is very high and several new species have been described. The current data indicate that Micromonospora saelicesensis is the most frequently isolated species from the nodular tissues of both leguminous and actinorhizal plants. Further studies have also been carried out to confirm the presence of Micromonospora inside the nodule tissues, mainly by specific in situ hybridization. The information derived from the genome of the model strain, Micromonospora lupini, Lupac 08, has provided useful information as to how this bacterium may relate with its host plant. Several strategies potentially necessary for Micromonospora to thrive in the soil, a highly competitive, and rough environment, and

The foundations of plant intelligence.

Science.gov (United States)

Trewavas, Anthony

2017-06-06

Intelligence is defined for wild plants and its role in fitness identified. Intelligent behaviour exhibited by single cells and systems similarity between the interactome and connectome indicates neural systems are not necessary for intelligent capabilities. Plants sense and respond to many environmental signals that are assessed to competitively optimize acquisition of patchily distributed resources. Situations of choice engender motivational states in goal-directed plant behaviour; consequent intelligent decisions enable efficient gain of energy over expenditure. Comparison of swarm intelligence and plant behaviour indicates the origins of plant intelligence lie in complex communication and is exemplified by cambial control of branch function. Error correction in behaviours indicates both awareness and intention as does the ability to count to five. Volatile organic compounds are used as signals in numerous plant interactions. Being complex in composition and often species and individual specific, they may represent the plant language and account for self and alien recognition between individual plants. Game theory has been used to understand competitive and cooperative interactions between plants and microbes. Some unexpected cooperative behaviour between individuals and potential aliens has emerged. Behaviour profiting from experience, another simple definition of intelligence, requires both learning and memory and is indicated in the priming of herbivory, disease and abiotic stresses.

Plant-hummingbird interactions and temporal nectar availability in a restinga from Brazil.

Science.gov (United States)

Fonseca, Lorena C N; Vizentin-Bugoni, Jeferson; Rech, André R; Alves, Maria Alice S

2015-01-01

Hummingbirds are the most important and specialized group of pollinating birds in the Neotropics and their interactions with plants are key components to many communities. In the present study we identified the assemblage of plants visited by hummingbirds and investigated the temporal availability of floral resources in an area of restinga, sandy plain coastal vegetation associated with the Atlantic forest, in Southeastern Brazil. We recorded flower and nectar features, flowering phenology and interactions between plants and hummingbirds and estimated the amount of calories produced per hectare from June 2005 to August 2006. Ten plant species were visited by two hummingbirds, Amazilia fimbriata and Eupetomena macroura. Resource availability was highly variable among plant species and over time. Nectar volume and concentration per flower were similar to other Neotropical hummingbird-visited plant assemblages. The estimated nectar resource availability between months varied from 0.85 to 5.97 Kcal per hectare/day, demanding an area between one and 6.8 ha to support a single hummingbird. Our study reports an unusual tropical setting where almost all interactions between hummingbirds and plants were performed by a single hummingbird species, A. fimbriata. Hence, the variable nectar availability is probably influencing hummingbird movements, its foraging area, and consequently plant pollination.

Genotype x environment interaction QTL mapping in plants: lessons from Arabidopsis

NARCIS (Netherlands)

El-Soda, M.; Malosetti, M.; Zwaan, B.J.; Koornneef, M.; Aarts, M.G.M.

2014-01-01

Plant growth and development are influenced by the genetic composition of the plant (G), the environment (E), and the interaction between them (G × E). To produce suitable genotypes for multiple environments, G × E should be accounted for and assessed in plant-breeding programs. Here, we review the

Plant-phytopathogen interactions: bacterial responses to environmental and plant stimuli.

Science.gov (United States)

Leonard, Simon; Hommais, Florence; Nasser, William; Reverchon, Sylvie

2017-05-01

Plant pathogenic bacteria attack numerous agricultural crops, causing devastating effects on plant productivity and yield. They survive in diverse environments, both in plants, as pathogens, and also outside their hosts as saprophytes. Hence, they are confronted with numerous changing environmental parameters. During infection, plant pathogens have to deal with stressful conditions, such as acidic, oxidative and osmotic stresses; anaerobiosis; plant defenses; and contact with antimicrobial compounds. These adverse conditions can reduce bacterial survival and compromise disease initiation and propagation. Successful bacterial plant pathogens must detect potential hosts and also coordinate their possibly conflicting programs for survival and virulence. Consequently, these bacteria have a strong and finely tuned capacity for sensing and responding to environmental and plant stimuli. This review summarizes our current knowledge of the signals and genetic circuits that affect survival and virulence factor expression in three important and well-studied plant pathogenic bacteria with wide host ranges and the capacity for long-term environmental survival. These are: Ralstonia solanacerarum, a vascular pathogen that causes wilt disease; Agrobacterium tumefaciens, a biotrophic tumorigenic pathogen responsible for crown gall disease and Dickeya, a brute force apoplastic pathogen responsible for soft-rot disease. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

Interactions between exotic invasive plants and soil microbes in the rhizosphere suggest that 'everything is not everywhere'.

Science.gov (United States)

Rout, Marnie E; Callaway, Ragan M

2012-07-01

The study of soil biota in the context of exotic plant invasions has led to an explosion in our understanding of the ecological roles of many different groups of microbes that function in roots or at the root-soil interface. Part of this progress has been the emergence of two biogeographic patterns involving invasive plants and soil microbes. First, in their non-native ranges invasive plants commonly interact differently with the same soil microbes than native plants. Second, in their native ranges, plants that are invasive elsewhere commonly interact functionally with soil microbes differently in their home ranges than they do in their non-native ranges. These studies pose a challenge to a long-held paradigm about microbial biogeography - the idea that microbes are not limited by dispersal and are thus free from the basic taxonomic, biogeographical and evolutionary framework that characterizes all other life on Earth. As an analogy, the global distribution of animals that function as carnivores does not negate the fascinating evolutionary biogeographic patterns of carnivores. Other challenges to this notion come from new measurements of genetic differences among microbes across geographic boundaries, which also suggest that meaningful biogeographic patterns exist for microorganisms. We expand this discussion of whether or not 'everything is everywhere' by using the inherently biogeographic context of plant invasions by reviewing the literature on interactions among invasive plants and the microorganisms in the rhizosphere. We find that these interactions can be delineated at multiple scales: from individual plants to continents. Thus the microbes that regulate major aspects of plant biology do not appear to be exempt from the fundamental evolutionary processes of geographical isolation and natural selection. At the important scales of taxonomy, ecotype and ecosystem functions, the fundamental ecology of invaders and soil microbes indicates that everything might

Understanding plant cell-wall remodelling during the symbiotic interaction between Tuber melanosporum and Corylus avellana using a carbohydrate microarray

DEFF Research Database (Denmark)

Sillo, Fabiano; Fangel, Jonatan Ulrik; Henrissat, Bernard

2016-01-01

. An important feature of these interactions concerns changes in the cell-wall composition during interaction with other organisms. In ectomycorrhizae, plant and fungal cell walls come into direct contact, and represent the interface between the two partners. However, very little information is available...... on the re-arrangement that could occur within the plant and fungal cell walls during ectomycorrhizal symbiosis. Taking advantage of the Comprehensive Microarray Polymer Profiling (CoMPP) technology, the current study has had the aim of monitoring the changes that take place in the plant cell wall in Corylus...

Methyl esterification of pectin plays a role during plant-pathogen interactions and affects plant resistance to diseases.

Science.gov (United States)

Lionetti, Vincenzo; Cervone, Felice; Bellincampi, Daniela

2012-11-01

The cell wall is a complex structure mainly composed by a cellulose-hemicellulose network embedded in a cohesive pectin matrix. Pectin is synthesized in a highly methyl esterified form and is de-esterified in muro by pectin methyl esterases (PMEs). The degree and pattern of methyl esterification affect the cell wall structure and properties with consequences on both the physiological processes of the plants and their resistance to pathogens. PME activity displays a crucial role in the outcome of the plant-pathogen interactions by making pectin more susceptible to the action of the enzymes produced by the pathogens. This review focuses on the impact of pectin methyl esterification in plant-pathogen interactions and on the dynamic role of its alteration during pathogenesis. Copyright © 2012 Elsevier GmbH. All rights reserved.

Interactions between plant hormones and heavy metals responses.

Science.gov (United States)

Bücker-Neto, Lauro; Paiva, Ana Luiza Sobral; Machado, Ronei Dorneles; Arenhart, Rafael Augusto; Margis-Pinheiro, Marcia

2017-01-01

Heavy metals are natural non-biodegradable constituents of the Earth's crust that accumulate and persist indefinitely in the ecosystem as a result of human activities. Since the industrial revolution, the concentration of cadmium, arsenic, lead, mercury and zinc, amongst others, have increasingly contaminated soil and water resources, leading to significant yield losses in plants. These issues have become an important concern of scientific interest. Understanding the molecular and physiological responses of plants to heavy metal stress is critical in order to maximize their productivity. Recent research has extended our view of how plant hormones can regulate and integrate growth responses to various environmental cues in order to sustain life. In the present review we discuss current knowledge about the role of the plant growth hormones abscisic acid, auxin, brassinosteroid and ethylene in signaling pathways, defense mechanisms and alleviation of heavy metal toxicity.

Negative, neutral, and positive interactions among nonnative plants: patterns, processes, and management implications.

Science.gov (United States)

Kuebbing, Sara E; Nuñez, Martin A

2015-02-01

The movement of species is one of the most pervasive forms of global change, and few ecosystems remain uninvaded by nonnative species. Studying species interactions is crucial for understanding their distribution and abundance, particularly for nonnative species because interactions may influence the probability of invasion and consequent ecological impact. Interactions among nonnatives are relatively understudied, though the likelihood of nonnative species co-occurrence is high. We quantify and describe the types of interactions among nonnative plants and determine what factors affect interaction outcomes for ecosystems globally. We reviewed 65 studies comprising 201 observations and recorded the interaction type, traits of the interacting species, and study characteristics. We conducted a census of interaction types and a meta-analysis of experiments that tested nonnative competition intensity. Both methods showed that negative and neutral interactions prevailed, and a number of studies reported that the removal of a dominant nonnative led to competitive release of other nonnatives. Positive interactions were less frequently reported and positive mean effect sizes were rare, but the plant characteristics nitrogen fixation, life cycle (annual or perennial), and functional group significantly influenced positive interactions. Positive interactions were three times more frequent when a neighboring nonnative was a nitrogen fixer and 3.5 times lower when a neighboring nonnative was an annual. Woody plants were two or four times more likely to have positive interactions relative to grasses or herbs, respectively. The prevalence of negative interactions suggests that managers should prepare for reinvasion of sites when treating dominant nonnatives. Though positive interactions were infrequent, managers may be able to anticipate positive interactions among nonnatives based upon traits of the co-occurring invaders. Predicting positive nonnative interactions is an

Understanding Early Elementary Children's Conceptual Knowledge of Plant Structure and Function through Drawings

Science.gov (United States)

Anderson, Janice L.; Ellis, Jane P.; Jones, Alan M.

2014-01-01

This study examined children's drawings to explain children's conceptual understanding of plant structure and function. The study explored whether the children's drawings accurately reflect their conceptual understanding about plants in a manner that can be interpreted by others. Drawing, survey, interview, and observational data were collected…

Plant community resistance to invasion by Bromus species – the roles of community attributes, Bromus Interactions with plant communities, and Bromus traits

Science.gov (United States)

Chambers, Jeanne; Germino, Matthew; Belnap, Jayne; Brown, Cynthia; Schupp, Eugene W.; St. Clair, Samuel B

2016-01-01

The factors that determine plant community resistance to exotic annual Bromus species (Bromushereafter) are diverse and context specific. They are influenced by the environmental characteristics and attributes of the community, the traits of Bromus species, and the direct and indirect interactions of Bromus with the plant community. Environmental factors, in particular ambient and soil temperatures, have significant effects on the ability of Bromus to establish and spread. Seasonality of precipitation relative to temperature influences plant community resistance toBromus through effects on soil water storage, timing of water and nutrient availability, and dominant plant life forms. Differences among plant communities in how well soil resource use by the plant community matches resource supply rates can influence the magnitude of resource fluctuations due to either climate or disturbance and thus the opportunities for invasion. The spatial and temporal patterns of resource availability and acquisition of growth resources by Bromus versus native species strongly influence resistance to invasion. Traits of Bromus that confer a “priority advantage” for resource use in many communities include early-season germination and high growth and reproductive rates. Resistance to Bromus can be overwhelmed by high propagule supply, low innate seed dormancy, and large, if short-lived, seed banks. Biological crusts can inhibit germination and establishment of invasive annual plants, including several annual Bromus species, but are effective only in the absence of disturbance. Herbivores can have negative direct effects on Bromus, but positive indirect effects through decreases in competitors. Management strategies can be improved through increased understanding of community resistance to exotic annual Bromus species.

Plant-plant interactions mediate the plastic and genotypic response of Plantago asiatica to CO2 : an experiment with plant populations from naturally high CO2 areas

NARCIS (Netherlands)

van Loon, Marloes P; Rietkerk, Max; Dekker, Stefan C; Hikosaka, Kouki; Ueda, Miki U; Anten, Niels P R

2016-01-01

Background and Aims The rising atmospheric CO2 concentration ([CO2]) is a ubiquitous selective force that may strongly impact species distribution and vegetation functioning. Plant–plant interactions could mediate the trajectory of vegetation responses to elevated [CO2], because some plants may

Competence and regulatory interactions during regeneration in plants

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Ajai Joseph Pulianmackal

2014-04-01

Full Text Available The ability to regenerate is widely exploited by multitudes of organisms ranging from unicellular bacteria to multicellular plants for their propagation and repair. But the levels of competence for regeneration vary from species to species. While variety of living cells of a plant display regeneration ability, only a few set of cells maintain their stemness in mammals. This highly pliable nature of plant cells in-terms of regeneration can be attributed to their high developmental plasticity. De novo organ initiation can be relatively easily achieved in plants by proper hormonal regulations. Elevated levels of plant hormone auxin induces the formation of proliferating mass of pluripotent cells called callus, which predominantly express lateral root meristem markers and hence is having an identity similar to lateral root primordia. Organ formation can be induced from the callus by modulating the ratio of hormones. An alternative for de novo organogenesis is by the forced expression of plant specific transcription factors. The mechanisms by which plant cells attain competence for regeneration on hormonal treatment or forced expression remain largely elusive. Recent studies have provided some insight into how the epigenetic modifications in plants affect this competence. In this review we discuss the present understanding of regenerative biology in plants and scrutinize the future prospectives of this topic. While discussing about the regeneration in the sporophyte of angiosperms which is well studied, here we outline the regenerative biology of the gametophytic phase and discuss about various strategies of regeneration that have evolved in the domain of life so that a common consensus on the entire process of regeneration can be made.

Plant-mediated Interactions Among Insects within a Community Ecological Perspective

NARCIS (Netherlands)

Poelman, E.H.; Dicke, M.

2014-01-01

Plants may be visited by many species of insects during their life-time. These insects include harmful herbivores above and belowground as well as beneficial natural enemies of herbivores and pollinators. Moreover, these interactions may take place sequentially or simultaneously. Responses of plants

Biotic interactions overrule plant responses to climate, depending on the species' biogeography.

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Astrid Welk

Full Text Available This study presents an experimental approach to assess the relative importance of climatic and biotic factors as determinants of species' geographical distributions. We asked to what extent responses of grassland plant species to biotic interactions vary with climate, and to what degree this variation depends on the species' biogeography. Using a gradient from oceanic to continental climate represented by nine common garden transplant sites in Germany, we experimentally tested whether congeneric grassland species of different geographic distribution (oceanic vs. continental plant range type responded differently to combinations of climate, competition and mollusc herbivory. We found the relative importance of biotic interactions and climate to vary between the different components of plant performance. While survival and plant height increased with precipitation, temperature had no effect on plant performance. Additionally, species with continental plant range type increased their growth in more benign climatic conditions, while those with oceanic range type were largely unable to take a similar advantage of better climatic conditions. Competition generally caused strong reductions of aboveground biomass and growth. In contrast, herbivory had minor effects on survival and growth. Against expectation, these negative effects of competition and herbivory were not mitigated under more stressful continental climate conditions. In conclusion we suggest variation in relative importance of climate and biotic interactions on broader scales, mediated via species-specific sensitivities and factor-specific response patterns. Our results have important implications for species distribution models, as they emphasize the large-scale impact of biotic interactions on plant distribution patterns and the necessity to take plant range types into account.

From bulk soil to intracrystalline investigation of plant-mineral interaction

Science.gov (United States)

Lemarchand, D.; Voinot, A.; Chabaux, F.; Turpault, M.

2011-12-01

Understanding the controls and feedbacks regulating the flux of matter between bio-geochemical reservoirs in forest ecosystems receives a fast growing interest for the last decades. A complex question is to understand how minerals and vegetation interact in soils to sustain life and, to a broader scope, how forest ecosystems may respond to human activity (acid rain, harvesting,...) and climate perturbations (temperature, precipitation,...). Many mineralogical and biogeochemical approaches have longtime been developed, and occasionally coupled, in order to investigate the mechanisms by which chemical elements either are exchanged between soil particles and solutions, or are transferred to plants or to deeper soil layers and finally leave the system. But the characterization of particular processes like the contribution of minor reactive minerals to plant nutrition and global fluxes or the mechanisms by which biology can modify reaction rates and balance the bioavailability of nutrients in response to environmental perturbation sometimes fails because of the lack of suitable tracers. Recent analytical and conceptual advances have opened new perspectives for the use of light "non traditional" stable isotopes. Showing a wild range of concentrations and isotopic compositions between biogeochemical reservoirs in forest ecosystem, boron has physico-chemical properties particularly relevant to the investigation of water/rock interactions even when evolving biologically-mediated reactions. In this study, we focused on the distribution of boron isotopes from intracrystalline to bulk soil scales. An overview of the boron distribution and annual fluxes in the soil-plant system clearly indicates that the vegetation cycling largely controls the mobility of boron. We also observe that the mineral and biological B pools have drastically different isotopic signature that makes the transfer of B between them very easy to follow. In particular, the podzol soil we analyzed shows a

Interactions between plant hormones and heavy metals responses

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Lauro Bücker-Neto

2017-04-01

Full Text Available Abstract Heavy metals are natural non-biodegradable constituents of the Earth's crust that accumulate and persist indefinitely in the ecosystem as a result of human activities. Since the industrial revolution, the concentration of cadmium, arsenic, lead, mercury and zinc, amongst others, have increasingly contaminated soil and water resources, leading to significant yield losses in plants. These issues have become an important concern of scientific interest. Understanding the molecular and physiological responses of plants to heavy metal stress is critical in order to maximize their productivity. Recent research has extended our view of how plant hormones can regulate and integrate growth responses to various environmental cues in order to sustain life. In the present review we discuss current knowledge about the role of the plant growth hormones abscisic acid, auxin, brassinosteroid and ethylene in signaling pathways, defense mechanisms and alleviation of heavy metal toxicity.

Interactive real-time nuclear plant simulations on a UNIX based supercomputer

International Nuclear Information System (INIS)

Behling, S.R.

1990-01-01

Interactive real-time nuclear plant simulations are critically important to train nuclear power plant engineers and operators. In addition, real-time simulations can be used to test the validity and timing of plant technical specifications and operational procedures. To accurately and confidently simulate a nuclear power plant transient in real-time, sufficient computer resources must be available. Since some important transients cannot be simulated using preprogrammed responses or non-physical models, commonly used simulation techniques may not be adequate. However, the power of a supercomputer allows one to accurately calculate the behavior of nuclear power plants even during very complex transients. Many of these transients can be calculated in real-time or quicker on the fastest supercomputers. The concept of running interactive real-time nuclear power plant transients on a supercomputer has been tested. This paper describes the architecture of the simulation program, the techniques used to establish real-time synchronization, and other issues related to the use of supercomputers in a new and potentially very important area. (author)

Nitric oxide production by necrotrophic pathogen Macrophomina phaseolina and the host plant in charcoal rot disease of jute: complexity of the interplay between necrotroph-host plant interactions.

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Tuhin Subhra Sarkar

Full Text Available M. phaseolina, a global devastating necrotrophic fungal pathogen causes charcoal rot disease in more than 500 host plants. With the aim of understanding the plant-necrotrophic pathogen interaction associated with charcoal rot disease of jute, biochemical approach was attempted to study cellular nitric oxide production under diseased condition. This is the first report on M. phaseolina infection in Corchorus capsularis (jute plants which resulted in elevated nitric oxide, reactive nitrogen species and S nitrosothiols production in infected tissues. Time dependent nitric oxide production was also assessed with 4-Amino-5-Methylamino-2',7'-Difluorofluorescein Diacetate using single leaf experiment both in presence of M. phaseolina and xylanases obtained from fungal secretome. Cellular redox status and redox active enzymes were also assessed during plant fungal interaction. Interestingly, M. phaseolina was found to produce nitric oxide which was detected in vitro inside the mycelium and in the surrounding medium. Addition of mammalian nitric oxide synthase inhibitor could block the nitric oxide production in M. phaseolina. Bioinformatics analysis revealed nitric oxide synthase like sequence with conserved amino acid sequences in M. phaseolina genome sequence. In conclusion, the production of nitric oxide and reactive nitrogen species may have important physiological significance in necrotrophic host pathogen interaction.

Bird-plant interaction networks: a study on frugivory in Brazilian urban areas

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Diego Silva Freitas Oliveira

2015-12-01

Full Text Available In Brazil, few studies compare the consumption of native and exotic fruits, especially in an urban environment. The Network Theory may be useful in such studies, because it allows evaluating many bird and plant species involved in interactions. The goals of this study were: evaluate a bird frugivory interaction network in an urban environment; checking the role played by native and exotic plants in the network and comparing the consumer assemblies of these two plant groups. A literature review on bird frugivory in Brazilian urban areas was conducted, as well as an analysis to create an interaction network on a regional scale. The analysis included 15 papers with 70 bird species eating fruits from 15 plant species (6 exotic and 9 native. The exotic and native fruit consumers did not form different groups and the interaction network was significantly nested (NODF = 0.30; p < 0.01 and not modular (M = 0.36; p = 0.16. Two exotic plant species are in the generalist core of the frugivory network (Ficus microcarpa and Michelia champaca. The results point out that a relatively diversified bird group eats fruits in Brazilian urban areas in an opportunistic way, with no preference for native or exotic plants.

Insect-plant-pathogen interactions as shaped by future climate: effects on biology, distribution, and implications for agriculture.

Science.gov (United States)

Trębicki, Piotr; Dáder, Beatriz; Vassiliadis, Simone; Fereres, Alberto

2017-12-01

Carbon dioxide (CO 2 ) is the main anthropogenic gas which has drastically increased since the industrial revolution, and current concentrations are projected to double by the end of this century. As a consequence, elevated CO 2 is expected to alter the earths' climate, increase global temperatures and change weather patterns. This is likely to have both direct and indirect impacts on plants, insect pests, plant pathogens and their distribution, and is therefore problematic for the security of future food production. This review summarizes the latest findings and highlights current knowledge gaps regarding the influence of climate change on insect, plant and pathogen interactions with an emphasis on agriculture and food production. Direct effects of climate change, including increased CO 2 concentration, temperature, patterns of rainfall and severe weather events that impact insects (namely vectors of plant pathogens) are discussed. Elevated CO 2 and temperature, together with plant pathogen infection, can considerably change plant biochemistry and therefore plant defense responses. This can have substantial consequences on insect fecundity, feeding rates, survival, population size, and dispersal. Generally, changes in host plant quality due to elevated CO 2 (e.g., carbon to nitrogen ratios in C3 plants) negatively affect insect pests. However, compensatory feeding, increased population size and distribution have also been reported for some agricultural insect pests. This underlines the importance of additional research on more targeted, individual insect-plant scenarios at specific locations to fully understand the impact of a changing climate on insect-plant-pathogen interactions. © 2017 Institute of Zoology, Chinese Academy of Sciences.

Arbuscular mycorrhizal interactions of mycoheterotrophic Thismia are more specialized than in autotrophic plants.

Science.gov (United States)

Gomes, Sofia I F; Aguirre-Gutiérrez, Jesús; Bidartondo, Martin I; Merckx, Vincent S F T

2017-02-01

In general, plants and arbuscular mycorrhizal (AM) fungi exchange photosynthetically fixed carbon for soil nutrients, but occasionally nonphotosynthetic plants obtain carbon from AM fungi. The interactions of these mycoheterotrophic plants with AM fungi are suggested to be more specialized than those of green plants, although direct comparisons are lacking. We investigated the mycorrhizal interactions of both green and mycoheterotrophic plants. We used next-generation DNA sequencing to compare the AM communities from roots of five closely related mycoheterotrophic species of Thismia (Thismiaceae), roots of surrounding green plants, and soil, sampled over the entire temperate distribution of Thismia in Australia and New Zealand. We observed that the fungal communities of mycoheterotrophic and green plants are phylogenetically more similar within than between these groups of plants, suggesting a specific association pattern according to plant trophic mode. Moreover, mycoheterotrophic plants follow a more restricted association with their fungal partners in terms of phylogenetic diversity when compared with green plants, targeting more clustered lineages of fungi, independent of geographic origin. Our findings demonstrate that these mycoheterotrophic plants target more narrow lineages of fungi than green plants, despite the larger fungal pool available in the soil, and thus they are more specialized towards mycorrhizal fungi than autotrophic plants. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

Genome Evolution of Plant-Parasitic Nematodes.

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Kikuchi, Taisei; Eves-van den Akker, Sebastian; Jones, John T

2017-08-04

Plant parasitism has evolved independently on at least four separate occasions in the phylum Nematoda. The application of next-generation sequencing (NGS) to plant-parasitic nematodes has allowed a wide range of genome- or transcriptome-level comparisons, and these have identified genome adaptations that enable parasitism of plants. Current genome data suggest that horizontal gene transfer, gene family expansions, evolution of new genes that mediate interactions with the host, and parasitism-specific gene regulation are important adaptations that allow nematodes to parasitize plants. Sequencing of a larger number of nematode genomes, including plant parasites that show different modes of parasitism or that have evolved in currently unsampled clades, and using free-living taxa as comparators would allow more detailed analysis and a better understanding of the organization of key genes within the genomes. This would facilitate a more complete understanding of the way in which parasitism has shaped the genomes of plant-parasitic nematodes.

Plant innate immunity against human bacterial pathogens

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Maeli eMelotto

2014-08-01

Full Text Available Certain human bacterial pathogens such as the enterohemorrhagic Escherichia coli and Salmonella enterica are not proven to be plant pathogens yet. Nonetheless, under certain conditions they can survive on, penetrate into, and colonize internal plant tissues causing serious food borne disease outbreaks. In this review, we highlight current understanding on the molecular mechanisms of plant responses against human bacterial pathogens and discuss salient common and contrasting themes of plant interactions with phytopathogens or human pathogens.

Multi-omics approach identifies molecular mechanisms of plant-fungus mycorrhizal interaction

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Peter E Larsen

2016-01-01

Full Text Available In mycorrhizal symbiosis, plant roots form close, mutually beneficial interactions with soil fungi. Before this mycorrhizal interaction can be established however, plant roots must be capable of detecting potential beneficial fungal partners and initiating the gene expression patterns necessary to begin symbiosis. To predict a plant root – mycorrhizal fungi sensor systems, we analyzed in vitro experiments of Populus tremuloides (aspen tree and Laccaria bicolor (mycorrhizal fungi interaction and leveraged over 200 previously published transcriptomic experimental data sets, 159 experimentally validated plant transcription factor binding motifs, and more than 120-thousand experimentally validated protein-protein interactions to generate models of pre-mycorrhizal sensor systems in aspen root. These sensor mechanisms link extracellular signaling molecules with gene regulation through a network comprised of membrane receptors, signal cascade proteins, transcription factors, and transcription factor biding DNA motifs. Modeling predicted four pre-mycorrhizal sensor complexes in aspen that interact with fifteen transcription factors to regulate the expression of 1184 genes in response to extracellular signals synthesized by Laccaria. Predicted extracellular signaling molecules include common signaling molecules such as phenylpropanoids, salicylate, and, jasmonic acid. This multi-omic computational modeling approach for predicting the complex sensory networks yielded specific, testable biological hypotheses for mycorrhizal interaction signaling compounds, sensor complexes, and mechanisms of gene regulation.

RNA-protein interactions in plant disease: hackers at the dinner table.

Science.gov (United States)

Spanu, Pietro D

2015-09-01

Plants are the source of most of our food, whether directly or as feed for the animals we eat. Our dinner table is a trophic level we share with the microbes that also feed on the primary photosynthetic producers. Microbes that enter into close interactions with plants need to evade or suppress detection and host immunity to access nutrients. They do this by deploying molecular tools - effectors - which target host processes. The mode of action of effector proteins in these events is varied and complex. Recent data from diverse systems indicate that RNA-interacting proteins and RNA itself are delivered by eukaryotic microbes, such as fungi and oomycetes, to host plants and contribute to the establishment of successful interactions. This is evidence that pathogenic microbes can interfere with the host software. We are beginning to see that pathogenic microbes are capable of hacking into the plants' immunity programs. © 2015 The Author. New Phytologist © 2015 New Phytologist Trust.

Disease interactions in a shared host plant: effects of pre-existing viral infection on cucurbit plant defense responses and resistance to bacterial wilt disease.

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Lori R Shapiro

Full Text Available Both biotic and abiotic stressors can elicit broad-spectrum plant resistance against subsequent pathogen challenges. However, we currently have little understanding of how such effects influence broader aspects of disease ecology and epidemiology in natural environments where plants interact with multiple antagonists simultaneously. In previous work, we have shown that healthy wild gourd plants (Cucurbita pepo ssp. texana contract a fatal bacterial wilt infection (caused by Erwinia tracheiphila at significantly higher rates than plants infected with Zucchini yellow mosaic virus (ZYMV. We recently reported evidence that this pattern is explained, at least in part, by reduced visitation of ZYMV-infected plants by the cucumber beetle vectors of E. tracheiphila. Here we examine whether ZYMV-infection may also directly elicit plant resistance to subsequent E. tracheiphila infection. In laboratory studies, we assayed the induction of key phytohormones (SA and JA in single and mixed infections of these pathogens, as well as in response to the feeding of A. vittatum cucumber beetles on healthy and infected plants. We also tracked the incidence and progression of wilt disease symptoms in plants with prior ZYMV infections. Our results indicate that ZYMV-infection slightly delays the progression of wilt symptoms, but does not significantly reduce E. tracheiphila infection success. This observation supports the hypothesis that reduced rates of wilt disease in ZYMV-infected plants reflect reduced visitation by beetle vectors. We also documented consistently strong SA responses to ZYMV infection, but limited responses to E. tracheiphila in the absence of ZYMV, suggesting that the latter pathogen may effectively evade or suppress plant defenses, although we observed no evidence of antagonistic cross-talk between SA and JA signaling pathways. We did, however, document effects of E. tracheiphila on induced responses to herbivory that may influence host-plant

Striga parasitizes transgenic hairy roots of Zea mays and provides a tool for studying plant-plant interactions

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Runo Steven

2012-06-01

Full Text Available Abstract Background Striga species are noxious root hemi-parasitic weeds that debilitate cereal production in sub-Saharan Africa (SSA. Control options for Striga are limited and developing Striga resistant crop germplasm is regarded as the best and most sustainable control measure. Efforts to improve germplasm for Striga resistance by a non-Genetic Modification (GM approach, for example by exploiting natural resistance, or by a GM approach are constrained by limited information on the biological processes underpinning host-parasite associations. Additionaly, a GM approach is stymied by lack of availability of candidate resistance genes for introduction into hosts and robust transformation methods to validate gene functions. Indeed, a majority of Striga hosts, the world’s most cultivated cereals, are recalcitrant to genetic transformation. In maize, the existing protocols for transformation and regeneration are tedious, lengthy, and highly genotype-specific with low efficiency of transformation. Results We used Agrobacterium rhizogenes strain K599 carrying a reporter gene construct, Green Fluorescent Protein (GFP, to generate transgenic composite maize plants that were challenged with the parasitic plant Striga hermonthica. Eighty five percent of maize plants produced transgenic hairy roots expressing GFP. Consistent with most hairy roots produced in other species, transformed maize roots exhibited a hairy root phenotype, the hallmark of A. rhizogenes mediated transformation. Transgenic hairy roots resulting from A. rhizogenes transformation were readily infected by S. hermonthica. There were no significant differences in the number and size of S. hermonthica individuals recovered from either transgenic or wild type roots. Conclusions This rapid, high throughput, transformation technique will advance our understanding of gene function in parasitic plant-host interactions.

Gardening for Therapeutic People-Plant Interactions during Long-Duration Space Missions

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Odeh Raymond

2017-02-01

Full Text Available Plants provide people with vital resources necessary to sustain life. Nutrition, vitamins, calories, oxygen, fuel, and medicinal phytochemicals are just a few of the life-supporting plant products, but does our relationship with plants transcend these physical and biochemical products? This review synthesizes some of the extant literature on people-plant interactions, and relates key findings relevant to space exploration and the psychosocial and neurocognitive benefits of plants and nature in daily life. Here, a case is made in support of utilizing plant-mediated therapeutic benefits to mitigate potential psychosocial and neurocognitive decrements associated with long-duration space missions, especially for missions that seek to explore increasingly distant places where ground-based support is limited.

Evolutionary dynamics of interactions between plants and their enemies: comparison of herbivorous insects and pathogens.

Science.gov (United States)

Wininger, Kerry; Rank, Nathan

2017-11-01

Plants colonized land over 400 million years ago. Shortly thereafter, organisms began to consume terrestrial plant tissue as a nutritional resource. Most plant enemies are plant pathogens or herbivores, and they impose natural selection for plants to evolve defenses. These traits generate selection pressures on enemies. Coevolution between terrestrial plants and their enemies is an important element of the evolutionary history of both groups. However, coevolutionary studies of plant-pathogen interactions have tended to focus on different research topics than plant-herbivore interactions. Specifically, studies of plant-pathogen interactions often adopt a "gene-for-gene" conceptual framework. In contrast, studies of plants and herbivores often investigate escalation or elaboration of plant defense and herbivore adaptations to overcome it. The main exceptions to the general pattern are studies that focus on small, sessile herbivores that share many features with plant pathogens, studies that incorporate both herbivores and pathogens into a single investigation, and studies that test aspects of Thompson's geographic mosaic theory for coevolution. We discuss the implications of these findings for future research. © 2017 New York Academy of Sciences.

CO2 EFFECTS ON MOJAVE DESERT PLANT INTERACTIONS

Energy Technology Data Exchange (ETDEWEB)

L. A. DEFALCO; G. C. FERNANDEZ; S. D. SMITH; R. S. NOWAK

2004-01-01

Seasonal and interannual droughts characteristic of deserts have the potential to modify plant interactions as atmospheric CO{sub 2} concentrations continue to rise. At the Nevada Desert FACE (free-air CO{sub 2} enrichment) facility in the northern Mojave Desert, the effects of elevated atmospheric C02 (550 vs. ambient {approx}360 {micro}mol mol{sup -1}) on plant interactions were examined during two years of high and low rainfall. Results suggest that CO{sub 2} effects on the interaction between native species and their understory herbs are dependent on the strength of competition when rainfall is plentiful, but are unimportant during annual drought. Seasonal rainfall for 1999 was 23% the long-term average for the area, and neither elevated CO{sub 2} nor the low production of herbaceous neighbors had an effect on relative growth rate (RGR, d{sup -1}) and reproductive effort (RE, number of flowers g{sup -1}) for Achnatherum hymenoides (early season perennial C{sub 3} grass), Pleuraphis rigida (late season perennial C{sub 4} grass), and Larrea tridentata (evergreen C{sub 3} shrub). In contrast, 1998 received 213% the average rainfall. Consequently, the decrease in RGR and increase in RE for Achnatherum, whose period of growth overlaps directly with that of its neighbors, was exaggerated at elevated CO{sub 2}. However, competitive effects of neighbors on Eriogonum trichopes (a winter annual growing in shrub interspaces), Pleuraphis and Larrea were not affected by elevated CO{sub 2}, and possible explanations are discussed. Contrary to expectations, the invasive annual neighbor Bromus madritensis ssp. rubens had little influence on target plant responses because densities in 1998 and 1999 at this site were well below those found in other studies where it has negatively affected perennial plant growth. The extent that elevated CO{sub 2} reduces the performance of Achnatherum in successive years to cause its loss from the plant community depends more on future pressure

Bears benefit plants via a cascade with both antagonistic and mutualistic interactions.

Science.gov (United States)

Grinath, Joshua B; Inouye, Brian D; Underwood, Nora

2015-02-01

Predators can influence primary producers by generating cascades of effects in ecological webs. These effects are often non-intuitive, going undetected because they involve many links and different types of species interactions. Particularly, little is understood about how antagonistic (negative) and mutualistic (positive) interactions combine to create cascades. Here, we show that black bears can benefit plants by consuming ants. The ants are mutualists of herbivores and protect herbivores from other arthropod predators. We found that plants near bear-damaged ant nests had greater reproduction than those near undamaged nests, due to weaker ant protection for herbivores, which allowed herbivore suppression by arthropod predators. Our results highlight the need to integrate mutualisms into trophic cascade theory, which is based primarily on antagonistic relationships. Predators are often conservation targets, and our results suggest that bears and other predators should be managed with the understanding that they can influence primary producers through many paths. © 2014 John Wiley & Sons Ltd/CNRS.

Investigation of the interaction of 85Kr with plants in model experiments

International Nuclear Information System (INIS)

Butkus, D.V.; Morkunas, G.S.; Bluvshtejn, D.Yu.; Styro, B.I.

1988-01-01

The method of investigation of the interaction of 85 Kr with plants is described using model experiments and data analysis. The dependencies of the coefficient of 85 Kr absorption by plants on the biological structure of the plant, the concentration of krypton-85 in the environment, the method of plant exposition in the environment with the 85 Kr admixture are provided. The time dependencies of 85 Kr desorption from plants are given. 4 refs.; 7 figs.; 3 tabs

Arabidopsis thaliana: A model host plant to study plant-pathogen interaction using Chilean field isolates of Botrytis cinerea

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JUAN GONZÁLEZ

2006-01-01

Full Text Available One of the fungal pathogens that causes more agriculture damage is Botrytis cinerea. Botrytis is a constant threat to crops because the fungus infects a wide range of host species, both native and cultivated. Furthermore, Botrytis persists on plant debris in and on the soil. Some of the most serious diseases caused by Botrytis include gray mold on vegetables and fruits, such as grapes and strawberries. Botrytis also causes secondary soft rot of fruits and vegetables during storage, transit and at the market. In many plant-pathogen interactions, resistance often is associated with the deposition of callose, accumulation of autofluorescent compounds, the synthesis and accumulation of salicylic acid as well as pathogenesis-related proteins. Arabidopsis thaliana has been used as a plant model to study plant-pathogen interaction. The genome of Arabidopsis has been completely sequenced and this plant serves as a good genetic and molecular model. In this study, we demonstrate that Chilean field isolates infect Arabidopsis thaliana and that Arabidopsis subsequently activates several defense response mechanisms associated with a hypersensitive response. Furthermore, we propose that Arabidopsis may be used as a model host species to analyze the diversity associated with infectivity among populations of Botrytis cinerea field isolates

[Allelopathic interactions between invasive plant Solidago canadensis and native plant Phragmites australis].

Science.gov (United States)

Li, Yu-Zhe; Fan, Jiang-Wen; Yin, Xin; Yang, En-Yi; Wei, Wei; Tian, Zhi-Hui; Da, Liang-Jun

2011-05-01

Taking the seeds of invasive plant Solidago canadensis and native plant Phragmites australis from their mono- and co-dominant communities as allelopathic acceptors, this paper analyzed the differences in the seed germination rate and sprout length after treated with five level (12.5, 25, 50, 100, and 200 mg x mL(-1)) S. canadensis and P. australis extracts, aimed to understand the allelopathic interactions between the two species. The 1000-grain weight and seed germination rate under distilled water treatment of the two species in co-dominated community were greater than those in mono-dominant community. Low level (12.5 and 25 mg x mL(-1)) S. canadensi extracts slightly promoted the seed germination rates of S. canadensis in both mono- and co-dominant communities, but high level (50, 100, and 200 mg x mL(-1)) S. canadensi extracts had strong inhibition effect, especially for the S. canadensis in co-dominated community. No significant patterns were observed about the effects of P. australis extract on S. canadensis seed germination. The sprout length of S. canadensis seeds in both mono- and co-dominant communities decreased with increasing level of S. canadensis extract, but decreased in a fluctuation way with increasing level of P. australis extract. After treated with the extracts of P. australis or S. canadensis, the seed germination rate of P. australis in mono-dominant community was significantly greater than that in co-dominant community (P < 0.05), but there was no significant difference between these two extracts.

Flower-Visiting Social Wasps and Plants Interaction: Network Pattern and Environmental Complexity

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Mateus Aparecido Clemente

2012-01-01

Full Text Available Network analysis as a tool for ecological interactions studies has been widely used since last decade. However, there are few studies on the factors that shape network patterns in communities. In this sense, we compared the topological properties of the interaction network between flower-visiting social wasps and plants in two distinct phytophysiognomies in a Brazilian savanna (Riparian Forest and Rocky Grassland. Results showed that the landscapes differed in species richness and composition, and also the interaction networks between wasps and plants had different patterns. The network was more complex in the Riparian Forest, with a larger number of species and individuals and a greater amount of connections between them. The network specialization degree was more generalist in the Riparian Forest than in the Rocky Grassland. This result was corroborated by means of the nestedness index. In both networks was found asymmetry, with a large number of wasps per plant species. In general aspects, most wasps had low niche amplitude, visiting from one to three plant species. Our results suggest that differences in structural complexity of the environment directly influence the structure of the interaction network between flower-visiting social wasps and plants.

Flavonoids as Important Molecules of Plant Interactions with the Environment

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Justyna Mierziak

2014-10-01

Full Text Available Flavonoids are small molecular secondary metabolites synthesized by plants with various biological activities. Due to their physical and biochemical properties, they are capable of participating in plants’ interactions with other organisms (microorganisms, animals and other plants and their reactions to environmental stresses. The majority of their functions result from their strong antioxidative properties. Although an increasing number of studies focus on the application of flavonoids in medicine or the food industry, their relevance for the plants themselves also deserves extensive investigations. This review summarizes the current knowledge on the functions of flavonoids in the physiology of plants and their relations with the environment.

Plant response-based sensing for control starategies in sustainable greenhouse production

International Nuclear Information System (INIS)

Kacira, M.; Sase, S.; Okushima, L.; Ling, P.P.

2005-01-01

The effect of environmental variability is one of the major concerns in experimental design for both research in plant systems and greenhouse plant production. Microclimates surrounding plants are not usually uniform. Therefore, many samples and sensors are required to obtain a true representation of the plant population. A plant monitoring system capable of reducing the required number of samples by reducing environmental variability would be more advantageous. To better understand plant-environment interaction, it is essential to study plants, microclimate surrounding the plants and the growth media. To achieve this, the monitoring system must be equipped with proper instrumentation. To achieve proper management practices and sustainable greenhouse production, it is essential first to understand plants and their interactions with their surroundings and then establish plant response-based sensing and control strategies for greenhouse processes. Therefore, an effort was conducted to review and discuss current sensing and control strategies in greenhouse research and plant production and provide recommendations on plant response-based sensing and control strategies for sustainable greenhouse production

Interactions between salt marsh plants and Cu nanoparticles - Effects on metal uptake and phytoremediation processes.

Science.gov (United States)

Andreotti, Federico; Mucha, Ana Paula; Caetano, Cátia; Rodrigues, Paula; Rocha Gomes, Carlos; Almeida, C Marisa R

2015-10-01

The increased use of metallic nanoparticles (NPs) raises the probability of finding NPs in the environment. A lot of information exists already regarding interactions between plants and metals, but information regarding interactions between metallic NPs and plants, including salt marsh plants, is still lacking. This work aimed to study interactions between CuO NPs and the salt marsh plants Halimione portulacoides and Phragmites australis. In addition, the potential of these plants for phytoremediation of Cu NPs was evaluated. Plants were exposed for 8 days to sediment elutriate solution doped either with CuO or with ionic Cu. Afterwards, total metal concentrations were determined in plant tissues. Both plants accumulated Cu in their roots, but this accumulation was 4 to 10 times lower when the metal was added in NP form. For P. australis, metal translocation occurred when the metal was added either in ionic or in NP form, but for H. portulacoides no metal translocation was observed when NPs were added to the medium. Therefore, interactions between plants and NPs differ with the plant species. These facts should be taken in consideration when applying these plants for phytoremediation of contaminated sediments in estuaries, as the environmental management of these very important ecological areas can be affected. Copyright © 2015 Elsevier Inc. All rights reserved.

The interplay of stress and mowing disturbance for the intensity and importance of plant interactions in dry calcareous grasslands.

Science.gov (United States)

Maalouf, Jean-Paul; Le Bagousse-Pinguet, Yoann; Marchand, Lilian; Touzard, Blaise; Michalet, Richard

2012-09-01

There is still debate regarding the direction and strength of plant interactions under intermediate to high levels of stress. Furthermore, little is known on how disturbance may interact with physical stress in unproductive environments, although recent theory and models have shown that this interplay may induce a collapse of plant interactions and diversity. The few studies assessing such questions have considered the intensity of biotic interactions but not their importance, although this latter concept has been shown to be very useful for understanding the role of interactions in plant communities. The objective of this study was to assess the interplay between stress and disturbance for plant interactions in dry calcareous grasslands. A field experiment was set up in the Dordogne, southern France, where the importance and intensity of biotic interactions undergone by four species were measured along a water stress gradient, and with and without mowing disturbance. The importance and intensity of interactions varied in a very similar way along treatments. Under undisturbed conditions, plant interactions switched from competition to neutral with increasing water stress for three of the four species, whereas the fourth species was not subject to any significant biotic interaction along the gradient. Responses to disturbance were more species-specific; for two species, competition disappeared with mowing in the wettest conditions, whereas for the two other species, competition switched to facilitation with mowing. Finally, there were no significant interactions for any species in the disturbed and driest conditions. At very high levels of stress, plant performances become too weak to allow either competition or facilitation and disturbance may accelerate the collapse of interactions in dry conditions. The results suggest that the importance and direction of interactions are more likely to be positively related in stressful environments.

The Fluctuation Niche in Plants

Directory of Open Access Journals (Sweden)

Jaume Terradas

2009-01-01

Full Text Available Classical approaches to niche in coexisting plants have undervalued temporal fluctuations. We propose that fluctuation niche is an important dimension of the total niche and interacts with habitat and life-history niches to provide a better understanding of the multidimensional niche space where ecological interactions occur. To scale a fluctuation niche, it is necessary to relate environmental constrictions or species performance not only to the absolute values of the usual environmental and ecophysiological variables but also to their variances or other measures of variability. We use Mediterranean plant communities as examples, because they present characteristic large seasonal and interannual fluctuations in water and nutrient availabilities, along an episodic-constant gradient, and because the plant responses include a number of syndromes coupled to this gradient.

The Fluctuation Niche in Plants

International Nuclear Information System (INIS)

Terradas, J.; Penuelas, J.; Lloret, F.; Penuelas, J.

2009-01-01

Classical approaches to niche in coexisting plants have undervalued temporal fluctuations. We propose that fluctuation niche is an important dimension of the total niche and interacts with habitat and life-history niches to provide a better understanding of the multidimensional niche space where ecological interactions occur. To scale a fluctuation niche, it is necessary to relate environmental constrictions or species performance not only to the absolute values of the usual environmental and eco physiological variables but also to their variances or other measures of variability. We use Mediterranean plant communities as examples, because they present characteristic large seasonal and inter annual fluctuations in water and nutrient availabilities, along an episodic-constant gradient, and because the plant responses include a number of syndromes coupled to this gradient.

Synthesis of plant phenology in the Fynbos biome

CSIR Research Space (South Africa)

Pierce, SM

1984-12-00

Full Text Available species in Australian and Cape mediterranean-type ecosystems is refuted for the Cape. Instead, in order to understand plant-function, investigations into root architecture, water budgets, plant-animal interactions and the influence of radiation...

Plant-ants use symbiotic fungi as a food source: new insight into the nutritional ecology of ant-plant interactions.

Science.gov (United States)

Blatrix, Rumsaïs; Djiéto-Lordon, Champlain; Mondolot, Laurence; La Fisca, Philippe; Voglmayr, Hermann; McKey, Doyle

2012-10-07

Usually studied as pairwise interactions, mutualisms often involve networks of interacting species. Numerous tropical arboreal ants are specialist inhabitants of myrmecophytes (plants bearing domatia, i.e. hollow structures specialized to host ants) and are thought to rely almost exclusively on resources derived from the host plant. Recent studies, following up on century-old reports, have shown that fungi of the ascomycete order Chaetothyriales live in symbiosis with plant-ants within domatia. We tested the hypothesis that ants use domatia-inhabiting fungi as food in three ant-plant symbioses: Petalomyrmex phylax/Leonardoxa africana, Tetraponera aethiops/Barteria fistulosa and Pseudomyrmex penetrator/Tachigali sp. Labelling domatia fungal patches in the field with either a fluorescent dye or (15)N showed that larvae ingested domatia fungi. Furthermore, when the natural fungal patch was replaced with a piece of a (15)N-labelled pure culture of either of two Chaetothyriales strains isolated from T. aethiops colonies, these fungi were also consumed. These two fungi often co-occur in the same ant colony. Interestingly, T. aethiops workers and larvae ingested preferentially one of the two strains. Our results add a new piece in the puzzle of the nutritional ecology of plant-ants.

Plant-ants use symbiotic fungi as a food source: new insight into the nutritional ecology of ant–plant interactions

Science.gov (United States)

Blatrix, Rumsaïs; Djiéto-Lordon, Champlain; Mondolot, Laurence; La Fisca, Philippe; Voglmayr, Hermann; McKey, Doyle

2012-01-01

Usually studied as pairwise interactions, mutualisms often involve networks of interacting species. Numerous tropical arboreal ants are specialist inhabitants of myrmecophytes (plants bearing domatia, i.e. hollow structures specialized to host ants) and are thought to rely almost exclusively on resources derived from the host plant. Recent studies, following up on century-old reports, have shown that fungi of the ascomycete order Chaetothyriales live in symbiosis with plant-ants within domatia. We tested the hypothesis that ants use domatia-inhabiting fungi as food in three ant–plant symbioses: Petalomyrmex phylax/Leonardoxa africana, Tetraponera aethiops/Barteria fistulosa and Pseudomyrmex penetrator/Tachigali sp. Labelling domatia fungal patches in the field with either a fluorescent dye or 15N showed that larvae ingested domatia fungi. Furthermore, when the natural fungal patch was replaced with a piece of a 15N-labelled pure culture of either of two Chaetothyriales strains isolated from T. aethiops colonies, these fungi were also consumed. These two fungi often co-occur in the same ant colony. Interestingly, T. aethiops workers and larvae ingested preferentially one of the two strains. Our results add a new piece in the puzzle of the nutritional ecology of plant-ants. PMID:22859596

Ecology and Genomic Insights into Plant-Pathogenic and Plant-Nonpathogenic Endophytes.

Science.gov (United States)

Brader, Günter; Compant, Stéphane; Vescio, Kathryn; Mitter, Birgit; Trognitz, Friederike; Ma, Li-Jun; Sessitsch, Angela

2017-08-04

Plants are colonized on their surfaces and in the rhizosphere and phyllosphere by a multitude of different microorganisms and are inhabited internally by endophytes. Most endophytes act as commensals without any known effect on their plant host, but multiple bacteria and fungi establish a mutualistic relationship with plants, and some act as pathogens. The outcome of these plant-microbe interactions depends on biotic and abiotic environmental factors and on the genotype of the host and the interacting microorganism. In addition, endophytic microbiota and the manifold interactions between members, including pathogens, have a profound influence on the function of the system plant and the development of pathobiomes. In this review, we elaborate on the differences and similarities between nonpathogenic and pathogenic endophytes in terms of host plant response, colonization strategy, and genome content. We furthermore discuss environmental effects and biotic interactions within plant microbiota that influence pathogenesis and the pathobiome.

Endophytic Actinobacteria and the Interaction of Micromonospora and Nitrogen Fixing Plants

OpenAIRE

Trujillo, Martha E.; Riesco, Ra?l; Benito, Patricia; Carro, Lorena

2015-01-01

For a long time, it was believed that a healthy plant did not harbor any microorganisms within its tissues, as these were often considered detrimental for the plant. In the last three decades, the numbers of studies on plant microbe-interactions has led to a change in our view and we now know that many of these invisible partners are essential for the overall welfare of the plant. The application of Next Generation Sequencing techniques is a powerful tool that has permitted the detection and ...

The Interaction between Plants and Bacteria in the Remediation of Petroleum Hydrocarbons: An Environmental Perspective

Directory of Open Access Journals (Sweden)

Panagiotis Gkorezis

2016-11-01

remediation of PHC contaminated soil in terms of overall cost and success rates for in situ implementation in a diversity of environments. Mechanistically, there remain biological unknowns that present challenges for applying bio- and phyto-remediation technologies without having a deep prior understanding of individual target sites. In this review, evidence from traditional and modern omics technologies is discussed to provide a framework for plant-microbe interactions during PHCs remediation. The potential for integrating multiple molecular and computational techniques to evaluate linkages between microbial communities, plant communities and ecosystem processes is explored with an eye on

The Interaction between Plants and Bacteria in the Remediation of Petroleum Hydrocarbons: An Environmental Perspective.

Science.gov (United States)

Gkorezis, Panagiotis; Daghio, Matteo; Franzetti, Andrea; Van Hamme, Jonathan D; Sillen, Wouter; Vangronsveld, Jaco

2016-01-01

contaminated soil in terms of overall cost and success rates for in situ implementation in a diversity of environments. Mechanistically, there remain biological unknowns that present challenges for applying bio- and phyto-remediation technologies without having a deep prior understanding of individual target sites. In this review, evidence from traditional and modern omics technologies is discussed to provide a framework for plant-microbe interactions during PHC remediation. The potential for integrating multiple molecular and computational techniques to evaluate linkages between microbial communities, plant communities and ecosystem processes is explored with an eye on improving phytoremediation of PHC contaminated sites.

Inter-varietal interactions among plants in genotypically diverse mixtures tend to decrease herbivore performance.

Science.gov (United States)

Grettenberger, Ian M; Tooker, John F

2016-09-01

Much research has explored the effects of plant species diversity on herbivore populations, but far less has considered effects of plant genotypic diversity, or how abiotic stressors, like drought, can modify effects. Mechanisms by which plant genotypic diversity affects herbivore populations remain largely unresolved. We used greenhouse studies with a model system of wheat (Triticum aestivum L.) and bird cherry-oat aphid (Rhopalosiphum padi L.) to determine whether the genotypic diversity of a plant's neighborhood influences performance and fitness of herbivores on a focal plant and if drought changes the influence of neighborhood diversity. Taken across all varieties we tested, plant-plant interactions in diverse neighborhoods reduced aphid performance and generated associational resistance, although effects on aphids depended on variety identity. In diverse mixtures, drought stress greatly diminished the genotypic diversity-driven reduction in aphid performance. Neighborhood diversity influenced mother aphid size, and appeared to partially explain how plant-plant interactions reduced the number of offspring produced in mixtures. Plant size did not mediate effects on aphid performance, although neighborhood diversity reduced plant mass across varieties and watering treatments. Our results suggest inter-varietal interactions in genotypic mixtures can affect herbivore performance in the absence of herbivore movement and that abiotic stress may diminish any effects. Accounting for how neighborhood diversity influences resistance of an individual plant to herbivores will help aid development of mixtures of varieties for managing insect pests and clarify the role of plant genotypic diversity in ecosystems.

Aboveground mechanical stimuli affect belowground plant-plant communication.

Science.gov (United States)

Elhakeem, Ali; Markovic, Dimitrije; Broberg, Anders; Anten, Niels P R; Ninkovic, Velemir

2018-01-01

Plants can detect the presence of their neighbours and modify their growth behaviour accordingly. But the extent to which this neighbour detection is mediated by abiotic stressors is not well known. In this study we tested the acclimation response of Zea mays L. seedlings through belowground interactions to the presence of their siblings exposed to brief mechano stimuli. Maize seedling simultaneously shared the growth solution of touched plants or they were transferred to the growth solution of previously touched plants. We tested the growth preferences of newly germinated seedlings toward the growth solution of touched (T_solution) or untouched plants (C_solution). The primary root of the newly germinated seedlings grew significantly less towards T_solution than to C_solution. Plants transferred to T_solution allocated more biomass to shoots and less to roots. While plants that simultaneously shared their growth solution with the touched plants produced more biomass. Results show that plant responses to neighbours can be modified by aboveground abiotic stress to those neighbours and suggest that these modifications are mediated by belowground interactions.

Aboveground mechanical stimuli affect belowground plant-plant communication.

Directory of Open Access Journals (Sweden)

Ali Elhakeem

Full Text Available Plants can detect the presence of their neighbours and modify their growth behaviour accordingly. But the extent to which this neighbour detection is mediated by abiotic stressors is not well known. In this study we tested the acclimation response of Zea mays L. seedlings through belowground interactions to the presence of their siblings exposed to brief mechano stimuli. Maize seedling simultaneously shared the growth solution of touched plants or they were transferred to the growth solution of previously touched plants. We tested the growth preferences of newly germinated seedlings toward the growth solution of touched (T_solution or untouched plants (C_solution. The primary root of the newly germinated seedlings grew significantly less towards T_solution than to C_solution. Plants transferred to T_solution allocated more biomass to shoots and less to roots. While plants that simultaneously shared their growth solution with the touched plants produced more biomass. Results show that plant responses to neighbours can be modified by aboveground abiotic stress to those neighbours and suggest that these modifications are mediated by belowground interactions.

KWU Nuclear Plant Analyzer

International Nuclear Information System (INIS)

Bennewitz, F.; Hummel, R.; Oelmann, K.

1986-01-01

The KWU Nuclear Plant Analyzer is a real time engineering simulator based on the KWU computer programs used in plant transient analysis and licensing. The primary goal is to promote the understanding of the technical and physical processes of a nuclear power plant at an on-site training facility. Thus the KWU Nuclear Plant Analyzer is available with comparable low costs right at the time when technical questions or training needs arise. This has been achieved by (1) application of the transient code NLOOP; (2) unrestricted operator interaction including all simulator functions; (3) using the mainframe computer Control Data Cyber 176 in the KWU computing center; (4) four color graphic displays controlled by a dedicated graphic computer, no control room equipment; and (5) coupling of computers by telecommunication via telephone

Food-Energy Interactive Tradeoff Analysis of Sustainable Urban Plant Factory Production Systems

OpenAIRE

Li-Chun Huang; Yu-Hui Chen; Ya-Hui Chen; Chi-Fang Wang; Ming-Che Hu

2018-01-01

This research aims to analyze the food–energy interactive nexus of sustainable urban plant factory systems. Plant factory systems grow agricultural products within artificially controlled growing environment and multi-layer vertical growing systems. The system controls the supply of light, temperature, humidity, nutrition, water, and carbon dioxide for growing plants. Plant factories are able to produce consistent and high-quality agricultural products within less production space for urban a...

Reactive oxygen species, essential molecules, during plant-pathogen interactions.

Science.gov (United States)

Camejo, Daymi; Guzmán-Cedeño, Ángel; Moreno, Alexander

2016-06-01

Reactive oxygen species (ROS) are continually generated as a consequence of the normal metabolism in aerobic organisms. Accumulation and release of ROS into cell take place in response to a wide variety of adverse environmental conditions including salt, temperature, cold stresses and pathogen attack, among others. In plants, peroxidases class III, NADPH oxidase (NOX) locates in cell wall and plasma membrane, respectively, may be mainly enzymatic systems involving ROS generation. It is well documented that ROS play a dual role into cells, acting as important signal transduction molecules and as toxic molecules with strong oxidant power, however some aspects related to its function during plant-pathogen interactions remain unclear. This review focuses on the principal enzymatic systems involving ROS generation addressing the role of ROS as signal molecules during plant-pathogen interactions. We described how the chloroplasts, mitochondria and peroxisomes perceive the external stimuli as pathogen invasion, and trigger resistance response using ROS as signal molecule. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Isolated and Community Contexts Produce Distinct Responses by Host Plants to the Presence of Ant-Aphid Interaction: Plant Productivity and Seed Viability

Science.gov (United States)

Santiago, Graziele Silva; Zurlo, Luana Fonseca; Ribas, Carla Rodrigues; Carvalho, Rafaela Pereira; Alves, Guilherme Pereira; Carvalho, Mariana Comanucci Silva; Souza, Brígida

2017-01-01

Ant-aphid interactions may affect host plants in several ways, however, most studies measure only the amount of fruit and seed produced, and do not test seed viability. Therefore, the aim of this study was to assess the effects of the presence of ant-aphid interactions upon host plant productivity and seed viability in two different contexts: isolated and within an arthropod community. For this purpose we tested the hypothesis that in both isolated and community contexts, the presence of an ant-aphid interaction will have a positive effect on fruit and seed production, seed biomass and rate of seed germination, and a negative effect on abnormal seedling rates, in comparison to plants without ants. We performed a field mesocosm experiment containing five treatments: Ant-aphid, Aphid, Community, Ant-free community and Control. We counted fruits and seeds produced by each treatment, and conducted experiments for seed biomass and germinability. We found that in the community context the presence of an ant-aphid interaction negatively affected fruit and seed production. We think this may be because aphid attendance by tending-ants promotes aphid damage to the host plant, but without an affect on seed weight and viability. On the other hand, when isolated, the presence of an ant-aphid interaction positively affected fruit and seed production. These positive effects are related to the cleaning services offered to aphids by tending-ants, which prevent the development of saprophytic fungi on the surface of leaves, which would cause a decrease in photosynthetic rates. Our study is important because we evaluated some parameters of plant fitness that have not been addressed very well by other studies involving the effects of ant-aphid interactions mainly on plants with short life cycles. Lastly, our context dependent approach sheds new light on how ecological interactions can vary among different methods of crop management. PMID:28141849

Isolated and Community Contexts Produce Distinct Responses by Host Plants to the Presence of Ant-Aphid Interaction: Plant Productivity and Seed Viability.

Directory of Open Access Journals (Sweden)

Ernesto Oliveira Canedo-Júnior

Full Text Available Ant-aphid interactions may affect host plants in several ways, however, most studies measure only the amount of fruit and seed produced, and do not test seed viability. Therefore, the aim of this study was to assess the effects of the presence of ant-aphid interactions upon host plant productivity and seed viability in two different contexts: isolated and within an arthropod community. For this purpose we tested the hypothesis that in both isolated and community contexts, the presence of an ant-aphid interaction will have a positive effect on fruit and seed production, seed biomass and rate of seed germination, and a negative effect on abnormal seedling rates, in comparison to plants without ants. We performed a field mesocosm experiment containing five treatments: Ant-aphid, Aphid, Community, Ant-free community and Control. We counted fruits and seeds produced by each treatment, and conducted experiments for seed biomass and germinability. We found that in the community context the presence of an ant-aphid interaction negatively affected fruit and seed production. We think this may be because aphid attendance by tending-ants promotes aphid damage to the host plant, but without an affect on seed weight and viability. On the other hand, when isolated, the presence of an ant-aphid interaction positively affected fruit and seed production. These positive effects are related to the cleaning services offered to aphids by tending-ants, which prevent the development of saprophytic fungi on the surface of leaves, which would cause a decrease in photosynthetic rates. Our study is important because we evaluated some parameters of plant fitness that have not been addressed very well by other studies involving the effects of ant-aphid interactions mainly on plants with short life cycles. Lastly, our context dependent approach sheds new light on how ecological interactions can vary among different methods of crop management.

A Hydroponic Co-cultivation System for Simultaneous and Systematic Analysis of Plant/Microbe Molecular Interactions and Signaling.

Science.gov (United States)

Nathoo, Naeem; Bernards, Mark A; MacDonald, Jacqueline; Yuan, Ze-Chun

2017-07-22

An experimental design mimicking natural plant-microbe interactions is very important to delineate the complex plant-microbe signaling processes. Arabidopsis thaliana-Agrobacterium tumefaciens provides an excellent model system to study bacterial pathogenesis and plant interactions. Previous studies of plant-Agrobacterium interactions have largely relied on plant cell suspension cultures, the artificial wounding of plants, or the artificial induction of microbial virulence factors or plant defenses by synthetic chemicals. However, these methods are distinct from the natural signaling in planta, where plants and microbes recognize and respond in spatial and temporal manners. This work presents a hydroponic cocultivation system where intact plants are supported by metal mesh screens and cocultivated with Agrobacterium. In this cocultivation system, no synthetic phytohormone or chemical that induces microbial virulence or plant defense is supplemented. The hydroponic cocultivation system closely resembles natural plant-microbe interactions and signaling homeostasis in planta. Plant roots can be separated from the medium containing Agrobacterium, and the signaling and responses of both the plant hosts and the interacting microbes can be investigated simultaneously and systematically. At any given timepoint/interval, plant tissues or bacteria can be harvested separately for various "omics" analyses, demonstrating the power and efficacy of this system. The hydroponic cocultivation system can be easily adapted to study: 1) the reciprocal signaling of diverse plant-microbe systems, 2) signaling between a plant host and multiple microbial species (i.e. microbial consortia or microbiomes), 3) how nutrients and chemicals are implicated in plant-microbe signaling, and 4) how microbes interact with plant hosts and contribute to plant tolerance to biotic or abiotic stresses.

Analysis of Metabolites in Stem Parasitic Plant Interactions: Interaction of Cuscuta–Momordica versus Cassytha–Ipomoea

Science.gov (United States)

Furuhashi, Takeshi; Nakamura, Takemichi; Iwase, Koji

2016-01-01

Cuscuta and Cassytha are two well-known stem parasitic plant genera with reduced leaves and roots, inducing haustoria in their stems. Their similar appearance in the field has been recognized, but few comparative studies on their respective plant interactions are available. To compare their interactions, we conducted a metabolite analysis of both the Cassytha–Ipomoea and the Cuscuta–Momordica interaction. We investigated the energy charge of the metabolites by UFLC (ultra-high performance liquid chromatography), and conducted GC-MS (gas chromatography-mass spectrometry) analysis for polar metabolites (e.g., saccharides, polyols) and steroids. The energy charge after parasitization changed considerably in Cassytha but not in Cusucta. Cuscuta changed its steroid pattern during the plant interaction, whereas Cassytha did not. In the polar metabolite analysis, the laminaribiose increase after parasitization was conspicuous in Cuscuta, but not in Cassytha. This metabolite profile difference points to different lifestyles and parasitic strategies. PMID:27941603

Analysis of Metabolites in Stem Parasitic Plant Interactions: Interaction of Cuscuta–Momordica versus Cassytha–Ipomoea

Directory of Open Access Journals (Sweden)

Takeshi Furuhashi

2016-12-01

Full Text Available Cuscuta and Cassytha are two well-known stem parasitic plant genera with reduced leaves and roots, inducing haustoria in their stems. Their similar appearance in the field has been recognized, but few comparative studies on their respective plant interactions are available. To compare their interactions, we conducted a metabolite analysis of both the Cassytha–Ipomoea and the Cuscuta–Momordica interaction. We investigated the energy charge of the metabolites by UFLC (ultra-high performance liquid chromatography, and conducted GC-MS (gas chromatography-mass spectrometry analysis for polar metabolites (e.g., saccharides, polyols and steroids. The energy charge after parasitization changed considerably in Cassytha but not in Cusucta. Cuscuta changed its steroid pattern during the plant interaction, whereas Cassytha did not. In the polar metabolite analysis, the laminaribiose increase after parasitization was conspicuous in Cuscuta, but not in Cassytha. This metabolite profile difference points to different lifestyles and parasitic strategies.

Analysis of Metabolites in Stem Parasitic Plant Interactions: Interaction of Cuscuta-Momordica versus Cassytha-Ipomoea.

Science.gov (United States)

Furuhashi, Takeshi; Nakamura, Takemichi; Iwase, Koji

2016-12-07

Cuscuta and Cassytha are two well-known stem parasitic plant genera with reduced leaves and roots, inducing haustoria in their stems. Their similar appearance in the field has been recognized, but few comparative studies on their respective plant interactions are available. To compare their interactions, we conducted a metabolite analysis of both the Cassytha-Ipomoea and the Cuscuta-Momordica interaction. We investigated the energy charge of the metabolites by UFLC (ultra-high performance liquid chromatography), and conducted GC-MS (gas chromatography-mass spectrometry) analysis for polar metabolites (e.g., saccharides, polyols) and steroids. The energy charge after parasitization changed considerably in Cassytha but not in Cusucta . Cuscuta changed its steroid pattern during the plant interaction, whereas Cassytha did not. In the polar metabolite analysis, the laminaribiose increase after parasitization was conspicuous in Cuscuta , but not in Cassytha . This metabolite profile difference points to different lifestyles and parasitic strategies.

Molecular Profiling of the Phytophthora plurivora Secretome: A Step towards Understanding the Cross-Talk between Plant Pathogenic Oomycetes and Their Hosts

Science.gov (United States)

Fleischmann, Frank; Dalio, Ronaldo J. D.; Di Maro, Antimo; Scognamiglio, Monica; Fiorentino, Antonio; Parente, Augusto; Osswald, Wolfgang; Chambery, Angela

2014-01-01

The understanding of molecular mechanisms underlying host–pathogen interactions in plant diseases is of crucial importance to gain insights on different virulence strategies of pathogens and unravel their role in plant immunity. Among plant pathogens, Phytophthora species are eliciting a growing interest for their considerable economical and environmental impact. Plant infection by Phytophthora phytopathogens is a complex process coordinated by a plethora of extracellular signals secreted by both host plants and pathogens. The characterization of the repertoire of effectors secreted by oomycetes has become an active area of research for deciphering molecular mechanisms responsible for host plants colonization and infection. Putative secreted proteins by Phytophthora species have been catalogued by applying high-throughput genome-based strategies and bioinformatic approaches. However, a comprehensive analysis of the effective secretome profile of Phytophthora is still lacking. Here, we report the first large-scale profiling of P. plurivora secretome using a shotgun LC-MS/MS strategy. To gain insight on the molecular signals underlying the cross-talk between plant pathogenic oomycetes and their host plants, we also investigate the quantitative changes of secreted protein following interaction of P. plurivora with the root exudate of Fagus sylvatica which is highly susceptible to the root pathogen. We show that besides known effectors, the expression and/or secretion levels of cell-wall-degrading enzymes were altered following the interaction with the host plant root exudate. In addition, a characterization of the F. sylvatica root exudate was performed by NMR and amino acid analysis, allowing the identification of the main released low-molecular weight components, including organic acids and free amino acids. This study provides important insights for deciphering the extracellular network involved in the highly susceptible P. plurivora-F. sylvatica interaction

A plant's perspective of extremes: terrestrial plant responses to changing climatic variability.

Science.gov (United States)

Reyer, Christopher P O; Leuzinger, Sebastian; Rammig, Anja; Wolf, Annett; Bartholomeus, Ruud P; Bonfante, Antonello; de Lorenzi, Francesca; Dury, Marie; Gloning, Philipp; Abou Jaoudé, Renée; Klein, Tamir; Kuster, Thomas M; Martins, Monica; Niedrist, Georg; Riccardi, Maria; Wohlfahrt, Georg; de Angelis, Paolo; de Dato, Giovanbattista; François, Louis; Menzel, Annette; Pereira, Marízia

2013-01-01

We review observational, experimental, and model results on how plants respond to extreme climatic conditions induced by changing climatic variability. Distinguishing between impacts of changing mean climatic conditions and changing climatic variability on terrestrial ecosystems is generally underrated in current studies. The goals of our review are thus (1) to identify plant processes that are vulnerable to changes in the variability of climatic variables rather than to changes in their mean, and (2) to depict/evaluate available study designs to quantify responses of plants to changing climatic variability. We find that phenology is largely affected by changing mean climate but also that impacts of climatic variability are much less studied, although potentially damaging. We note that plant water relations seem to be very vulnerable to extremes driven by changes in temperature and precipitation and that heat-waves and flooding have stronger impacts on physiological processes than changing mean climate. Moreover, interacting phenological and physiological processes are likely to further complicate plant responses to changing climatic variability. Phenological and physiological processes and their interactions culminate in even more sophisticated responses to changing mean climate and climatic variability at the species and community level. Generally, observational studies are well suited to study plant responses to changing mean climate, but less suitable to gain a mechanistic understanding of plant responses to climatic variability. Experiments seem best suited to simulate extreme events. In models, temporal resolution and model structure are crucial to capture plant responses to changing climatic variability. We highlight that a combination of experimental, observational, and/or modeling studies have the potential to overcome important caveats of the respective individual approaches. © 2012 Blackwell Publishing Ltd.

Plant analyzer for high-speed interactive simulation of BWR plant transients

International Nuclear Information System (INIS)

Cheng, H.S.; Lekach, S.V.; Mallen, A.N.; Wulff, W.; Cerbone, R.J.

1984-01-01

A combination of advanced modeling techniques and modern, special-purpose peripheral minicomputer technology was utilized to develop a plant analyzer which affords realistic predictions of plant transients and severe off-normal events in LWR power plants through on-line simulations at speeds up to 10 times faster than actual process speeds. The mathematical models account for nonequilibrium, nonhomogeneous two-phase flow effects in the coolant, for acoustical effects in the steam line and for the dynamics of the entire balance of the plant. Reactor core models include point kinetics with reactivity feedback due to void fraction, fuel temperature, coolant temperature, and boron concentration as well as a conduction model for predicting fuel and clad temperatures. Control systems and trip logic for plant protection systems are also simulated. The AD10 of Applied Dynamics International, a special-purpose peripheral processor, is used as the principal hardware of the plant analyzer

Canadian programs on understanding and managing aging degradation of nuclear power plant components

International Nuclear Information System (INIS)

Chadha, J.A.; Pachner, J.

1989-06-01

Maintaining adequate safety and reliability of nuclear power plants and nuclear power plant life assurance and life extension are growing in importance as nuclear plants get older. Age-related degradation of plant components is complex and not fully understood. This paper provides an overview of the Canadian approach and the main activities and their results towards understanding and managing age-related degradation of nuclear power plant components, structures and systems. A number of pro-active programs have been initiated to anticipate, detect and mitigate potential aging degradation at an early stage before any serious impact on plant safety and reliability. These programs include Operational Safety Management Program, Nuclear Plant Life Assurance Program, systematic plant condition assessment, refurbishment and upgrading, post-service examination and testing, equipment qualification, research and development, and participation in the IAEA programs on safety aspects of nuclear power plant aging and life extension. A regulatory policy on nuclear power plants is under development and will be based on the domestic as well as foreign and international studies and experience

Flavonoids and Strigolactones in Root Exudates as Signals in Symbiotic and Pathogenic Plant-Fungus Interactions

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Horst Vierheilig

2007-07-01

Full Text Available Secondary plant compounds are important signals in several symbiotic and pathogenic plant-microbe interactions. The present review is limited to two groups of secondary plant compounds, flavonoids and strigolactones, which have been reported in root exudates. Data on flavonoids as signaling compounds are available from several symbiotic and pathogenic plant-microbe interactions, whereas only recently initial data on the role of strigolactones as plant signals in the arbuscular mycorrhizal symbiosis have been reported. Data from other plant-microbe interactions and strigolactones are not available yet. In the present article we are focusing on flavonoids in plant-fungalinteractions such as the arbuscular mycorrhizal (AM association and the signaling between different Fusarium species and plants. Moreover the role of strigolactones in the AM association is discussed and new data on the effect of strigolactones on fungi, apart from arbuscular mycorrhizal fungi (AMF, are provided.

The Interaction between Plants and Bacteria in the Remediation of Petroleum Hydrocarbons: An Environmental Perspective

Science.gov (United States)

Gkorezis, Panagiotis; Daghio, Matteo; Franzetti, Andrea; Van Hamme, Jonathan D.; Sillen, Wouter; Vangronsveld, Jaco

2016-01-01

contaminated soil in terms of overall cost and success rates for in situ implementation in a diversity of environments. Mechanistically, there remain biological unknowns that present challenges for applying bio- and phyto-remediation technologies without having a deep prior understanding of individual target sites. In this review, evidence from traditional and modern omics technologies is discussed to provide a framework for plant–microbe interactions during PHC remediation. The potential for integrating multiple molecular and computational techniques to evaluate linkages between microbial communities, plant communities and ecosystem processes is explored with an eye on improving phytoremediation of PHC contaminated sites. PMID:27917161

The structures of lipopolysaccharides from plant-associated gram-negative bacteria

DEFF Research Database (Denmark)

Molinaro, Antonio; Newman, Mari-Anne; Lanzetta, Rosa

2009-01-01

Gram-negative bacterial lipopolysaccharides (LPSs) have multiple roles in plant-microbe interactions. LPSs contribute to the low permeabilities of bacterial outer membranes, which act as barriers to protect bacteria from plant-derived antimicrobial substances. Conversely, perception of LPSs...... is an important prerequisite for any further understanding of the biological processes in plant-microbe interactions. Moreover, the LPSs from Gram-negative bacteria - especially those originating from plant-associated bacteria - are a great source of novel monosaccharides with unusual and occasionally astounding...

The tri-trophic interactions hypothesis: interactive effects of host plant quality, diet breadth and natural enemies on herbivores.

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Kailen A Mooney

Full Text Available Several influential hypotheses in plant-herbivore and herbivore-predator interactions consider the interactive effects of plant quality, herbivore diet breadth, and predation on herbivore performance. Yet individually and collectively, these hypotheses fail to address the simultaneous influence of all three factors. Here we review existing hypotheses, and propose the tri-trophic interactions (TTI hypothesis to consolidate and integrate their predictions. The TTI hypothesis predicts that dietary specialist herbivores (as compared to generalists should escape predators and be competitively dominant due to faster growth rates, and that such differences should be greater on low quality (as compared to high quality host plants. To provide a preliminary test of these predictions, we conducted an empirical study comparing the effects of plant (Baccharis salicifolia quality and predators between a specialist (Uroleucon macolai and a generalist (Aphis gossypii aphid herbivore. Consistent with predictions, these three factors interactively determine herbivore performance in ways not addressed by existing hypotheses. Compared to the specialist, the generalist was less fecund, competitively inferior, and more sensitive to low plant quality. Correspondingly, predator effects were contingent upon plant quality only for the generalist. Contrary to predictions, predator effects were weaker for the generalist and on low-quality plants, likely due to density-dependent benefits provided to the generalist by mutualist ants. Because the TTI hypothesis predicts the superior performance of specialists, mutualist ants may be critical to A. gossypii persistence under competition from U. macolai. In summary, the integrative nature of the TTI hypothesis offers novel insight into the determinants of plant-herbivore and herbivore-predator interactions and the coexistence of specialist and generalist herbivores.

Different foraging preferences of hummingbirds on artificial and natural flowers reveal mechanisms structuring plant-pollinator interactions.

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Maglianesi, María A; Böhning-Gaese, Katrin; Schleuning, Matthias

2015-05-01

In plant-pollinator networks, the floral morphology of food plants is an important determinant of the interaction niche of pollinators. Studies on foraging preferences of pollinators combining experimental and observational approaches may help to understand the mechanisms behind patterns of interactions and niche partitioning within pollinator communities. In this study, we tested whether morphological floral traits were associated with foraging preferences of hummingbirds for artificial and natural flower types in Costa Rica. We performed field experiments with artificial feeders, differing in length and curvature of flower types, to quantify the hummingbirds' interaction niche under unlimited nectar resources. To quantify the interaction niche under real-world conditions of limited nectar resources, we measured foraging preferences of hummingbirds for a total of 34 plant species. Artificial feeders were visited by Eupherusa nigriventris and Phaethornis guy in the pre-montane forest, and Lampornis calolaemus in the lower montane forest. Under experimental conditions, all three hummingbird species overlapped their interaction niches and showed a preference for the short artificial flower type over the long-straight and the long-curved flower types. Under natural conditions, the two co-occurring hummingbird species preferred to feed on plant species with floral traits corresponding to their bill morphology. The short-billed hummingbird E. nigriventris preferred to feed on short and straight flowers, whereas the long- and curved-billed P. guy preferred long and curved natural flowers. The medium-size billed species L. calolaemus preferred to feed on flowers of medium length and did not show preferences for plant species with specific corolla curvature. Our results show that floral morphological traits constrain access by short-billed hummingbird species to nectar resources. Morphological constraints, therefore, represent one important mechanism structuring trophic

[Development of Plant Metabolomics and Medicinal Plant Genomics].

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Saito, Kazuki

2018-01-01

 A variety of chemicals produced by plants, often referred to as 'phytochemicals', have been used as medicines, food, fuels and industrial raw materials. Recent advances in the study of genomics and metabolomics in plant science have accelerated our understanding of the mechanisms, regulation and evolution of the biosynthesis of specialized plant products. We can now address such questions as how the metabolomic diversity of plants is originated at the levels of genome, and how we should apply this knowledge to drug discovery, industry and agriculture. Our research group has focused on metabolomics-based functional genomics over the last 15 years and we have developed a new research area called 'Phytochemical Genomics'. In this review, the development of a research platform for plant metabolomics is discussed first, to provide a better understanding of the chemical diversity of plants. Then, representative applications of metabolomics to functional genomics in a model plant, Arabidopsis thaliana, are described. The extension of integrated multi-omics analyses to non-model specialized plants, e.g., medicinal plants, is presented, including the identification of novel genes, metabolites and networks for the biosynthesis of flavonoids, alkaloids, sulfur-containing metabolites and terpenoids. Further, functional genomics studies on a variety of medicinal plants is presented. I also discuss future trends in pharmacognosy and related sciences.

The importance of phenology in studies of plant-herbivore-parasitoid interactions

NARCIS (Netherlands)

Fei, Minghui

2016-01-01

Thesis title: The importance of phenology in studies of plant-herbivore-parasitoid interactions Author: Minghui Fei Abstract As food resources of herbivorous insects, the quality and quantity of plants can directly affect the performance of herbivorous insects and indirectly affect

Senior Secondary School Children's Understanding of Plant Nutrition

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Mosothwane, Modise

2011-01-01

The purpose of this study was to assess children's understanding of plant nutrition. The research was done on a sample of secondary school pupils in the age range of 16 to 19 years in two senior secondary schools in Botswana. The sample contained 137 senior secondary pupils all in their final year of study. These children were above average…

Interactions between Plant Metabolites Affect Herbivores: A Study with Pyrrolizidine Alkaloids and Chlorogenic Acid

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Liu, Xiaojie; Vrieling, Klaas; Klinkhamer, Peter G.L.

2017-01-01

The high structural diversity of plant metabolites suggests that interactions among them should be common. We investigated the effects of single metabolites and combinations of plant metabolites on insect herbivores. In particular we studied the interacting effects of pyrrolizidine alkaloid (PAs), and chlorogenic acid (CGA), on a generalist herbivore, Frankliniella occidentalis. We studied both the predominantly occurring PA N-oxides and the less frequent PA free bases. We found antagonistic effects between CGA and PA free bases on thrips mortality. In contrast PA N-oxides showed synergistic interactions with CGA. PA free bases caused a higher thrips mortality than PA N-oxides while the reverse was through for PAs in combination with CGA. Our results provide an explanation for the predominate storage of PA N-oxides in plants. We propose that antagonistic interactions represent a constraint on the accumulation of plant metabolites, as we found here for Jacobaea vulgaris. The results show that the bioactivity of a given metabolite is not merely dependent upon the amount and chemical structure of that metabolite, but also on the co-occurrence metabolites in, e.g., plant cells, tissues and organs. The significance of this study is beyond the concerns of the two specific groups tested here. The current study is one of the few studies so far that experimentally support the general conception that the interactions among plant metabolites are of great importance to plant-environment interactions. PMID:28611815

Interactions between Plant Metabolites Affect Herbivores: A Study with Pyrrolizidine Alkaloids and Chlorogenic Acid

Directory of Open Access Journals (Sweden)

Xiaojie Liu

2017-05-01

Full Text Available The high structural diversity of plant metabolites suggests that interactions among them should be common. We investigated the effects of single metabolites and combinations of plant metabolites on insect herbivores. In particular we studied the interacting effects of pyrrolizidine alkaloid (PAs, and chlorogenic acid (CGA, on a generalist herbivore, Frankliniella occidentalis. We studied both the predominantly occurring PA N-oxides and the less frequent PA free bases. We found antagonistic effects between CGA and PA free bases on thrips mortality. In contrast PA N-oxides showed synergistic interactions with CGA. PA free bases caused a higher thrips mortality than PA N-oxides while the reverse was through for PAs in combination with CGA. Our results provide an explanation for the predominate storage of PA N-oxides in plants. We propose that antagonistic interactions represent a constraint on the accumulation of plant metabolites, as we found here for Jacobaea vulgaris. The results show that the bioactivity of a given metabolite is not merely dependent upon the amount and chemical structure of that metabolite, but also on the co-occurrence metabolites in, e.g., plant cells, tissues and organs. The significance of this study is beyond the concerns of the two specific groups tested here. The current study is one of the few studies so far that experimentally support the general conception that the interactions among plant metabolites are of great importance to plant-environment interactions.

Soil-Plant-Microbe Interactions in Stressed Agriculture Management: A Review

Institute of Scientific and Technical Information of China (English)

Shobhit Raj VIMAL; Jay Shankar SINGH; Naveen Kumar ARORA; Surendra SINGH

2017-01-01

The expected rise in temperature and decreased precipitation owing to climate change and unabated anthropogenic activities add complexity and uncertainty to agro-industry.The impact of soil nutrient imbalance,mismanaged use of chemicals,high temperature,flood or drought,soil salinity,and heavy metal pollutions,with regard to food security,is increasingly being explored worldwide.This review describes the role of soil-plant-microbe interactions along with organic manure in solving stressed agriculture problems.Beneficial microbes associated with plants are known to stimulate plant growth and enhance plant resistance to biotic (diseases) and abiotic (salinity,drought,pollutions,etc.) stresses.The plant growth-promoting rhizobacteria (PGPR) and mycorrhizae,a key component of soil microbiota,could play vital roles in the maintenance of plant fitness and soil health under stressed environments.The application of organic manure as a soil conditioner to stressed soils along with suitable microbial strains could further enhance the plant-microbe associations and increase the crop yield.A combination of plant,stress-tolerant microbe,and organic amendment represents the tripartite association to offer a favourable environment to the proliferation of beneficial rhizosphere microbes that in turn enhance the plant growth performance in disturbed agro-ecosystem.Agriculture land use patterns with the proper exploitation of plant-microbe associations,with compatible beneficial microbial agents,could be one of the most effective strategies in the management of the concerned agriculture lands owing to climate change resilience.However,the association of such microbes with plants for stressed agriculture management still needs to be explored in greater depth.

Elucidating the interaction between light competition and herbivore feeding patterns using functional-structural plant modelling.

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de Vries, Jorad; Poelman, Erik H; Anten, Niels; Evers, Jochem B

2018-01-24

Plants usually compete with neighbouring plants for resources such as light as well as defend themselves against herbivorous insects. This requires investment of limiting resources, resulting in optimal resource distribution patterns and trade-offs between growth- and defence-related traits. A plant's competitive success is determined by the spatial distribution of its resources in the canopy. The spatial distribution of herbivory in the canopy in turn differs between herbivore species as the level of herbivore specialization determines their response to the distribution of resources and defences in the canopy. Here, we investigated to what extent competition for light affects plant susceptibility to herbivores with different feeding preferences. To quantify interactions between herbivory and competition, we developed and evaluated a 3-D spatially explicit functional-structural plant model for Brassica nigra that mechanistically simulates competition in a dynamic light environment, and also explicitly models leaf area removal by herbivores with different feeding preferences. With this novel approach, we can quantitatively explore the extent to which herbivore feeding location and light competition interact in their effect on plant performance. Our results indicate that there is indeed a strong interaction between levels of plant-plant competition and herbivore feeding preference. When plants did not compete, herbivory had relatively small effects irrespective of feeding preference. Conversely, when plants competed, herbivores with a preference for young leaves had a strong negative effect on the competitiveness and subsequent performance of the plant, whereas herbivores with a preference for old leaves did not. Our study predicts how plant susceptibility to herbivory depends on the composition of the herbivore community and the level of plant competition, and highlights the importance of considering the full range of dynamics in plant-plant-herbivore interactions

Atlantic frugivory: a plant-frugivore interaction data set for the Atlantic Forest.

Science.gov (United States)

Bello, Carolina; Galetti, Mauro; Montan, Denise; Pizo, Marco A; Mariguela, Tatiane C; Culot, Laurence; Bufalo, Felipe; Labecca, Fabio; Pedrosa, Felipe; Constantini, Rafaela; Emer, Carine; Silva, Wesley R; da Silva, Fernanda R; Ovaskainen, Otso; Jordano, Pedro

2017-06-01

The data set provided here includes 8,320 frugivory interactions (records of pairwise interactions between plant and frugivore species) reported for the Atlantic Forest. The data set includes interactions between 331 vertebrate species (232 birds, 90 mammals, 5 fishes, 1 amphibian, and 3 reptiles) and 788 plant species. We also present information on traits directly related to the frugivory process (endozoochory), such as the size of fruits and seeds and the body mass and gape size of frugivores. Data were extracted from 166 published and unpublished sources spanning from 1961 to 2016. While this is probably the most comprehensive data set available for a tropical ecosystem, it is arguably taxonomically and geographically biased. The plant families better represented are Melastomataceae, Myrtaceae, Moraceae, Urticaceae, and Solanaceae. Myrsine coriacea, Alchornea glandulosa, Cecropia pachystachya, and Trema micrantha are the plant species with the most animal dispersers (83, 76, 76, and 74 species, respectively). Among the animal taxa, the highest number of interactions is reported for birds (3,883) followed by mammals (1,315). The woolly spider monkey or muriqui, Brachyteles arachnoides, and Rufous-bellied Thrush, Turdus rufiventris, are the frugivores with the most diverse fruit diets (137 and 121 plants species, respectively). The most important general patterns that we note are that larger seeded plant species (>12 mm) are mainly eaten by terrestrial mammals (rodents, ungulates, primates, and carnivores) and that birds are the main consumers of fruits with a high concentration of lipids. Our data set is geographically biased, with most interactions recorded for the southeast Atlantic Forest. © 2017 by the Ecological Society of America.

Biological nitrogen fixation in non-legume plants.

Science.gov (United States)

Santi, Carole; Bogusz, Didier; Franche, Claudine

2013-05-01

Nitrogen is an essential nutrient in plant growth. The ability of a plant to supply all or part of its requirements from biological nitrogen fixation (BNF) thanks to interactions with endosymbiotic, associative and endophytic symbionts, confers a great competitive advantage over non-nitrogen-fixing plants. Because BNF in legumes is well documented, this review focuses on BNF in non-legume plants. Despite the phylogenic and ecological diversity among diazotrophic bacteria and their hosts, tightly regulated communication is always necessary between the microorganisms and the host plant to achieve a successful interaction. Ongoing research efforts to improve knowledge of the molecular mechanisms underlying these original relationships and some common strategies leading to a successful relationship between the nitrogen-fixing microorganisms and their hosts are presented. Understanding the molecular mechanism of BNF outside the legume-rhizobium symbiosis could have important agronomic implications and enable the use of N-fertilizers to be reduced or even avoided. Indeed, in the short term, improved understanding could lead to more sustainable exploitation of the biodiversity of nitrogen-fixing organisms and, in the longer term, to the transfer of endosymbiotic nitrogen-fixation capacities to major non-legume crops.

PLANT-MICROBIAL INTERACTIONS IN THE RHIZOSPHERE – STRATEGIES FOR PLANT GROWTH-PROMOTION

Directory of Open Access Journals (Sweden)

Marius Stefan

2012-03-01

Full Text Available Plant growth-promoting rhizobacteria (PGPR are a group of bacteria that can actively colonize plant rootsand enhance plant growth using different mechanisms: production of plant growth regulators like indoleacetic acid,gibberellic acid, cytokinins and ethylene(Zahir et al., 2003, providing the host plant with fixed nitrogen, solubilizationof soil phosphorus, enhance Fe uptake, biocontrol, reducing the concentration of heavy metals. PGPR are perfectcandidates to be used as biofertilizers – eco-friendly alternative to common applied chemical fertilizer in today’sagriculture. The most important benefit of PGPR usage is related to the reduction of environmental pollution in conditionof increasing crop yield. This review presents the main mechanisms involved in PGPR promotion of plant growth.

Effect of plant-animal interactions on individual performance and population dynamics of Scorzonera hispanica

OpenAIRE

Červenková, Zita

2016-01-01

The population dynamics of plants with regard to plant-animal interactions is a remarkably complex topic. To look into how individual life stages are influenced in different directions by various animals is beyond the scope of a single paper. For each of the studies described below, I and my co-authors attempted to collect data that would cover as much of the plant life cycle as possible, focusing on interactions between plants and different animals during the flowering period and their conse...

Wired to the roots: impact of root-beneficial microbe interactions on aboveground plant physiology and protection.

Science.gov (United States)

Kumar, Amutha Sampath; Bais, Harsh P

2012-12-01

Often, plant-pathogenic microbe interactions are discussed in a host-microbe two-component system, however very little is known about how the diversity of rhizospheric microbes that associate with plants affect host performance against pathogens. There are various studies, which specially direct the importance of induced systemic defense (ISR) response in plants interacting with beneficial rhizobacteria, yet we don't know how rhizobacterial associations modulate plant physiology. In here, we highlight the many dimensions within which plant roots associate with beneficial microbes by regulating aboveground physiology. We review approaches to study the causes and consequences of plant root association with beneficial microbes on aboveground plant-pathogen interactions. The review provides the foundations for future investigations into the impact of the root beneficial microbial associations on plant performance and innate defense responses.

Plant-parasitic nematodes: towards understanding molecular players in stress responses.

Science.gov (United States)

Gillet, François-Xavier; Bournaud, Caroline; Antonino de Souza Júnior, Jose Dijair; Grossi-de-Sa, Maria Fatima

2017-03-01

Plant-parasitic nematode interactions occur within a vast molecular plant immunity network. Following initial contact with the host plant roots, plant-parasitic nematodes (PPNs) activate basal immune responses. Defence priming involves the release in the apoplast of toxic molecules derived from reactive species or secondary metabolism. In turn, PPNs must overcome the poisonous and stressful environment at the plant-nematode interface. The ability of PPNs to escape this first line of plant immunity is crucial and will determine its virulence. Nematodes trigger crucial regulatory cytoprotective mechanisms, including antioxidant and detoxification pathways. Knowledge of the upstream regulatory components that contribute to both of these pathways in PPNs remains elusive. In this review, we discuss how PPNs probably orchestrate cytoprotection to resist plant immune responses, postulating that it may be derived from ancient molecular mechanisms. The review focuses on two transcription factors, DAF-16 and SKN-1 , which are conserved in the animal kingdom and are central regulators of cell homeostasis and immune function. Both regulate the unfolding protein response and the antioxidant and detoxification pathways. DAF-16 and SKN-1 target a broad spectrum of Caenorhabditis elegans genes coding for numerous protein families present in the secretome of PPNs. Moreover, some regulatory elements of DAF-16 and SKN-1 from C. elegans have already been identified as important genes for PPN infection. DAF-16 and SKN-1 genes may play a pivotal role in PPNs during parasitism. In the context of their hub status and mode of regulation, we suggest alternative strategies for control of PPNs through RNAi approaches. © The Author 2017. Published by Oxford University Press on behalf of the Annals of Botany Company.

Cytokinins as key regulators in plant–microbe–insect interactions: connecting plant growth and defence

NARCIS (Netherlands)

Giron, D.; Frago, E.; Glevarec, G.; Pieterse, C.M.J.; Dicke, M.

2013-01-01

1. Plant hormones play important roles in regulating plant growth and defence by mediating developmental processes and signalling networks involved in plant responses to a wide range of parasitic and mutualistic biotic interactions. 2. Plants are known to rapidly respond to pathogen and herbivore

Plant interactions with changes in coverage of biological soil crusts and water regime in Mu Us Sandland, China.

Science.gov (United States)

Gao, Shuqin; Pan, Xu; Cui, Qingguo; Hu, Yukun; Ye, Xuehua; Dong, Ming

2014-01-01

Plant interactions greatly affect plant community structure. Dryland ecosystems are characterized by low amounts of unpredictable precipitation as well as by often having biological soil crusts (BSCs) on the soil surface. In dryland plant communities, plants interact mostly as they compete for water resources, and the direction and intensity of plant interaction varies as a function of the temporal fluctuation in water availability. Since BSCs influence water redistribution to some extent, a greenhouse experiment was conducted to test the hypothesis that the intensity and direction of plant interactions in a dryland plant community can be modified by BSCs. In the experiment, 14 combinations of four plant species (Artemisia ordosica, Artemisia sphaerocephala, Chloris virgata and Setaria viridis) were subjected to three levels of coverage of BSCs and three levels of water supply. The results show that: 1) BSCs affected plant interaction intensity for the four plant species: a 100% coverage of BSCs significantly reduced the intensity of competition between neighboring plants, while it was highest with a 50% coverage of BSCs in combination with the target species of A. sphaerocephala and C. virgata; 2) effects of the coverage of BSCs on plant interactions were modified by water regime when the target species were C. virgata and S. viridis; 3) plant interactions were species-specific. In conclusion, the percent coverage of BSCs affected plant interactions, and the effects were species-specific and could be modified by water regimes. Further studies should focus on effects of the coverage of BSCs on plant-soil hydrological processes.

Plant interactions with changes in coverage of biological soil crusts and water regime in Mu Us Sandland, China.

Directory of Open Access Journals (Sweden)

Shuqin Gao

Full Text Available Plant interactions greatly affect plant community structure. Dryland ecosystems are characterized by low amounts of unpredictable precipitation as well as by often having biological soil crusts (BSCs on the soil surface. In dryland plant communities, plants interact mostly as they compete for water resources, and the direction and intensity of plant interaction varies as a function of the temporal fluctuation in water availability. Since BSCs influence water redistribution to some extent, a greenhouse experiment was conducted to test the hypothesis that the intensity and direction of plant interactions in a dryland plant community can be modified by BSCs. In the experiment, 14 combinations of four plant species (Artemisia ordosica, Artemisia sphaerocephala, Chloris virgata and Setaria viridis were subjected to three levels of coverage of BSCs and three levels of water supply. The results show that: 1 BSCs affected plant interaction intensity for the four plant species: a 100% coverage of BSCs significantly reduced the intensity of competition between neighboring plants, while it was highest with a 50% coverage of BSCs in combination with the target species of A. sphaerocephala and C. virgata; 2 effects of the coverage of BSCs on plant interactions were modified by water regime when the target species were C. virgata and S. viridis; 3 plant interactions were species-specific. In conclusion, the percent coverage of BSCs affected plant interactions, and the effects were species-specific and could be modified by water regimes. Further studies should focus on effects of the coverage of BSCs on plant-soil hydrological processes.

Vegetarian on purpose: Understanding the motivations of plant-based dieters.

Science.gov (United States)

Rosenfeld, Daniel L; Burrow, Anthony L

2017-09-01

Much recent research has explored vegetarians' dietary motivations, recurrently highlighting the significant influence they exert on how people view themselves and others. For vegetarians and other plant-based dieters, dietary motivations have been theorized to be a central aspect of identity. Yet not all plant-based dieters are motivated to follow their diets; rather, some face aversions and constraints. In this paper, we propose that motivations, aversions, and constraints constitute three distinct reasons for consuming a plant-based diet. After conceptually distinguishing motivations from aversions and constraints, we critically evaluate the advantages and disadvantages of two conceptual frameworks that exist for studying these motivations systematically: the ethical-health framework and the Unified Model of Vegetarian Identity (UMVI) motivational orientations framework. Importantly, these frameworks serve different purposes, and their suitability often depends on the research question at hand. Particularly given an increasing prevalence of plant-based dieting, cultivating a more holistic understanding of these two frameworks is necessary for advancing this discipline. Directions for future research are discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Phytohormones in plant-endophyte interactions: investigating the role of these compounds in the recruitment of tomato root fungal endophytes

DEFF Research Database (Denmark)

Manzotti, Andrea; Jørgensen, Hans Jørgen Lyngs; Collinge, David B.

in this interaction, but little is known about the specific way by which they influence the recruitment and the colonization of the host tissues. The aim of the current project is to go deeper into the role of these signalling compounds in plant-endophyte interactions. The isolation of endophytic fungi from tomato......-colonization frequency appears to be influenced by the presence/absence of specific phytohormones. In order to obtain a deeper understanding of the role of these compounds in the plant-endophyte interaction, the selected isolates are currently being screened using confocal microscopy and qPCR in order to find candidates...... whose colonization rate is critically affected by the phytohormones of interest. A transcriptomic analysis of tomato plants inoculated with the isolates selected from the screening will provide further clues as to which physiological mechanisms, associated with endophyte recruitment, are influenced...

Chemical signaling between plants and plant-pathogenic bacteria.

Science.gov (United States)

Venturi, Vittorio; Fuqua, Clay

2013-01-01

Studies of chemical signaling between plants and bacteria in the past have been largely confined to two models: the rhizobial-legume symbiotic association and pathogenesis between agrobacteria and their host plants. Recent studies are beginning to provide evidence that many plant-associated bacteria undergo chemical signaling with the plant host via low-molecular-weight compounds. Plant-produced compounds interact with bacterial regulatory proteins that then affect gene expression. Similarly, bacterial quorum-sensing signals result in a range of functional responses in plants. This review attempts to highlight current knowledge in chemical signaling that takes place between pathogenic bacteria and plants. This chemical communication between plant and bacteria, also referred to as interkingdom signaling, will likely become a major research field in the future, as it allows the design of specific strategies to create plants that are resistant to plant pathogens.

Evolution of polyploidy and the diversification of plant-pollinator interactions.

Science.gov (United States)

Thompson, John N; Merg, Kurt F

2008-08-01

One of the major mechanisms of plant diversification has been the evolution of polyploid populations that differ from their diploid progenitors in morphology, physiology, and environmental tolerances. Recent studies have indicated that polyploidy may also have major effects on ecological interactions with herbivores and pollinators. We evaluated pollination of sympatric diploid and tetraploid plants of the rhizomatous herb Heuchera grossulariifolia (Saxifragaceae) along the Selway and Salmon Rivers of northern Idaho, USA, during four consecutive years. Previous molecular and ecological analyses had indicated that the tetraploid populations along these two river systems are independently derived and differ from each other in multiple traits. In each region, we evaluated floral visitation rate by all insect visitors, pollination efficacy of all major visitors, and relative contribution of all major pollinators to seed set. In both regions, diploid and tetraploid plants attracted different suites of floral visitors. Most pollination was attributable to several bee species and the moth Greya politella. Lasioglossum bees preferentially visited diploid plants at Lower Salmon but not at Upper Selway, queen Bombus centralis preferentially visited tetraploids at both sites, and worker B. centralis differed between sites in their cytotype preference. Hence, diploid and autotetraploid H. grossulariifolia plants act essentially as separate ecological species and may experience partial reproductive isolation through differential visitation and pollination by their major floral visitors. Overall the results, together with recent results from other studies, suggest that the repeated evolution of polyploidy in plants may contribute importantly to the structure and diversification of ecological interactions in terrestrial communities.

Ecological responses to UV radiation: interactions between the biological effects of UV on plants and on associated organisms.

Science.gov (United States)

Paul, Nigel D; Moore, Jason P; McPherson, Martin; Lambourne, Cathryn; Croft, Patricia; Heaton, Joanna C; Wargent, Jason J

2012-08-01

Solar ultraviolet (UV)-B radiation (280-315 nm) has a wide range of effects on terrestrial ecosystems, yet our understanding of how UV-B influences the complex interactions of plants with pest, pathogen and related microorganisms remains limited. Here, we report the results of a series of experiments in Lactuca sativa which aimed to characterize not only key plant responses to UV radiation in a field environment but also consequential effects for plant interactions with a sap-feeding insect, two model plant pathogens and phylloplane microorganism populations. Three spectrally modifying filters with contrasting UV transmissions were used to filter ambient sunlight, and when compared with our UV-inclusive filter, L. sativa plants grown in a zero UV-B environment showed significantly increased shoot fresh weight, reduced foliar pigment concentrations and suppressed population growth of green peach aphid (Myzus persicae). Plants grown under a filter which allowed partial transmission of UV-A radiation and negligible UV-B transmission showed increased density of leaf surface phylloplane microbes compared with the UV-inclusive treatment. Effects of UV treatment on the severity of two plant pathogens, Bremia lactucae and Botrytis cinerea, were complex as both the UV-inclusive and zero UV-B filters reduced the severity of pathogen persistence. These results are discussed with reference to known spectral responses of plants, insects and microorganisms, and contrasted with established fundamental responses of plants and other organisms to solar UV radiation, with particular emphasis on the need for future integration between different experimental approaches when investigating the effects of solar UV radiation. Copyright © Physiologia Plantarum 2011.

Interspecific Plant Interactions Reflected in Soil Bacterial Community Structure and Nitrogen Cycling in Primary Succession.

Science.gov (United States)

Knelman, Joseph E; Graham, Emily B; Prevéy, Janet S; Robeson, Michael S; Kelly, Patrick; Hood, Eran; Schmidt, Steve K

2018-01-01

Past research demonstrating the importance plant-microbe interactions as drivers of ecosystem succession has focused on how plants condition soil microbial communities, impacting subsequent plant performance and plant community assembly. These studies, however, largely treat microbial communities as a black box. In this study, we sought to examine how emblematic shifts from early successional Alnus viridus ssp. sinuata (Sitka alder) to late successional Picea sitchensis (Sitka spruce) in primary succession may be reflected in specific belowground changes in bacterial community structure and nitrogen cycling related to the interaction of these two plants. We examined early successional alder-conditioned soils in a glacial forefield to delineate how alders alter the soil microbial community with increasing dominance. Further, we assessed the impact of late-successional spruce plants on these early successional alder-conditioned microbiomes and related nitrogen cycling through a leachate addition microcosm experiment. We show how increasingly abundant alder select for particular bacterial taxa. Additionally, we found that spruce leachate significantly alters the composition of these microbial communities in large part by driving declines in taxa that are enriched by alder, including bacterial symbionts. We found these effects to be spruce specific, beyond a general leachate effect. Our work also demonstrates a unique influence of spruce on ammonium availability. Such insights bolster theory relating the importance of plant-microbe interactions with late-successional plants and interspecific plant interactions more generally.

Uptake of mineral elements by plants

International Nuclear Information System (INIS)

Ven Babu, P.

2008-01-01

Scientific investigations into the mineral nutrition of plants, date back to the late 17th century and vast amount of literature has accumulated since then, encompassing the occurrence of mineral elements, their interaction in soil and within plants, kinetics of their uptake, role in metabolism, toxicity to plants and animals and so on. Despite great advances made in the fields of plant physiology, plant biochemistry and genetic engineering and application of sophisticated analytical and biochemical techniques, many aspects of nutrient uptake by plants, their movement within roots and the long distance transport to shoots remain yet to be fully answered and a combination of hypothesis and assumptions are taken into account, for understanding the phenomena. This write up deals with the subject in a brief and narrative manner, so as to enable the reader to get an insight into the field

The role of the plasma membrane H+-ATPase in plant-microbe interactions.

Science.gov (United States)

Elmore, James Mitch; Coaker, Gitta

2011-05-01

Plasma membrane (PM) H+-ATPases are the primary pumps responsible for the establishment of cellular membrane potential in plants. In addition to regulating basic aspects of plant cell function, these enzymes contribute to signaling events in response to diverse environmental stimuli. Here, we focus on the roles of the PM H+-ATPase during plant-pathogen interactions. PM H+-ATPases are dynamically regulated during plant immune responses and recent quantitative proteomics studies suggest complex spatial and temporal modulation of PM H+-ATPase activity during early pathogen recognition events. Additional data indicate that PM H+-ATPases cooperate with the plant immune signaling protein RIN4 to regulate stomatal apertures during bacterial invasion of leaf tissue. Furthermore, pathogens have evolved mechanisms to manipulate PM H+-ATPase activity during infection. Thus, these ubiquitous plant enzymes contribute to plant immune responses and are targeted by pathogens to increase plant susceptibility.

Tritrophic Interactions Mediated by Herbivore-Induced Plant Volatiles: Mechanisms, Ecological Relevance, and Application Potential.

Science.gov (United States)

Turlings, Ted C J; Erb, Matthias

2018-01-07

Tritrophic interactions between plants, herbivores, and their natural enemies are an integral part of all terrestrial ecosystems. Herbivore-induced plant volatiles (HIPVs) play a key role in these interactions, as they can attract predators and parasitoids to herbivore-attacked plants. Thirty years after this discovery, the ecological importance of the phenomena is widely recognized. However, the primary function of HIPVs is still subject to much debate, as is the possibility of using these plant-produced cues in crop protection. In this review, we summarize the current knowledge on the role of HIPVs in tritrophic interactions from an ecological as well as a mechanistic perspective. This overview focuses on the main gaps in our knowledge of tritrophic interactions, and we argue that filling these gaps will greatly facilitate efforts to exploit HIPVs for pest control.

Biogeomorphic feedbacks within riparian corridors: the role of positive interactions between riparian plants

Science.gov (United States)

Corenblit, Dov; Steiger, Johannes; Till-Bottraud, Irène

2017-04-01

Riparian vegetation affects hydrogeomorphic processes and leads to the construction of wooded fluvial landforms within riparian corridors. Multiple plants form dense multi- and mono-specific stands that enhance plant resistance as grouped plants are less prone to be uprooted than free-standing individuals. Riparian plants which grow in dense stands also enhance their role as ecosystem engineers through the trapping of sediment, organic matter and nutrients. The wooded biogeomorphic landforms which originate from the effect of vegetation on geomorphology lead in return to an improved capacity of the plants to survive, exploit resources, and reach sexual maturity in the intervals between destructive floods. Thus, these vegetated biogeomorphic landforms likely represent a positive niche construction of riparian plants. The nature and intensity of biotic interactions between riparian plants of different species (inter-specific) or the same species (intra-specific) which form dense stands and construct together the niche remain unclear. We strongly suspect that indirect inter-specific positive interactions (facilitation) occur between plants but that more direct intra-specific interactions, such as cooperation and altruism, also operate during the niche construction process. Our aim is to propose an original theoretical framework of inter and intra-specific positive interactions between riparian plants. We suggest that positive interactions between riparian plants are maximized in river reaches with an intermediate level of hydrogeomorphic disturbance. During establishment, plants that grow within dense stands improve their survival and growth because individuals protect each other from shear stress. In addition to the improved capacity to trap mineral and organic matter, individuals which constitute the dense stand can cooperate to mutually support a mycorrhizal fungi network that will connect plants, soil and ground water and influence nutrient transfer, cycling and

Interactive videodisc training for power plant operations

International Nuclear Information System (INIS)

Nolan, R.; Nolan, J.; Campos, M.; Haukom, R.; Quentin, G.

1990-01-01

During the last several years, professionals in the personal computer and video fields have seen their two technologies coming together. This merging has created a new medium called multimedia. Multimedia provides the user with the interactivity of the personal computer and the realism of live-action television. It appears to be a perfect marriage for education, training and selling applications. As multimedia productions continue to be produced and tested with high marks, business and industry are becoming interested. The Interactive Videodisc Trainer (IVT) is a demonstration of how multimedia technology can be used by the electric power industry for operator training. Although the subject for this pilot program is the Claus sulfur recovery unit at the Cool Water Integrated Gasification Combined Cycle plant, similar courseware can be put to use for training at any type of power plant. The goal is to show many of the features and capabilities inherent in this powerful new training tool, so that utilities can begin to see how it could work for them

Understanding plant response to nitrogen limitation for the improvement of crop nitrogen use efficiency.

Science.gov (United States)

Kant, Surya; Bi, Yong-Mei; Rothstein, Steven J

2011-02-01

Development of genetic varieties with improved nitrogen use efficiency (NUE) is essential for sustainable agriculture. Generally, NUE can be divided into two parts. First, assimilation efficiency involves nitrogen (N) uptake and assimilation and second utilization efficiency involves N remobilization. Understanding the mechanisms regulating these processes is crucial for the improvement of NUE in crop plants. One important approach is to develop an understanding of the plant response to different N regimes, especially to N limitation, using various methods including transcription profiling, analysing mutants defective in their normal response to N limitation, and studying plants that show better growth under N-limiting conditions. One can then attempt to improve NUE in crop plants using the knowledge gained from these studies. There are several potential genetic and molecular approaches for the improvement of crop NUE discussed in this review. Increased knowledge of how plants respond to different N levels as well as to other environmental conditions is required to achieve this.

Interactions between plant and rhizosphere microbial communities in a metalliferous soil

International Nuclear Information System (INIS)

Epelde, Lur; Becerril, Jose M.; Barrutia, Oihana; Gonzalez-Oreja, Jose A.; Garbisu, Carlos

2010-01-01

In the present work, the relationships between plant consortia, consisting of 1-4 metallicolous pseudometallophytes with different metal-tolerance strategies (Thlaspi caerulescens: hyperaccumulator; Jasione montana: accumulator; Rumex acetosa: indicator; Festuca rubra: excluder), and their rhizosphere microbial communities were studied in a mine soil polluted with high levels of Cd, Pb and Zn. Physiological response and phytoremediation potential of the studied pseudometallophytes were also investigated. The studied metallicolous populations are tolerant to metal pollution and offer potential for the development of phytoextraction and phytostabilization technologies. T. caerulescens appears very tolerant to metal stress and most suitable for metal phytoextraction; the other three species enhance soil functionality. Soil microbial properties had a stronger effect on plant biomass rather than the other way around (35.2% versus 14.9%). An ecological understanding of how contaminants, ecosystem functions and biological communities interact in the long-term is needed for proper management of these fragile metalliferous ecosystems. - Rhizosphere microbial communities in highly polluted mine soils are determinant for the growth of pseudometallophytes.

Interactions between plant and rhizosphere microbial communities in a metalliferous soil

Energy Technology Data Exchange (ETDEWEB)

Epelde, Lur [NEIKER-Tecnalia, Department of Ecosystems, c/Berreaga 1, E-48160 Derio (Spain); Becerril, Jose M.; Barrutia, Oihana [Department of Plant Biology and Ecology, University of the Basque Country, UPV/EHU, P.O. Box 644, E-48080 Bilbao (Spain); Gonzalez-Oreja, Jose A. [NEIKER-Tecnalia, Department of Ecosystems, c/Berreaga 1, E-48160 Derio (Spain); Garbisu, Carlos, E-mail: cgarbisu@neiker.ne [NEIKER-Tecnalia, Department of Ecosystems, c/Berreaga 1, E-48160 Derio (Spain)

2010-05-15

In the present work, the relationships between plant consortia, consisting of 1-4 metallicolous pseudometallophytes with different metal-tolerance strategies (Thlaspi caerulescens: hyperaccumulator; Jasione montana: accumulator; Rumex acetosa: indicator; Festuca rubra: excluder), and their rhizosphere microbial communities were studied in a mine soil polluted with high levels of Cd, Pb and Zn. Physiological response and phytoremediation potential of the studied pseudometallophytes were also investigated. The studied metallicolous populations are tolerant to metal pollution and offer potential for the development of phytoextraction and phytostabilization technologies. T. caerulescens appears very tolerant to metal stress and most suitable for metal phytoextraction; the other three species enhance soil functionality. Soil microbial properties had a stronger effect on plant biomass rather than the other way around (35.2% versus 14.9%). An ecological understanding of how contaminants, ecosystem functions and biological communities interact in the long-term is needed for proper management of these fragile metalliferous ecosystems. - Rhizosphere microbial communities in highly polluted mine soils are determinant for the growth of pseudometallophytes.

Plant analyzer development for high-speed interactive simulation of BWR plant transients

International Nuclear Information System (INIS)

Wulff, W.; Cheng, H.S.; Mallen, A.N.

1986-01-01

Advanced modeling techniques have been combined with modern, special-purpose peripheral minicomputer technology to develop a plant analyzer which provides realistic and accurate predictions of plant transients and severe off-normal events in nuclear power plants through on-line simulations at speeds of approximately 10 times faster than actual process speeds. The new simulation technology serves not only for carrying out routinely and efficiently safety analyses, optimizations of emergency procedures and design changes, parametric studies for obtaining safety margins and for generic training but also for assisting plant operations. Five modeling principles are presented which serve to achieve high-speed simulation of neutron kinetics, thermal conduction, nonhomogeneous and nonequilibrium two-phase flow coolant dynamics, steam line acoustical effects, and the dynamics of the balance of plant and containment systems, control systems and plant protection systems. 21 refs

Role of ethylene and related gene expression in the interaction between strawberry plants and the plant growth-promoting bacterium Azospirillum brasilense.

Science.gov (United States)

Elías, J M; Guerrero-Molina, M F; Martínez-Zamora, M G; Díaz-Ricci, J C; Pedraza, R O

2018-05-01

Induced systemic resistance (ISR) is one of the indirect mechanisms of growth promotion exerted by plant growth-promoting bacteria, and can be mediated by ethylene (ET). We assessed ET production and the expression of related genes in the Azospirillum-strawberry plant interaction. Ethylene production was evaluated by gas chromatography in plants inoculated or not with A. brasilense REC3. Also, plants were treated with AgNO 3 , an inhibitor of ET biosynthesis; with 1-aminocyclopropane-1-carboxylic acid (ACC), a precursor of ET biosynthesis; and with indole acetic acid (IAA). Plant dry biomass and the growth index were determined to assess the growth-promoting effect of A. brasilense REC3 in strawberry plants. Quantitative real time PCR (qRT-PCR) was performed to analyse relative expression of the genes Faetr1, Faers1 and Faein4, which encode ET receptors; Factr1 and Faein2, involved in the ET signalling pathway; Faacs1 encoding ACC synthase; Faaco1 encoding ACC oxidase; and Faaux1 and Faami1 for IAA synthesis enzymes. Results showed that ET acts as a rapid and transient signal in the first 12 h post-treatment. A. brasilense REC3-inoculated plants had a significantly higher growth index compared to control plants. Modulation of the genes Faetr1, Faers1, Faein4, Factr1, Faein2 and Faaco1 indicated activation of ET synthesis and signalling pathways. The up-regulation of Faaux1 and Faami1 involved in IAA synthesis suggested that inoculation with A. brasilense REC3 induces production of this auxin, modulating ET signalling. Ethylene production and up-regulation of genes associated with ET signalling in strawberry plants inoculated with A. brasilense REC3 support the priming activation characteristic of ISR. This type of resistance and the activation of systemic acquired resistance previously observed in this interaction indicate that both are present in strawberry plants, could act synergistically and increase protection against pathogens. © 2018 German Society

Plant rhabdoviruses: new insights and research needs in the interplay of negative-strand RNA viruses with plant and insect hosts.

Science.gov (United States)

Mann, Krin S; Dietzgen, Ralf G

2014-08-01

Rhabdoviruses are taxonomically classified in the family Rhabdoviridae, order Mononegavirales. As a group, rhabdoviruses can infect plants, invertebrates and vertebrates. Plant cyto- and nucleorhabdoviruses infect a wide variety of species across both monocot and dicot families, including agriculturally important crops such as lettuce, wheat, barley, rice, maize, potato and tomato. Plant rhabdoviruses are transmitted by and replicate in hemipteran insects such as aphids (Aphididae), leafhoppers (Cicadellidae), or planthoppers (Delphacidae). These specific interactions between plants, viruses and insects offer new insights into host adaptation and molecular virus evolution. This review explores recent advances as well as knowledge gaps in understanding of replication, RNA silencing suppression and movement of plant rhabdoviruses with respect to both plant and insect hosts.

Food-Energy Interactive Tradeoff Analysis of Sustainable Urban Plant Factory Production Systems

Directory of Open Access Journals (Sweden)

Li-Chun Huang

2018-02-01

Full Text Available This research aims to analyze the food–energy interactive nexus of sustainable urban plant factory systems. Plant factory systems grow agricultural products within artificially controlled growing environment and multi-layer vertical growing systems. The system controls the supply of light, temperature, humidity, nutrition, water, and carbon dioxide for growing plants. Plant factories are able to produce consistent and high-quality agricultural products within less production space for urban areas. The production systems use less labor, pesticide, water, and nutrition. However, food production of plant factories has many challenges including higher energy demand, energy costs, and installation costs of artificially controlled technologies. In the research, stochastic optimization model and linear complementarity models are formulated to conduct optimal and equilibrium food–energy analysis of plant factory production. A case study of plant factories in the Taiwanese market is presented.

Genetic diversity within a dominant plant outweighs plant species diversity in structuring an arthropod community.

Science.gov (United States)

Crawford, Kerri M; Rudgers, Jennifer A

2013-05-01

Plant biodiversity is being lost at a rapid rate. This has spurred much interest in elucidating the consequences of this loss for higher trophic levels. Experimental tests have shown that both plant species diversity and genetic diversity within a plant species can influence arthropod community structure. However, the majority of these studies have been conducted in separate systems, so their relative importance is currently unresolved. Furthermore, potential interactions between the two levels of diversity, which likely occur in natural systems, have not been investigated. To clarify these issues, we conducted three experiments in a freshwater sand dune ecosystem. We (1) independently manipulated plant species diversity, (2) independently manipulated genetic diversity within the dominant plant species, Ammophila breviligulata, and (3) jointly manipulated genetic diversity within the dominant plant and species diversity. We found that genetic diversity within the dominant plant species, Ammophila breviligulata, more strongly influenced arthropod communities than plant species diversity, but this effect was dependent on the presence of other species. In species mixtures, A. breviligulata genetic diversity altered overall arthropod community composition, and arthropod richness and abundance peaked at the highest level of genetic diversity. Positive nonadditive effects of diversity were detected, suggesting that arthropods respond to emergent properties of diverse plant communities. However, in the independent manipulations where A. breviligulata was alone, effects of genetic diversity were weaker, with only arthropod richness responding. In contrast, plant species diversity only influenced arthropods when A. breviligulata was absent, and then only influenced herbivore abundance. In addition to showing that genetic diversity within a dominant plant species can have large effects on arthropod community composition, these results suggest that understanding how species

Plant-climate interactions over historical and geological time

Energy Technology Data Exchange (ETDEWEB)

Cowling, Sharon A.

2000-04-01

Data-model comparisons are a useful approach to elucidating the relative influence of past climate change on vegetation dynamics over various spatial (global, regional, stand) and temporal (historical, geological) scales. Comparisons between changes in tree species abundance reconstructed from pollen and simulated from a forest gap model, for example, indicate that based solely on climate change over the past 1500 years, southern Scandinavian forests should be co-dominated by Tilia and Fagus. Picea has begun to more closely track changes in climate since 1000 years ago, however in the last few centuries the realised range limit of Picea has overshot the potential limit because of planting and establishment during favourable years. Not only can palaeodata-model comparisons provide practical information for forest managers, but they can help further our appreciation of the climatic catalysts underlying evolution of terrestrial ecosystems. Past changes in atmospheric CO{sub 2}, independently or in combination with changes in climate, may have altered vegetation form and function such that palaeoplant assemblages were much different than today, speciation may have been promoted via biological vicariance, and some species may have been pushed to extinction. A thorough understanding of modern plant-climate interactions requires consideration of how past climate and atmospheric CO{sub 2} events could have shaped physiological, biochemical and biophysical functioning of existing vegetation.

Plant-climate interactions over historical and geological time

International Nuclear Information System (INIS)

Cowling, Sharon A.

2000-04-01

Data-model comparisons are a useful approach to elucidating the relative influence of past climate change on vegetation dynamics over various spatial (global, regional, stand) and temporal (historical, geological) scales. Comparisons between changes in tree species abundance reconstructed from pollen and simulated from a forest gap model, for example, indicate that based solely on climate change over the past 1500 years, southern Scandinavian forests should be co-dominated by Tilia and Fagus. Picea has begun to more closely track changes in climate since 1000 years ago, however in the last few centuries the realised range limit of Picea has overshot the potential limit because of planting and establishment during favourable years. Not only can palaeodata-model comparisons provide practical information for forest managers, but they can help further our appreciation of the climatic catalysts underlying evolution of terrestrial ecosystems. Past changes in atmospheric CO 2 , independently or in combination with changes in climate, may have altered vegetation form and function such that palaeoplant assemblages were much different than today, speciation may have been promoted via biological vicariance, and some species may have been pushed to extinction. A thorough understanding of modern plant-climate interactions requires consideration of how past climate and atmospheric CO 2 events could have shaped physiological, biochemical and biophysical functioning of existing vegetation

Interactions among predators and plant specificity protect herbivores from top predators.

Science.gov (United States)

Bosc, Christopher; Pauw, Anton; Roets, Francois; Hui, Cang

2018-05-04

The worldwide loss of top predators from natural and agricultural systems has heightened the need to understand how important they are in controlling herbivore abundance. The effect of top predators on herbivore species is likely to depend on 1) the importance of the consumption of intermediate predators by top predators (intra-guild predation; IGP), but also on 2) plant specificity by herbivores, because specialists may defend themselves better (enemy-free space; EFS). Insectivorous birds, as top predators, are generally known to effectively control herbivorous insects, despite also consuming intermediate predators such as spiders, but how this effect varies among herbivore species in relation to the cascading effects of IGP and EFS is not known. To explore this, we excluded birds from natural fynbos vegetation in South Africa using large netted cages and recorded changes in abundance relative to control plots for 199 plant-dwelling intermediate predator and 341 herbivore morpho-species that varied in their estimated plant specificity. We found a strong negative effect of birds on the total abundance of all intermediate predators, with especially clear effects on spiders (strong IGP). In contrast with previous studies, which document a negative effect of birds on herbivores, we found an overall neutral effect of birds on herbivore abundance, but the effect varied among species: some species were negatively affected by birds, suggesting that they were mainly consumed by birds, whereas others, likely released from spiders by IGP, were positively affected. Some species were also effectively neutrally affected by birds. These tended to be more specialized to plants compared to the other species, which may imply that some plant specialists benefited from protection provided by EFS from both birds and spiders. These results suggest that the response of herbivore species to top predators may depend on cascading effects of interactions among predators and on their degree

Mechanisms and ecological implications of plant-mediated interactions between belowground and aboveground insect herbivores

NARCIS (Netherlands)

Papadopoulou, G.V.; Dam, N.M. van

2017-01-01

Plant-mediated interactions between belowground (BG) and aboveground (AG) herbivores have received increasing interest recently. However, the molecular mechanisms underlying ecological consequences of BG–AG interactions are not fully clear yet. Herbivore-induced plant defenses are complex and

Calcium signaling during reproduction and biotrophic fungal interactions in plants.

Science.gov (United States)

Chen, Junyi; Gutjahr, Caroline; Bleckmann, Andrea; Dresselhaus, Thomas

2015-04-01

Many recent studies have indicated that cellular communications during plant reproduction, fungal invasion, and defense involve identical or similar molecular players and mechanisms. Indeed, pollen tube invasion and sperm release shares many common features with infection of plant tissue by fungi and oomycetes, as a tip-growing intruder needs to communicate with the receptive cells to gain access into a cell and tissue. Depending on the compatibility between cells, interactions may result in defense, invasion, growth support, or cell death. Plant cells stimulated by both pollen tubes and fungal hyphae secrete, for example, small cysteine-rich proteins and receptor-like kinases are activated leading to intracellular signaling events such as the production of reactive oxygen species (ROS) and the generation of calcium (Ca(2+)) transients. The ubiquitous and versatile second messenger Ca(2+) thereafter plays a central and crucial role in modulating numerous downstream signaling processes. In stimulated cells, it elicits both fast and slow cellular responses depending on the shape, frequency, amplitude, and duration of the Ca(2+) transients. The various Ca(2+) signatures are transduced into cellular information via a battery of Ca(2+)-binding proteins. In this review, we focus on Ca(2+) signaling and discuss its occurrence during plant reproduction and interactions of plant cells with biotrophic filamentous microbes. The participation of Ca(2+) in ROS signaling pathways is also discussed. Copyright © 2015 The Author. Published by Elsevier Inc. All rights reserved.

Plant vs. Animal, Which is the Most Prefer Understanding of Evolution?

Directory of Open Access Journals (Sweden)

Hana Gardenia Mahbubah

2017-12-01

Full Text Available Evolution is one of the main subjects of biology taught in science colleges. Unfortunately, students seem less attention to this subject. In the subject of evolution, the lesson commonly uses the animal as a model to improve the students understanding. The purpose of this study is to compare the ability of tree thinking students who use animals and plants as a model in the evolution lesson. Tree thinking refers to an approach to evolution that emphasizes reading and interpreting phylogenetic tree. This study involved 20 undergraduate students enrolled in the evolution course for biology majors at Universitas Pendidikan Indonesia (UPI. The tree thinking ability of students was measured using Tree Thinking Concept Inventory (TTCI of Naegle with a little modification. In this test, we analyzed student preferences using animal or plant models using phylogenetic tree diagrams. Results showed that students’ TTCI score was higher when using animal models (65.42% than plant models (55%. These results suggested that students remain to prefer animal models compare to plant models to study evolution. Nevertheless, the use of plants as models can be an alternative to learning evolution in the future.

The Use of Arabidopsis to Study Interactions between Parasitic Angiosperms and Their Plant Hosts

Science.gov (United States)

Goldwasser, Y.; Westwood, J. H.; Yoder, J. I.

2002-01-01

Parasitic plants invade host plants in order to rob them of water, minerals and nutrients. The consequences to the infected hosts can be debilitating and some of the world's most pernicious agricultural weeds are parasitic. Parasitic genera of the Scrophulariaceae and Orobanchaceae directly invade roots of neighboring plants via underground structures called haustoria. The mechanisms by which these parasites identify and associate with host plants present unsurpassed opportunities for studying chemical signaling in plant-plant interactions. Seeds of some parasites require specific host factors for efficient germination, thereby insuring the availability of an appropriate host root prior to germination. A second set of signal molecules is required to induce haustorium development and the beginning of heterotrophy. Later stages in parasitism also require the presence of host factors, although these have not yet been well characterized. Arabidopsis is being used as a model host plant to identify genetic loci associated with stimulating parasite germination, haustorium development, and parasite support. Arabidopsis is also being employed to explore how host plants respond to parasite attack. Current methodologies and recent findings in Arabidopsis – parasitic plant interactions will be discussed. PMID:22303205

Understanding nitrate uptake, signaling and remobilisation for improving plant nitrogen use efficiency.

Science.gov (United States)

Kant, Surya

2018-02-01

The majority of terrestrial plants use nitrate as their main source of nitrogen. Nitrate also acts as an important signalling molecule in vital physiological processes required for optimum plant growth and development. Improving nitrate uptake and transport, through activation by nitrate sensing, signalling and regulatory processes, would enhance plant growth, resulting in improved crop yields. The increased remobilisation of nitrate, and assimilated nitrogenous compounds, from source to sink tissues further ensures higher yields and quality. An updated knowledge of various transporters, genes, activators, and microRNAs, involved in nitrate uptake, transport, remobilisation, and nitrate-mediated root growth, is presented. An enhanced understanding of these components will allow for their orchestrated fine tuning in efforts to improving nitrogen use efficiency in plants. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

Herbivore-plant interactions and desertification in arid lands

Science.gov (United States)

Arid lands around the world have experienced or are currently experiencing degradation that is known as desertification. Animal-plant interactions that have an effect on desertification are among the most important function of animals in arid ecosystems. Desertification has been defined as land de...

Competitive ability, stress tolerance and plant interactions along stress gradients.

Science.gov (United States)

Qi, Man; Sun, Tao; Xue, SuFeng; Yang, Wei; Shao, DongDong; Martínez-López, Javier

2018-04-01

Exceptions to the generality of the stress-gradient hypothesis (SGH) may be reconciled by considering species-specific traits and stress tolerance strategies. Studies have tested stress tolerance and competitive ability in mediating interaction outcomes, but few have incorporated this to predict how species interactions shift between competition and facilitation along stress gradients. We used field surveys, salt tolerance and competition experiments to develop a predictive model interspecific interaction shifts across salinity stress gradients. Field survey and greenhouse tolerance tests revealed tradeoffs between stress tolerance and competitive ability. Modeling showed that along salinity gradients, (1) plant interactions shifted from competition to facilitation at high salinities within the physiological limits of salt-intolerant plants, (2) facilitation collapsed when salinity stress exceeded the physiological tolerance of salt-intolerant plants, and (3) neighbor removal experiments overestimate interspecific facilitation by including intraspecific effects. A community-level field experiment, suggested that (1) species interactions are competitive in benign and, facilitative in harsh condition, but fuzzy under medium environmental stress due to niche differences of species and weak stress amelioration, and (2) the SGH works on strong but not weak stress gradients, so SGH confusion arises when it is applied across questionable stress gradients. Our study clarifies how species interactions vary along stress gradients. Moving forward, focusing on SGH applications rather than exceptions on weak or nonexistent gradients would be most productive. © 2018 by the Ecological Society of America.

Negative plant-soil feedbacks increase with plant abundance, and are unchanged by competition

Science.gov (United States)

John L. Maron; Alyssa Laney Smith; Yvette K. Ortega; Dean E. Pearson; Ragan M. Callaway

2016-01-01

Plant-soil feedbacks and interspecific competition are ubiquitous interactions that strongly influence the performance of plants. Yet few studies have examined whether the strength of these interactions corresponds with the abundance of plant species in the field, or whether feedbacks and competition interact in ways that either ameliorate or exacerbate their...

Belowground Plant–Herbivore Interactions Vary among Climate-Driven Range-Expanding Plant Species with Different Degrees of Novel Chemistry

Directory of Open Access Journals (Sweden)

Rutger A. Wilschut

2017-10-01

Full Text Available An increasing number of studies report plant range expansions to higher latitudes and altitudes in response to global warming. However, consequences for interactions with other species in the novel ranges are poorly understood. Here, we examine how range-expanding plant species interact with root-feeding nematodes from the new range. Root-feeding nematodes are ubiquitous belowground herbivores that may impact the structure and composition of natural vegetation. Because of their ecological novelty, we hypothesized that range-expanding plant species will be less suitable hosts for root-feeding nematodes than native congeneric plant species. In greenhouse and lab trials we compared nematode preference and performance of two root-feeding nematode species between range-expanding plant species and their congeneric natives. In order to understand differences in nematode preferences, we compared root volatile profiles of all range-expanders and congeneric natives. Nematode preferences and performances differed substantially among the pairs of range-expanders and natives. The range-expander that had the most unique volatile profile compared to its related native was unattractive and a poor host for nematodes. Other range-expanding plant species that differed less in root chemistry from native congeners, also differed less in nematode attraction and performance. We conclude that the three climate-driven range-expanding plant species studied varied considerably in their chemical novelty compared to their congeneric natives, and therefore affected native root-feeding nematodes in species-specific ways. Our data suggest that through variation in chemical novelty, range-expanding plant species may vary in their impacts on belowground herbivores in the new range.

Plant species distribution along environmental gradient: do belowground interactions with fungi matter?

Directory of Open Access Journals (Sweden)

Loïc ePellissier

2013-12-01

Full Text Available The distribution of plants along environmental gradients is constrained by abiotic and biotic factors. Cumulative evidence attests of the impact of abiotic factors on plant distributions, but only few studies discuss the role of belowground communities. Soil fungi, in particular, are thought to play an important role in how plant species assemble locally into communities. We first review existing evidence, and then test the effect of the number of soil fungal operational taxonomic units (OTUs on plant species distributions using a recently collected dataset of plant and metagenomic information on soil fungi in the Western Swiss Alps. Using species distribution models, we investigated whether the distribution of individual plant species is correlated to the number of OTUs of two important soil fungal classes known to interact with plants: the Glomeromycetes, that are obligatory symbionts of plants, and the Agaricomycetes, that may be facultative plant symbionts, pathogens, or wood decayers. We show that including the fungal richness information in the models of plant species distributions improves predictive accuracy. Number of fungal OTUs is especially correlated to the distribution of high elevation plant species. We suggest that high elevation soil show greater variation in fungal assemblages that may in turn impact plant turnover among communities. We finally discuss how to move beyond correlative analyses, through the design of field experiments manipulating plant and fungal communities along environmental gradients.

Interactions among invasive plants: Lessons from Hawai‘i

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D'Antonio, Carla M.; Ostertag, Rebecca; Cordell, Susan; Yelenik, Stephanie G.

2017-01-01

Most ecosystems have multiple-plant invaders rather than single-plant invaders, yet ecological studies and management actions focus largely on single invader species. There is a need for general principles regarding invader interactions across varying environmental conditions, so that secondary invasions can be anticipated and managers can allocate resources toward pretreatment or postremoval actions. By reviewing removal experiments conducted in three Hawaiian ecosystems (a dry tropical forest, a seasonally dry mesic forest, and a lowland wet forest), we evaluate the roles environmental harshness, priority effects, productivity potential, and species interactions have in influencing secondary invasions, defined here as invasions that are influenced either positively (facilitation) or negatively (inhibition/priority effects) by existing invaders. We generate a conceptual model with a surprise index to describe whether long-term plant invader composition and dominance is predictable or stochastic after a system perturbation such as a removal experiment. Under extremely low resource availability, the surprise index is low, whereas under intermediate-level resource environments, invader dominance is more stochastic and the surprise index is high. At high resource levels, the surprise index is intermediate: Invaders are likely abundant in the environment but their response to a perturbation is more predictable than at intermediate resource levels. We suggest further testing across environmental gradients to determine key variables that dictate the predictability of postremoval invader composition.

Ecological and evolutionary consequences of tri-trophic interactions: Spatial variation and effects of plant density.

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Abdala-Roberts, Luis; Parra-Tabla, Víctor; Moreira, Xoaquín; Ramos-Zapata, José

2017-02-01

The factors driving variation in species interactions are often unknown, and few studies have made a link between changes in interactions and the strength of selection. We report on spatial variation in functional responses by a seed predator (SP) and its parasitic wasps associated with the herb Ruellia nudiflora . We assessed the influence of plant density on consumer responses and determined whether density effects and spatial variation in functional responses altered natural selection by these consumers on the plant. We established common gardens at two sites in Yucatan, Mexico, and planted R. nudiflora at two densities in each garden. We recorded fruit output and SP and parasitoid attack; calculated relative fitness (seed number) under scenarios of three trophic levels (accounting for SP and parasitoid effects), two trophic levels (accounting for SP but not parasitoid effects), and one trophic level (no consumer effects); and compared selection strength on fruit number under these scenarios across sites and densities. There was spatial variation in SP recruitment, whereby the SP functional response was negatively density-dependent at one site but density-independent at the other; parasitoid responses were density-independent and invariant across sites. Site variation in SP attack led, in turn, to differences in SP selection on fruit output, and parasitoids did not alter SP selection. There were no significant effects of density at either site. Our results provide a link between consumer functional responses and consumer selection on plants, which deepens our understanding of geographic variation in the evolutionary outcomes of multitrophic interactions. © 2017 Botanical Society of America.

Elucidating the interaction between light competition and herbivore feeding patterns using functional–structural plant modelling

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de Vries, Jorad; Poelman, Erik H; Anten, Niels; Evers, Jochem B

2018-01-01

Abstract Background and Aims Plants usually compete with neighbouring plants for resources such as light as well as defend themselves against herbivorous insects. This requires investment of limiting resources, resulting in optimal resource distribution patterns and trade-offs between growth- and defence-related traits. A plant’s competitive success is determined by the spatial distribution of its resources in the canopy. The spatial distribution of herbivory in the canopy in turn differs between herbivore species as the level of herbivore specialization determines their response to the distribution of resources and defences in the canopy. Here, we investigated to what extent competition for light affects plant susceptibility to herbivores with different feeding preferences. Methods To quantify interactions between herbivory and competition, we developed and evaluated a 3-D spatially explicit functional–structural plant model for Brassica nigra that mechanistically simulates competition in a dynamic light environment, and also explicitly models leaf area removal by herbivores with different feeding preferences. With this novel approach, we can quantitatively explore the extent to which herbivore feeding location and light competition interact in their effect on plant performance. Key Results Our results indicate that there is indeed a strong interaction between levels of plant–plant competition and herbivore feeding preference. When plants did not compete, herbivory had relatively small effects irrespective of feeding preference. Conversely, when plants competed, herbivores with a preference for young leaves had a strong negative effect on the competitiveness and subsequent performance of the plant, whereas herbivores with a preference for old leaves did not. Conclusions Our study predicts how plant susceptibility to herbivory depends on the composition of the herbivore community and the level of plant competition, and highlights the importance of considering

Do competitive interactions in dry heathlands explain plant abundance patterns and species coexistence?

DEFF Research Database (Denmark)

Ransijn, Johannes; Damgaard, Christian; Schmidt, Inger K

2015-01-01

Plant community patterns in space and time may be explained by the interactions between competing plant species. The presented study investigates this in a nutrient and species poor ecosystem. The study presents a methodology for inferring competitive interactions from yearly vegetation inventories...... to predict the community dynamics of C. vulgaris and D. flexuosa. This was compared with the observed plant community structure at 198 Danish dry heathland sites. Interspecific competition will most likely lead to competitive exclusion of D. flexuosa at the observed temporal and spatial scale...... and uses this to assess the outcome of competitive interactions and to predict community patterns and dynamics in a Northwest-European dry heathland. Inferred competitive interactions from five consecutive years of measurements in permanent vegetation frames at a single dry heathland site were used...

Structural breakdown of specialized plant-herbivore interaction networks in tropical forest edges

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Bruno Ximenes Pinho

2017-10-01

Full Text Available Plant-herbivore relationships are essential for ecosystem functioning, typically forming an ecological network with a compartmentalized (i.e. modular structure characterized by highly specialized interactions. Human disturbances can favor habitat generalist species and thus cause the collapse of this modular structure, but its effects are rarely assessed using a network-based approach. We investigate how edge proximity alters plant-insect herbivore networks by comparing forest edge and interior in a large remnant (3.500 ha of the Brazilian Atlantic forest. Given the typical dominance of pioneer plants and generalist herbivores in edge-affected habitats, we test the hypothesis that the specialized structure of plant-herbivore networks collapse in forest edges, resulting in lower modularity and herbivore specialization. Despite no differences in the number of species and interactions, the network structure presented marked differences between forest edges and interior. Herbivore specialization, modularity and number of modules were significantly higher in forest interior than edge-affected habitats. When compared to a random null model, two (22.2% and eight (88.8% networks were significantly modular in forest edge and interior, respectively. The loss of specificity and modularity in plant-herbivore networks in forest edges may be related to the loss of important functions, such as density-dependent control of superior plant competitors, which is ultimately responsible for the maintenance of biodiversity and ecosystem functions. Our results support previous warnings that focusing on traditional community measures only (e.g. species diversity may overlook important modifications in species interactions and ecosystem functioning.

Profiling the extended phenotype of plant pathogens: Challenges in Bacterial Molecular Plant Pathology.

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Preston, Gail M

2017-04-01

One of the most fundamental questions in plant pathology is what determines whether a pathogen grows within a plant? This question is frequently studied in terms of the role of elicitors and pathogenicity factors in the triggering or overcoming of host defences. However, this focus fails to address the basic question of how the environment in host tissues acts to support or restrict pathogen growth. Efforts to understand this aspect of host-pathogen interactions are commonly confounded by several issues, including the complexity of the plant environment, the artificial nature of many experimental infection systems and the fact that the physiological properties of a pathogen growing in association with a plant can be very different from the properties of the pathogen in culture. It is also important to recognize that the phenotype and evolution of pathogen and host are inextricably linked through their interactions, such that the environment experienced by a pathogen within a host, and its phenotype within the host, is a product of both its interaction with its host and its evolutionary history, including its co-evolution with host plants. As the phenotypic properties of a pathogen within a host cannot be defined in isolation from the host, it may be appropriate to think of pathogens as having an 'extended phenotype' that is the product of their genotype, host interactions and population structure within the host environment. This article reflects on the challenge of defining and studying this extended phenotype, in relation to the questions posed below, and considers how knowledge of the phenotype of pathogens in the host environment could be used to improve disease control. What determines whether a pathogen grows within a plant? What aspects of pathogen biology should be considered in describing the extended phenotype of a pathogen within a host? How can we study the extended phenotype in ways that provide insights into the phenotypic properties of pathogens

Plant-plant interactions influence developmental phase transitions, grain productivity and root system architecture in Arabidopsis via auxin and PFT1/MED25 signalling.

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Muñoz-Parra, Edith; Pelagio-Flores, Ramón; Raya-González, Javier; Salmerón-Barrera, Guadalupe; Ruiz-Herrera, León Francisco; Valencia-Cantero, Eduardo; López-Bucio, José

2017-09-01

Transcriptional regulation of gene expression influences plant growth, environmental interactions and plant-plant communication. Here, we report that population density is a key factor for plant productivity and a major root architectural determinant in Arabidopsis thaliana. When grown in soil at varied densities from 1 to 32 plants, high number of individuals decreased stem growth and accelerated senescence, which negatively correlated with total plant biomass and seed production at the completion of the life cycle. Root morphogenesis was also a major trait modulated by plant density, because an increasing number of individuals grown in vitro showed repression of primary root growth, lateral root formation and root hair development while affecting auxin-regulated gene expression and the levels of auxin transporters PIN1 and PIN2. We also found that mutation of the Mediator complex subunit PFT1/MED25 renders plants insensitive to high density-modulated root traits. Our results suggest that plant density is critical for phase transitions, productivity and root system architecture and reveal a role of Mediator in self-plant recognition. © 2017 John Wiley & Sons Ltd.

Whole plant extracts versus single compounds for the treatment of malaria: synergy and positive interactions.

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Rasoanaivo, Philippe; Wright, Colin W; Willcox, Merlin L; Gilbert, Ben

2011-03-15

In traditional medicine whole plants or mixtures of plants are used rather than isolated compounds. There is evidence that crude plant extracts often have greater in vitro or/and in vivo antiplasmodial activity than isolated constituents at an equivalent dose. The aim of this paper is to review positive interactions between components of whole plant extracts, which may explain this. Narrative review. There is evidence for several different types of positive interactions between different components of medicinal plants used in the treatment of malaria. Pharmacodynamic synergy has been demonstrated between the Cinchona alkaloids and between various plant extracts traditionally combined. Pharmacokinetic interactions occur, for example between constituents of Artemisia annua tea so that its artemisinin is more rapidly absorbed than the pure drug. Some plant extracts may have an immunomodulatory effect as well as a direct antiplasmodial effect. Several extracts contain multidrug resistance inhibitors, although none of these has been tested clinically in malaria. Some plant constituents are added mainly to attenuate the side-effects of others, for example ginger to prevent nausea. More clinical research is needed on all types of interaction between plant constituents. This could include clinical trials of combinations of pure compounds (such as artemisinin + curcumin + piperine) and of combinations of herbal remedies (such as Artemisia annua leaves + Curcuma longa root + Piper nigum seeds). The former may enhance the activity of existing pharmaceutical preparations, and the latter may improve the effectiveness of existing herbal remedies for use in remote areas where modern drugs are unavailable.

Whole plant extracts versus single compounds for the treatment of malaria: synergy and positive interactions

Directory of Open Access Journals (Sweden)

Wright Colin W

2011-03-01

Full Text Available Abstract Background In traditional medicine whole plants or mixtures of plants are used rather than isolated compounds. There is evidence that crude plant extracts often have greater in vitro or/and in vivo antiplasmodial activity than isolated constituents at an equivalent dose. The aim of this paper is to review positive interactions between components of whole plant extracts, which may explain this. Methods Narrative review. Results There is evidence for several different types of positive interactions between different components of medicinal plants used in the treatment of malaria. Pharmacodynamic synergy has been demonstrated between the Cinchona alkaloids and between various plant extracts traditionally combined. Pharmacokinetic interactions occur, for example between constituents of Artemisia annua tea so that its artemisinin is more rapidly absorbed than the pure drug. Some plant extracts may have an immunomodulatory effect as well as a direct antiplasmodial effect. Several extracts contain multidrug resistance inhibitors, although none of these has been tested clinically in malaria. Some plant constituents are added mainly to attenuate the side-effects of others, for example ginger to prevent nausea. Conclusions More clinical research is needed on all types of interaction between plant constituents. This could include clinical trials of combinations of pure compounds (such as artemisinin + curcumin + piperine and of combinations of herbal remedies (such as Artemisia annua leaves + Curcuma longa root + Piper nigum seeds. The former may enhance the activity of existing pharmaceutical preparations, and the latter may improve the effectiveness of existing herbal remedies for use in remote areas where modern drugs are unavailable.

Fertilization Mechanisms in Flowering Plants.

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Dresselhaus, Thomas; Sprunck, Stefanie; Wessel, Gary M

2016-02-08

Compared with the animal kingdom, fertilization is particularly complex in flowering plants (angiosperms). Sperm cells of angiosperms have lost their motility and require transportation as a passive cargo by the pollen tube cell to the egg apparatus (egg cell and accessory synergid cells). Sperm cell release from the pollen tube occurs after intensive communication between the pollen tube cell and the receptive synergid, culminating in the lysis of both interaction partners. Following release of the two sperm cells, they interact and fuse with two dimorphic female gametes (the egg and the central cell) forming the major seed components embryo and endosperm, respectively. This process is known as double fertilization. Here, we review the current understanding of the processes of sperm cell reception, gamete interaction, their pre-fertilization activation and fusion, as well as the mechanisms plants use to prevent the fusion of egg cells with multiple sperm cells. The role of Ca(2+) is highlighted in these various processes and comparisons are drawn between fertilization mechanisms in flowering plants and other eukaryotes, including mammals. Copyright © 2016 Elsevier Ltd. All rights reserved.

Troublesome toxins: Time to re-think plant-herbivore interactions in vertebrate ecology

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Swihart, R.K.; DeAngelis, D.L.; Feng, Z.; Bryant, J.P.

2009-01-01

Earlier models of plant-herbivore interactions relied on forms of functional response that related rates of ingestion by herbivores to mechanical or physical attributes such as bite size and rate. These models fail to predict a growing number of findings that implicate chemical toxins as important determinants of plant-herbivore dynamics. Specifically, considerable evidence suggests that toxins set upper limits on food intake for many species of herbivorous vertebrates. Herbivores feeding on toxin-containing plants must avoid saturating their detoxification systems, which often occurs before ingestion rates are limited by mechanical handling of food items. In light of the importance of plant toxins, a new approach is needed to link herbivores to their food base. We discuss necessary features of such an approach, note recent advances in herbivore functional response models that incorporate effects of plant toxins, and mention predictions that are consistent with observations in natural systems. Future ecological studies will need to address explicitly the importance of plant toxins in shaping plant and herbivore communities.

Interannual variability of plant phenology in tussock tundra: modelling interactions of plant productivity, plant phenology, snowmelt and soil thaw

NARCIS (Netherlands)

Wijk, van M.T.; Williams, M.; Laundre, J.A.; Shaver, G.R.

2003-01-01

We present a linked model of plant productivity, plant phenology, snowmelt and soil thaw in order to estimate interannual variability of arctic plant phenology and its effects on plant productivity. The model is tested using 8 years of soil temperature data, and three years of bud break data of

Effects of soil depth and plant-soil interaction on microbial community in temperate grasslands of northern China.

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Yao, Xiaodong; Zhang, Naili; Zeng, Hui; Wang, Wei

2018-07-15

Although the patterns and drivers of soil microbial community composition are well studied, little is known about the effects of plant-soil interactions and soil depth on soil microbial distribution at a regional scale. We examined 195 soil samples from 13 sites along a climatic transect in the temperate grasslands of northern China to measure the composition of and factors influencing soil microbial communities within a 1-m soil profile. Soil microbial community composition was measured using phospholipid fatty acids (PLFA) analysis. Fungi predominated in topsoil (0-10 cm) and bacteria and actinomycetes in deep soils (40-100 cm), independent of steppe types. This variation was explained by contemporary environmental factors (including above- and below-ground plant biomass, soil physicochemical and climatic factors) >58% in the 0-40 cm of soil depth, but soils. Interestingly, when we considered the interactive effects between plant traits (above ground biomass and root biomass) and soil factors (pH, clay content, and soil total carbon, nitrogen, phosphorous), we observed a significant interaction effect occurring at depths of 10-20 cm soil layer, due to different internal and external factors of the plant-soil system along the soil profile. These results improve understanding of the drivers of soil microbial community composition at regional scales. Copyright © 2018 Elsevier B.V. All rights reserved.

Plant–plant interactions mediate the plastic and genotypic response of Plantago asiatica to CO2: an experiment with plant populations from naturally high CO2 areas

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van Loon, Marloes P.; Rietkerk, Max; Dekker, Stefan C.; Hikosaka, Kouki; Ueda, Miki U.; Anten, Niels P. R.

2016-01-01

Background and Aims The rising atmospheric CO2 concentration ([CO2]) is a ubiquitous selective force that may strongly impact species distribution and vegetation functioning. Plant–plant interactions could mediate the trajectory of vegetation responses to elevated [CO2], because some plants may benefit more from [CO2] elevation than others. The relative contribution of plastic (within the plant’s lifetime) and genotypic (over several generations) responses to elevated [CO2] on plant performance was investigated and how these patterns are modified by plant–plant interactions was analysed. Methods Plantago asiatica seeds originating from natural CO2 springs and from ambient [CO2] sites were grown in mono stands of each one of the two origins as well as mixtures of both origins. In total, 1944 plants were grown in [CO2]-controlled walk-in climate rooms, under a [CO2] of 270, 450 and 750 ppm. A model was used for upscaling from leaf to whole-plant photosynthesis and for quantifying the influence of plastic and genotypic responses. Key Results It was shown that changes in canopy photosynthesis, specific leaf area (SLA) and stomatal conductance in response to changes in growth [CO2] were mainly determined by plastic and not by genotypic responses. We further found that plants originating from high [CO2] habitats performed better in terms of whole-plant photosynthesis, biomass and leaf area, than those from ambient [CO2] habitats at elevated [CO2] only when both genotypes competed. Similarly, plants from ambient [CO2] habitats performed better at low [CO2], also only when both genotypes competed. No difference in performance was found in mono stands. Conclusion The results indicate that natural selection under increasing [CO2] will be mainly driven by competitive interactions. This supports the notion that plant–plant interactions have an important influence on future vegetation functioning and species distribution. Furthermore, plant performance was mainly

Chemical Plant Accidents in a Nuclear Hydrogen Generation Scheme

International Nuclear Information System (INIS)

Brown, Nicholas R.; Revankar, Shripad T.

2011-01-01

A high temperature nuclear reactor (HTR) could be used to drive a steam reformation plant, a coal gasification facility, an electrolysis plant, or a thermochemical hydrogen production cycle. Most thermochemical cycles are purely thermodynamic, and thus achieve high thermodynamic efficiency. HTRs produce large amounts of heat at high temperature (1100 K). Helium-cooled HTRs have many passive, or inherent, safety characteristics. This inherent safety is due to the high design basis limit of the maximum fuel temperature. Due to the severity of a potential release, containment of fission products is the single most important safety issue in any nuclear reactor facility. A HTR coupled to a chemical plant presents a complex system, due primarily to the interactive nature of both plants. Since the chemical plant acts as the heat sink for the nuclear reactor, it important to understand the interaction and feedback between the two systems. Process heat plants and HTRs are generally very different. Some of the major differences include: time constants of plants, safety standards, failure probability, and transient response. While both the chemical plant and the HTR are at advanced stages of testing individually, no serious effort has been made to understand the operation of the integrated system, especially during accident events that are initiated in the chemical plant. There is a significant lack of knowledge base regarding scaling and system integration for large scale process heat plants coupled to HTRs. Consideration of feedback between the two plants during time-dependent scenarios is absent from literature. Additionally, no conceptual studies of the accidents that could occur in either plant and impact the entire coupled system are present in literature

Membrane trafficking pathways and their roles in plant-microbe interactions.

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Inada, Noriko; Ueda, Takashi

2014-04-01

Membrane trafficking functions in the delivery of proteins that are newly synthesized in the endoplasmic reticulum (ER) to their final destinations, such as the plasma membrane (PM) and the vacuole, and in the internalization of extracellular components or PM-associated proteins for recycling or degradative regulation. These trafficking pathways play pivotal roles in the rapid responses to environmental stimuli such as challenges by microorganisms. In this review, we provide an overview of the current knowledge of plant membrane trafficking and its roles in plant-microbe interactions. Although there is little information regarding the mechanism of pathogenic modulation of plant membrane trafficking thus far, recent research has identified many membrane trafficking factors as possible targets of microbial modulation.

Understanding the nature of nuclear power plant risk

International Nuclear Information System (INIS)

Denning, R. S.

2012-01-01

This paper describes the evolution of understanding of severe accident consequences from the non-mechanistic assumptions of WASH-740 to WASH-1400, NUREG-1150, SOARCA and today in the interpretation of the consequences of the accident at Fukushima. As opposed to the general perception, the radiological human health consequences to members of the Japanese public from the Fukushima accident will be small despite meltdowns at three reactors and loss of containment integrity. In contrast, the radiation-related societal impacts present a substantial additional economic burden on top of the monumental task of economic recovery from the nonnuclear aspects of the earthquake and tsunami damage. The Fukushima accident provides additional evidence that we have mis-characterized the risk of nuclear power plant accidents to ourselves and to the public. The human health risks are extremely small even to people living next door to a nuclear power plant. The principal risk associated with a nuclear power plant accident involves societal impacts: relocation of people, loss of land use, loss of contaminated products, decontamination costs and the need for replacement power. Although two of the three probabilistic safety goals of the NRC address societal risk, the associated quantitative health objectives in reality only address individual human health risk. This paper describes the types of analysis that would address compliance with the societal goals. (authors)

Plant fibre composites - porosity and volumetric interaction

DEFF Research Database (Denmark)

Madsen, Bo; Thygesen, Anders; Lilholt, Hans

2007-01-01

the combination of a high fibre volume fraction, a low porosity and a high composite density is optimal. Experimental data from the literature on volumetric composition and density of four types of plant fibre composites are used to validate the model. It is demonstrated that the model provides a concept......Plant fibre composites contain typically a relative large amount of porosity, which considerably influences properties and performance of the composites. The large porosity must be integrated in the conversion of weight fractions into volume fractions of the fibre and matrix parts. A model...... is presented to predict the porosity as a function of the fibre weight fractions, and to calculate the related fibre and matrix volume fractions, as well as the density of the composite. The model predicts two cases of composite volumetric interaction separated by a transition fibre weight fraction, at which...

Resilience in plant-herbivore networks during secondary succession.

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Edith Villa-Galaviz

Full Text Available Extensive land-use change in the tropics has produced a mosaic of successional forests within an agricultural and cattle-pasture matrix. Post-disturbance biodiversity assessments have found that regeneration speed depends upon propagule availability and the intensity and duration of disturbance. However, reestablishment of species interactions is still poorly understood and this limits our understanding of the anthropogenic impacts upon ecosystem resilience. This is the first investigation that evaluates plant-herbivore interaction networks during secondary succession. In particular we investigated succession in a Mexican tropical dry forest using data of caterpillar associations with plants during 2007-2010. Plant-herbivore networks showed high resilience. We found no differences in most network descriptors between secondary and mature forest and only recently abandoned fields were found to be different. No significant nestedness or modularity network structure was found. Plant-herbivore network properties appear to quickly reestablish after perturbation, despite differences in species richness and composition. This study provides some valuable guidelines for the implement of restoration efforts that can enhance ecological processes such as the interaction between plants and their herbivores.

Introducing the term 'Biocontrol Plants' for integrated pest management

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Pia Parolin

2014-02-01

Full Text Available Studies of interactions between crops, additional plants, pests and beneficial organisms already exist as well as studies of natural enemy preference, dispersal, and abundance. However, these studies focus on tri-trophic interactions from an "arthropod" point of view. We think that in order to optimize crop protection methods we need to understand the effects that plant structures have on the various arthropods and on subsequent tri-trophic interactions. Although studies and reviews describing the role of secondary plants in Integrated Pest Management (IPM exist, to date a general term which encompasses all plants added to a cropping system with the aim of enhancing IPM strategies has yet to be formulated. Therefore, we suggest a new term, "biocontrol plants", which we define as plants that are intentionally added to a crop system with the aim of enhancing crop productivity through pest attraction and/or pest regulation; a term that will promote the use of biocontrol services, and can ultimately lead to an increase in the sustainability of cropping systems.

Consumptive and nonconsumptive effect ratios depend on interaction between plant quality and hunting behavior of omnivorous predators.

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Stephan, Jörg G; Stenberg, Johan A; Björkman, Christer

2017-04-01

Predators not only consume prey but exert nonconsumptive effects in form of scaring, consequently disturbing feeding or reproduction. However, how alternative food sources and hunting mode interactively affect consumptive and nonconsumptive effects with implications for prey fitness have not been addressed, impending functional understanding of such tritrophic interactions. With a herbivorous beetle, two omnivorous predatory bugs (plant sap as alternative food, contrasting hunting modes), and four willow genotypes (contrasting suitability for beetle/omnivore), we investigated direct and indirect effects of plant quality on the beetles key reproductive traits (oviposition rate, clutch size). Using combinations of either or both omnivores on different plant genotypes, we calculated the contribution of consumptive (eggs predated) and nonconsumptive (fewer eggs laid) effect on beetle fitness, including a prey density-independent measure (c:nc ratio). We found that larger clutches increase egg survival in presence of the omnivore not immediately consuming all eggs. However, rather than lowering mean, the beetles generally responded with a frequency shift toward smaller clutches. However, female beetles decreased mean and changed clutch size frequency with decreasing plant quality, therefore reducing intraspecific exploitative competition among larvae. More importantly, variation in host plant quality (to omnivore) led to nonconsumptive effects between one-third and twice as strong as the consumptive effects. Increased egg consumption on plants less suitable to the omnivore may therefore be accompanied by less searching and disturbing the beetle, representing a "cost" to the indirect plant defense in the form of a lower nonconsumptive effect. Many predators are omnivores and altering c:nc ratios (with egg retention as the most direct link to prey fitness) via plant quality and hunting behavior should be fundamental to advance ecological theory and applications

Invasive plant architecture alters trophic interactions by changing predator abundance and behavior

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Dean E. Pearson

2009-01-01

As primary producers, plants are known to influence higher trophic interactions by initiating food chains. However, as architects, plants may bypass consumers to directly affect predators with important but underappreciated trophic ramifications. Invasion of western North American grasslands by the perennial forb, spotted knapweed (Centaurea maculosa...

Selenium promotes sulfur accumulation and plant growth in wheat (Triticum aestivum)

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Selenium (Se) is an essential micronutrient for animals and humans and a target for biofortification in crops. Sulfur (S) is a crucial nutrient for plant growth. To gain better understanding of Se and S nutrition and interaction in plants, the effects of Se dosages and forms on plant growth as well ...

Can alien plants support generalist insect herbivores?

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Douglas Tallamy; Meg Ballard; Vincent D' Amico

2009-01-01

Rearing experiments were conducted to address two questions relevant to understanding how generalist lepidopteran herbivores interact with alien plants. We reared 10 yellow-striped armyworms (Spodoptera ornithogalli),...

PLANT BIOPRINTING: NOVEL PERSPECTIVE FOR PLANT BIOTECHNOLOGY

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Adhityo WICAKSONO

2015-12-01

Full Text Available Bioprinting is a technical innovation that has revolutionized tissue engineering. Using conventional printer cartridges filled with cells as well as a suitable scaffold, major advances have been made in the biomedical field, and it is now possible to print skin, bones, blood vessels, and even organs. Unlike animal systems, the application of bioprinting in simple plant tissue cells is still in a nascent phase and has yet to be studied. One major advantage of plants is that all living parts are reprogrammable in the form of totipotent cells. Plant bioprinting may improve scientists’understanding of plant shape and morphogenesis, and could serve for the mass production of desired tissues or plants, or even the production of plant-based biomaterial for industrial uses. This perspectives paper explores these possibilities using knowledge on what is known about bioprinting in other biosystems.

How common is within-plant signaling via volatiles?

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Li, Tao; Blande, James D

2017-08-03

Many plants respond to herbivory by releasing a complex blend of volatiles that may differ from that emitted by intact counterparts. These herbivore-induced plant volatiles (HIPV) mediate many interactions among plants and their community members, including alerting undamaged leaves of the attacked or neighboring plants to impending danger. It has been postulated that HIPVs evolved for within-plant signaling and that other organisms subsequently evolved to use them. However, only 7 studies have reported HIPV-mediated within-plant signaling, most conducted in the laboratory or greenhouse. This leaves open the ecological relevance and evolutionary underpinning of the phenomenon. We recently observed within-plant signaling in hybrid aspen under laboratory and field conditions. Greenhouse experiments showed that HIPVs mediated the process. While our study adds an aspen hybrid to the list of plants in which within-plant signaling has been demonstrated, we lack understanding of how common the process is and whether plants obtain fitness benefits.

Separating the role of biotic interactions and climate in determining adaptive response of plants to climate change.

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Tomiolo, Sara; Van der Putten, Wim H; Tielbörger, Katja

2015-05-01

Altered rainfall regimes will greatly affect the response of plant species to climate change. However, little is known about how direct effects of changing precipitation on plant performance may depend on other abiotic factors and biotic interactions. We used reciprocal transplants between climatically very different sites with simultaneous manipulation of soil, plant population origin, and neighbor conditions to evaluate local adaptation and possible adaptive response of four Eastern Mediterranean annual plant species to climate change. The effect of site on plant performance was negligible, but soil origin had a strong effect on fecundity, most likely due to differential water retaining ability. Competition by neighbors strongly reduced fitness. We separated the effects of the abiotic and biotic soil properties on plant performance by repeating the field experiment in a greenhouse under homogenous environmental conditions and including a soil biota manipulation treatment. As in the field, plant performance differed among soil origins and neighbor treatments. Moreover, we found plant species-specific responses to soil biota that may be best explained by the differential sensitivity to negative and positive soil biota effects. Overall, under the conditions of our experiment with two contrasting sites, biotic interactions had a strong effect on plant fitness that interacted with and eventually overrode climate. Because climate and biotic interactions covary, reciprocal transplants and climate gradient studies should consider soil biotic interactions and abiotic conditions when evaluating climate change effects on plant performance.

Interactive effects of herbivory and competition intensity determine invasive plant performance.

Science.gov (United States)

Huang, Wei; Carrillo, Juli; Ding, Jianqing; Siemann, Evan

2012-10-01

Herbivory can reduce plant fitness, and its effects can be increased by competition. Though numerous studies have examined the joint effects of herbivores and competitors on plant performance, these interactive effects are seldom considered in the context of plant invasions. Here, we examined variation in plant performance within a competitive environment in response to both specialist and generalist herbivores using Chinese tallow as a model species. We combined tallow plants from native and invasive populations to form all possible pairwise combinations, and designated invasive populations as stronger neighbours and native populations as weaker neighbours. We found that when no herbivory was imposed, invasive populations always had higher total biomass than natives, regardless of their neighbours, which is consistent with our assumption of increased competitive ability. Defoliation by either generalist or specialist herbivores suppressed plant growth but the effects of specialists were generally stronger for invasive populations. Invasive populations had their lowest biomass when fed upon by specialists while simultaneously competing with stronger neighbours. The root/shoot ratios of invasive populations were lower than those of native populations under almost all conditions, and invasive plants were taller than native plants overall, especially when herbivores were present, suggesting that invasive populations may adopt an "aboveground first" strategy to cope with herbivory and competition. These results suggest that release from herbivores, especially specialists, improves an invader's performance and helps to increase its competitive ability. Therefore, increasing interspecific competition intensity by planting a stronger neighbour while simultaneously releasing a specialist herbivore may be an especially effective method of managing invasive plants.

Measuring competition in plant communities where it is difficult to distinguish individual plants

DEFF Research Database (Denmark)

Damgaard, Christian

2011-01-01

A novel method for measuring plant-plant interactions in undisturbed semi-natural and natural plant communities where it is difficult to distinguish individual plants is discussed. It is assumed that the ecological success of the different plant species in the plant community may be adequately...... measured by plant cover and vertical density (a measure that is correlated to the 3-dimensional space occupancy and biomass). Both plant cover and vertical density are measured in a standard pin-point analysis in the beginning and at the end of the growing season. In the outlined competition model....... The method allows direct measurements of the competitive effects of neighbouringzplants on plant performance and the estimation of parameters that describe the ecological processes of plantplant interactions during the growing season as well as the process of survival and recruitment between growing seasons...

Reactive Oxygen Species Generation-Scavenging and Signaling during Plant-Arbuscular Mycorrhizal and Piriformospora indica Interaction under Stress Condition.

Science.gov (United States)

Nath, Manoj; Bhatt, Deepesh; Prasad, Ram; Gill, Sarvajeet S; Anjum, Naser A; Tuteja, Narendra

2016-01-01

A defined balance between the generation and scavenging of reactive oxygen species (ROS) is essential to utilize ROS as an adaptive defense response of plants under biotic and abiotic stress conditions. Moreover, ROS are not only a major determinant of stress response but also act as signaling molecule that regulates various cellular processes including plant-microbe interaction. In particular, rhizosphere constitutes the biologically dynamic zone for plant-microbe interactions which forms a mutual link leading to reciprocal signaling in both the partners. Among plant-microbe interactions, symbiotic associations of arbuscular mycorrhizal fungi (AMF) and arbuscular mycorrhizal-like fungus especially Piriformospora indica with plants are well known to improve plant growth by alleviating the stress-impacts and consequently enhance the plant fitness. AMF and P. indica colonization mainly enhances ROS-metabolism, maintains ROS-homeostasis, and thereby averts higher ROS-level accrued inhibition in plant cellular processes and plant growth and survival under stressful environments. This article summarizes the major outcomes of the recent reports on the ROS-generation, scavenging and signaling in biotic-abiotic stressed plants with AMF and P. indica colonization. Overall, a detailed exploration of ROS-signature kinetics during plant-AMF/ P. indica interaction can help in designing innovative strategies for improving plant health and productivity under stress conditions.

A global analysis of bidirectional interactions in alpine plant communities shows facilitators experiencing strong reciprocal fitness costs.

Science.gov (United States)

Schöb, Christian; Michalet, Richard; Cavieres, Lohengrin A; Pugnaire, Francisco I; Brooker, Rob W; Butterfield, Bradley J; Cook, Bradley J; Kikvidze, Zaal; Lortie, Christopher J; Xiao, Sa; Al Hayek, Patrick; Anthelme, Fabien; Cranston, Brittany H; García, Mary-Carolina; Le Bagousse-Pinguet, Yoann; Reid, Anya M; le Roux, Peter C; Lingua, Emanuele; Nyakatya, Mawethu J; Touzard, Blaise; Zhao, Liang; Callaway, Ragan M

2014-04-01

Facilitative interactions are defined as positive effects of one species on another, but bidirectional feedbacks may be positive, neutral, or negative. Understanding the bidirectional nature of these interactions is a fundamental prerequisite for the assessment of the potential evolutionary consequences of facilitation. In a global study combining observational and experimental approaches, we quantified the impact of the cover and richness of species associated with alpine cushion plants on reproductive traits of the benefactor cushions. We found a decline in cushion seed production with increasing cover of cushion-associated species, indicating that being a benefactor came at an overall cost. The effect of cushion-associated species was negative for flower density and seed set of cushions, but not for fruit set and seed quality. Richness of cushion-associated species had positive effects on seed density and modulated the effects of their abundance on flower density and fruit set, indicating that the costs and benefits of harboring associated species depend on the composition of the plant assemblage. Our study demonstrates 'parasitic' interactions among plants over a wide range of species and environments in alpine systems, and we consider their implications for the possible selective effects of interactions between benefactor and beneficiary species. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

Uncertainties in soil-plant interactions in advanced models for long-timescale dose assessment

Energy Technology Data Exchange (ETDEWEB)

Klos, R. [Aleksandria Sciences Ltd. (United Kingdom); Limer, L. [Limer Scientific Ltd. (United Kingdom); Perez-Sanchez, D. [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas - CIEMAT (Spain); Xu, S.; Andersson, P. [Swedish Radiation Safty Authority (Sweden)

2014-07-01

looks more closely at the soil-plant interaction in agricultural soils employing a variant of a ten-soil layer, monthly varying model. Results from a simple three-layer representation of the same system allows a comparison of calculated crop concentrations by the two uptake models. Depending on spatio-temporal resolution and conceptual interpretation soil-plant system, results indicate that for weakly and moderately sorbing redox sensitive radionuclides (illustrated here by {sup 79}Se and {sup 129}I respectively) conceptual model uncertainty can be as high as an order of magnitude. Alternative interpretations of contaminant availability and an inverse relationship between soil k{sub d} and availability for uptake further indicate uncertainties of up to one order of magnitude for {sup 79}Se, three for {sup 129}I and as much as four orders of magnitudes for the strongly sorbing {sup 226}Ra. The temporal dynamics of crop inventories suggest a better understanding of soil-plant interactions is required in models for circumstances where prior accumulation is important and short-timescale transients are of concern. The advanced modelling tools employed here offer flexibility. Alternative parameter configurations also allow NORM waste and LLRW as well as HLRW scenarios. Document available in abstract form only. (authors)

Biosurfactants in plant-Pseudomonas interactions and their importance to biocontrol.

Science.gov (United States)

D'aes, Jolien; De Maeyer, Katrien; Pauwelyn, Ellen; Höfte, Monica

2010-06-01

Production of biosurfactants is a common feature in bacteria, and in particular in plant-associated species. These bacteria include many plant beneficial and plant pathogenic Pseudomonas spp., which produce primarily cyclic lipopeptide and rhamnolipid type biosurfactants. Pseudomonas-derived biosurfactants are involved in many important bacterial functions. By modifying surface properties, biosurfactants can influence common traits such as surface motility, biofilm formation and colonization. Biosurfactants can alter the bio-availability of exogenous compounds, such as nutrients, to promote their uptake, and of endogenous metabolites, including phenazine antibiotics, resulting in an enhanced biological activity. Antibiotic activity of biosurfactants towards microbes could play a role in intraspecific competition, self-defence and pathogenesis. In addition, bacterial surfactants can affect plants in different ways, either protecting them from disease, or acting as a toxin in a plant-pathogen interaction. Biosurfactants are involved in the biocontrol activity of an increasing number of Pseudomonas strains. Consequently, further insight into the roles and activities of surfactants produced by bacteria could provide means to optimize the use of biological control as an alternative crop protection strategy. © 2009 Society for Applied Microbiology and Blackwell Publishing Ltd.

Interactive effect of herbivory and competition on the invasive plant Mikania micrantha.

Science.gov (United States)

Li, Junmin; Xiao, Tao; Zhang, Qiong; Dong, Ming

2013-01-01

A considerable number of host-specific biological control agents fail to control invasive plants in the field, and exploring the mechanism underlying this phenomenon is important and helpful for the management of invasive plants. Herbivory and competition are two of the most common biotic stressors encountered by invasive plants in their recipient communities. We predicted that the antagonistic interactive effect between herbivory and competition would weaken the effect of herbivory on invasive plants and result in the failure of herbivory to control invasive plants. To examine this prediction, thus, we conducted an experiment in which both invasive Mikania micrantha and native Coix lacryma-job i were grown together and subjected to herbivory-mimicking defoliation. Both defoliation and competition had significantly negative effects on the growth of the invader. However, the negative effect of 75% respective defoliation on the above- and below-ground biomass of Mikania micrantha was alleviated by presence of Coix lacryma-jobi. The negative effect of competition on the above- and below-ground biomass was equally compensated at 25%, 50% and 100% defoliation and overcompensated at 75% defoliation. The interactive effect was antagonistic and dependent on the defoliation intensity, with the maximum effect at 75% defoliation. The antagonistic interaction between defoliation and competition appears to be able to release the invader from competition, thus facilitating the invasiveness of Mikania, a situation that might make herbivory fail to inhibit the growth of invasive Mikania in the invaded community.

Getting to the Edge: Protein dynamical networks as a new frontier in plant-microbe interactions

Directory of Open Access Journals (Sweden)

Cassandra C Garbutt

2014-06-01

Full Text Available A systems perspective on diverse phenotypes, mechanisms of infection, and responses to environmental stresses can lead to considerable advances in agriculture and medicine. A significant promise of systems biology within plants is the development of disease-resistant crop varieties, which would maximize yield output for food, clothing, building materials and biofuel production. A systems or -omics perspective frames the next frontier in the search for enhanced knowledge of plant network biology. The functional understanding of network structure and dynamics s is vital to expanding our knowledge of how the intercellular communication processes are executed. . This review article will systematically discuss various levels of organization of systems biology beginning with the building blocks termed –omes and ending with complex transcriptional and protein-protein interaction networks. We will also highlight the prevailing computational modeling approaches of biological regulatory network dynamics. The latest developments in the -omics approach will be reviewed and discussed to underline and highlight novel technologies and research directions in plant network biology.

Combining Phylogenetic and Occurrence Information for Risk Assessment of Pest and Pathogen Interactions with Host Plants

Directory of Open Access Journals (Sweden)

Ángel L. Robles-Fernández

2017-08-01

Full Text Available Phytosanitary agencies conduct plant biosecurity activities, including early detection of potential introduction pathways, to improve control and eradication of pest and pathogen incursions. For such actions, analytical tools based on solid scientific knowledge regarding plant-pest or pathogen relationships for pest risk assessment are needed. Recent evidence indicating that closely related species share a higher chance of becoming infected or attacked by pests has allowed the identification of taxa with different degrees of vulnerability. Here, we use information readily available online about pest-host interactions and their geographic distributions, in combination with host phylogenetic reconstructions, to estimate a pest-host interaction (in some cases infection index in geographic space as a more comprehensive, spatially explicit tool for risk assessment. We demonstrate this protocol using phylogenetic relationships for 20 beetle species and 235 host plant genera: first, we estimate the probability of a host sharing pests, and second, we project the index in geographic space. Overall, the predictions allow identification of the pest-host interaction type (e.g., generalist or specialist, which is largely determined by both host range and phylogenetic constraints. Furthermore, the results can be valuable in terms of identifying hotspots where pests and vulnerable hosts interact. This knowledge is useful for anticipating biological invasions or spreading of disease. We suggest that our understanding of biotic interactions will improve after combining information from multiple dimensions of biodiversity at multiple scales (e.g., phylogenetic signal and host-vector-pathogen geographic distribution.

Effect of the structure of gallic acid and its derivatives on their interaction with plant ferritin.

Science.gov (United States)

Wang, Qunqun; Zhou, Kai; Ning, Yong; Zhao, Guanghua

2016-12-15

Gallic acid and its derivatives co-exist with protein components in foodstuffs, but there is few report on their interaction with proteins. On the other hand, plant ferritin represents not only a novel class of iron supplement, but also a new nanocarrier for encapsulation of bioactive nutrients. However, plant ferritin is easy to be degraded by pepsin in the stomach, thereby limiting its application. Herein, we investigated the interaction of gallic acid and its derivatives with recombinant soybean seed H-2 ferritin (rH-2). We found that these phenolic acids interacted with rH-2 in a structure-dependent manner; namely, gallic acid (GA), methyl gallate (MEGA) and propyl gallate (PG) having three HO groups can bind to rH-2, while their analogues with two HO groups cannot. Consequently, such binding largely inhibited ferritin degradation by pepsin. These findings advance our understanding of the relationship between the structure and function of phenolic acids. Copyright © 2016 Elsevier Ltd. All rights reserved.

Late Palaeozoic plants.

Science.gov (United States)

Feng, Zhuo

2017-09-11

Land plants are one of the major constituents of terrestrial ecosystems on Earth, and play an irreplaceable role in human activities today. If we are to understand the extant plants, it is imperative that we have some understanding of the fossil plants from the deep geological past, particularly those that occurred during their early evolutionary history, in the late Palaeozoic. Copyright © 2017 Elsevier Ltd. All rights reserved.

The plant microbiome explored: implications for experimental botany

Energy Technology Data Exchange (ETDEWEB)

Berg, Gabriele; Rybakova, Daria; Grube, Martin; Köberl, Martina

2015-11-07

The importance of microbial root inhabitants for plant growth and health was recognized as early as 100 years ago. Recent insights reveal a close symbiotic relationship between plants and their associated microorganisms, and high structural and functional diversity within plant microbiomes. Plants provide microbial communities with specific habitats, which can be broadly categorized as the rhizosphere, phyllosphere, and endosphere. Plant-associated microbes interact with their host in essential functional contexts. They can stimulate germination and growth, help plants fend off disease, promote stress resistance, and influence plant fitness. Therefore, plants have to be considered as metaorganisms within which the associated microbes usually outnumber the cells belonging to the plant host. The structure of the plant microbiome is determined by biotic and abiotic factors but follows ecological rules. Metaorganisms are coevolved species assemblages. The metabolism and morphology of plants and their microbiota are intensively connected with each other, and the interplay of both maintains the functioning and fitness of the holobiont. Our study of the current literature shows that analysis of plant microbiome data has brought about a paradigm shift in our understanding of the diverse structure and functioning of the plant microbiome with respect to the following: (i) the high interplay of bacteria, archaea, fungi, and protists; (ii) the high specificity even at cultivar level; (iii) the vertical transmission of core microbiomes; (iv) the extraordinary function of endophytes; and (v) several unexpected functions and metabolic interactions. The plant microbiome should be recognized as an additional factor in experimental botany and breeding strategies.

Specific interactions between arbuscular mycorrhizal fungi and plant growth-promoting bacteria--as revealed by different combinations

Energy Technology Data Exchange (ETDEWEB)

Jaderlund, Lotta; Arthurson, Veronica; Granhall, Ulf; Jansson, Janet K.

2008-05-15

The interactions between two plant growth promoting rhizobacteria (PGPR), Pseudomonas fluorescens SBW25 and Paenibacillus brasilensis PB177, two arbuscular mycorrhizal (AM) fungi (Glomus mosseae and G. intraradices) and one pathogenic fungus (Microdochium nivale) were investigated on winter wheat (Triticum aestivum cultivar Tarso) in a greenhouse trial. PB177, but not SBW25, had strong inhibitory effects on M. nivale in dual culture plate assays. The results from the greenhouse experiment show very specific interactions; e.g. the two AM fungi react differently when interacting with the same bacteria on plants. G. intraradices (single inoculation or together with SBW25) increased plant dry weight on M. nivale infested plants, suggesting that the pathogenic fungus is counteracted by G. intraradices, but PB177 inhibited this positive effect. This is an example of two completely different reactions between the same AM fungus and two species of bacteria, previously known to enhance plant growth and inhibit pathogens. When searching for plant growth promoting microorganisms it is therefore important to test for the most suitable combination of plant, bacteria and fungi in order to get satisfactory plant growth benefits.

Troublesome toxins: time to re-think plant-herbivore interactions in vertebrate ecology

Directory of Open Access Journals (Sweden)

Feng Zhilan

2009-02-01

Full Text Available Abstract Earlier models of plant-herbivore interactions relied on forms of functional response that related rates of ingestion by herbivores to mechanical or physical attributes such as bite size and rate. These models fail to predict a growing number of findings that implicate chemical toxins as important determinants of plant-herbivore dynamics. Specifically, considerable evidence suggests that toxins set upper limits on food intake for many species of herbivorous vertebrates. Herbivores feeding on toxin-containing plants must avoid saturating their detoxification systems, which often occurs before ingestion rates are limited by mechanical handling of food items. In light of the importance of plant toxins, a new approach is needed to link herbivores to their food base. We discuss necessary features of such an approach, note recent advances in herbivore functional response models that incorporate effects of plant toxins, and mention predictions that are consistent with observations in natural systems. Future ecological studies will need to address explicitly the importance of plant toxins in shaping plant and herbivore communities.

Interaction of historical and nonhistorical disturbances maintains native plant communities.

Science.gov (United States)

Davies, K W; Svejcar, T J; Bates, J D

2009-09-01

Historical disturbance regimes are often considered a critical element in maintaining native plant communities. However, the response of plant communities to disturbance may be fundamentally altered as a consequence of invasive plants, climate change, or prior disturbances. The appropriateness of historical disturbance patterns under modern conditions and the interactions among disturbances are issues that ecologists must address to protect and restore native plant communities. We evaluated the response of Artemisia tridentata ssp. wyomingensis (Beetle & A. Young) S.L. Welsh plant communities to their historical disturbance regime compared to other disturbance regimes. The historical disturbance regime of these plant communities was periodic fires with minimal grazing by large herbivores. We also investigated the influence of prior disturbance (grazing) on the response of these communities to subsequent disturbance (burning). Treatments were: (1) ungrazed (livestock grazing excluded since 1936) and unburned, (2) grazed and unburned, (3) ungrazed and burned (burned in 1993), and (4) grazed and burned. The ungrazed-burned treatment emulated the historical disturbance regime. Vegetation cover, density, and biomass production were measured the 12th, 13th, and 14th year post-burning. Prior to burning the presence of Bromus tectorum L., an exotic annual grass, was minimal (resilience to more severe disturbances. Modern deviations from historical conditions can alter ecosystem response to disturbances, thus restoring the historical disturbance regime may not be an appropriate strategy for all ecosystems.

Unraveling the plant microbiome: looking back and future perspectives

Directory of Open Access Journals (Sweden)

Gabriele eBerg

2014-06-01

Full Text Available Most eukaryotes develop close interactions with microorganisms that are essential for their performance and survival. Thus, eukaryotes and prokaryotes in nature can be considered as meta-organisms or holobionts. Consequently, microorganisms that colonize different plant compartments contain the plant’s second genome. In this respect, many studies in the last decades have shown that plant-microbe interactions are not only crucial in understanding plant growth and health, but also for sustainable crop production in a changing world. This mini-review acting as editorial presents retrospectives and future perspectives for plant microbiome studies as well as information gaps in this emerging research field. In addition, the contribution of this research topic to the solution of various issues is discussed.

Contrasting effects of land use intensity and exotic host plants on the specialization of interactions in plant-herbivore networks.

Science.gov (United States)

de Araújo, Walter Santos; Vieira, Marcos Costa; Lewinsohn, Thomas M; Almeida-Neto, Mário

2015-01-01

Human land use tends to decrease the diversity of native plant species and facilitate the invasion and establishment of exotic ones. Such changes in land use and plant community composition usually have negative impacts on the assemblages of native herbivorous insects. Highly specialized herbivores are expected to be especially sensitive to land use intensification and the presence of exotic plant species because they are neither capable of consuming alternative plant species of the native flora nor exotic plant species. Therefore, higher levels of land use intensity might reduce the proportion of highly specialized herbivores, which ultimately would lead to changes in the specialization of interactions in plant-herbivore networks. This study investigates the community-wide effects of land use intensity on the degree of specialization of 72 plant-herbivore networks, including effects mediated by the increase in the proportion of exotic plant species. Contrary to our expectation, the net effect of land use intensity on network specialization was positive. However, this positive effect of land use intensity was partially canceled by an opposite effect of the proportion of exotic plant species on network specialization. When we analyzed networks composed exclusively of endophagous herbivores separately from those composed exclusively of exophagous herbivores, we found that only endophages showed a consistent change in network specialization at higher land use levels. Altogether, these results indicate that land use intensity is an important ecological driver of network specialization, by way of reducing the local host range of herbivore guilds with highly specialized feeding habits. However, because the effect of land use intensity is offset by an opposite effect owing to the proportion of exotic host species, the net effect of land use in a given herbivore assemblage will likely depend on the extent of the replacement of native host species with exotic ones.

Herbivore-plant interactions: mixed-function oxidases and secondary plant substances.

Science.gov (United States)

Brattsten, L B; Wilkinson, C F; Eisner, T

1977-06-17

The mixed-function oxidases of a polyphagous insect larva (the southern armyworm, Spodoptera eridania) were found to be induced by a diversity of secondary plant substances. The induction proceeds rapidly and in response to a small quantity of secondary substance. Following induction, the larva is less susceptible to dietary poisoning. It is argued that mixed-function oxidases play a major role in protecting herbivores against chemical stress from secondary plant substances.

Interaction of a plant pseudo-response regulator with a calmodulin-like protein

International Nuclear Information System (INIS)

Perochon, Alexandre; Dieterle, Stefan; Pouzet, Cecile; Aldon, Didier; Galaud, Jean-Philippe; Ranty, Benoit

2010-01-01

Research highlights: → The pseudo-response regulator PRR2 specifically binds CML9, a calmodulin-like protein → The interaction is confirmed in plant cell nuclei → The interaction requires an intact PRR2 protein. -- Abstract: Calmodulin (CaM) plays a crucial role in the regulation of diverse cellular processes by modulating the activities of numerous target proteins. Plants possess an extended CaM family including numerous CaM-like proteins (CMLs), most of which appear to be unique to plants. We previously demonstrated a role for CML9 in abiotic stress tolerance and seed germination in Arabidopsis thaliana. We report here the isolation of PRR2, a pseudo-response regulator as a CML9 interacting protein by screening an expression library prepared from Arabidopsis seedlings with CML9 as bait in a yeast two-hybrid system. PRR2 is similar to the response regulators of the two-component system, but lacks the invariant residue required for phosphorylation by which response regulators switch their output response, suggesting the existence of alternative regulatory mechanisms. PRR2 was found to bind CML9 and closely related CMLs but not a canonical CaM. Mapping analyses indicate that an almost complete form of PRR2 is required for interaction with CML9, suggesting a recognition mode different from the classical CaM-target peptide complex. PRR2 contains several features that are typical of transcription factors, including a GARP DNA recognition domain, a Pro-rich region and a Golden C-terminal box. PRR2 and CML9 as fusion proteins with fluorescent tags co-localized in the nucleus of plant cells, and their interaction in the nuclear compartment was validated in planta by using a fluorophore-tagged protein interaction assay. These findings suggest that binding of PRR2 to CML9 may be an important mechanism to modulate the physiological role of this transcription factor in plants.

Interaction of a plant pseudo-response regulator with a calmodulin-like protein

Energy Technology Data Exchange (ETDEWEB)

Perochon, Alexandre; Dieterle, Stefan; Pouzet, Cecile; Aldon, Didier; Galaud, Jean-Philippe [UMR 5546 CNRS/Universite Toulouse 3, Pole de Biotechnologie vegetale, BP 42617 Auzeville, 31326 Castanet-Tolosan cedex (France); Ranty, Benoit, E-mail: ranty@scsv.ups-tlse.fr [UMR 5546 CNRS/Universite Toulouse 3, Pole de Biotechnologie vegetale, BP 42617 Auzeville, 31326 Castanet-Tolosan cedex (France)

2010-08-06

Research highlights: {yields} The pseudo-response regulator PRR2 specifically binds CML9, a calmodulin-like protein {yields} The interaction is confirmed in plant cell nuclei {yields} The interaction requires an intact PRR2 protein. -- Abstract: Calmodulin (CaM) plays a crucial role in the regulation of diverse cellular processes by modulating the activities of numerous target proteins. Plants possess an extended CaM family including numerous CaM-like proteins (CMLs), most of which appear to be unique to plants. We previously demonstrated a role for CML9 in abiotic stress tolerance and seed germination in Arabidopsis thaliana. We report here the isolation of PRR2, a pseudo-response regulator as a CML9 interacting protein by screening an expression library prepared from Arabidopsis seedlings with CML9 as bait in a yeast two-hybrid system. PRR2 is similar to the response regulators of the two-component system, but lacks the invariant residue required for phosphorylation by which response regulators switch their output response, suggesting the existence of alternative regulatory mechanisms. PRR2 was found to bind CML9 and closely related CMLs but not a canonical CaM. Mapping analyses indicate that an almost complete form of PRR2 is required for interaction with CML9, suggesting a recognition mode different from the classical CaM-target peptide complex. PRR2 contains several features that are typical of transcription factors, including a GARP DNA recognition domain, a Pro-rich region and a Golden C-terminal box. PRR2 and CML9 as fusion proteins with fluorescent tags co-localized in the nucleus of plant cells, and their interaction in the nuclear compartment was validated in planta by using a fluorophore-tagged protein interaction assay. These findings suggest that binding of PRR2 to CML9 may be an important mechanism to modulate the physiological role of this transcription factor in plants.

Proximal Sensing of Plant-Pathogen Interactions in Spring Barley with Three Fluorescence Techniques

Directory of Open Access Journals (Sweden)

Georg Leufen

2014-06-01

Full Text Available In the last years fluorescence spectroscopy has come to be viewed as an essential approach in key research fields of applied plant sciences. However, the quantity and particularly the quality of information produced by different equipment might vary considerably. In this study we investigate the potential of three optical devices for the proximal sensing of plant-pathogen interactions in four genotypes of spring barley. For this purpose, the fluorescence lifetime, the image-resolved multispectral fluorescence and selected indices of a portable multiparametric fluorescence device were recorded at 3, 6, and 9 days after inoculation (dai from healthy leaves as well as from leaves inoculated with powdery mildew (Blumeria graminis or leaf rust (Puccinia hordei. Genotype-specific responses to pathogen infections were revealed already at 3 dai by higher fluorescence mean lifetimes in the spectral range from 410 to 560 nm in the less susceptible varieties. Noticeable pathogen-induced modifications were also revealed by the ‘Blue-to-Far-Red Fluorescence Ratio’ and the ‘Simple Fluorescence Ratio’. Particularly in the susceptible varieties the differences became more evident in the time-course of the experiment i.e., following the pathogen development. The relevance of the blue and green fluorescence to exploit the plant-pathogen interaction was demonstrated by the multispectral fluorescence imaging system. As shown, mildewed leaves were characterized by exceptionally high blue fluorescence, contrasting the values observed in rust inoculated leaves. Further, we confirm that the intensity of green fluorescence depends on the pathogen infection and the stage of disease development; this information might allow a differentiation of both diseases. Moreover, our results demonstrate that the detection area might influence the quality of the information, although it had a minor impact only in the current study. Finally, we highlight the relevance of

The Multiple Impacts of Tropical Forest Fragmentation on Arthropod Biodiversity and on their Patterns of Interactions with Host Plants.

Science.gov (United States)

Benítez-Malvido, Julieta; Dáttilo, Wesley; Martínez-Falcón, Ana Paola; Durán-Barrón, César; Valenzuela, Jorge; López, Sara; Lombera, Rafael

2016-01-01

Tropical rain forest fragmentation affects biotic interactions in distinct ways. Little is known, however, about how fragmentation affects animal trophic guilds and their patterns of interactions with host plants. In this study, we analyzed changes in biotic interactions in forest fragments by using a multitrophic approach. For this, we classified arthropods associated with Heliconia aurantiaca herbs into broad trophic guilds (omnivores, herbivores and predators) and assessed the topological structure of intrapopulation plant-arthropod networks in fragments and continuous forests. Habitat type influenced arthropod species abundance, diversity and composition with greater abundance in fragments but greater diversity in continuous forest. According to trophic guilds, coleopteran herbivores were more abundant in continuous forest and overall omnivores in fragments. Continuous forest showed a greater diversity of interactions than fragments. Only in fragments, however, did the arthropod community associated with H aurantiaca show a nested structure, suggesting novel and/or opportunistic host-arthropod associations. Plants, omnivores and predators contributed more to nestedness than herbivores. Therefore, Heliconia-arthropod network properties do not appear to be maintained in fragments mainly caused by the decrease of herbivores. Our study contributes to the understanding of the impact of fragmentation on the structure and dynamics of multitrophic arthropod communities associated with a particular plant species of the highly biodiverse tropical forests. Nevertheless, further replication of study sites is needed to strengthen the conclusion that forest fragmentation negatively affects arthropod assemblages.

Plant walkdown

International Nuclear Information System (INIS)

Kostov, M.

2000-01-01

This report covers the following: preparatory steps for performing plant walk-down; the objective of the first plant walk-down; plant walk-down procedures; earthquake screening evaluation; walk-down documentation; second plant walk-down. The following objectives concerning the plant walk-down(s) were achieved. The plant system configuration is verified in order to proceed with event tree and fault tree analyses. Systems interactions, other types of dependencies or plant unique features are identified. he safety related components that are judged to generically possess high capacities (i.e., larger than the earthquake review level) have been verified to contain no weaknesses. Further analyses needed to establish the capacities of remaining safety-related components are identified and necessary field data are obtained. Information on components is obtained to assist in HCLPF (fragility) evaluation and peer review of the seismic margin study

The potential of plant viruses to promote genotypic diversity via genotype x environment interactions

DEFF Research Database (Denmark)

van Mölken, Tamara; Stuefer, Josef F.

2011-01-01

† Background and Aims Genotype by environment (G × E) interactions are important for the long-term persistence of plant species in heterogeneous environments. It has often been suggested that disease is a key factor for the maintenance of genotypic diversity in plant populations. However, empirical...... and the G × E interactions were examined with respect to genotypespecific plant responses to WClMV infection. Thus, the environment is defined as the presence or absence of the virus. † Key Results WClMV had a negative effect on plant performance as shown by a decrease in biomass and number of ramets...... evidence for this contention is scarce. Here virus infection is proposed as a possible candidate for maintaining genotypic diversity in their host plants. † Methods The effects of White clover mosaic virus (WClMV) on the performance and development of different Trifolium repens genotypes were analysed...

Interspecific Plant Interactions Reflected in Soil Bacterial Community Structure and Nitrogen Cycling in Primary Succession

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Joseph E. Knelman

2018-02-01

Full Text Available Past research demonstrating the importance plant–microbe interactions as drivers of ecosystem succession has focused on how plants condition soil microbial communities, impacting subsequent plant performance and plant community assembly. These studies, however, largely treat microbial communities as a black box. In this study, we sought to examine how emblematic shifts from early successional Alnus viridus ssp. sinuata (Sitka alder to late successional Picea sitchensis (Sitka spruce in primary succession may be reflected in specific belowground changes in bacterial community structure and nitrogen cycling related to the interaction of these two plants. We examined early successional alder-conditioned soils in a glacial forefield to delineate how alders alter the soil microbial community with increasing dominance. Further, we assessed the impact of late-successional spruce plants on these early successional alder-conditioned microbiomes and related nitrogen cycling through a leachate addition microcosm experiment. We show how increasingly abundant alder select for particular bacterial taxa. Additionally, we found that spruce leachate significantly alters the composition of these microbial communities in large part by driving declines in taxa that are enriched by alder, including bacterial symbionts. We found these effects to be spruce specific, beyond a general leachate effect. Our work also demonstrates a unique influence of spruce on ammonium availability. Such insights bolster theory relating the importance of plant–microbe interactions with late-successional plants and interspecific plant interactions more generally.

Understanding transfer modes of radionuclides to plants

International Nuclear Information System (INIS)

Hurtevent, P.

2010-01-01

This article briefly comments recent works performed by the IRSN in order to better quantify the transfer of radionuclides from the environment to plants. Three major processes have been studied: root transfer or uptake, translocation, and organic matter recycling (or contamination recycling). The first one depends on the plant and on the soil where it grows. As far as translocation is concerned, the aerial contamination penetrates the plant through the leaves. The third one occurs when broken branches and leaves which have been contaminated, fall on the ground. Some measurements performed in forests near Chernobyl are evoked

Buzz in Paris: flower production and plant-pollinator interactions in plants from contrasted urban and rural origins.

Science.gov (United States)

Desaegher, James; Nadot, Sophie; Dajoz, Isabelle; Colas, Bruno

2017-12-01

Urbanisation, associated with habitat fragmentation, affects pollinator communities and insect foraging behaviour. These biotic changes are likely to select for modified traits in insect-pollinated plants from urban populations compared to rural populations. To test this hypothesis, we conducted an experiment involving four plant species commonly found in both urban and rural landscapes of the Île-de-France region (France): Cymbalaria muralis, Geranium robertianum, Geum urbanum and Prunella vulgaris. The four species were grown in four urban and four rural experimental sites in 2015. For each species and each experimental site, plants were grown from seeds collected in five urban and five rural locations. During flowering, we observed flower production and insect-flower interactions during 14 weeks and tested for the effects of experimental site location and plant origin on flower production and on the number of floral visits. The study species had various flower morphology and hence were visited by different floral visitors. The effect of experimental sites and seed origin also varied among study species. We found that (1) insect visits on P. vulgaris were more frequent in rural than in urban sites; (2) for C. muralis, the slope relating the number of pollinator visits to the number of flowers per individual was steeper in urban versus rural sites, suggesting a greater benefit in allocating resources to flower production in urban conditions; (3) as a likely consequence, C. muralis tended to produce more flowers in plants from urban versus rural origin.