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Sample records for roots enables plants

  1. GLO-Roots: an imaging platform enabling multidimensional characterization of soil-grown root systems

    Science.gov (United States)

    Rellán-Álvarez, Rubén; Lobet, Guillaume; Lindner, Heike; Pradier, Pierre-Luc; Sebastian, Jose; Yee, Muh-Ching; Geng, Yu; Trontin, Charlotte; LaRue, Therese; Schrager-Lavelle, Amanda; Haney, Cara H; Nieu, Rita; Maloof, Julin; Vogel, John P; Dinneny, José R

    2015-01-01

    Root systems develop different root types that individually sense cues from their local environment and integrate this information with systemic signals. This complex multi-dimensional amalgam of inputs enables continuous adjustment of root growth rates, direction, and metabolic activity that define a dynamic physical network. Current methods for analyzing root biology balance physiological relevance with imaging capability. To bridge this divide, we developed an integrated-imaging system called Growth and Luminescence Observatory for Roots (GLO-Roots) that uses luminescence-based reporters to enable studies of root architecture and gene expression patterns in soil-grown, light-shielded roots. We have developed image analysis algorithms that allow the spatial integration of soil properties, gene expression, and root system architecture traits. We propose GLO-Roots as a system that has great utility in presenting environmental stimuli to roots in ways that evoke natural adaptive responses and in providing tools for studying the multi-dimensional nature of such processes. DOI: http://dx.doi.org/10.7554/eLife.07597.001 PMID:26287479

  2. Diversification of Root Hair Development Genes in Vascular Plants.

    Science.gov (United States)

    Huang, Ling; Shi, Xinhui; Wang, Wenjia; Ryu, Kook Hui; Schiefelbein, John

    2017-07-01

    The molecular genetic program for root hair development has been studied intensively in Arabidopsis ( Arabidopsis thaliana ). To understand the extent to which this program might operate in other plants, we conducted a large-scale comparative analysis of root hair development genes from diverse vascular plants, including eudicots, monocots, and a lycophyte. Combining phylogenetics and transcriptomics, we discovered conservation of a core set of root hair genes across all vascular plants, which may derive from an ancient program for unidirectional cell growth coopted for root hair development during vascular plant evolution. Interestingly, we also discovered preferential diversification in the structure and expression of root hair development genes, relative to other root hair- and root-expressed genes, among these species. These differences enabled the definition of sets of genes and gene functions that were acquired or lost in specific lineages during vascular plant evolution. In particular, we found substantial divergence in the structure and expression of genes used for root hair patterning, suggesting that the Arabidopsis transcriptional regulatory mechanism is not shared by other species. To our knowledge, this study provides the first comprehensive view of gene expression in a single plant cell type across multiple species. © 2017 American Society of Plant Biologists. All Rights Reserved.

  3. Root morphology of Ni-treated plants

    International Nuclear Information System (INIS)

    Leskova, A.; Fargasova, A.; Giehl, R. F. H.; Wiren, N. von

    2015-01-01

    Plant roots are very important organs in terms of nutrient and water acquisition but they also serve as anchorages for the aboveground parts of the plants. The roots display extraordinary plasticity towards stress conditions as a result of integration of environmental cues into the developmental processes of the roots. Our aim was to investigate the root morphology of Arabidopsis thaliana plants exposed to a particular stress condition, excess Ni supply. We aimed to find out which cellular processes - cell division, elongation and differentiation are affected by Ni, thereby explaining the seen root phenotype. Our results reveal that a distinct sensitivity exists between roots of different order and interference with various cellular processes is responsible for the effects of Ni on roots. We also show that Ni-treated roots have several auxin-related phenotypes. (authors)

  4. Nutrition and adventitious rooting in woody plants

    Directory of Open Access Journals (Sweden)

    Fernanda Bortolanza Pereira

    2016-09-01

    Full Text Available Vegetative propagation success of commercial genotypes via cutting techniques is related to several factors, including nutritional status of mother trees and of propagation material. The nutritional status determines the carbohydrate quantities, auxins and other compounds of plant essential metabolism for root initiation and development. Each nutrient has specific functions in plant, acting on plant structure or on plant physiology. Although the importance of mineral nutrition for success of woody plants vegetative propagation and its relation with adventitious rooting is recognized, the role of some mineral nutrients is still unknown. Due to biochemical and physiological complexity of adventitious rooting process, there are few researches to determine de role of nutrients on development of adventitious roots. This review intends to explore de state of the art about the effect of mineral nutrition on adventitious rooting of woody plants.

  5. Apoplastic interactions between plants and plant root intruders

    Directory of Open Access Journals (Sweden)

    Kanako eMitsumasu

    2015-08-01

    Full Text Available Numerous pathogenic or parasitic organisms attack plant roots to obtain nutrients, and the apoplast including the plant cell wall is where the plant cell meets such organisms. Root-parasitic angiosperms and nematodes are two distinct types of plant root parasites but share some common features in their strategies for breaking into plant roots. Striga and Orobanche are obligate root parasitic angiosperms that cause devastating agricultural problems worldwide. Parasitic plants form an invasion organ called a haustorium, where plant cell wall degrading enzymes (PCWDEs are highly expressed. Plant-parasitic nematodes are another type of agriculturally important plant root parasite. These nematodes breach the plant cell walls by protruding a sclerotized stylet from which PCWDEs are secreted. Responding to such parasitic invasion, host plants activate their own defense responses against parasites. Endoparasitic nematodes secrete apoplastic effectors to modulate host immune responses and to facilitate the formation of a feeding site. Apoplastic communication between hosts and parasitic plants also contributes to their interaction. Parasitic plant germination stimulants, strigolactones (SLs, are recently identified apoplastic signals that are transmitted over long distances from biosynthetic sites to functioning sites. Here, we discuss recent advances in understanding the importance of apoplastic signals and cell walls for plant-parasite interactions.

  6. Apoplastic interactions between plants and plant root intruders.

    Science.gov (United States)

    Mitsumasu, Kanako; Seto, Yoshiya; Yoshida, Satoko

    2015-01-01

    Numerous pathogenic or parasitic organisms attack plant roots to obtain nutrients, and the apoplast including the plant cell wall is where the plant cell meets such organisms. Root parasitic angiosperms and nematodes are two distinct types of plant root parasites but share some common features in their strategies for breaking into plant roots. Striga and Orobanche are obligate root parasitic angiosperms that cause devastating agricultural problems worldwide. Parasitic plants form an invasion organ called a haustorium, where plant cell wall degrading enzymes (PCWDEs) are highly expressed. Plant-parasitic nematodes are another type of agriculturally important plant root parasite. These nematodes breach the plant cell walls by protruding a sclerotized stylet from which PCWDEs are secreted. Responding to such parasitic invasion, host plants activate their own defense responses against parasites. Endoparasitic nematodes secrete apoplastic effectors to modulate host immune responses and to facilitate the formation of a feeding site. Apoplastic communication between hosts and parasitic plants also contributes to their interaction. Parasitic plant germination stimulants, strigolactones, are recently identified apoplastic signals that are transmitted over long distances from biosynthetic sites to functioning sites. Here, we discuss recent advances in understanding the importance of apoplastic signals and cell walls for plant-parasite interactions.

  7. Hydrologic regulation of plant rooting depth.

    Science.gov (United States)

    Fan, Ying; Miguez-Macho, Gonzalo; Jobbágy, Esteban G; Jackson, Robert B; Otero-Casal, Carlos

    2017-10-03

    Plant rooting depth affects ecosystem resilience to environmental stress such as drought. Deep roots connect deep soil/groundwater to the atmosphere, thus influencing the hydrologic cycle and climate. Deep roots enhance bedrock weathering, thus regulating the long-term carbon cycle. However, we know little about how deep roots go and why. Here, we present a global synthesis of 2,200 root observations of >1,000 species along biotic (life form, genus) and abiotic (precipitation, soil, drainage) gradients. Results reveal strong sensitivities of rooting depth to local soil water profiles determined by precipitation infiltration depth from the top (reflecting climate and soil), and groundwater table depth from below (reflecting topography-driven land drainage). In well-drained uplands, rooting depth follows infiltration depth; in waterlogged lowlands, roots stay shallow, avoiding oxygen stress below the water table; in between, high productivity and drought can send roots many meters down to the groundwater capillary fringe. This framework explains the contrasting rooting depths observed under the same climate for the same species but at distinct topographic positions. We assess the global significance of these hydrologic mechanisms by estimating root water-uptake depths using an inverse model, based on observed productivity and atmosphere, at 30″ (∼1-km) global grids to capture the topography critical to soil hydrology. The resulting patterns of plant rooting depth bear a strong topographic and hydrologic signature at landscape to global scales. They underscore a fundamental plant-water feedback pathway that may be critical to understanding plant-mediated global change.

  8. Hydrologic regulation of plant rooting depth

    Science.gov (United States)

    Fan, Ying; Miguez-Macho, Gonzalo; Jobbágy, Esteban G.; Jackson, Robert B.; Otero-Casal, Carlos

    2017-10-01

    Plant rooting depth affects ecosystem resilience to environmental stress such as drought. Deep roots connect deep soil/groundwater to the atmosphere, thus influencing the hydrologic cycle and climate. Deep roots enhance bedrock weathering, thus regulating the long-term carbon cycle. However, we know little about how deep roots go and why. Here, we present a global synthesis of 2,200 root observations of >1,000 species along biotic (life form, genus) and abiotic (precipitation, soil, drainage) gradients. Results reveal strong sensitivities of rooting depth to local soil water profiles determined by precipitation infiltration depth from the top (reflecting climate and soil), and groundwater table depth from below (reflecting topography-driven land drainage). In well-drained uplands, rooting depth follows infiltration depth; in waterlogged lowlands, roots stay shallow, avoiding oxygen stress below the water table; in between, high productivity and drought can send roots many meters down to the groundwater capillary fringe. This framework explains the contrasting rooting depths observed under the same climate for the same species but at distinct topographic positions. We assess the global significance of these hydrologic mechanisms by estimating root water-uptake depths using an inverse model, based on observed productivity and atmosphere, at 30″ (˜1-km) global grids to capture the topography critical to soil hydrology. The resulting patterns of plant rooting depth bear a strong topographic and hydrologic signature at landscape to global scales. They underscore a fundamental plant-water feedback pathway that may be critical to understanding plant-mediated global change.

  9. Plant responsiveness to root-root communication of stress cues.

    Science.gov (United States)

    Falik, Omer; Mordoch, Yonat; Ben-Natan, Daniel; Vanunu, Miriam; Goldstein, Oron; Novoplansky, Ariel

    2012-07-01

    Phenotypic plasticity is based on the organism's ability to perceive, integrate and respond to multiple signals and cues informative of environmental opportunities and perils. A growing body of evidence demonstrates that plants are able to adapt to imminent threats by perceiving cues emitted from their damaged neighbours. Here, the hypothesis was tested that unstressed plants are able to perceive and respond to stress cues emitted from their drought- and osmotically stressed neighbours and to induce stress responses in additional unstressed plants. Split-root Pisum sativum, Cynodon dactylon, Digitaria sanguinalis and Stenotaphrum secundatum plants were subjected to osmotic stress or drought while sharing one of their rooting volumes with an unstressed neighbour, which in turn shared its other rooting volume with additional unstressed neighbours. Following the kinetics of stomatal aperture allowed testing for stress responses in both the stressed plants and their unstressed neighbours. In both P. sativum plants and the three wild clonal grasses, infliction of osmotic stress or drought caused stomatal closure in both the stressed plants and in their unstressed neighbours. While both continuous osmotic stress and drought induced prolonged stomatal closure and limited acclimation in stressed plants, their unstressed neighbours habituated to the stress cues and opened their stomata 3-24 h after the beginning of stress induction. The results demonstrate a novel type of plant communication, by which plants might be able to increase their readiness to probable future osmotic and drought stresses. Further work is underway to decipher the identity and mode of operation of the involved communication vectors and to assess the potential ecological costs and benefits of emitting and perceiving drought and osmotic stress cues under various ecological scenarios.

  10. Flavins secreted by roots of iron-deficient Beta vulgaris enable mining of ferric oxide via reductive mechanisms.

    Science.gov (United States)

    Sisó-Terraza, Patricia; Rios, Juan J; Abadía, Javier; Abadía, Anunciación; Álvarez-Fernández, Ana

    2016-01-01

    Iron (Fe) is abundant in soils but generally poorly soluble. Plants, with the exception of Graminaceae, take up Fe using an Fe(III)-chelate reductase coupled to an Fe(II) transporter. Whether or not nongraminaceous species can convert scarcely soluble Fe(III) forms into soluble Fe forms has deserved little attention so far. We have used Beta vulgaris, one among the many species whose roots secrete flavins upon Fe deficiency, to study whether or not flavins are involved in Fe acquisition. Flavins secreted by Fe-deficient plants were removed from the nutrient solution, and plants were compared with Fe-sufficient plants and Fe-deficient plants without flavin removal. Solubilization of a scarcely soluble Fe(III)-oxide was assessed in the presence or absence of flavins, NADH (nicotinamide adenine dinucleotide, reduced form) or plant roots, and an Fe(II) trapping agent. The removal of flavins from the nutrient solution aggravated the Fe deficiency-induced leaf chlorosis. Flavins were able to dissolve an Fe(III)-oxide in the presence of NADH. The addition of extracellular flavins enabled roots of Fe-deficient plants to reductively dissolve an Fe(III)-oxide. We concluded that root-secretion of flavins improves Fe nutrition in B. vulgaris. Flavins allow B. vulgaris roots to mine Fe from Fe(III)-oxides via reductive mechanisms. © 2015 CSIC New Phytologist © 2015 New Phytologist Trust.

  11. A review of the influence of root-associating fungi and root exudates on the success of invasive plants

    Directory of Open Access Journals (Sweden)

    Cindy Bongard

    2012-08-01

    Full Text Available Plant-fungal interactions are essential for understanding the distribution and abundance of plants species. Recently, arbuscular mycorrhizal fungal (AMF partners of non-indigenous invasive plants have been hypothesized to be a critical factor influencing the invasion processes. AMF are known to improve nutrient and moisture uptake, as well as disrupt parasitic and pathogenic microbes in the host plant. Such benefits may enable invaders to establish significant and persistent populations in environments previously dominated by natives. Coupling these findings with studies on invader pathogen-disrupting root exudates is not well documented in the literature describing plant invasion strategies. The interaction effects of altered AMF associations and the impact of invader root exudates would be more relevant than understanding the AMF dynamics or the phytochemistry of successful invaders in isolation, particularly given that AMF and root exudates can have a similar role in pathogen control but function quite differently. One means to achieve this goal is to assess these strategies concurrently by characterizing both the general (mostly pathogens or commensals and AM-specific fungal colonization patterns found in field collected root samples of successful invaders, native plants growing within dense patches of invaders, and native plants growing separately from invaders. In this review I examine the emerging evidence of the ways in which AMF-plant interactions and the production of defensive root exudates provide pathways to invasive plant establishment and expansion, and conclude that interaction studies must be pursued to achieve a more comprehensive understanding of successful plant invasion.

  12. Functional traits and root morphology of alpine plants.

    Science.gov (United States)

    Pohl, Mandy; Stroude, Raphaël; Buttler, Alexandre; Rixen, Christian

    2011-09-01

    Vegetation has long been recognized to protect the soil from erosion. Understanding species differences in root morphology and functional traits is an important step to assess which species and species mixtures may provide erosion control. Furthermore, extending classification of plant functional types towards root traits may be a useful procedure in understanding important root functions. In this study, pioneer data on traits of alpine plant species, i.e. plant height and shoot biomass, root depth, horizontal root spreading, root length, diameter, tensile strength, plant age and root biomass, from a disturbed site in the Swiss Alps are presented. The applicability of three classifications of plant functional types (PFTs), i.e. life form, growth form and root type, was examined for above- and below-ground plant traits. Plant traits differed considerably among species even of the same life form, e.g. in the case of total root length by more than two orders of magnitude. Within the same root diameter, species differed significantly in tensile strength: some species (Geum reptans and Luzula spicata) had roots more than twice as strong as those of other species. Species of different life forms provided different root functions (e.g. root depth and horizontal root spreading) that may be important for soil physical processes. All classifications of PFTs were helpful to categorize plant traits; however, the PFTs according to root type explained total root length far better than the other PFTs. The results of the study illustrate the remarkable differences between root traits of alpine plants, some of which cannot be assessed from simple morphological inspection, e.g. tensile strength. PFT classification based on root traits seems useful to categorize plant traits, even though some patterns are better explained at the individual species level.

  13. Novel scanning procedure enabling the vectorization of entire rhizotron-grown root systems

    Directory of Open Access Journals (Sweden)

    Lobet Guillaume

    2013-01-01

    Full Text Available Abstract This paper presents an original spit-and-combine imaging procedure that enables the complete vectorization of complex root systems grown in rhizotrons. The general principle of the method is to (1 separate the root system into a small number of large pieces to reduce root overlap, (2 scan these pieces one by one, (3 analyze separate images with a root tracing software and (4 combine all tracings into a single vectorized root system. This method generates a rich dataset containing morphological, topological and geometrical information of entire root systems grown in rhizotrons. The utility of the method is illustrated with a detailed architectural analysis of a 20-day old maize root system, coupled with a spatial analysis of water uptake patterns.

  14. Novel scanning procedure enabling the vectorization of entire rhizotron-grown root systems.

    Science.gov (United States)

    Lobet, Guillaume; Draye, Xavier

    2013-01-04

    : This paper presents an original spit-and-combine imaging procedure that enables the complete vectorization of complex root systems grown in rhizotrons. The general principle of the method is to (1) separate the root system into a small number of large pieces to reduce root overlap, (2) scan these pieces one by one, (3) analyze separate images with a root tracing software and (4) combine all tracings into a single vectorized root system. This method generates a rich dataset containing morphological, topological and geometrical information of entire root systems grown in rhizotrons. The utility of the method is illustrated with a detailed architectural analysis of a 20-day old maize root system, coupled with a spatial analysis of water uptake patterns.

  15. Root Traits and Phenotyping Strategies for Plant Improvement.

    Science.gov (United States)

    Paez-Garcia, Ana; Motes, Christy M; Scheible, Wolf-Rüdiger; Chen, Rujin; Blancaflor, Elison B; Monteros, Maria J

    2015-06-15

    Roots are crucial for nutrient and water acquisition and can be targeted to enhance plant productivity under a broad range of growing conditions. A current challenge for plant breeding is the limited ability to phenotype and select for desirable root characteristics due to their underground location. Plant breeding efforts aimed at modifying root traits can result in novel, more stress-tolerant crops and increased yield by enhancing the capacity of the plant for soil exploration and, thus, water and nutrient acquisition. Available approaches for root phenotyping in laboratory, greenhouse and field encompass simple agar plates to labor-intensive root digging (i.e., shovelomics) and soil boring methods, the construction of underground root observation stations and sophisticated computer-assisted root imaging. Here, we summarize root architectural traits relevant to crop productivity, survey root phenotyping strategies and describe their advantages, limitations and practical value for crop and forage breeding programs.

  16. Root Traits and Phenotyping Strategies for Plant Improvement

    Directory of Open Access Journals (Sweden)

    Ana Paez-Garcia

    2015-06-01

    Full Text Available Roots are crucial for nutrient and water acquisition and can be targeted to enhance plant productivity under a broad range of growing conditions. A current challenge for plant breeding is the limited ability to phenotype and select for desirable root characteristics due to their underground location. Plant breeding efforts aimed at modifying root traits can result in novel, more stress-tolerant crops and increased yield by enhancing the capacity of the plant for soil exploration and, thus, water and nutrient acquisition. Available approaches for root phenotyping in laboratory, greenhouse and field encompass simple agar plates to labor-intensive root digging (i.e., shovelomics and soil boring methods, the construction of underground root observation stations and sophisticated computer-assisted root imaging. Here, we summarize root architectural traits relevant to crop productivity, survey root phenotyping strategies and describe their advantages, limitations and practical value for crop and forage breeding programs.

  17. Root bacterial endophytes alter plant phenotype, but not physiology

    DEFF Research Database (Denmark)

    Henning, Jeremiah A.; Weston, David J.; Pelletier, Dale A.

    2016-01-01

    (root:shoot, biomass production, root and leaf growth rates) and physiological traits (chlorophyll content, net photosynthesis, net photosynthesis at saturating light-Asat, and saturating CO2-Amax). Overall, we found that bacterial root endophyte infection increased root growth rate up to 184% and leaf...... growth rate up to 137% relative to non-inoculated control plants, evidence that plants respond to bacteria by modifying morphology. However, endophyte inoculation had no influence on total plant biomass and photosynthetic traits (net photosynthesis, chlorophyll content). In sum, bacterial inoculation did......Plant traits, such as root and leaf area, influence how plants interact with their environment and the diverse microbiota living within plants can influence plant morphology and physiology. Here, we explored how three bacterial strains isolated from the Populus root microbiome, influenced plant...

  18. A review on the molecular mechanism of plants rooting modulated ...

    African Journals Online (AJOL)

    Phytohormones, especially auxin, played an essential role in regulating roots developments. This review focused on recent advances in the research of plants rooting genomics and proteomics, including auxin biosynthesis, metabolism, transport, and signaling pathway which are involved in modulating plants rooting and ...

  19. Rooting depths of plants relative to biological and environmental factors

    International Nuclear Information System (INIS)

    Foxx, T.S.; Tierney, G.D.; Williams, J.M.

    1984-11-01

    In 1981 to 1982 an extensive bibliographic study was completed to document rooting depths of native plants in the United States. The data base presently contains 1034 citations with approximately 12,000 data elements. In this paper the data were analyzed for rooting depths as related to life form, soil type, geographical region, root type, family, root depth to shoot height ratios, and root depth to root lateral ratios. Average rooting depth and rooting frequencies were determined and related to present low-level waste site maintenance

  20. Root Traits and Phenotyping Strategies for Plant Improvement

    OpenAIRE

    Ana Paez-Garcia; Christy M. Motes; Wolf-Rüdiger Scheible; Rujin Chen; Elison B. Blancaflor; Maria J. Monteros

    2015-01-01

    Roots are crucial for nutrient and water acquisition and can be targeted to enhance plant productivity under a broad range of growing conditions. A current challenge for plant breeding is the limited ability to phenotype and select for desirable root characteristics due to their underground location. Plant breeding efforts aimed at modifying root traits can result in novel, more stress-tolerant crops and increased yield by enhancing the capacity of the plant for soil exploration and, thus, wa...

  1. Root Formation in Ethylene-Insensitive Plants1

    Science.gov (United States)

    Clark, David G.; Gubrium, Erika K.; Barrett, James E.; Nell, Terril A.; Klee, Harry J.

    1999-01-01

    Experiments with ethylene-insensitive tomato (Lycopersicon esculentum) and petunia (Petunia × hybrida) plants were conducted to determine if normal or adventitious root formation is affected by ethylene insensitivity. Ethylene-insensitive Never ripe (NR) tomato plants produced more belowground root mass but fewer aboveground adventitious roots than wild-type Pearson plants. Applied auxin (indole-3-butyric acid) increased adventitious root formation on vegetative stem cuttings of wild-type plants but had little or no effect on rooting of NR plants. Reduced adventitious root formation was also observed in ethylene-insensitive transgenic petunia plants. Applied 1-aminocyclopropane-1-carboxylic acid increased adventitious root formation on vegetative stem cuttings from NR and wild-type plants, but NR cuttings produced fewer adventitious roots than wild-type cuttings. These data suggest that the promotive effect of auxin on adventitious rooting is influenced by ethylene responsiveness. Seedling root growth of tomato in response to mechanical impedance was also influenced by ethylene sensitivity. Ninety-six percent of wild-type seedlings germinated and grown on sand for 7 d grew normal roots into the medium, whereas 47% of NR seedlings displayed elongated taproots, shortened hypocotyls, and did not penetrate the medium. These data indicate that ethylene has a critical role in various responses of roots to environmental stimuli. PMID:10482660

  2. Action of plant root exudates in bioremediations: a review

    Directory of Open Access Journals (Sweden)

    Peter Dundek

    2011-01-01

    Full Text Available This work presents a summary of literature dealing with the use of plant root exudates in bioremediations. Bioremediation using plants (phytoremediation or rhizoremediation and associate rhizosphere to decontaminate polluted soil is a method based on the catabolic potential of root-associated microorganisms, which are supported by the organic substrates released from roots. These substrates are called “root exudates”. Root exudates support metabolism of pollutants-decomposing microorganisms in the rhizosphere, and affect sorption / desorption of pollutants. Awareness of exudation rates is necessary for testing soil decontamination. Commonly, water-soluble root exudates of different plants are studied for their qualitative composition which should be related to total carbon of exuded water-soluble compounds. This paper presents the determined rate of plant root exudation and the amount of root exudates carbon used to form artificial rhizosphere.

  3. Root distribution pattern of Colocasia- 32P plant injection technique

    International Nuclear Information System (INIS)

    Eapen, Suja; Salam, M.A.; Wahid, P.A.

    1995-01-01

    A 32 P plant injection technique was employed to study the variation in the root production and distribution patterns of colocasia var. Cheruchempu grown in the coconut garden and in the open. Root production of colocasia was more with the plants grown in the open compared to the plants grown in the coconut garden. The root distribution pattern of colocasia differed with light environments under which the plants are grown. Colocasia grown in the coconut garden developed a compact root system while that grown in the open condition developed a spreading root system. The root zone comprising 20 cm laterally around the plant and 40 cm vertically from the surface (L 0-20 D 0-40 ) can be considered as the active root zone of colocasia. (author). 9 refs., 4 figs., 1 tab

  4. Fundamental plant biology enabled by the space shuttle.

    Science.gov (United States)

    Paul, Anna-Lisa; Wheeler, Ray M; Levine, Howard G; Ferl, Robert J

    2013-01-01

    The relationship between fundamental plant biology and space biology was especially synergistic in the era of the Space Shuttle. While all terrestrial organisms are influenced by gravity, the impact of gravity as a tropic stimulus in plants has been a topic of formal study for more than a century. And while plants were parts of early space biology payloads, it was not until the advent of the Space Shuttle that the science of plant space biology enjoyed expansion that truly enabled controlled, fundamental experiments that removed gravity from the equation. The Space Shuttle presented a science platform that provided regular science flights with dedicated plant growth hardware and crew trained in inflight plant manipulations. Part of the impetus for plant biology experiments in space was the realization that plants could be important parts of bioregenerative life support on long missions, recycling water, air, and nutrients for the human crew. However, a large part of the impetus was that the Space Shuttle enabled fundamental plant science essentially in a microgravity environment. Experiments during the Space Shuttle era produced key science insights on biological adaptation to spaceflight and especially plant growth and tropisms. In this review, we present an overview of plant science in the Space Shuttle era with an emphasis on experiments dealing with fundamental plant growth in microgravity. This review discusses general conclusions from the study of plant spaceflight biology enabled by the Space Shuttle by providing historical context and reviews of select experiments that exemplify plant space biology science.

  5. Root traits contributing to plant productivity under drought

    Directory of Open Access Journals (Sweden)

    Louise eComas

    2013-11-01

    Full Text Available Geneticists and breeders are positioned to breed plants with root traits that improve productivity under drought. However, a better understanding of root functional traits and how traits are related to whole plant strategies to increase crop productivity under different drought conditions is needed. Root traits associated with maintaining plant productivity under drought include small fine root diameters, long specific root length (SRL, and considerable root length density, especially at depths in soil with available water. In environments with late season water deficits, small xylem diameters in targeted seminal roots save soil water deep in the soil profile for use during crop maturation and result in improved yields. Capacity for deep root growth and large xylem diameters in deep roots may also improve root acquisition of water when ample water at depth is available. Xylem pit anatomy that makes xylem less ‘leaky’ and prone to cavitation warrants further exploration holding promise that such traits may improve plant productivity in water-limited environments without negatively impacting yield under adequate water conditions. Rapid resumption of root growth following soil rewetting may improve plant productivity under episodic drought. Genetic control of many of these traits through breeding appears feasible. Several recent reviews have covered methods for screening root traits but an appreciation for the complexity of root systems (e.g. functional differences between fine and coarse roots needs to be paired with these methods to successfully identify relevant traits for crop improvement. Screening of root traits at early stages in plant development can proxy traits at mature stages but verification is needed on a case by case basis that traits are linked to increased crop productivity under drought. Examples in lesquerella (Physaria and rice (Oryza show approaches to phenotyping of root traits and current understanding of root trait

  6. Sensors Enable Plants to Text Message Farmers

    Science.gov (United States)

    2013-01-01

    Long-term human spaceflight means long-term menu planning. Since every pound of cargo comes with a steep price tag, NASA has long researched technologies and techniques to allow astronauts to grow their own food, both on the journey and in some cases at their destination. Sustainable food technologies designed for space have resulted in spinoffs that improve the nutrition, safety, and durability of food on Earth. There are of course tradeoffs involved in making astronauts part-time farmers. Any time spent tending plants is time that can t be spent elsewhere: collecting data, exploring, performing routine maintenance, or sleeping. And as scarce as time is for astronauts, resources are even more limited. It is highly practical, therefore, to ensure that farming in space is as automated and precise as possible.

  7. Light as stress factor to plant roots - case of root halotropism.

    Science.gov (United States)

    Yokawa, Ken; Fasano, Rossella; Kagenishi, Tomoko; Baluška, František

    2014-01-01

    Despite growing underground, largely in darkness, roots emerge to be very sensitive to light. Recently, several important papers have been published which reveal that plant roots not only express all known light receptors but also that their growth, physiology and adaptive stress responses are light-sensitive. In Arabidopsis, illumination of roots speeds-up root growth via reactive oxygen species-mediated and F-actin dependent process. On the other hand, keeping Arabidopsis roots in darkness alters F-actin distribution, polar localization of PIN proteins as well as polar transport of auxin. Several signaling components activated by phytohormones are overlapping with light-related signaling cascade. We demonstrated that the sensitivity of roots to salinity is altered in the light-grown Arabidopsis roots. Particularly, light-exposed roots are less effective in their salt-avoidance behavior known as root halotropism. Here we discuss these new aspects of light-mediated root behavior from cellular, physiological and evolutionary perspectives.

  8. Plant root absorption and metabolic fate of technetium in plants

    International Nuclear Information System (INIS)

    Cataldo, D.A.; Garland, T.R.; Wildung, R.E.

    1984-10-01

    Root absorption characteristics for the pertechnetate ion (TcO 4 - ) were determined using hydroponically grown soybean seedlings (Glycine max, cv. Williams). Absorption of TcO 4 - was found to be linear with time, sensitive to metabolic inhibitors, and exhibit multiple absorption isotherms over the concentration range 0.02 to 10 μM. The isotherms had calculated K/sub s/ values of 0.09, 8.9, and 54 μM for intact seedlings. The uptake of TcO 4 - (0.25 μM) was inhibited by a fourfold concentration excess of sulfate, phosphate, and selenate, but not by borate, nitrate, tungstate, perrhenate, iodate or vanadate. Kinetic studies demonstrated that sulfate, phosphate, and selenate were competitive inhibitors of TcO 4 - absorption. Once absorbed, Tc was readily transported as TcO 4 - to shoot tissues of soybean and subsequently associated with protein constituents. The chemical fate of Tc in plants varies with plant species. Plants high in nonprotein sulfhydryl compounds (Allium species) exhibited markedly different root/shoot distribution and protein incorporation patterns from species with low sulfur requirements (soybean, alfalfa, mustard). Based on these differences, Tc/S/Se tracer studies were employed to resolve the comparative fate of these probable analogs. 20 references, 5 figures, 5 tables

  9. Scaling root processes based on plant functional traits (Invited)

    Science.gov (United States)

    Eissenstat, D. M.; McCormack, M. L.; Gaines, K.; Adams, T.

    2013-12-01

    There are great challenges to scaling root processes as variation across species and variation of a particular species over different spatial and temporal scales is poorly understood. We have examined tree species variation using multispecies plantings, often referred to by ecologists as 'common gardens'. Choosing species with wide variation in growth rate, root morphology (diameter, branching intensity) and root chemistry (root N and Ca concentration), we found that variation in root lifespan was well correlated with plant functional traits across 12 species. There was also evidence that localized liquid N addition could increase root lifespan and localized water addition diminished root lifespan over untreated controls, with effects strongest in the species of finest root diameter. In an adjacent forest, we have also seen tree species variation in apparent depth of rooting using water isotopes. In particular species of wood anatomy that was ring porous (e.g. oaks) typically had the deepest rooting depth, whereas those that had either diffuse-porous sapwood (maples) or tracheid sapwood (pines) were shallower rooted. These differences in rooting depth were related to sap flux of trees during and immediately after periods of drought. The extent that the patterns observed in central Pennsylvania are modulated by environment or indicative of other plant species will be discussed.

  10. Bacteria from Wheat and Cucurbit Plant Roots Metabolize PAHs and Aromatic Root Exudates: Implications for Rhizodegradation

    DEFF Research Database (Denmark)

    Ely, Cairn S; Smets, Barth F.

    2017-01-01

    The chemical interaction between plants and bacteria in the root zone can lead to soil decontamination. Bacteria which degrade PAHs have been isolated from the rhizospheres of plant species with varied biological traits, however, it is not known what phytochemicals promote contaminant degradation....... One monocot and two dicotyledon plants were grown in PAH-contaminated soil from a manufactured gas plant (MGP) site. A phytotoxicity assay confirmed greater soil decontamination in rhizospheres when compared to bulk soil controls. Bacteria were isolated from plant roots (rhizobacteria) and selected...

  11. Roots, plant production and nutrient use efficiency

    NARCIS (Netherlands)

    Willigen, de P.; Noordwijk, van M.

    1987-01-01

    The role of roots in obtaining high crop production levels as well as a high nutrient use efficiency is discussed. Mathematical models of diffusion and massflow of solutes towards roots are developed for a constant daily uptake requirement. Analytical solutions are given for simple and more

  12. Composite Cucurbita pepo plants with transgenic roots as a tool to study root development.

    Science.gov (United States)

    Ilina, Elena L; Logachov, Anton A; Laplaze, Laurent; Demchenko, Nikolay P; Pawlowski, Katharina; Demchenko, Kirill N

    2012-07-01

    In most plant species, initiation of lateral root primordia occurs above the elongation zone. However, in cucurbits and some other species, lateral root primordia initiation and development takes place in the apical meristem of the parental root. Composite transgenic plants obtained by Agrobacterium rhizogenes-mediated transformation are known as a suitable model to study root development. The aim of the present study was to establish this transformation technique for squash. The auxin-responsive promoter DR5 was cloned into the binary vectors pKGW-RR-MGW and pMDC162-GFP. Incorporation of 5-ethynyl-2'-deoxyuridine (EdU) was used to evaluate the presence of DNA-synthesizing cells in the hypocotyl of squash seedlings to find out whether they were suitable for infection. Two A. rhizogenes strains, R1000 and MSU440, were used. Roots containing the respective constructs were selected based on DsRED1 or green fluorescent protein (GFP) fluorescence, and DR5::Egfp-gusA or DR5::gusA insertion, respectively, was verified by PCR. Distribution of the response to auxin was visualized by GFP fluorescence or β-glucuronidase (GUS) activity staining and confirmed by immunolocalization of GFP and GUS proteins, respectively. Based on the distribution of EdU-labelled cells, it was determined that 6-day-old squash seedlings were suited for inoculation by A. rhizogenes since their root pericycle and the adjacent layers contain enough proliferating cells. Agrobacterium rhizogenes R1000 proved to be the most virulent strain on squash seedlings. Squash roots containing the respective constructs did not exhibit the hairy root phenotype and were morphologically and structurally similar to wild-type roots. The auxin response pattern in the root apex of squash resembled that in arabidopsis roots. Composite squash plants obtained by A. rhizogenes-mediated transformation are a good tool for the investigation of root apical meristem development and root branching.

  13. GiA Roots: software for the high throughput analysis of plant root system architecture

    Science.gov (United States)

    2012-01-01

    Background Characterizing root system architecture (RSA) is essential to understanding the development and function of vascular plants. Identifying RSA-associated genes also represents an underexplored opportunity for crop improvement. Software tools are needed to accelerate the pace at which quantitative traits of RSA are estimated from images of root networks. Results We have developed GiA Roots (General Image Analysis of Roots), a semi-automated software tool designed specifically for the high-throughput analysis of root system images. GiA Roots includes user-assisted algorithms to distinguish root from background and a fully automated pipeline that extracts dozens of root system phenotypes. Quantitative information on each phenotype, along with intermediate steps for full reproducibility, is returned to the end-user for downstream analysis. GiA Roots has a GUI front end and a command-line interface for interweaving the software into large-scale workflows. GiA Roots can also be extended to estimate novel phenotypes specified by the end-user. Conclusions We demonstrate the use of GiA Roots on a set of 2393 images of rice roots representing 12 genotypes from the species Oryza sativa. We validate trait measurements against prior analyses of this image set that demonstrated that RSA traits are likely heritable and associated with genotypic differences. Moreover, we demonstrate that GiA Roots is extensible and an end-user can add functionality so that GiA Roots can estimate novel RSA traits. In summary, we show that the software can function as an efficient tool as part of a workflow to move from large numbers of root images to downstream analysis. PMID:22834569

  14. Root chemistry and soil fauna, but not soil abiotic conditions explain the effects of plant diversity on root decomposition

    NARCIS (Netherlands)

    Chen, Hongmei; Oram, Natalie J.; Barry, Kathryn E.; Mommer, Liesje; Ruijven, van Jasper; Kroon, de Hans; Ebeling, Anne; Eisenhauer, Nico; Fischer, Christine; Gleixner, Gerd; Gessler, Arthur; González Macé, Odette; Hacker, Nina; Hildebrandt, Anke; Lange, Markus; Scherer-lorenzen, Michael; Scheu, Stefan; Oelmann, Yvonne; Wagg, Cameron; Wilcke, Wolfgang; Wirth, Christian; Weigelt, Alexandra

    2017-01-01

    Plant diversity influences many ecosystem functions including root decomposition. However, due to the presence of multiple pathways via which plant diversity may affect root decomposition, our mechanistic understanding of their relationships is limited. In a grassland biodiversity experiment, we

  15. Plant roots use a patterning mechanism to position lateral root branches toward available water.

    Science.gov (United States)

    Bao, Yun; Aggarwal, Pooja; Robbins, Neil E; Sturrock, Craig J; Thompson, Mark C; Tan, Han Qi; Tham, Cliff; Duan, Lina; Rodriguez, Pedro L; Vernoux, Teva; Mooney, Sacha J; Bennett, Malcolm J; Dinneny, José R

    2014-06-24

    The architecture of the branched root system of plants is a major determinant of vigor. Water availability is known to impact root physiology and growth; however, the spatial scale at which this stimulus influences root architecture is poorly understood. Here we reveal that differences in the availability of water across the circumferential axis of the root create spatial cues that determine the position of lateral root branches. We show that roots of several plant species can distinguish between a wet surface and air environments and that this also impacts the patterning of root hairs, anthocyanins, and aerenchyma in a phenomenon we describe as hydropatterning. This environmental response is distinct from a touch response and requires available water to induce lateral roots along a contacted surface. X-ray microscale computed tomography and 3D reconstruction of soil-grown root systems demonstrate that such responses also occur under physiologically relevant conditions. Using early-stage lateral root markers, we show that hydropatterning acts before the initiation stage and likely determines the circumferential position at which lateral root founder cells are specified. Hydropatterning is independent of endogenous abscisic acid signaling, distinguishing it from a classic water-stress response. Higher water availability induces the biosynthesis and transport of the lateral root-inductive signal auxin through local regulation of tryptophan aminotransferase of Arabidopsis 1 and PIN-formed 3, both of which are necessary for normal hydropatterning. Our work suggests that water availability is sensed and interpreted at the suborgan level and locally patterns a wide variety of developmental processes in the root.

  16. Random River Fluctuations Shape the Root Profile of Riparian Plants

    Science.gov (United States)

    Perona, P.; Tron, S.; Gorla, L.; Schwarz, M.; Laio, F.; Ridolfi, L.

    2015-12-01

    Plant roots are recognized to play a key role in the riparian ecosystems: they contribute to the plant as well as to the streambank and bedforms stability, help to enhance the water quality of the river, and sustain the belowground biodiversity. The complexity of the root-system architecture recalls their remarkable ability to respond to environmental conditions, notably including soil heterogeneity, resource availability, and climate. In fluvial environments where nutrient availability is not a limiting factor for plant to grow, the root growth of phreatophytic plants is strongly influenced by water and oxygen availability in the soil. In this work, we demonstrate that the randomness of water table fluctuations, determined by streamflow stochastic variability, is likely to be the main driver for the root development strategy of riparian plants. A collection of root measurements from field and outdoor controlled experiments is used to demonstrate that the vertical root density distribution can be described by a simple analytical expression, whose parameters are linked to properties of soil, plant and water table fluctuations. This physically-based expression is able to predict riparian plant roots adaptability to different hydrological and pedologic scenarios in riverine environments. Hence, this model has great potential towards the comprehension of the effects of future climate and environmental changing conditions on plant adaptation and river ecomorphodynamic processes. Finally, we present an open access graphical user interface that we developed in order to estimate the vertical root distribution in fluvial environments and to make the model easily available to a wider scientific and professional audience.

  17. Bacteria from wheat and cucurbit plant roots metabolize PAHs and aromatic root exudates: Implications for rhizodegradation.

    Science.gov (United States)

    Ely, Cairn S; Smets, Barth F

    2017-10-03

    The chemical interaction between plants and bacteria in the root zone can lead to soil decontamination. Bacteria that degrade polycyclic aromatic hydrocarbons (PAHs) have been isolated from the rhizospheres of plant species with varied biological traits; however, it is not known what phytochemicals promote contaminant degradation. One monocot and two dicotyledon plants were grown in PAH-contaminated soil from a manufactured gas plant (MGP) site. A phytotoxicity assay confirmed greater soil decontamination in rhizospheres when compared to bulk soil controls. Bacteria were isolated from plant roots (rhizobacteria) and selected for growth on anthracene and chrysene on PAH-amended plates. Rhizosphere isolates metabolized 3- and 4-ring PAHs and PAH catabolic intermediates in liquid incubations. Aromatic root exudate compounds, namely flavonoids and simple phenols, were also substrates for isolated rhizobacteria. In particular, the phenolic compounds-morin, caffeic acid, and protocatechuic acid-appear to be linked to bacterial degradation of 3- and 4-ring PAHs in the rhizosphere.

  18. Hydrologic Regulation of Plant Rooting Depth and Vice Versa

    Science.gov (United States)

    Fan, Y.; Miguez-Macho, G.

    2017-12-01

    How deep plant roots go and why may hold the answer to several questions regarding the co-evolution of terrestrial life and its environment. In this talk we explore how plant rooting depth responds to the hydrologic plumbing system in the soil/regolith/bedrocks, and vice versa. Through analyzing 2200 root observations of >1000 species along biotic (life form, genus) and abiotic (precipitation, soil, drainage) gradients, we found strong sensitivities of rooting depth to local soil water profiles determined by precipitation infiltration depth from the top (reflecting climate and soil), and groundwater table depth from below (reflecting topography-driven land drainage). In well-drained uplands, rooting depth follows infiltration depth; in waterlogged lowlands, roots stay shallow avoiding oxygen stress below the water table; in between, high productivity and drought can send roots many meters down to groundwater capillary fringe. We explore the global significance of this framework using an inverse model, and the implications to the coevolution of deep roots and the CZ in the Early-Mid Devonian when plants colonized the upland environments.

  19. Light as stress factor to plant roots – case of root halotropism

    Science.gov (United States)

    Yokawa, Ken; Fasano, Rossella; Kagenishi, Tomoko; Baluška, František

    2014-01-01

    Despite growing underground, largely in darkness, roots emerge to be very sensitive to light. Recently, several important papers have been published which reveal that plant roots not only express all known light receptors but also that their growth, physiology and adaptive stress responses are light-sensitive. In Arabidopsis, illumination of roots speeds-up root growth via reactive oxygen species-mediated and F-actin dependent process. On the other hand, keeping Arabidopsis roots in darkness alters F-actin distribution, polar localization of PIN proteins as well as polar transport of auxin. Several signaling components activated by phytohormones are overlapping with light-related signaling cascade. We demonstrated that the sensitivity of roots to salinity is altered in the light-grown Arabidopsis roots. Particularly, light-exposed roots are less effective in their salt-avoidance behavior known as root halotropism. Here we discuss these new aspects of light-mediated root behavior from cellular, physiological and evolutionary perspectives. PMID:25566292

  20. Estimating plant root water uptake using a neural network approach

    DEFF Research Database (Denmark)

    Qiao, D M; Shi, H B; Pang, H B

    2010-01-01

    but has not yet been addressed. This paper presents and tests such an approach. The method is based on a neural network model, estimating the water uptake using different types of data that are easy to measure in the field. Sunflower grown in a sandy loam subjected to water stress and salinity was taken......Water uptake by plant roots is an important process in the hydrological cycle, not only for plant growth but also for the role it plays in shaping microbial community and bringing in physical and biochemical changes to soils. The ability of roots to extract water is determined by combined soil...... and plant characteristics, and how to model it has been of interest for many years. Most macroscopic models for water uptake operate at soil profile scale under the assumption that the uptake rate depends on root density and soil moisture. Whilst proved appropriate, these models need spatio-temporal root...

  1. A Novel Plant Root Foraging Algorithm for Image Segmentation Problems

    Directory of Open Access Journals (Sweden)

    Lianbo Ma

    2014-01-01

    Full Text Available This paper presents a new type of biologically-inspired global optimization methodology for image segmentation based on plant root foraging behavior, namely, artificial root foraging algorithm (ARFO. The essential motive of ARFO is to imitate the significant characteristics of plant root foraging behavior including branching, regrowing, and tropisms for constructing a heuristic algorithm for multidimensional and multimodal problems. A mathematical model is firstly designed to abstract various plant root foraging patterns. Then, the basic process of ARFO algorithm derived in the model is described in details. When tested against ten benchmark functions, ARFO shows the superiority to other state-of-the-art algorithms on several benchmark functions. Further, we employed the ARFO algorithm to deal with multilevel threshold image segmentation problem. Experimental results of the new algorithm on a variety of images demonstrated the suitability of the proposed method for solving such problem.

  2. Bacteria from Wheat and Cucurbit Plant Roots Metabolize PAHs and Aromatic Root Exudates: Implications for Rhizodegradation

    DEFF Research Database (Denmark)

    Ely, Cairn S; Smets, Barth F.

    2017-01-01

    The chemical interaction between plants and bacteria in the root zone can lead to soil decontamination. Bacteria which degrade PAHs have been isolated from the rhizospheres of plant species with varied biological traits, however, it is not known what phytochemicals promote contaminant degradation...

  3. Plant root and shoot dynamics during subsurface obstacle interaction

    Science.gov (United States)

    Conn, Nathaniel; Aguilar, Jeffrey; Benfey, Philip; Goldman, Daniel

    As roots grow, they must navigate complex underground environments to anchor and retrieve water and nutrients. From gravity sensing at the root tip to pressure sensing along the tip and elongation zone, the complex mechanosensory feedback system of the root allows it to bend towards greater depths and avoid obstacles of high impedance by asymmetrically suppressing cell elongation. Here we investigate the mechanical and physiological responses of roots to rigid obstacles. We grow Maize, Zea mays, plants in quasi-2D glass containers (22cm x 17cm x 1.4cm) filled with photoelastic gel and observe that, regardless of obstacle interaction, smaller roots branch off the primary root when the upward growing shoot (which contains the first leaf) reaches an average length of 40 mm, coinciding with when the first leaf emerges. However, prior to branching, contacts with obstacles result in reduced root growth rates. The growth rate of the root relative to the shoot is sensitive to the angle of the obstacle surface, whereby the relative root growth is greatest for horizontally oriented surfaces. We posit that root growth is prioritized when horizontal obstacles are encountered to ensure anchoring and access to nutrients during later stages of development. NSF Physics of Living Systems.

  4. Root Systems of Individual Plants, and the Biotic and Abiotic Factors Controlling Their Depth and Distribution: a Synthesis Using a Global Database.

    Science.gov (United States)

    Tumber-Davila, S. J.; Schenk, H. J.; Jackson, R. B.

    2017-12-01

    This synthesis examines plant rooting distributions globally, by doubling the number of entries in the Root Systems of Individual Plants database (RSIP) created by Schenk and Jackson. Root systems influence many processes, including water and nutrient uptake and soil carbon storage. Root systems also mediate vegetation responses to changing climatic and environmental conditions. Therefore, a collective understanding of the importance of rooting systems to carbon sequestration, soil characteristics, hydrology, and climate, is needed. Current global models are limited by a poor understanding of the mechanisms affecting rooting, carbon stocks, and belowground biomass. This improved database contains an extensive bank of records describing the rooting system of individual plants, as well as detailed information on the climate and environment from which the observations are made. The expanded RSIP database will: 1) increase our understanding of rooting depths, lateral root spreads and above and belowground allometry; 2) improve the representation of plant rooting systems in Earth System Models; 3) enable studies of how climate change will alter and interact with plant species and functional groups in the future. We further focus on how plant rooting behavior responds to variations in climate and the environment, and create a model that can predict rooting behavior given a set of environmental conditions. Preliminary results suggest that high potential evapotranspiration and seasonality of precipitation are indicative of deeper rooting after accounting for plant growth form. When mapping predicted deep rooting by climate, we predict deepest rooting to occur in equatorial South America, Africa, and central India.

  5. A Latex Metabolite Benefits Plant Fitness under Root Herbivore Attack

    NARCIS (Netherlands)

    Huber, M.; Epping, Janina; Schulze Gronover, C.; Fricke, Julia; Aziz, Zohra; Brillatz, Théo; Swyers, Michael; Kollner, T.G.; Vogel, H.; Hammerbacher, Almuth; Triebwasser-Freese, Daniella; Robert, Christelle A.M.; Verhoeven, K.J.F.; Preite, V.; Gershenzon, J.; Erb, M.

    2016-01-01

    Plants produce large amounts of secondary metabolites in their shoots and roots and store them in specialized secretory structures. Although secondary metabolites and their secretory structures are commonly assumed to have a defensive function, evidence that they benefit plant fitness under

  6. Plant regeneration via somatic embryogenesis from root explants of ...

    African Journals Online (AJOL)

    A system for induction of callus and plant regeneration via somatic embryogenesis from root explants of Hevea brasiliensis Muell. Arg. clone Reyan 87-6-62 was evaluated. The influence of plant growth regulators (PGRs) including 2,4-dichlorophenoxyacetic acid (2,4-D), 6-benzylaminopurine (6-BA) and kinetin (KT) on ...

  7. Helical growth trajectories in plant roots interacting with stiff barriers

    Science.gov (United States)

    Gerbode, Sharon; Noar, Roslyn; Harrison, Maria

    2009-03-01

    Plant roots successfully navigate heterogeneous soil environments with varying nutrient and water concentrations, as well as a variety of stiff obstacles. While it is thought that the ability of roots to penetrate into a stiff lower soil layer is important for soil erosion, little is known about how a root actually responds to a rigid interface. We have developed a laser sheet imaging technique for recording the 3D growth dynamics of plant roots interacting with stiff barriers. We find that a root encountering an angled interface does not grow in a straight line along the surface, but instead follows a helical trajectory. These experiments build on the pioneering studies of roots grown on a tilted 2D surface, which reported ``root waving,'' a similar curved pattern thought to be caused by the root's sensitivity to both gravity and the rigid surface on which it is grown. Our measurements extend these results to the more physiologically relevant case of 3D growth, where the spiral trajectory can be altered by tuning the relative strengths of the gravity and touch stimuli, providing some intuition for the physical mechanism driving it.

  8. Analysis of peptide uptake and location of root hair-promoting peptide accumulation in plant roots.

    Science.gov (United States)

    Matsumiya, Yoshiki; Taniguchi, Rikiya; Kubo, Motoki

    2012-03-01

    Peptide uptake by plant roots from degraded soybean-meal products was analyzed in Brassica rapa and Solanum lycopersicum. B. rapa absorbed about 40% of the initial water volume, whereas peptide concentration was decreased by 75% after 24 h. Analysis by reversed-phase HPLC showed that number of peptides was absorbed by the roots during soaking in degraded soybean-meal products for 24 h. Carboxyfluorescein-labeled root hair-promoting peptide was synthesized, and its localization, movement, and accumulation in roots were investigated. The peptide appeared to be absorbed by root hairs and then moved to trichoblasts. Furthermore, the peptide was moved from trichoblasts to atrichoblasts after 24 h. The peptide was accumulated in epidermal cells, suggesting that the peptide may have a function in both trichoblasts and atrichoblasts. Copyright © 2012 European Peptide Society and John Wiley & Sons, Ltd.

  9. Absorption behavior of technetium and rhenium through plant roots

    International Nuclear Information System (INIS)

    Tagami, K.; Uchida, S.

    2004-01-01

    The absorption behavior of technetium (Tc) and rhenium (Re) through plant roots was studied using nutrient solution culture. Radish samples, grown in culture solutions for 20-30 days in a green house, were transferred into plastic vessels containing nutrient solutions contaminated with multi-tracer solutions including Tc-95m and Re-183. The plant samples were grown individually for 1-7 days under laboratory conditions. The activities of radionuclides in nutrient solutions and oven-dried plant parts (roots, fleshy roots and leaves) were measured with Ge detecting systems. The concentrations of Tc-95m and Re-183 in the nutrient solutions after harvesting the plants were almost the same as those in the initial solution. Possibly, the radionuclides were taken up with water through plant roots. The distributions of Tc and Re in the plants showed no differences, thus, soluble Tc and Re absorption by plant samples were the same. It is suggested that Re could be used as a geochemical tracer of Tc in the soil environment. (author)

  10. Unleashing the potential of the root hair cell as a single plant cell type model in root systems biology

    Directory of Open Access Journals (Sweden)

    Zhenzhen eQiao

    2013-11-01

    Full Text Available Plant root is an organ composed of multiple cell types with different functions. This multicellular complexity limits our understanding of root biology because –omics studies performed at the level of the entire root reflect the average responses of all cells composing the organ. To overcome this difficulty and allow a more comprehensive understanding of root cell biology, an approach is needed that would focus on one single cell type in the plant root. Because of its biological functions (i.e. uptake of water and various nutrients; primary site of infection by nitrogen-fixing bacteria in legumes, the root hair cell is an attractive single cell model to study root cell response to various stresses and treatments. To fully study their biology, we have recently optimized procedures in obtaining root hair cell samples. We culture the plants using an ultrasound aeroponic system maximizing root hair cell density on the entire root systems and allowing the homogeneous treatment of the root system. We then isolate the root hair cells in liquid nitrogen. Isolated root hair yields could be up to 800 to 1000 mg of plant cells from 60 root systems. Using soybean as a model, the purity of the root hair was assessed by comparing the expression level of genes previously identified as soybean root hair specific between preparations of isolated root hair cells and stripped roots, roots devoid in root hairs. Enlarging our tests to include other plant species, our results support the isolation of large quantities of highly purified root hair cells which is compatible with a systems biology approach.

  11. Root Zone Respiration on Hydroponically Grown Wheat Plant Systems

    Science.gov (United States)

    Soler-Crespo, R. A.; Monje, O. A.

    2010-01-01

    Root respiration is a biological phenomenon that controls plant growth and physiological development during a plant's lifespan. This process is dependent on the availability of oxygen in the system where the plant is located. In hydroponic systems, where plants are submerged in a solution containing vital nutrients but no type of soil, the availability of oxygen arises from the dissolved oxygen concentration in the solution. This oxygen concentration is dependent on the , gas-liquid interface formed on the upper surface of the liquid, as given by Henry's Law, depending on pressure and temperature conditions. Respiration rates of the plants rise as biomass and root zone increase with age. The respiration rate of Apogee wheat plants (Triticum aestivum) was measured as a function of light intensity (catalytic for photosynthesis) and CO2 concentration to determine their effect on respiration rates. To determine their effects on respiration rate and plant growth microbial communities were introduced into the system, by Innoculum. Surfactants were introduced, simulating gray-water usage in space, as another factor to determine their effect on chemical oxygen demand of microbials and on respiration rates of the plants. It is expected to see small effects from changes in CO2 concentration or light levels, and to see root respiration decrease in an exponential manner with plant age and microbial activity.

  12. Morphological change of plant root revealed by neutron radiography

    International Nuclear Information System (INIS)

    Makino-Nakanishi, Tomoko; Matsumoto, Satoshi; Kobayashi, Hisao.

    1992-01-01

    Morphological change with soybean root development was investigated non-destructively by neutron radiography. Not only the main root but also the side roots were shown as an clear image on both X-ray and dry films. In the case of dry film, the resolution of the image obtained was about the same as that by X-ray film and the thermal neutron flux was reduced to be about one fifteenth. The image of the root was much clearly obtained in the sand than in the soil where the soil aggregates were randomly shown. In order to know to which degree the root can be shown in the image, the aluminum containers with various thickness were tested. Even when the thickness of the container was increased up to 1.7 cm, the image of the main root was clearly observed through the soil. It was shown that by neutron radiography the morphology of the plant root could be traced non-destructively during the development of the plant. (author)

  13. Plant ABC transporters enable many unique aspects of a terrestrial plant's lifestyle

    DEFF Research Database (Denmark)

    Hwang, Jae-Ung; Song, Won-Yong; Hong, Daewoong

    2016-01-01

    Terrestrial plants have two to four times more ATP-binding cassette (ABC) transporter genes than other organisms, including their ancestral microalgae. Recent studies found that plants harboring mutations in these transporters exhibit dramatic phenotypes, many of which are related to developmental...... to propose that diverse ABC transporters enabled many unique and essential aspects of a terrestrial plant's lifestyle, by transporting various compounds across specific membranes of the plant....

  14. Uncovering the roots of paranoid suicidal plants

    DEFF Research Database (Denmark)

    Lolle, Signe

    is that forms of plant autoimmunity are due to inappropriate NLR activation. We show here that NLR triggered immunity in pat1 can be prevented by the expression of a dominant negative (DN) allele of the NLR SUMM2. We further find that this DN approach is faster than crossing in knock-outs, and has the advantage...

  15. Soil Penetration Rates by Earthworms and Plant Roots- Mechanical and Energetic Considerations

    Science.gov (United States)

    Ruiz, Siul; Schymanski, Stan; Or, Dani

    2016-04-01

    We analyze the implications of different soil burrowing rates by earthworms and growing plant roots using mechanical models that consider soil rheological properties. We estimate the energetic requirements for soil elasto-viscoplastic displacement at different rates for similar burrows and water contents. In the core of the mechanical model is a transient cavity expansion into viscoplastic wet soil that mimic an earthworm or root tip cone-like penetration and subsequent cavity expansion due to pressurized earthworm hydrostatic skeleton or root radial growth. Soil matrix viscoplatic considerations enable separation of the respective energetic requirements for earthworms penetrating at 2 μm/s relative to plant roots growing at 0.2 μm/s . Typical mechanical and viscous parameters are obtained inversely for soils under different fixed water contents utilizing custom miniaturized cone penetrometers at different fixed penetration rates (1 to 1000 μm/s). Experimental results determine critical water contents where soil exhibits pronounced viscoplatic behavior (close to saturation), bellow which the soil strength limits earthworms activity and fracture propagation by expanding plant roots becomes the favorable mechanical mode. The soil mechanical parameters in conjunction with earthworm and plant root physiological pressure limitations (200 kPa and 2000 kPa respectively) enable delineation of the role of soil saturation in regulating biotic penetration rates for different soil types under different moisture contents. Furthermore, this study provides a quantitative framework for estimating rates of energy expenditure for soil penetration, which allowed us to determine maximum earthworm population densities considering soil mechanical properties and the energy stored in soil organic matter.

  16. Fluorescence Imaging of the Cytoskeleton in Plant Roots.

    Science.gov (United States)

    Dyachok, Julia; Paez-Garcia, Ana; Yoo, Cheol-Min; Palanichelvam, Karuppaiah; Blancaflor, Elison B

    2016-01-01

    During the past two decades the use of live cytoskeletal probes has increased dramatically due to the introduction of the green fluorescent protein. However, to make full use of these live cell reporters it is necessary to implement simple methods to maintain plant specimens in optimal growing conditions during imaging. To image the cytoskeleton in living Arabidopsis roots, we rely on a system involving coverslips coated with nutrient supplemented agar where the seeds are directly germinated. This coverslip system can be conveniently transferred to the stage of a confocal microscope with minimal disturbance to the growth of the seedling. For roots with a larger diameter such as Medicago truncatula, seeds are first germinated in moist paper, grown vertically in between plastic trays, and roots mounted on glass slides for confocal imaging. Parallel with our live cell imaging approaches, we routinely process fixed plant material via indirect immunofluorescence. For these methods we typically use non-embedded vibratome-sectioned and whole mount permeabilized root tissue. The clearly defined developmental regions of the root provide us with an elegant system to further understand the cytoskeletal basis of plant development.

  17. CHARACTERIZATION OF CADMIUM UPTAKE BY ROOTS OF DURUM WHEAT PLANTS

    Directory of Open Access Journals (Sweden)

    Lyubka Koleva

    2009-03-01

    Full Text Available Root Cd uptake of durum wheat plants (cv. Beloslava was characterized in hydroponics conditions. The uptake experiments have been performed in Cd concentration range of 0 – 2 μM adjusted by both stable Cd and radiolabeled (109Cd tracer. Cd removal from the solution over duration of 1 hour reached 50%. The part of loosely adsorbed Cd ions on root surface accounted for about 20%. Over 30% of absorbed Cd at 0.5 μM Cd treatment was retained in root cell walls. The apparent root Cd accumulation showed concentration-dependant tendency with the highest accumulation value of 7.45 nmol Cd g FW-1.

  18. How Plant Root Exudates Shape the Nitrogen Cycle.

    Science.gov (United States)

    Coskun, Devrim; Britto, Dev T; Shi, Weiming; Kronzucker, Herbert J

    2017-08-01

    Although the global nitrogen (N) cycle is largely driven by soil microbes, plant root exudates can profoundly modify soil microbial communities and influence their N transformations. A detailed understanding is now beginning to emerge regarding the control that root exudates exert over two major soil N processes - nitrification and N 2 fixation. We discuss recent breakthroughs in this area, including the identification of root exudates as nitrification inhibitors and as signaling compounds facilitating N-acquisition symbioses. We indicate gaps in current knowledge, including questions of how root exudates affect newly discovered microbial players and N-cycle components. A better understanding of these processes is urgent given the widespread inefficiencies in agricultural N use and their links to N pollution and climate change. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Benefits of flooding-induced aquatic adventitious roots depend on the duration of submergence: linking plant performance to root functioning.

    Science.gov (United States)

    Zhang, Qian; Huber, Heidrun; Beljaars, Simone J M; Birnbaum, Diana; de Best, Sander; de Kroon, Hans; Visser, Eric J W

    2017-07-01

    Temporal flooding is a common environmental stress for terrestrial plants. Aquatic adventitious roots (aquatic roots) are commonly formed in flooding-tolerant plant species and are generally assumed to be beneficial for plant growth by supporting water and nutrient uptake during partial flooding. However, the actual contribution of these roots to plant performance under flooding has hardly been quantified. As the investment into aquatic root development in terms of carbohydrates may be costly, these costs may - depending on the specific environmental conditions - offset the beneficial effects of aquatic roots. This study tested the hypothesis that the balance between potential costs and benefits depends on the duration of flooding, as the benefits are expected to outweigh the costs in long-term but not in short-term flooding. The contribution of aquatic roots to plant performance was tested in Solanum dulcamara during 1-4 weeks of partial submergence and by experimentally manipulating root production. Nutrient uptake by aquatic roots, transpiration and photosynthesis were measured in plants differing in aquatic root development to assess the specific function of these roots. As predicted, flooded plants benefited from the presence of aquatic roots. The results showed that this was probably due to the contribution of roots to resource uptake. However, these beneficial effects were only present in long-term but not in short-term flooding. This relationship could be explained by the correlation between nutrient uptake and the flooding duration-dependent size of the aquatic root system. The results indicate that aquatic root formation is likely to be selected for in habitats characterized by long-term flooding. This study also revealed only limited costs associated with adventitious root formation, which may explain the maintenance of the ability to produce aquatic roots in habitats characterized by very rare or short flooding events. © The Author 2017. Published by

  20. A latex metabolite benefits plant fitness under root herbivore attack

    OpenAIRE

    Huber, M.; Epping, J.; Gronover, C.S.; Fricke, J.; Aziz, Z.; Brillatz, T.; Swyers, M.; Köllner, T.G.; Vogel, H.; Hammerbacher, A.; Triebwasser-Freese, D.; Robert, C.A.M.; Verhoeven, K.; Preite, V.; Gershenzon, J.

    2016-01-01

    Plants produce large amounts of secondary metabolites in their shoots and roots and store them in specialized secretory structures. Although secondary metabolites and their secretory structures are commonly assumed to have a defensive function, evidence that they benefit plant fitness under herbivore attack is scarce, especially below ground. Here, we tested whether latex secondary metabolites produced by the common dandelion (Taraxacum officinale agg.) decrease the performance of its major n...

  1. Transfer of radionuclides to crop plants through roots. Radioiodine

    Energy Technology Data Exchange (ETDEWEB)

    Uchida, Shigeo; Sumiya, Misako; Ohmomo, Yoichiro

    1987-07-01

    In an atmospheric discharge of radioiodines, direct deposition of the nuclides onto leaf surface must be the most significant pathway. However, root uptake is also of importance specifically for /sup 129/I because of its long half life of 1.57 x 10/sup 7/ years. In order to estimate the amount of the nuclide transferred to the crop plants from contaminated field, the experiments were carried out using solution culture. Rice plant, Oryza sativa cv. koshihikari, spinach, Spinacea oleracea L., radish, Raphanus sativus L., and the other four kinds of crop plants were exposed to culture solution in which Na/sup 131/I were contained. The transfer rates, defined as the ratio of activity of plant sample per day to the mean activity of culture solution, were calculated. And the differences by the organs of each crop plant and by plant species were discussed in this paper. Temporal critical crop plants for /sup 129/I were selected.

  2. [Effects and mechanisms of plant roots on slope reinforcement and soil erosion resistance: a research review].

    Science.gov (United States)

    Xiong, Yan-Mei; Xia, Han-Ping; Li, Zhi-An; Cai, Xi-An

    2007-04-01

    Plant roots play an important role in resisting the shallow landslip and topsoil erosion of slopes by raising soil shear strength. Among the models in interpreting the mechanisms of slope reinforcement by plant roots, Wu-Waldron model is a widely accepted one. In this model, the reinforced soil strength by plant roots is positively proportional to average root tensile strength and root area ratio, the two most important factors in evaluating slope reinforcement effect of plant roots. It was found that soil erosion resistance increased with the number of plant roots, though no consistent quantitative functional relationship was observed between them. The increase of soil erosion resistance by plant roots was mainly through the actions of fiber roots less than 1 mm in diameter, while fiber roots enhanced the soil stability to resist water dispersion via increasing the number and diameter of soil water-stable aggregates. Fine roots could also improve soil permeability effectively to decrease runoff and weaken soil erosion.

  3. Growth is required for perception of water availability to pattern root branches in plants.

    Science.gov (United States)

    Robbins, Neil E; Dinneny, José R

    2018-01-23

    Water availability is a potent regulator of plant development and induces root branching through a process termed hydropatterning. Hydropatterning enables roots to position lateral branches toward regions of high water availability, such as wet soil or agar media, while preventing their emergence where water is less available, such as in air. The mechanism by which roots perceive the spatial distribution of water during hydropatterning is unknown. Using primary roots of Zea mays (maize) we reveal that developmental competence for hydropatterning is limited to the growth zone of the root tip. Past work has shown that growth generates gradients in water potential across an organ when asymmetries exist in the distribution of available water. Using mathematical modeling, we predict that substantial growth-sustained water potential gradients are also generated in the hydropatterning competent zone and that such biophysical cues inform the patterning of lateral roots. Using diverse chemical and environmental treatments we experimentally demonstrate that growth is necessary for normal hydropatterning of lateral roots. Transcriptomic characterization of the local response of tissues to a moist surface or air revealed extensive regulation of signaling and physiological pathways, some of which we show are growth-dependent. Our work supports a "sense-by-growth" mechanism governing hydropatterning, by which water availability cues are rendered interpretable through growth-sustained water movement. Copyright © 2018 the Author(s). Published by PNAS.

  4. Using three-dimensional plant root architecture in models of shallow-slope stability.

    Science.gov (United States)

    Danjon, Frédéric; Barker, David H; Drexhage, Michael; Stokes, Alexia

    2008-05-01

    The contribution of vegetation to shallow-slope stability is of major importance in landslide-prone regions. However, existing slope stability models use only limited plant root architectural parameters. This study aims to provide a chain of tools useful for determining the contribution of tree roots to soil reinforcement. Three-dimensional digitizing in situ was used to obtain accurate root system architecture data for mature Quercus alba in two forest stands. These data were used as input to tools developed, which analyse the spatial position of roots, topology and geometry. The contribution of roots to soil reinforcement was determined by calculating additional soil cohesion using the limit equilibrium model, and the factor of safety (FOS) using an existing slope stability model, Slip4Ex. Existing models may incorrectly estimate the additional soil cohesion provided by roots, as the spatial position of roots crossing the potential slip surface is usually not taken into account. However, most soil reinforcement by roots occurs close to the tree stem and is negligible at a distance >1.0 m from the tree, and therefore global values of FOS for a slope do not take into account local slippage along the slope. Within a forest stand on a landslide-prone slope, soil fixation by roots can be minimal between uniform rows of trees, leading to local soil slippage. Therefore, staggered rows of trees would improve overall slope stability, as trees would arrest the downward movement of soil. The chain of tools consisting of both software (free for non-commercial use) and functions available from the first author will enable a more accurate description and use of root architectural parameters in standard slope stability analyses.

  5. Methods of plant root exudates analysis: a review

    Directory of Open Access Journals (Sweden)

    Peter Dundek

    2011-01-01

    Full Text Available The aim of this review is to summarise current knowledge on methods being used to determine individual compounds and properties of water-soluble plant root exudates. These compounds include amino acids, organic acids and simple sugars, as well as polysaccharides, proteins and organic substances. Qualitative composition of water-soluble root exudates and exudation rate are commonly measured with the aim of consequent synthetic preparation of plant root exudates to be supplied to soil to create artificial rhizosphere for different experimental purposes. Root exudates collection usually requires consequent filtration or centrifugation to remove solids, root detritus and microbial cell debris, and consequent concentration using an evaporator, lyophilizator or ultrafiltration. Methods used for analysis of total groups of compounds (total proteins and total carbohydrates and total organic carbon are simple. On the other hand, HPLC or GS/MS are commonly used to analyse individual low molecular weight organic molecules (sugars, organic acids and amino acids with separation using different columns. Other properties such as pH, conductivity or activity of different enzymes as well as gel electrophoresis of proteins are sometimes assessed. All of these methods are discussed in this work.

  6. Use of sediment CO2 by submersed rooted plants

    DEFF Research Database (Denmark)

    Winkel, Anders; Borum, Jens

    2009-01-01

    freshwater plants with different morphology and growth characteristics (Lobelia dortmanna, Lilaeopsis macloviana, Ludwigia repens, Vallisneria americana and Hydrocotyle verticillata) are able to support photosynthesis supplied by uptake of CO2 from the sediment. Methods: Gross photosynthesis was measured......Background and Aims: Submersed plants have different strategies to overcome inorganic carbon limitation. It is generally assumed that only small rosette species (isoetids) are able to utilize the high sediment CO2 availability. The present study examined to what extent five species of submersed......, the shoot to root ratio on an areal basis was the single factor best explaining variability in the importance of sediment CO2. For Ludwigia, diffusion barriers limited uptake or transport from roots to stems and transport from stems to leaves. Conclusions: Submersed plants other than isoetids can utilize...

  7. Endophytic colonization of plant roots by nitrogen-fixing bacteria

    International Nuclear Information System (INIS)

    Cocking, Edward C.

    2001-01-01

    Nitrogen-fixing bacteria are able to enter into roots from the rhizosphere, particularly at the base of emerging lateral roots, between epidermal cells and through root hairs. In the rhizosphere growing root hairs play an important role in symbiotic recognition in legume crops. Nodulated legumes in endosymbiosis with rhizobia are amongst the most prominent nitrogen-fixing systems in agriculture. The inoculation of non-legumes, especially cereals, with various non-rhizobial diazotrophic bacteria has been undertaken with the expectation that they would establish themselves intercellularly within the root system, fixing nitrogen endophytic ally and providing combined nitrogen for enhanced crop production. However, in most instances bacteria colonize only the surface of the roots and remain vulnerable to competition from other rhizosphere micro-organisms, even when the nitrogen-fixing bacteria are endophytic, benefits to the plant may result from better uptake of soil nutrients rather than from endophytic nitrogen fixation. Azorhizobium caulinodans is known to enter the root system of cereals, other nonlegume crops and Arabidopsis, by intercellular invasion between epidermal cells and to internally colonize the plant intercellularly, including the xylem. This raises the possibility that xylem colonization might provide a nonnodular niche for endosymbiotic nitrogen fixation in rice, wheat, maize, sorghum and other non-legume crops. A particularly interesting, naturally occurring, non-qodular xylem colonising endophytic diazotrophic interaction with evidence for endophytic nitrogen fixation is that of Gluconacetobacter diazotrophicus in sugarcane. Could this beneficial endophytic colonization of sugarcane by G. diazotrophicus be extended to other members of the Gramineae, including the major cereals, and to other major non-legume crops of the World? (author)

  8. Differences in U root-to-shoot translocation between plant species explained by U distribution in roots

    Energy Technology Data Exchange (ETDEWEB)

    Straczek, Anne; Duquene, Lise [Belgium Nuclear Research Centre (SCK.CEN), Biosphere Impact Studies, Boeretang 200, 2400 Mol (Belgium); Wegrzynek, Dariusz [IAEA, Seibersdorf Laboratories, A-2444 Seibersdorf (Austria); Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, Al. Mickiewicza 30, 30-059 Krakow (Poland); Chinea-Cano, Ernesto [IAEA, Seibersdorf Laboratories, A-2444 Seibersdorf (Austria); Wannijn, Jean [Belgium Nuclear Research Centre (SCK.CEN), Biosphere Impact Studies, Boeretang 200, 2400 Mol (Belgium); Navez, Jacques [Royal Museum of Africa, Department of Geology, Leuvensesteenweg 13, 3080 Tervuren (Belgium); Vandenhove, Hildegarde, E-mail: hvandenh@sckcen.b [Belgium Nuclear Research Centre (SCK.CEN), Biosphere Impact Studies, Boeretang 200, 2400 Mol (Belgium)

    2010-03-15

    Accumulation and distribution of uranium in roots and shoots of four plants species differing in their cation exchange capacity of roots (CECR) was investigated. After exposure in hydroponics for seven days to 100 mumol U L{sup -1}, distribution of uranium in roots was investigated through chemical extraction of roots. Higher U concentrations were measured in roots of dicots which showed a higher CECR than monocot species. Chemical extractions indicated that uranium is mostly located in the apoplasm of roots of monocots but that it is predominantly located in the symplasm of roots of dicots. Translocation of U to shoot was not significantly affected by the CECR or distribution of U between symplasm and apoplasm. Distribution of uranium in roots was investigated through chemical extraction of roots for all species. Additionally, longitudinal and radial distribution of U in roots of maize and Indian mustard, respectively showing the lowest and the highest translocation, was studied following X-ray fluorescence (XRF) analysis of specific root sections. Chemical analysis and XRF analysis of roots of maize and Indian mustard clearly indicated a higher longitudinal and radial transport of uranium in roots of Indian mustard than in roots of maize, where uranium mostly accumulated in root tips. These results showed that even if CECR could partly explain U accumulation in roots, other mechanisms like radial and longitudinal transport are implied in the translocation of U to the shoot.

  9. Differences in U root-to-shoot translocation between plant species explained by U distribution in roots

    International Nuclear Information System (INIS)

    Straczek, Anne; Duquene, Lise; Wegrzynek, Dariusz; Chinea-Cano, Ernesto; Wannijn, Jean; Navez, Jacques; Vandenhove, Hildegarde

    2010-01-01

    Accumulation and distribution of uranium in roots and shoots of four plants species differing in their cation exchange capacity of roots (CECR) was investigated. After exposure in hydroponics for seven days to 100 μmol U L -1 , distribution of uranium in roots was investigated through chemical extraction of roots. Higher U concentrations were measured in roots of dicots which showed a higher CECR than monocot species. Chemical extractions indicated that uranium is mostly located in the apoplasm of roots of monocots but that it is predominantly located in the symplasm of roots of dicots. Translocation of U to shoot was not significantly affected by the CECR or distribution of U between symplasm and apoplasm. Distribution of uranium in roots was investigated through chemical extraction of roots for all species. Additionally, longitudinal and radial distribution of U in roots of maize and Indian mustard, respectively showing the lowest and the highest translocation, was studied following X-ray fluorescence (XRF) analysis of specific root sections. Chemical analysis and XRF analysis of roots of maize and Indian mustard clearly indicated a higher longitudinal and radial transport of uranium in roots of Indian mustard than in roots of maize, where uranium mostly accumulated in root tips. These results showed that even if CECR could partly explain U accumulation in roots, other mechanisms like radial and longitudinal transport are implied in the translocation of U to the shoot.

  10. Developing a method of fabricating microchannels using plant root structure

    Science.gov (United States)

    Nakashima, Shota; Tokumaru, Kazuki; Tsumori, Fujio

    2018-06-01

    Complicated three-dimensional (3D) microchannels are expected to be applied to a lab-on-a-chip, especially an organ-on-a-chip. There are fine microchannel networks such as blood vessels in a living organ. However, it is difficult to recreate the complicated 3D microchannels of real living structures. Plant roots have a similar structure to blood vessels. They spread radially and three-dimensionally, and become thinner as they branch. In this research, we propose a method of fabricating microchannels using a live plant root as a template to mimic a blood vessel structure. We grew a plant in ceramic slurry instead of soil. The slurry consists of ceramic powder, binder and water, so it plays a similar role to soil consisting of fine particles in water. After growing the plant, the roots inside the slurry were burned and a sintered ceramic body with channel structures was obtained by heating. We used two types of slurry with different composition ratios, and compared the internal channel structures before and after sintering.

  11. A Latex Metabolite Benefits Plant Fitness under Root Herbivore Attack.

    Directory of Open Access Journals (Sweden)

    Meret Huber

    2016-01-01

    Full Text Available Plants produce large amounts of secondary metabolites in their shoots and roots and store them in specialized secretory structures. Although secondary metabolites and their secretory structures are commonly assumed to have a defensive function, evidence that they benefit plant fitness under herbivore attack is scarce, especially below ground. Here, we tested whether latex secondary metabolites produced by the common dandelion (Taraxacum officinale agg. decrease the performance of its major native insect root herbivore, the larvae of the common cockchafer (Melolontha melolontha, and benefit plant vegetative and reproductive fitness under M. melolontha attack. Across 17 T. officinale genotypes screened by gas and liquid chromatography, latex concentrations of the sesquiterpene lactone taraxinic acid β-D-glucopyranosyl ester (TA-G were negatively associated with M. melolontha larval growth. Adding purified TA-G to artificial diet at ecologically relevant concentrations reduced larval feeding. Silencing the germacrene A synthase ToGAS1, an enzyme that was identified to catalyze the first committed step of TA-G biosynthesis, resulted in a 90% reduction of TA-G levels and a pronounced increase in M. melolontha feeding. Transgenic, TA-G-deficient lines were preferred by M. melolontha and suffered three times more root biomass reduction than control lines. In a common garden experiment involving over 2,000 T. officinale individuals belonging to 17 different genotypes, high TA-G concentrations were associated with the maintenance of high vegetative and reproductive fitness under M. melolontha attack. Taken together, our study demonstrates that a latex secondary metabolite benefits plants under herbivore attack, a result that provides a mechanistic framework for root herbivore driven natural selection and evolution of plant defenses below ground.

  12. A Latex Metabolite Benefits Plant Fitness under Root Herbivore Attack.

    Science.gov (United States)

    Huber, Meret; Epping, Janina; Schulze Gronover, Christian; Fricke, Julia; Aziz, Zohra; Brillatz, Théo; Swyers, Michael; Köllner, Tobias G; Vogel, Heiko; Hammerbacher, Almuth; Triebwasser-Freese, Daniella; Robert, Christelle A M; Verhoeven, Koen; Preite, Veronica; Gershenzon, Jonathan; Erb, Matthias

    2016-01-01

    Plants produce large amounts of secondary metabolites in their shoots and roots and store them in specialized secretory structures. Although secondary metabolites and their secretory structures are commonly assumed to have a defensive function, evidence that they benefit plant fitness under herbivore attack is scarce, especially below ground. Here, we tested whether latex secondary metabolites produced by the common dandelion (Taraxacum officinale agg.) decrease the performance of its major native insect root herbivore, the larvae of the common cockchafer (Melolontha melolontha), and benefit plant vegetative and reproductive fitness under M. melolontha attack. Across 17 T. officinale genotypes screened by gas and liquid chromatography, latex concentrations of the sesquiterpene lactone taraxinic acid β-D-glucopyranosyl ester (TA-G) were negatively associated with M. melolontha larval growth. Adding purified TA-G to artificial diet at ecologically relevant concentrations reduced larval feeding. Silencing the germacrene A synthase ToGAS1, an enzyme that was identified to catalyze the first committed step of TA-G biosynthesis, resulted in a 90% reduction of TA-G levels and a pronounced increase in M. melolontha feeding. Transgenic, TA-G-deficient lines were preferred by M. melolontha and suffered three times more root biomass reduction than control lines. In a common garden experiment involving over 2,000 T. officinale individuals belonging to 17 different genotypes, high TA-G concentrations were associated with the maintenance of high vegetative and reproductive fitness under M. melolontha attack. Taken together, our study demonstrates that a latex secondary metabolite benefits plants under herbivore attack, a result that provides a mechanistic framework for root herbivore driven natural selection and evolution of plant defenses below ground.

  13. Deciphering composition and function of the root microbiome of a legume plant

    NARCIS (Netherlands)

    Hartman, Kyle; van der Heijden, Marcel G A|info:eu-repo/dai/nl/240923901; Roussely-Provent, Valexia; Walser, Jean-Claude; Schlaeppi, Klaus

    2017-01-01

    BACKGROUND: Diverse assemblages of microbes colonize plant roots and collectively function as a microbiome. Earlier work has characterized the root microbiomes of numerous plant species, but little information is available for legumes despite their key role in numerous ecosystems including

  14. Plant iodine-131 uptake in relation to root concentration as measured in minirhizotron by video camera:

    International Nuclear Information System (INIS)

    Moss, K.J.

    1990-09-01

    Glass viewing tubes (minirhizotrons) were placed in the soil beneath native perennial bunchgrass (Agropyron spicatum). The tubes provided access for observing and quantifying plant roots with a miniature video camera and soil moisture estimates by neutron hydroprobe. The radiotracer I-131 was delivered to the root zone at three depths with differing root concentrations. The plant was subsequently sampled and analyzed for I-131. Plant uptake was greater when I-131 was applied at soil depths with higher root concentrations. When I-131 was applied at soil depths with lower root concentrations, plant uptake was less. However, the relationship between root concentration and plant uptake was not a direct one. When I-131 was delivered to deeper soil depths with low root concentrations, the quantity of roots there appeared to be less effective in uptake than the same quantity of roots at shallow soil depths with high root concentration. 29 refs., 6 figs., 11 tabs

  15. Soil-root Shear Strength Properties of Some Slope Plants

    International Nuclear Information System (INIS)

    Normaniza Osman; Mohamad Nordin Abdullah; Faisal Haji Ali

    2011-01-01

    Rapid development in hilly areas in Malaysia has become a trend that put a stress to the sloping area. It reduces the factor of safety by reducing the resistant force and therefore leads to slope failure. Vegetation plays a big role in reinforcement functions via anchoring the soils and forms a binding network within the soil layer that tied the soil masses together. In this research, three plant species namely Acacia mangium, Dillenia suffruticosa and Leucaena leucocaphala were assessed in term of their soil-root shear strength properties. Our results showed that Acacia mangium had the highest shear strength values, 30.4 kPa and 50.2 kPa at loads 13.3 kPa and 24.3 kPa, respectively. Leucaena leucocaphala showed the highest in cohesion factor, which was almost double the value in those of Dillenia suffruticosa and Acacia mangium. The root profile analysis indicated Dillenia suffruticosa exhibited the highest values in both root length density and root volume, whilst Leucaena leucocaphala had the highest average of root diameter. (author)

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

    Science.gov (United States)

    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

  17. The distribution of 32P in the rice plant applied to a single root and to the whole root system

    International Nuclear Information System (INIS)

    Sisworo, E.L.; Gandanegara, S.; Sisworo, W.H.; Rasyid, H.; Sumarna, Nana

    1982-01-01

    Two greenhouse experiments to study the distribution of 32 P applied to a single root and to the whole root system have been carried out. Data from experiment 1 showed that 32 P activity in shoots rose with the progress of time; where 32 P was applied to a single root 6 hours after isotope application the 32 P activity in the shoots of plants was higher than if the isotope was applied to the whole root system. Three hours after 32 P application, plants with 50% of roots had a higher 32 P activity than plants with no root cutting. Data from experiment 2 showed that 32 P activity of plants that received 32 P through a single root only was lower than those that received 32 P through the whole root system. This was in contradiction with the data obtained in experiment 1. Experiment 2 also showed that 32 P activity increased with time. Autoradiographs of plants in experiment 1 and 2 showed that 32 P was distributed through the whole plant, although when the isotope was only applied to a single root. (author)

  18. Composite potato plants with transgenic roots on non-transgenic shoots: a model system for studying gene silencing in roots.

    Science.gov (United States)

    Horn, Patricia; Santala, Johanna; Nielsen, Steen Lykke; Hühns, Maja; Broer, Inge; Valkonen, Jari P T

    2014-12-01

    Composite potato plants offer an extremely fast, effective and reliable system for studies on gene functions in roots using antisense or inverted-repeat but not sense constructs for gene inactivation. Composite plants, with transgenic roots on a non-transgenic shoot, can be obtained by shoot explant transformation with Agrobacterium rhizogenes. The aim of this study was to generate composite potato plants (Solanum tuberosum) to be used as a model system in future studies on root-pathogen interactions and gene silencing in the roots. The proportion of transgenic roots among the roots induced was high (80-100%) in the four potato cultivars tested (Albatros, Desirée, Sabina and Saturna). No wild-type adventitious roots were formed at mock inoculation site. All strains of A. rhizogenes tested induced phenotypically normal roots which, however, showed a reduced response to cytokinin as compared with non-transgenic roots. Nevertheless, both types of roots were infected to a similar high rate with the zoospores of Spongospora subterranea, a soilborne potato pathogen. The transgenic roots of composite potato plants expressed significantly higher amounts of β-glucuronidase (GUS) than the roots of a GUS-transgenic potato line event. Silencing of the uidA transgene (GUS) was tested by inducing roots on the GUS-transgenic cv. Albatros event with strains of A. rhizogenes over-expressing either the uidA sense or antisense transcripts, or inverted-repeat or hairpin uidA RNA. The three last mentioned constructs caused 2.5-4.0 fold reduction in the uidA mRNA expression. In contrast, over-expression of uidA resulted in over 3-fold increase in the uidA mRNA and GUS expression, indicating that sense-mediated silencing (co-suppression) was not functional in roots. The results suggest that composite plants offer a useful experimental system for potato research, which has gained little previous attention.

  19. Monitoring Spongospora subterranea Development in Potato Roots Reveals Distinct Infection Patterns and Enables Efficient Assessment of Disease Control Methods.

    Directory of Open Access Journals (Sweden)

    Tamilarasan Thangavel

    Full Text Available Spongospora subterranea is responsible for significant potato root and tuber disease globally. Study of this obligate (non-culturable pathogen that infects below-ground plant parts is technically difficult. The capacity to measure the dynamics and patterns of root infections can greatly assist in determining the efficacy of control treatments on disease progression. This study used qPCR and histological analysis in time-course experiments to measure temporal patterns of pathogen multiplication and disease development in potato (and tomato roots and tubers. Effects of delayed initiation of infection and fungicidal seed tuber and soil treatments were assessed. This study found roots at all plant developmental ages were susceptible to infection but that delaying infection significantly reduced pathogen content and resultant disease at final harvest. The pathogen was first detected in roots 15-20 days after inoculation (DAI and the presence of zoosporangia noted 15-45 DAI. Following initial infection pathogen content in roots increased at a similar rate regardless of plant age at inoculation. All fungicide treatments (except soil-applied mancozeb which had a variable response suppressed pathogen multiplication and root and tuber disease. In contrast to delayed inoculation, the fungicide treatments slowed disease progress (rate rather than delaying onset of infection. Trials under suboptimal temperatures for disease expression provided valuable data on root infection rate, demonstrating the robustness of monitoring root infection. These results provide an early measure of the efficacy of control treatments and indicate two possible patterns of disease suppression by either delayed initiation of infection which then proceeds at a similar rate or diminished epidemic rate.

  20. Monitoring Spongospora subterranea Development in Potato Roots Reveals Distinct Infection Patterns and Enables Efficient Assessment of Disease Control Methods.

    Science.gov (United States)

    Thangavel, Tamilarasan; Tegg, Robert S; Wilson, Calum R

    2015-01-01

    Spongospora subterranea is responsible for significant potato root and tuber disease globally. Study of this obligate (non-culturable) pathogen that infects below-ground plant parts is technically difficult. The capacity to measure the dynamics and patterns of root infections can greatly assist in determining the efficacy of control treatments on disease progression. This study used qPCR and histological analysis in time-course experiments to measure temporal patterns of pathogen multiplication and disease development in potato (and tomato) roots and tubers. Effects of delayed initiation of infection and fungicidal seed tuber and soil treatments were assessed. This study found roots at all plant developmental ages were susceptible to infection but that delaying infection significantly reduced pathogen content and resultant disease at final harvest. The pathogen was first detected in roots 15-20 days after inoculation (DAI) and the presence of zoosporangia noted 15-45 DAI. Following initial infection pathogen content in roots increased at a similar rate regardless of plant age at inoculation. All fungicide treatments (except soil-applied mancozeb which had a variable response) suppressed pathogen multiplication and root and tuber disease. In contrast to delayed inoculation, the fungicide treatments slowed disease progress (rate) rather than delaying onset of infection. Trials under suboptimal temperatures for disease expression provided valuable data on root infection rate, demonstrating the robustness of monitoring root infection. These results provide an early measure of the efficacy of control treatments and indicate two possible patterns of disease suppression by either delayed initiation of infection which then proceeds at a similar rate or diminished epidemic rate.

  1. Accumulation of uranium in plant roots absorbed from aqueous solutions

    International Nuclear Information System (INIS)

    Dohi, Terumi; Haga, Nobuhiko; Nakashima, Satoru; Tagai, Tokuhei

    2007-01-01

    In order to study accumulation mechanisms of uranium (U) in terrestrial plants, uptake experiments for U have been carried out by using Indian mustard (Brassica juncea). This plant is edible and known as a heavy metal accumulator, especially for cadmium (Cd). About 30 rootsstocks of Indian mustard grown hydroponically in laboratory dishes were kept in uranyl (UO 2 2+ ) nitrate solutions (initially 0.5 mmol/l) at 25degC for 24, 48 and 72 hours (h). The average U concentrations in leaves increased until 48 h up to about 0.6 mg/g and then decreased slightly. Those in roots showed similar trends, but with much higher maximum U concentrations of about 30 mg/g. Backscattered electron images under SEM of the roots showed that U was accumulated on the cell edges. EPMA elemental mapping indicated that phosphorus (P) distribution had a very strong correlation with that of U. The distribution of sulfur (S) appeared to be somewhat different form these U and P distributions. These results suggest that U can be absorbed into plant roots as uranyl (UO 2 2+ ) and might be fixed at the phospholipid rich cell membranes. This U accumulation mechanism appeared to be different from that for Cd which has a close association with S. (author)

  2. Gravity sensing and signal transduction in vascular plant primary roots.

    Science.gov (United States)

    Baldwin, Katherine L; Strohm, Allison K; Masson, Patrick H

    2013-01-01

    During gravitropism, the potential energy of gravity is converted into a biochemical signal. How this transfer occurs remains one of the most exciting mysteries in plant cell biology. New experiments are filling in pieces of the puzzle. In this review, we introduce gravitropism and give an overview of what we know about gravity sensing in roots of vascular plants, with special highlight on recent papers. When plant roots are reoriented sideways, amyloplast resedimentation in the columella cells is a key initial step in gravity sensing. This process somehow leads to cytoplasmic alkalinization of these cells followed by relocalization of auxin efflux carriers (PINs). This changes auxin flow throughout the root, generating a lateral gradient of auxin across the cap that upon transmission to the elongation zone leads to differential cell elongation and gravibending. We will present the evidence for and against the following players having a role in transferring the signal from the amyloplast sedimentation into the auxin signaling cascade: mechanosensitive ion channels, actin, calcium ions, inositol trisphosphate, receptors/ligands, ARG1/ARL2, spermine, and the TOC complex. We also outline auxin transport and signaling during gravitropism.

  3. Colonization of Plant Growth Promoting Rhizobacteria (PGPR) on Two Different Root Systems

    International Nuclear Information System (INIS)

    Chaudhry, M. Z.; Naz, A. U.; Nawaz, A.; Nawaz, A.; Mukhtar, H.

    2016-01-01

    Phytohormones producing bacteria enhance the plants growth by positively affecting growth of the root. Plant growth promoting bacteria (PGPR) must colonize the plant roots to contribute to the plant's endogenous pool of phytohormones. Colonization of these plant growth promoting rhizobacteria isolated from rhizosplane and soil of different crops was evaluated on different root types to establish if the mechanism of host specificity exist. The bacteria were isolated from maize, wheat, rice, canola and cotton and phytohormone production was detected and quantified by HPLC. Bacteria were inoculated on surface sterilized seeds of different crops and seeds were germinated. After 7 days the bacteria were re-isolated from the roots and the effect of these bacteria was observed by measuring increase in root length. Bacteria isolated from one plant family (monocots) having fibrous root performed well on similar root system and failed to give significant results on other roots (tap root) of dicots. Some aggressive strains were able to colonize both root systems. The plant growth promoting activities of the bacteria were optimum on the same plant from whom roots they were isolated. The results suggest that bacteria adapt to the root they naturally inhabit and colonize the same plant root systems preferably. Although the observe trend indicate host specificity but some bacteria were aggressive colonizers which grew on all the plants used in experiment. (author)

  4. 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.

  5. Root plasticity buffers competition among plants: theory meets experimental data.

    Science.gov (United States)

    Schiffers, Katja; Tielbörger, Katja; Tietjen, Britta; Jeltsch, Florian

    2011-03-01

    Morphological plasticity is a striking characteristic of plants in natural communities. In the context of foraging behavior particularly, root plasticity has been documented for numerous species. Root plasticity is known to mitigate competitive interactions by reducing the overlap of the individuals' rhizospheres. But despite its obvious effect on resource acquisition, plasticity has been generally neglected in previous empirical and theoretical studies estimating interaction intensity among plants. In this study, we developed a semi-mechanistic model that addresses this shortcoming by introducing the idea of compensatory growth into the classical-zone-of influence (ZOI) and field-of-neighborhood (FON) approaches. The model parameters describing the belowground plastic sphere of influence (PSI) were parameterized using data from an accompanying field experiment. Measurements of the uptake of a stable nutrient analogue at distinct distances to the neighboring plants showed that the study species responded plastically to belowground competition by avoiding overlap of individuals' rhizospheres. An unexpected finding was that the sphere of influence of the study species Bromus hordeaceus could be best described by a unimodal function of distance to the plant's center and not with a continuously decreasing function as commonly assumed. We employed the parameterized model to investigate the interplay between plasticity and two other important factors determining the intensity of competitive interactions: overall plant density and the distribution of individuals in space. The simulation results confirm that the reduction of competition intensity due to morphological plasticity strongly depends on the spatial structure of the competitive environment. We advocate the use of semi-mechanistic simulations that explicitly consider morphological plasticity to improve our mechanistic understanding of plant interactions.

  6. Fate of polycyclic aromatic hydrocarbons in plant-soil systems: Plant responses to a chemical stress in the root zone

    Energy Technology Data Exchange (ETDEWEB)

    Hoylman, Anne M. [Univ. of Tennessee, Knoxville, TN (United States)

    1994-01-01

    Under laboratory conditions selected to maximize root uptake, plant tissue distribution of PAH-derived 14C was largely limited to root tissue of Malilotus alba. These results suggest that plant uptake of PAHs from contaminated soil via roots, and translocation to aboveground plant tissues (stems and leaves), is a limited mechanism for transport into terrestrial food chains. However, these data also indicate that root surface sorption of PAHs may be important for plants grown in soils containing elevated concentration PAHs. Root surface sorption of PAHs may be an important route of exposure for plants in soils containing elevated concentrations of PAHS. Consequently, the root-soil interface may be the site of plant-microbial interactions in response to a chemical stress. In this study, evidence of a shift in carbon allocation to the root zone of plants exposed to phenanthrene and corresponding increases in soil respiration and heterotrophic plate counts provide evidence of a plant-microbial response to a chemical stress. The results of this study establish the importance of the root-soil interface for plants growing in PAH contaminated soil and indicate the existence of plant-microbial interactions in response to a chemical stress. These results may provide new avenues of inquiry for studies of plant toxicology, plant-microbial interactions in the rhizosphere, and environmental fates of soil contaminants. In addition, the utilization of plants to enhance the biodegradation of soil contaminants may require evaluation of plant physiological changes and plant shifts in resource allocation.

  7. Quantification of effective plant rooting depth: advancing global hydrological modelling

    Science.gov (United States)

    Yang, Y.; Donohue, R. J.; McVicar, T.

    2017-12-01

    Plant rooting depth (Zr) is a key parameter in hydrological and biogeochemical models, yet the global spatial distribution of Zr is largely unknown due to the difficulties in its direct measurement. Moreover, Zr observations are usually only representative of a single plant or several plants, which can differ greatly from the effective Zr over a modelling unit (e.g., catchment or grid-box). Here, we provide a global parameterization of an analytical Zr model that balances the marginal carbon cost and benefit of deeper roots, and produce a climatological (i.e., 1982-2010 average) global Zr map. To test the Zr estimates, we apply the estimated Zr in a highly transparent hydrological model (i.e., the Budyko-Choudhury-Porporato (BCP) model) to estimate mean annual actual evapotranspiration (E) across the globe. We then compare the estimated E with both water balance-based E observations at 32 major catchments and satellite grid-box retrievals across the globe. Our results show that the BCP model, when implemented with Zr estimated herein, optimally reproduced the spatial pattern of E at both scales and provides improved model outputs when compared to BCP model results from two already existing global Zr datasets. These results suggest that our Zr estimates can be effectively used in state-of-the-art hydrological models, and potentially biogeochemical models, where the determination of Zr currently largely relies on biome type-based look-up tables.

  8. Community-Weighted Mean Plant Traits Predict Small Scale Distribution of Insect Root Herbivore Abundance.

    Directory of Open Access Journals (Sweden)

    Ilja Sonnemann

    Full Text Available Small scale distribution of insect root herbivores may promote plant species diversity by creating patches of different herbivore pressure. However, determinants of small scale distribution of insect root herbivores, and impact of land use intensity on their small scale distribution are largely unknown. We sampled insect root herbivores and measured vegetation parameters and soil water content along transects in grasslands of different management intensity in three regions in Germany. We calculated community-weighted mean plant traits to test whether the functional plant community composition determines the small scale distribution of insect root herbivores. To analyze spatial patterns in plant species and trait composition and insect root herbivore abundance we computed Mantel correlograms. Insect root herbivores mainly comprised click beetle (Coleoptera, Elateridae larvae (43% in the investigated grasslands. Total insect root herbivore numbers were positively related to community-weighted mean traits indicating high plant growth rates and biomass (specific leaf area, reproductive- and vegetative plant height, and negatively related to plant traits indicating poor tissue quality (leaf C/N ratio. Generalist Elaterid larvae, when analyzed independently, were also positively related to high plant growth rates and furthermore to root dry mass, but were not related to tissue quality. Insect root herbivore numbers were not related to plant cover, plant species richness and soil water content. Plant species composition and to a lesser extent plant trait composition displayed spatial autocorrelation, which was not influenced by land use intensity. Insect root herbivore abundance was not spatially autocorrelated. We conclude that in semi-natural grasslands with a high share of generalist insect root herbivores, insect root herbivores affiliate with large, fast growing plants, presumably because of availability of high quantities of food. Affiliation of

  9. A fungal endophyte helps plants to tolerate root herbivory through changes in gibberellin and jasmonate signaling

    NARCIS (Netherlands)

    Rebeca Cosme, M.P.

    2016-01-01

    Plant–microbe mutualisms can improve plant defense, but the impact of root endophytes on below-ground herbivore interactions remains unknown. We investigated the effects of the root endophyte Piriformospora indica on interactions between rice (Oryza sativa) plants and its root herbivore rice water

  10. Microbial genome-enabled insights into plant-microorganism interactions.

    Science.gov (United States)

    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.

  11. Plant root research: the past, the present and the future

    OpenAIRE

    Lux, Alexander; Rost, Thomas L.

    2012-01-01

    This special issue is dedicated to root biologists past and present who have been exploring all aspects of root structure and function with an extensive publication record going over 100 years. The content of the Special Issue on Root Biology covers a wide scale of contributions, spanning interactions of roots with microorganisms in the rhizosphere, the anatomy of root cells and tissues, the subcellular components of root cells, and aspects of metal accumulation and stresses on root function ...

  12. Differences in root uptake of radiocaesium by 30 plant taxa

    Energy Technology Data Exchange (ETDEWEB)

    Broadley, M R; Willey, N J [University of the West of England, Bristol (United Kingdom). Faculty of Applied Sciences

    1998-12-31

    The concentration of Cs was measured in the shoots of 30 taxa of plants after exposing the roots for 6 h to 0.1 {mu}g radiolabelled Cs g{sup -1} soil. There were maximum differences between Chenopodium quinoa and Koeleria macrantha of 20-fold in Cs concentration and 100-fold in total Cs accumulated. There was a weak relationship between Rb(K) and Cs concentration across the 30 taxa, but a strong relationship within the Gramineae and Chenopodiaceae. Taxa in the Chenopodiaceae discriminated approximately nine times less between Rb and Cs during uptake than did those in the Gramineae. The lowest Cs concentrations occurred in slow growing Gramineae and the highest in fast growing Chenopodiaceae. If radiocaesium uptake by the Chenopodiaceae during chronic exposures shows similar patterns to those reported here after acute exposure, then the food contamination implications and the potential for phytoremediation of radiocaesium contaminated soils using plants in this family may be worth investigating. (author).

  13. Root cause analysis for fire events at nuclear power plants

    International Nuclear Information System (INIS)

    1999-09-01

    Fire hazard has been identified as a major contributor to a plant' operational safety risk. The International nuclear power community (regulators, operators, designers) has been studying and developing tools for defending against this hazed. Considerable advances have been achieved during past two decades in design and regulatory requirements for fire safety, fire protection technology and related analytical techniques. The IAEA endeavours to provide assistance to Member States in improving fire safety in nuclear power plants. A task was launched by IAEA in 1993 with the purpose to develop guidelines and good practices, to promote advanced fire safety assessment techniques, to exchange state of the art information, and to provide engineering safety advisory services and training in the implementation of internationally accepted practices. This TECDOC addresses a systematic assessment of fire events using the root cause analysis methodology, which is recognized as an important element of fire safety assessment

  14. Differences in root uptake of radiocaesium by 30 plant taxa

    International Nuclear Information System (INIS)

    Broadley, M.R.; Willey, N.J.

    1997-01-01

    The concentration of Cs was measured in the shoots of 30 taxa of plants after exposing the roots for 6 h to 0.1 μg radiolabelled Cs g -1 soil. There were maximum differences between Chenopodium quinoa and Koeleria macrantha of 20-fold in Cs concentration and 100-fold in total Cs accumulated. There was a weak relationship between Rb(K) and Cs concentration across the 30 taxa, but a strong relationship within the Gramineae and Chenopodiaceae. Taxa in the Chenopodiaceae discriminated approximately nine times less between Rb and Cs during uptake than did those in the Gramineae. The lowest Cs concentrations occurred in slow growing Gramineae and the highest in fast growing Chenopodiaceae. If radiocaesium uptake by the Chenopodiaceae during chronic exposures shows similar patterns to those reported here after acute exposure, then the food contamination implications and the potential for phytoremediation of radiocaesium contaminated soils using plants in this family may be worth investigating. (author)

  15. Differences in root uptake of radiocaesium by 30 plant taxa

    Energy Technology Data Exchange (ETDEWEB)

    Broadley, M.R.; Willey, N.J. [University of the West of England, Bristol (United Kingdom). Faculty of Applied Sciences

    1997-12-31

    The concentration of Cs was measured in the shoots of 30 taxa of plants after exposing the roots for 6 h to 0.1 {mu}g radiolabelled Cs g{sup -1} soil. There were maximum differences between Chenopodium quinoa and Koeleria macrantha of 20-fold in Cs concentration and 100-fold in total Cs accumulated. There was a weak relationship between Rb(K) and Cs concentration across the 30 taxa, but a strong relationship within the Gramineae and Chenopodiaceae. Taxa in the Chenopodiaceae discriminated approximately nine times less between Rb and Cs during uptake than did those in the Gramineae. The lowest Cs concentrations occurred in slow growing Gramineae and the highest in fast growing Chenopodiaceae. If radiocaesium uptake by the Chenopodiaceae during chronic exposures shows similar patterns to those reported here after acute exposure, then the food contamination implications and the potential for phytoremediation of radiocaesium contaminated soils using plants in this family may be worth investigating. (author).

  16. Operational Evaluation of the Root Modules of the Advanced Plant Habitat

    Science.gov (United States)

    Monje, O.

    2014-01-01

    Photosynthetic and growth data were collected on APH Root Module. Described Stand pipe system for active moisture control. Tested germination in wicks. Evaluated EC-5 moisture sensors. Demonstrated that Wheat plants can grow in the APH Root Module.

  17. A review on the molecular mechanism of plants rooting modulated ...

    African Journals Online (AJOL)

    Adventitious root formation is a key step in vegetative propagation of woody or horticul-tural species, and it is a complex process known to be affected by multiple factors. The process of roots development could be divided into three stages: root induction, root initiation, and root protrusion. Phytohormones, especially auxin ...

  18. Spatial root distribution of plants growing in vertical media for use in living walls

    DEFF Research Database (Denmark)

    Jørgensen, Lars; Dresbøll, Dorte Bodin; Thorup-Kristensen, Kristian

    2014-01-01

    Background and Aims: For plants growing in living walls, the growth potential is correlated to the roots ability to utilize resources in all parts of the growing medium and thereby to the spatial root distribution. The aim of the study was to test how spatial root distribution was affected...... root growth was limited for plants in the middle or lower parts of the medium and 15N measurements confirmed that only plants in the bottom of the box had active roots in the bottom of the medium. The species differed in root architecture and spatial root distribution. Conclusions: The choice...... by growing medium, planting position and competition from other plants. Methods: Five species (Campanula poscharskyana cv. 'Stella', Fragaria vesca cv. 'Småland', Geranium sanguineum cv. 'Max Frei', Sesleria heufleriana and Veronica officinalis cv. 'Allgrün') were grown in three growing media (coir and two...

  19. Roles of abiotic losses, microbes, plant roots, and root exudates on phytoremediation of PAHs in a barren soil.

    Science.gov (United States)

    Sun, Tian-Ran; Cang, Long; Wang, Quan-Ying; Zhou, Dong-Mei; Cheng, Jie-Min; Xu, Hui

    2010-04-15

    Phytoremediation is an emerging technology for the remediation of polycyclic aromatic hydrocarbons (PAHs). In this study, pot experiments were conducted to evaluate the efficacy of phytoremediation of phenanthrene and pyrene in a typical low organic matter soil (3.75 g kg(-1)), and the contribution proportions of abiotic losses, microbes, plant roots, and root exudates were ascertained during the PAHs dissipation. The results indicated that contribution of abiotic losses from this soil was high both for phenanthrene (83.4%) and pyrene (57.2%). The contributions of root-exudates-enhanced biodegradation of phenanthrene (15.5%) and pyrene (21.3%) were higher than those of indigenous microbial degradation. The role of root exudates on dissipation of phenanthrene and pyrene was evident in this experiment. By the way, with the increasing of ring numbers in PAHs structures, the root-exudates-enhanced degradation became more and more important. BIOLOG-ECO plate analysis indicated that microbial community structure of the soil receiving root exudates had changed. The removal efficiency and substrate utilization rate in the treatment with plant roots were lower than the treatment only with root exudates, which suggested that possible competition between roots and microbes for nutrients had occurred in a low organic matter soil. 2009. Published by Elsevier B.V.

  20. 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.

  1. 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.

  2. How genetic modification of roots affects rhizosphere processes and plant performance

    NARCIS (Netherlands)

    Kabouw, P.; Van Dam, N.M.; Van der Putten, W.H.; Biere, A.

    2012-01-01

    Genetic modification of plants has become common practice. However, root-specific genetic modifications have only recently been advocated. Here, a review is presented regarding how root-specific modifications can have both plant internal and rhizosphere-mediated effects on aboveground plant

  3. Root-zone temperature and water availability affect early root growth of planted longleaf pine

    Science.gov (United States)

    M.A. Sword

    1995-01-01

    Longleaf pine seedlings from three seed sources were exposed to three root-zone temperatures and three levels of water availability for 28 days. Root growth declined as temperature and water availability decreased. Root growth differed by seed source. Results suggest that subtle changes in the regeneration environment may influence early root growth of longleaf pine...

  4. Advancements in Root Growth Measurement Technologies and Observation Capabilities for Container-Grown Plants

    Directory of Open Access Journals (Sweden)

    Lesley A. Judd

    2015-07-01

    Full Text Available The study, characterization, observation, and quantification of plant root growth and root systems (Rhizometrics has been and remains an important area of research in all disciplines of plant science. In the horticultural industry, a large portion of the crops grown annually are grown in pot culture. Root growth is a critical component in overall plant performance during production in containers, and therefore it is important to understand the factors that influence and/or possible enhance it. Quantifying root growth has varied over the last several decades with each method of quantification changing in its reliability of measurement and variation among the results. Methods such as root drawings, pin boards, rhizotrons, and minirhizotrons initiated the aptitude to measure roots with field crops, and have been expanded to container-grown plants. However, many of the published research methods are monotonous and time-consuming. More recently, computer programs have increased in use as technology advances and measuring characteristics of root growth becomes easier. These programs are instrumental in analyzing various root growth characteristics, from root diameter and length of individual roots to branching angle and topological depth of the root architecture. This review delves into the expanding technologies involved with expertly measuring root growth of plants in containers, and the advantages and disadvantages that remain.

  5. Advancements in Root Growth Measurement Technologies and Observation Capabilities for Container-Grown Plants.

    Science.gov (United States)

    Judd, Lesley A; Jackson, Brian E; Fonteno, William C

    2015-07-03

    The study, characterization, observation, and quantification of plant root growth and root systems (Rhizometrics) has been and remains an important area of research in all disciplines of plant science. In the horticultural industry, a large portion of the crops grown annually are grown in pot culture. Root growth is a critical component in overall plant performance during production in containers, and therefore it is important to understand the factors that influence and/or possible enhance it. Quantifying root growth has varied over the last several decades with each method of quantification changing in its reliability of measurement and variation among the results. Methods such as root drawings, pin boards, rhizotrons, and minirhizotrons initiated the aptitude to measure roots with field crops, and have been expanded to container-grown plants. However, many of the published research methods are monotonous and time-consuming. More recently, computer programs have increased in use as technology advances and measuring characteristics of root growth becomes easier. These programs are instrumental in analyzing various root growth characteristics, from root diameter and length of individual roots to branching angle and topological depth of the root architecture. This review delves into the expanding technologies involved with expertly measuring root growth of plants in containers, and the advantages and disadvantages that remain.

  6. Plant Reproduction: AMOR Enables Males to Respond to Female Signals.

    Science.gov (United States)

    Dresselhaus, Thomas; Coimbra, Silvia

    2016-04-25

    The pollen tube of flowering plants undertakes a long journey to transport two sperm cells for double fertilization. New work on pollen tube guidance has identified an arabinogalactan-derived ovular factor that primes tubes to respond to female gametophyte-secreted attraction signals. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Antifreeze proteins enable plants to survive in freezing conditions

    Indian Academy of Sciences (India)

    2014-10-20

    Oct 20, 2014 ... Recent studies have shown that plant AFPs bind to both prism planes and basal ... Abbreviations used: AFP, antifreeze protein; ECP, extra-cellular protein; IAC, ice adsorption ...... This work was partially supported by a grant (BT/PR10799/ ... ity in Ammopiptanthus mongolicus (in Chinese with English.

  8. A Model of Uranium Uptake by Plant Roots Allowing for Root-Induced Changes in the soil.

    Science.gov (United States)

    Boghi, Andrea; Roose, Tiina; Kirk, Guy J D

    2018-03-20

    We develop a model with which to study the poorly understood mechanisms of uranium (U) uptake by plants. The model is based on equations for transport and reaction of U and acids and bases in the rhizosphere around cylindrical plant roots. It allows for the speciation of U with hydroxyl, carbonate, and organic ligands in the soil solution; the nature and kinetics of sorption reactions with the soil solid; and the effects of root-induced changes in rhizosphere pH. A sensitivity analysis showed the importance of soil sorption and speciation parameters as influenced by pH and CO 2 pressure; and of root geometry and root-induced acid-base changes linked to the form of nitrogen taken up by the root. The root absorbing coefficient for U, relating influx to the concentration of U species in solution at the root surface, was also important. Simplified empirical models of U uptake by different plant species and soil types need to account for these effects.

  9. A novel life cycle arising from leaf segments in plants regenerated from horseradish hairy roots.

    Science.gov (United States)

    Mano, Y; Matsuhashi, M

    1995-03-01

    Horseradish (Armoracia rusticana) hairy root clones were established from hairy roots which were transformed with the Ri plasmid in Agrobacterium rhizogenes 15834. The transformed plants, which were regenerated from hairy root clones, had thicker roots with extensive lateral branches and thicker stems, and grew faster compared with non-transformed horseradish plants. Small sections of leaves of the transformed plants generated adventitious roots in phytohormone-free G (modified Gamborg's) medium. Root proliferation was followed by adventitious shoot formation and plant regeneration. Approximately twenty plants were regenerated per square centimeter of leaf. The transformed plants were easily transferable from sterile conditions to soil. When leaf segments of the transformed plants were cultured in a liquid fertilizer under non-sterile conditions, adventitious roots were generated at the cut ends of the leaves. Adventitious shoots were generated at the boundary between the leaf and the adventitious roots and developed into complete plants. This novel life cycle arising from leaf segments is a unique property of the transformed plants derived from hairy root clones.

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

    Science.gov (United States)

    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

  11. Root exudate-induced alterations in Bacillus cereus cell wall contribute to root colonization and plant growth promotion.

    Directory of Open Access Journals (Sweden)

    Swarnalee Dutta

    Full Text Available The outcome of an interaction between plant growth promoting rhizobacteria and plants may depend on the chemical composition of root exudates (REs. We report the colonization of tobacco, and not groundnut, roots by a non-rhizospheric Bacillus cereus (MTCC 430. There was a differential alteration in the cell wall components of B. cereus in response to the REs from tobacco and groundnut. Attenuated total reflectance infrared spectroscopy revealed a split in amide I region of B. cereus cells exposed to tobacco-root exudates (TRE, compared to those exposed to groundnut-root exudates (GRE. In addition, changes in exopolysaccharides and lipid-packing were observed in B. cereus grown in TRE-amended minimal media that were not detectable in GRE-amended media. Cell-wall proteome analyses revealed upregulation of oxidative stress-related alkyl hydroperoxide reductase, and DNA-protecting protein chain (Dlp-2, in response to GRE and TRE, respectively. Metabolism-related enzymes like 2-amino-3-ketobutyrate coenzyme A ligase and 2-methylcitrate dehydratase and a 60 kDa chaperonin were up-regulated in response to TRE and GRE. In response to B. cereus, the plant roots altered their exudate-chemodiversity with respect to carbohydrates, organic acids, alkanes, and polyols. TRE-induced changes in surface components of B. cereus may contribute to successful root colonization and subsequent plant growth promotion.

  12. Electric current precedes emergence of a lateral root in higher plants.

    Science.gov (United States)

    Hamada, S; Ezaki, S; Hayashi, K; Toko, K; Yamafuji, K

    1992-10-01

    Stable electrochemical patterns appear spontaneously around roots of higher plants and are closely related to growth. An electric potential pattern accompanied by lateral root emergence was measured along the surface of the primary root of adzuki bean (Phaseolus angularis) over 21 h using a microelectrode manipulated by a newly developed apparatus. The electric potential became lower at the point where a lateral root emerged. This change preceded the emergence of the lateral root by about 10 h. A theory is presented for calculating two-dimensional patterns of electric potential and electric current density around the primary root (and a lateral root) using only data on the one-dimensional electric potential measured near the surface of the primary root. The development of the lateral root inside the primary root is associated with the influx of electric current of about 0.7 muA.cm(-2) at the surface.

  13. Root growth and hydraulic conductivity of southern pine seedlings in response to soil temperature and water availability after planting

    Science.gov (United States)

    Mary Anne Sword Sayer; John C. Brissette; James P. Barnett

    2005-01-01

    Comparison of the root system growth and water transport of southern pine species after planting in different root-zone environments is needed to guide decisions regarding when, and what species to plant. Evaluation of how seed source affects root system responses to soil conditions will allow seed sources to be matched to planting conditions. The root growth and...

  14. Bilaterally symmetric axes with rhizoids composed the rooting structure of the common ancestor of vascular plants.

    Science.gov (United States)

    Hetherington, Alexander J; Dolan, Liam

    2018-02-05

    There are two general types of rooting systems in extant land plants: gametophyte rhizoids and sporophyte root axes. These structures carry out the rooting function in the free-living stage of almost all land plant gametophytes and sporophytes, respectively. Extant vascular plants develop a dominant, free-living sporophyte on which roots form, with the exception of a small number of taxa that have secondarily lost roots. However, fossil evidence indicates that early vascular plants did not develop sporophyte roots. We propose that the common ancestor of vascular plants developed a unique rooting system-rhizoidal sporophyte axes. Here we present a synthesis and reinterpretation of the rootless sporophytes of Horneophyton lignieri , Aglaophyton majus , Rhynia gwynne-vaughanii and Nothia aphylla preserved in the Rhynie chert. We show that the sporophyte rooting structures of all four plants comprised regions of plagiotropic (horizontal) axes that developed unicellular rhizoids on their underside. These regions of axes with rhizoids developed bilateral symmetry making them distinct from the other regions which were radially symmetrical. We hypothesize that rhizoidal sporophyte axes constituted the rooting structures in the common ancestor of vascular plants because the phylogenetic positions of these plants span the origin of the vascular lineage.This article is part of a discussion meeting issue 'The Rhynie cherts: our earliest terrestrial ecosystem revisited'. © 2017 The Authors.

  15. Sugars en route to the roots. Transport, metabolism and storage within plant roots and towards microorganisms of the rhizosphere.

    Science.gov (United States)

    Hennion, Nils; Durand, Mickael; Vriet, Cécile; Doidy, Joan; Maurousset, Laurence; Lemoine, Rémi; Pourtau, Nathalie

    2018-04-28

    In plants, root is a typical sink organ that relies exclusively on the import of sugar from the aerial parts. Sucrose is delivered by the phloem to the most distant root tips and, en route to the tip, is used by the different root tissues for metabolism and storage. Besides, a certain portion of this carbon is exuded in the rhizosphere, supplied to beneficial microorganisms and diverted by parasitic microbes. The transport of sugars towards these numerous sinks either occurs symplastically through cell connections (plasmodesmata) or is apoplastically mediated through membrane transporters (MST, SUT/SUC and SWEET) that control monosaccharide and sucrose fluxes. Here, we review recent progresses on carbon partitioning within and outside roots, discussing membrane transporters involved in plant responses to biotic and abiotic factors. This article is protected by copyright. All rights reserved.

  16. The Influence of Plant Root Systems on Subsurface Flow: Implications for Slope Stability

    Science.gov (United States)

    Although research has explained how plant roots mechanically stabilize soils, in this article we explore how root systems create networks of preferential flow and thus influence water pressures in soils to trigger landslides. Root systems may alter subsurface flow: Hydrological m...

  17. Characterizing the effects of brassinosteroids on root development in monocot plant species

    DEFF Research Database (Denmark)

    de Bang, Louise

    . With TILLING, two mutants of selected BR-related genes were identified in a Brachypodium distachyon mutant population. However, compared to the wild type, the mutants did not produce more biomass. The work with BR effects on plant root growth stimulated an interest for roots and root development, which...

  18. Competition between Plant-Populations with Different Rooting Depths. 3. Field Experiments

    NARCIS (Netherlands)

    Berendse, F.

    1982-01-01

    The model proposed in the first paper in this series predicts that in mixtures of plant species with different rooting depths there will be an inverse correlation between the relative crowding coefficient of the deep rooting species with respect to the shallow rooting one and the frequency of the

  19. Volatile oils from the plant and hairy root cultures of Ageratum conyzoides L.

    Science.gov (United States)

    Abdelkader, Mohamed Salaheldin A; Lockwood, George B

    2011-05-01

    Two lines of hairy root culture of Ageratum conyzoides L. induced by Agrobacterium rhizogenes ATCC 15834 were established under either complete darkness or 16 h light/8 h dark photoperiod conditions. The volatile oil yields from aerial parts and roots of the parent plant, the hairy root culture photoperiod line and the hairy root culture dark line were 0.2%, 0.08%, 0.03% and 0.02%, (w/w), respectively. The compositions of the volatiles from the hairy roots, plant roots and aerial parts were analysed by GC and GC-MS. The main components of the volatiles from the hairy root cultures were β-farnesene, precocene I and β-caryophyllene, in different amounts, depending on light conditions and also on the age of cultures. Precocene I, β-farnesene, precocene II and β-caryophyllene were the main constituents of the volatile oils from the parent plant roots, whereas precocene I, germacrene D, β-caryophyllene and precocene II were the main constituents of the aerial parts of the parent plant. Growth and time-course studies of volatile constituents of the two hairy root lines were compared. Qualitative and quantitative differences were found between the volatile oils from the roots of the parent plant and those from the hairy roots.

  20. A global Fine-Root Ecology Database to address below-ground challenges in plant ecology.

    Science.gov (United States)

    Iversen, Colleen M; McCormack, M Luke; Powell, A Shafer; Blackwood, Christopher B; Freschet, Grégoire T; Kattge, Jens; Roumet, Catherine; Stover, Daniel B; Soudzilovskaia, Nadejda A; Valverde-Barrantes, Oscar J; van Bodegom, Peter M; Violle, Cyrille

    2017-07-01

    Variation and tradeoffs within and among plant traits are increasingly being harnessed by empiricists and modelers to understand and predict ecosystem processes under changing environmental conditions. While fine roots play an important role in ecosystem functioning, fine-root traits are underrepresented in global trait databases. This has hindered efforts to analyze fine-root trait variation and link it with plant function and environmental conditions at a global scale. This Viewpoint addresses the need for a centralized fine-root trait database, and introduces the Fine-Root Ecology Database (FRED, http://roots.ornl.gov) which so far includes > 70 000 observations encompassing a broad range of root traits and also includes associated environmental data. FRED represents a critical step toward improving our understanding of below-ground plant ecology. For example, FRED facilitates the quantification of variation in fine-root traits across root orders, species, biomes, and environmental gradients while also providing a platform for assessments of covariation among root, leaf, and wood traits, the role of fine roots in ecosystem functioning, and the representation of fine roots in terrestrial biosphere models. Continued input of observations into FRED to fill gaps in trait coverage will improve our understanding of changes in fine-root traits across space and time. © 2017 UT-Battelle LLC. New Phytologist © 2017 New Phytologist Trust.

  1. Translocation of nitrogen and carbon from levels to roots of different nodes in rice plants

    International Nuclear Information System (INIS)

    Tatsumi, Jiro; Kono, Yasuhiro; Okano, Kunio.

    1983-01-01

    The whole shoot of the plant at the stage of developing the 12th leaf (12L) and the 9th nodal roots (9nR) was fed with 13 C-labelled CO 2 gas for 60 minutes after bein g sprayed with 15 N-labeled urea solution, and the fate of 15 N and 13 C in the plant was followed over 12 days. 15 N and 13 C were translocated to all parts of the plant, preferentially to the expanding 12L and the root system. Among the roots, the upper roots (9nR) were the largest sink of 15 N and 13 C exported from the expanded leaves. However, not only the young upper roots, but also the old lower roots were the sinks of the nitrogenous compounds. The difference in the 13 C/ 15 N ratio among the nodal roots suggests that the C/N ratio of the foliar products imported into the roots varied with their node positions; lower roots received the products containing richer N relative to C than the upper roots. Each leaf at different node seemed to play a specific role to supply the root system with the products of variable C/N ratio; upper leaves supplied the products of higher C/N ratio mainly to upper roots, while lower leaves fed the products of lower C/N ratio to lower roots. (Kaihara, S.)

  2. A fungal endophyte helps plants to tolerate root herbivory through changes in gibberellin and jasmonate signaling.

    Science.gov (United States)

    Cosme, Marco; Lu, Jing; Erb, Matthias; Stout, Michael Joseph; Franken, Philipp; Wurst, Susanne

    2016-08-01

    Plant-microbe mutualisms can improve plant defense, but the impact of root endophytes on below-ground herbivore interactions remains unknown. We investigated the effects of the root endophyte Piriformospora indica on interactions between rice (Oryza sativa) plants and its root herbivore rice water weevil (RWW; Lissorhoptrus oryzophilus), and how plant jasmonic acid (JA) and GA regulate this tripartite interaction. Glasshouse experiments with wild-type rice and coi1-18 and Eui1-OX mutants combined with nutrient, jasmonate and gene expression analyses were used to test: whether RWW adult herbivory above ground influences subsequent damage caused by larval herbivory below ground; whether P. indica protects plants against RWW; and whether GA and JA signaling mediate these interactions. The endophyte induced plant tolerance to root herbivory. RWW adults and larvae acted synergistically via JA signaling to reduce root growth, while endophyte-elicited GA biosynthesis suppressed the herbivore-induced JA in roots and recovered plant growth. Our study shows for the first time the impact of a root endophyte on plant defense against below-ground herbivores, adds to growing evidence that induced tolerance may be an important root defense, and implicates GA as a signal component of inducible plant tolerance against biotic stress. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

  3. Searching for plant root traits to improve soil cohesion and resist soil erosion

    Science.gov (United States)

    De Baets, Sarah; Smyth, Kevin; Denbigh, Tom; Weldon, Laura; Higgins, Ben; Matyjaszkiewicz, Antoni; Meersmans, Jeroen; Chenchiah, Isaac; Liverpool, Tannie; Quine, Tim; Grierson, Claire

    2017-04-01

    Soil erosion poses a serious threat to future food and environmental security. Soil erosion protection measures are therefore of great importance for soil conservation and food security. Plant roots have proven to be very effective in stabilizing the soil and protecting the soil against erosion. However, no clear insights are yet obtained into the root traits that are responsible for root-soil cohesion. This is important in order to better select the best species for soil protection. Research using Arabidopsis mutants has made great progress towards explaining how root systems are generated by growth, branching, and responses to gravity, producing mutants that affect root traits. In this study, the performance of selected Arabidopsis mutants is analyzed in three root-soil cohesion assays. Measurements of detachment, uprooting force and soil detachment are here combined with the microscopic analysis of root properties, such as the presence, length and density of root hairs in this case. We found that Arabidopsis seedlings with root hairs (wild type, wer myb23, rsl4) were more difficult to detach from gel media than hairless (cpc try) or short haired (rsl4, rhd2) roots. Hairy roots (wild type, wer myb23) on mature, non-reproductive rosettes were more difficult to uproot from compost or clay soil than hairless roots (cpc try). At high root densities, erosion rates from soils with hairless roots (cpc try) were as much as 10 times those seen from soils occupied by roots with hairs (wer myb23, wild type). We find therefore root hairs play a significant role in root-soil cohesion and in minimizing erosion. This framework and associated suite of experimental assays demonstrates its ability to measure the effect of any root phenotype on the effectiveness of plant roots in binding substrates and reducing erosion.

  4. Efflux of inorganic substances from young barley roots. II. Movement in roots and efflux of sodium in plants with divided root systems

    Energy Technology Data Exchange (ETDEWEB)

    Fujimoto, H; Kojima, S [Radiation Center of Osaka Prefecture, Sakai (Japan)

    1977-09-01

    The root system of young barley was almost halved, and the two portions were planted in culture grounds with different composition after severing the capillary connection between both root groups. With one portion in the acid medium solution of various compositions and the other in the /sup 22/Na-absorbing medium solution, the sodium absorbed from one root group moved to and flowed out from the other root group, and this state was observed. Also, the efflux of potassium from the root was observed. (1) The Na efflux was small in the culture ground with dilute hydrochloric acid, and larger in that with AlCl/sub 3/ or phosphate. (2) The K efflux was large under short-day condition. (3) Under short-day condition, in the culture ground with soluble Al, the K efflux was promoted by nitrogen-source addition, but the Na efflux was suppressed.

  5. Artificial Plant Root System Growth for Distributed Optimization: Models and Emergent Behaviors

    Directory of Open Access Journals (Sweden)

    Su Weixing

    2016-01-01

    Full Text Available Plant root foraging exhibits complex behaviors analogous to those of animals, including the adaptability to continuous changes in soil environments. In this work, we adapt the optimality principles in the study of plant root foraging behavior to create one possible bio-inspired optimization framework for solving complex engineering problems. This provides us with novel models of plant root foraging behavior and with new methods for global optimization. This framework is instantiated as a new search paradigm, which combines the root tip growth, branching, random walk, and death. We perform a comprehensive simulation to demonstrate that the proposed model accurately reflects the characteristics of natural plant root systems. In order to be able to climb the noise-filled gradients of nutrients in soil, the foraging behaviors of root systems are social and cooperative, and analogous to animal foraging behaviors.

  6. Root excretions in tobacco plants and possible implications on the Iron nutrition of higher plants

    Energy Technology Data Exchange (ETDEWEB)

    Wallace, A

    1969-01-01

    Several pieces of evidence indicate that riboflavin produced in roots and perhaps other compounds produced either in roots or in microorganisms can facilitate either or both the absorption and translocation of iron in higher plants. Riboflavin production and increased iron transport are characteristic of iron-deficient plants, both are decreased by nitrogen deficiency, both evidently can be regulated by a microorganism. When large amounts of iron was transported in the xylem exudate of tobacco, riboflavin was also. An excess of the chelating agent, EDTA, without iron seems to increase the iron uptake from an iron chelate, EDDHA. All these effects are probably related and knowledge of them may help solve iron deficiency problems in horticultural crops.

  7. Root biomass and exudates link plant diversity with soil bacterial and fungal biomass

    NARCIS (Netherlands)

    Eisenhauer, Nico; Lanoue, Arnaud; Strecker, Tanja; Scheu, Stefan; Steinauer, Katja; Thakur, Madhav P.; Mommer, Liesje

    2017-01-01

    Plant diversity has been shown to determine the composition and functioning of soil biota. Although root-derived organic inputs are discussed as the main drivers of soil communities, experimental evidence is scarce. While there is some evidence that higher root biomass at high plant diversity

  8. Data from: Root biomass and exudates link plant diversity with soil bacterial and fungal biomass

    NARCIS (Netherlands)

    Eisenhauer, Nico; Strecker, Tanja; Lanoue, Arnaud; Scheu, Stefan; Steinauer, Katja; Thakur, Madhav P.; Mommer, L.

    2017-01-01

    Plant diversity has been shown to determine the composition and functioning of soil biota. Although root-derived organic inputs are discussed as the main drivers of soil communities, experimental evidence is scarce. While there is some evidence that higher root biomass at high plant diversity

  9. Effects of plant growth regulators on callus, shoot and root formation ...

    African Journals Online (AJOL)

    Root and stem explants of fluted pumpkin were cultured in medium containing different types and concentrations of plant growth regulators (PGRs). The explants were observed for callus, root and shoot formation parameters after four months. Differences among explants, plant growth regulators and their interaction were ...

  10. Competition between Plant-Populations with Different Rooting Depths. 2. Pot Experiments

    NARCIS (Netherlands)

    Berendse, F.

    1981-01-01

    In a previous paper in this series a model was proposed lor the competition between plant populations with different rooting depths. This model predicts that in mixtures of plant populations with different rooting depths the Relative Yield Total will exceed unity. Secondly it predicts that in these

  11. Competition between Plant-Populations with Different Rooting Depths. 1. Theoretical Considerations

    NARCIS (Netherlands)

    Berendse, F.

    1979-01-01

    As an extension of De Wit's competition theory a theoretical description has been developed of competition between plant populations with different rooting depths. This model shows that in mixtures of plants with different rooting depths the value of the Relative Yield Total can be expected to

  12. Competition Between Plant Populations with Different Rooting Depths I. Theoretical Considerations

    NARCIS (Netherlands)

    Berendse, Frank

    1979-01-01

    As an extension of De Wit’s competition theory a theoretical description has been developed of competition between plant populations with different rooting depths. This model shows that in mixtures of plants with different rooting depths the value of the Relative Yield Total can be expected to

  13. CLE peptides regulate lateral root development in response to nitrogen nutritional status of plants.

    Science.gov (United States)

    Araya, Takao; von Wirén, Nicolaus; Takahashi, Hideki

    2014-01-01

    CLE (CLAVATA3/embryo surrounding region (ESR)) peptides control meristem functions in plants. Our recent study highlights the critical role of a peptide-receptor signaling module composed of nitrogen (N)-responsive CLE peptides and the CLAVATA1 (CLV1) leucine-rich repeat receptor-like kinase in controlling lateral root development in Arabidopsis thaliana. CLE1, -3, -4 and -7 are expressed in root pericycle cells in Arabidopsis roots under N-limited growth conditions. Overexpression of these CLE genes inhibits lateral root emergence from the primary root. The inhibitory action of N-responsive CLE peptides on lateral root development requires the function of CLV1 expressed in phloem companion cells in roots, suggesting that downstream signals are transferred through phloem for systemic regulation of root system architecture. An additional mechanism downstream of CLV1 feedback-regulates transcript levels of N-responsive CLE genes in roots for fine-tuning the signal amplitude.

  14. Rooting out Defense Mechanisms in Wheat against Plant Parasitic Nematodes

    Science.gov (United States)

    Root-lesion nematodes (Pratylenchus spp.) are soil borne pathogens of many important agricultural crops including wheat. Pratylenchus invade root cells and feed using a stylet, resulting in cell death. Common signs of Pratylenchus damage are root lesions, girdling, and lack of lateral branching. ...

  15. Rooting depths of plants on low-level waste disposal sites

    International Nuclear Information System (INIS)

    Foxx, T.S.; Tierney, G.D.; Williams, J.M.

    1984-11-01

    In 1981-1982 an extensive bibliographic study was done to reference rooting depths of native plants in the United States. The data base presently contains 1034 different rooting citations with approximately 12,000 data elements. For this report, data were analyzed for rooting depths related to species found on low-level waste (LLW) sites at Los Alamos National Laboratory. Average rooting depth and rooting frequencies were determined and related to present LLW maintenance. The data base was searched for information on rooting depths of 53 species found on LLW sites at Los Alamos National Laboratory. The study indicates 12 out of 13 grasses found on LLW sites root below 91 cm. June grass [Koeleria cristata (L.) Pers.] (76 cm) was the shallowest rooting grass and side-oats grama [Bouteloua curtipendula (Michx.) Torr.] was the deepest rooting grass (396 cm). Forbs were more variable in rooting depths. Indian paintbrush (Castelleja spp.) (30 cm) was the shallowest rooting forb and alfalfa (Medicago sativa L.) was the deepest (>3900 cm). Trees and shrubs commonly rooted below 457 cm. The shallowest rooting tree was elm (Ulmus pumila L.) (127 cm) and the deepest was one-seed juniper [Juniperus monosperma (Engelm) Sarg.] (>6000 cm). Apache plume [Fallugia paradoxa (D. Don) Endl.] rooted to 140 cm, whereas fourwing saltbush [Atriplex canecens (Pursh) Nutt.] rooted to 762 cm

  16. Interspecies Interactions in Relation to Root Distribution Across the Rooting Profile in Wheat-Maize Intercropping Under Different Plant Densities

    Directory of Open Access Journals (Sweden)

    Yifan Wang

    2018-04-01

    Full Text Available In wheat-maize intercropping systems, the maize is often disadvantageous over the wheat during the co-growth period. It is unknown whether the impaired growth of maize can be recovered through the enhancement of the belowground interspecies interactions. In this study, we (i determined the mechanism of the belowground interaction in relation to root growth and distribution under different maize plant densities, and (ii quantified the “recovery effect” of maize after wheat harvest. The three-year (2014–2016 field experiment was conducted at the Oasis Agriculture Research Station of Gansu Agricultural University, Wuwei, Northwest China. Root weight density (RWD, root length density (RLD, and root surface area density (RSAD, were measured in single-cropped maize (M, single-cropped wheat (W, and three intercropping systems (i wheat-maize intercropping with no root barrier (i.e., complete belowground interaction, IC, (ii nylon mesh root barrier (partial belowground interaction, IC-PRI, and (iii plastic sheet root barrier (no belowground interaction, IC-NRI. The intercropped maize was planted at low (45,000 plants ha−1 and high (52,000 plants ha−1 densities. During the wheat/maize co-growth period, the IC treatment increased the RWD, RLD, and RSAD of the intercropped wheat in the 20–100 cm soil depth compared to the IC-PRI and IC-NRI systems; intercropped maize had 53% lower RWD, 81% lower RLD, and 70% lower RSAD than single-cropped maize. After wheat harvest, the intercropped maize recovered the growth with the increase of RWD by 40%, RLD by 44% and RSAD by 11%, compared to the single-cropped maize. Comparisons among the three intercropping systems revealed that the “recovery effect” of the intercropped maize was attributable to complete belowground interspecies interaction by 143%, the compensational effect due to root overlap by 35%, and the compensational effect due to water and nutrient exchange (CWN by 80%. The higher maize plant

  17. A Pipeline for 3D Digital Optical Phenotyping Plant Root System Architecture

    Science.gov (United States)

    Davis, T. W.; Shaw, N. M.; Schneider, D. J.; Shaff, J. E.; Larson, B. G.; Craft, E. J.; Liu, Z.; Kochian, L. V.; Piñeros, M. A.

    2017-12-01

    This work presents a new pipeline for digital optical phenotyping the root system architecture of agricultural crops. The pipeline begins with a 3D root-system imaging apparatus for hydroponically grown crop lines of interest. The apparatus acts as a self-containing dark room, which includes an imaging tank, motorized rotating bearing and digital camera. The pipeline continues with the Plant Root Imaging and Data Acquisition (PRIDA) software, which is responsible for image capturing and storage. Once root images have been captured, image post-processing is performed using the Plant Root Imaging Analysis (PRIA) command-line tool, which extracts root pixels from color images. Following the pre-processing binarization of digital root images, 3D trait characterization is performed using the next-generation RootReader3D software. RootReader3D measures global root system architecture traits, such as total root system volume and length, total number of roots, and maximum rooting depth and width. While designed to work together, the four stages of the phenotyping pipeline are modular and stand-alone, which provides flexibility and adaptability for various research endeavors.

  18. GROWTH PROCESS OF ORGANIC VETIVER ROOT WITH POTATO AS INTERCROPPING PLANT

    Directory of Open Access Journals (Sweden)

    Asep Kadarohman

    2012-02-01

    Full Text Available Vetiver oil (Vetiveria zizanoides is one of Indonesia main export commodities. Vetiver root is perennial plant and generally planted with vegetables as intercropping plant. Increasing the selling price of vetiver oil can be done by transferring the production of conventional vetiver oil (non-organic to organic vetiver oil. Demonstration of land used was one hectare, which 2,000 m2 for planting vetiver root with potato (Solanum tuberosum as inter-cropping plant and 8,000 m2 for vetiver root without intercropping, in Sukakarya-Samarang, Garut. The planting used goat and cow dung as manure, distillate water of vetiver oil and liquid bio-pesticide as pesticide. Variables studied included plant height, number of leaf and crotch. In the first quarter of the years, the number of leaf and crotch of vetiver root with intercropping was better than vetiver root without inter-cropping. However, there was not significant difference for plant height of vetiver root, both with and without intercropping. Products of organic potato as intercropping plant of vetiver root were less than those of non-organic potato, but the latter had a better texture and durability.

  19. 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.

  20. Novel enabling technologies of gene isolation and plant transformation for improved crop protection

    Energy Technology Data Exchange (ETDEWEB)

    Torok, Tamas

    2013-02-04

    Meeting the needs of agricultural producers requires the continued development of improved transgenic crop protection products. The completed project focused on developing novel enabling technologies of gene discovery and plant transformation to facilitate the generation of such products.

  1. Maize root culture as a model system for studying azoxystrobin biotransformation in plants

    DEFF Research Database (Denmark)

    Gautam, Maheswor; Elhiti, Mohamed Abdelsamad A; Fomsgaard, Inge S.

    2018-01-01

    Hairy roots induced by Agrobacterium rhizogenes are well established models to study the metabolism of xenobiotics in plants for phytoremediation purposes. However, the model requires special skills and resources for growing and is a time-consuming process. The roots induction process alters...... the genetic construct of a plant and is known to express genes that are normally absent from the non-transgenic plants. In this study, we propose and establish a non-transgenic maize root model to study xenobiotic metabolism in plants for phytoremediation purpose using azoxystrobin as a xenobiotic compound...

  2. Aquatic adventitious roots of the wetland plant Meionectes brownii can photosynthesize

    DEFF Research Database (Denmark)

    Rich, Sarah Meghan; Ludwig, Martha; Pedersen, Ole

    2011-01-01

    • Many wetland plants produce aquatic adventitious roots from submerged stems. Aquatic roots can form chloroplasts, potentially producing endogenous carbon and oxygen. Here, aquatic root photosynthesis was evaluated in the wetland plant Meionectes brownii, which grows extensive stem-borne aquatic...... roots during submergence. • Underwater photosynthetic light and CO(2) response curves were determined for aquatic-adapted leaves, stems and aquatic roots of M. brownii. Oxygen microelectrode and (14)CO(2)-uptake experiments determined shoot inputs of O(2) and photosynthate into aquatic roots. • Aquatic...... adventitious roots contain a complete photosynthetic pathway. Underwater photosynthetic rates are similar to those of stems, with a maximum net photosynthetic rate (P(max)) of 0.38 µmol O(2) m(-2) s(-1); however, this is c. 30-fold lower than that of aquatic-adapted leaves. Under saturating light with 300 mmol...

  3. Root porosity and radial oxygen loss related to arsenic tolerance and uptake in wetland plants

    International Nuclear Information System (INIS)

    Li, H.; Ye, Z.H.; Wei, Z.J.; Wong, M.H.

    2011-01-01

    The rates of radial oxygen loss (ROL), root porosity, concentrations of arsenic (As), iron (Fe) and manganese (Mn) in shoot and root tissues and on root surfaces, As tolerances, and their relationships in different wetland plants were investigated based on a hydroponic experiment (control, 0.8, 1.6 mg As L -1 ) and a soil pot trail (control, 60 mg As kg -1 ). The results revealed that wetland plants showed great differences in root porosity (9-64%), rates of ROL (55-1750 mmo1 O 2 kg -1 root d.w. d -1 ), As uptake (e.g., 8.8-151 mg kg -1 in shoots in 0.8 mg As L -1 treatment), translocation factor (2.1-47% in 0.8 mg As L -1 ) and tolerance (29-106% in 0.8 mg As L -1 ). Wetland plants with higher rates of ROL and root porosity tended to form more Fe/Mn plaque, possess higher As tolerance, higher concentrations of As on root surfaces and a lower As translocation factor so decreasing As toxicity. - Research highlights: → There is significant correlation between the porosity of roots and rates of ROL. → The rates of ROL are significantly correlated with tolerance indices and concentrations of As, Fe, Mn on root surface. → The rates of ROL is negatively correlated with As translocation factor. - Wetland plants with high rates of ROL tended to form more Fe plaque on root surfaces and possess higher As tolerance.

  4. Can diversity in root architecture explain plant water use efficiency? A modeling study.

    Science.gov (United States)

    Tron, Stefania; Bodner, Gernot; Laio, Francesco; Ridolfi, Luca; Leitner, Daniel

    2015-09-24

    Drought stress is a dominant constraint to crop production. Breeding crops with adapted root systems for effective uptake of water represents a novel strategy to increase crop drought resistance. Due to complex interaction between root traits and high diversity of hydrological conditions, modeling provides important information for trait based selection. In this work we use a root architecture model combined with a soil-hydrological model to analyze whether there is a root system ideotype of general adaptation to drought or water uptake efficiency of root systems is a function of specific hydrological conditions. This was done by modeling transpiration of 48 root architectures in 16 drought scenarios with distinct soil textures, rainfall distributions, and initial soil moisture availability. We find that the efficiency in water uptake of root architecture is strictly dependent on the hydrological scenario. Even dense and deep root systems are not superior in water uptake under all hydrological scenarios. Our results demonstrate that mere architectural description is insufficient to find root systems of optimum functionality. We find that in environments with sufficient rainfall before the growing season, root depth represents the key trait for the exploration of stored water, especially in fine soils. Root density, instead, especially near the soil surface, becomes the most relevant trait for exploiting soil moisture when plant water supply is mainly provided by rainfall events during the root system development. We therefore concluded that trait based root breeding has to consider root systems with specific adaptation to the hydrology of the target environment.

  5. Cadmium induces hypodermal periderm formation in the roots of the monocotyledonous medicinal plant Merwilla plumbea.

    Science.gov (United States)

    Lux, Alexander; Vaculík, Marek; Martinka, Michal; Lisková, Desana; Kulkarni, Manoj G; Stirk, Wendy A; Van Staden, Johannes

    2011-02-01

    Merwilla plumbea is an important African medicinal plant. As the plants grow in soils contaminated with metals from mining activities, the danger of human intoxication exists. An experiment with plants exposed to cadmium (Cd) was performed to investigate the response of M. plumbea to this heavy metal, its uptake and translocation to plant organs and reaction of root tissues. Plants grown from seeds were cultivated in controlled conditions. Hydroponic cultivation is not suitable for this species as roots do not tolerate aquatic conditions, and additional stress by Cd treatment results in total root growth inhibition and death. After cultivation in perlite the plants exposed to 1 and 5 mg Cd L(-1) in half-strength Hoagland's solution were compared with control plants. Growth parameters were evaluated, Cd content was determined by inductively coupled plasma mass spectroscopy (ICP-MS) and root structure was investigated using various staining procedures, including the fluorescent stain Fluorol yellow 088 to detect suberin deposition in cell walls. The plants exposed to Cd were significantly reduced in growth. Most of the Cd taken up by plants after 4 weeks cultivation was retained in roots, and only a small amount was translocated to bulbs and leaves. In reaction to higher Cd concentrations, roots developed a hypodermal periderm close to the root tip. Cells produced by cork cambium impregnate their cell walls by suberin. It is suggested that the hypodermal periderm is developed in young root parts in reaction to Cd toxicity to protect the root from radial uptake of Cd ions. Secondary meristems are usually not present in monocotyledonous species. Another interpretation explaining formation of protective suberized layers as a result of periclinal divisions of the hypodermis is discussed. This process may represent an as yet unknown defence reaction of roots when exposed to elemental stress.

  6. Rhizosphere microbial community structure in relation to root location and plant iron nutritional status.

    Science.gov (United States)

    Yang, C H; Crowley, D E

    2000-01-01

    Root exudate composition and quantity vary in relation to plant nutritional status, but the impact of the differences on rhizosphere microbial communities is not known. To examine this question, we performed an experiment with barley (Hordeum vulgare) plants under iron-limiting and iron-sufficient growth conditions. Plants were grown in an iron-limiting soil in root box microcosms. One-half of the plants were treated with foliar iron every day to inhibit phytosiderophore production and to alter root exudate composition. After 30 days, the bacterial communities associated with different root zones, including the primary root tips, nonelongating secondary root tips, sites of lateral root emergence, and older roots distal from the tip, were characterized by using 16S ribosomal DNA (rDNA) fingerprints generated by PCR-denaturing gradient gel electrophoresis (DGGE). Our results showed that the microbial communities associated with the different root locations produced many common 16S rDNA bands but that the communities could be distinguished by using correspondence analysis. Approximately 40% of the variation between communities could be attributed to plant iron nutritional status. A sequence analysis of clones generated from a single 16S rDNA band obtained at all of the root locations revealed that there were taxonomically different species in the same band, suggesting that the resolving power of DGGE for characterization of community structure at the species level is limited. Our results suggest that the bacterial communities in the rhizosphere are substantially different in different root zones and that a rhizosphere community may be altered by changes in root exudate composition caused by changes in plant iron nutritional status.

  7. Classroom Modified Split-Root Technique and Its Application in a Plant Habitat Selection Experiment at the College Level

    Science.gov (United States)

    Elliott, Shannon S.; Winter, Peggy A.

    2011-01-01

    The split-root technique produces a plant with two equal root masses. Traditionally, the two root masses of the single plant are cultivated in adjacent pots with or without roots from competitors for the purpose of elucidating habitat preferences. We have tailored this technology for the classroom, adjusting protocols to match resources and time…

  8. In situ stimulation vs. bioaugmentation: Can microbial inoculation of plant roots enhance biodegradation of organic compounds?

    Energy Technology Data Exchange (ETDEWEB)

    Kingsley, M.T.; Metting, F.B. Jr.; Fredrickson, J.K. [Pacific Northwest Lab., Richland, WA (United States); Seidler, R.J. [Environmental Protection Agency, Corvallis, OR (United States). Environmental Research Lab.

    1993-06-01

    The use of plant roots and their associated rhizosphere bacteria for biocontainment and biorestoration offers several advantages for treating soil-dispersed contaminants and for application to large land areas. Plant roots function as effective delivery systems, since root growth transports bacteria vertically and laterally along the root in the soil column (see [ 1,2]). Movement of microbes along roots and downward in the soil column can be enhanced via irrigation [1-4]. For example, Ciafardini et al. [3] increased the nodulation and the final yield of soybeans during pod filling by including Bradyrhizobium japonicum in the irrigation water. Using rhizosphere microorganisms is advantageous for biodegradation of compounds that are degraded mainly by cometabolic processes, e.g., trichloroethylene (TCE). The energy source for bacterial growth and metabolism is supplied by the plant in the form of root exudates and other sloughed organic material. Plants are inexpensive, and by careful choice of species that possess either tap or fibrous root growth patterns, they can be used to influence mass transport of soil contaminants to the root surface via the transpiration stream [5]. Cropping of plants to remove heavy metals from contaminated soils has been proposed as a viable, low-cost, low-input treatment option [6]. The interest in use of plants as a remediation strategy has even reached the popular press [7], where the use of ragweed for the reclamation of sites contaminated with tetraethyl lead and other heavy metals was discussed.

  9. Field performance of Quercus bicolor established as repeatedly air-root-pruned container and bareroot planting stock

    Science.gov (United States)

    J.W." Jerry" Van Sambeek; Larry D. Godsey; William D. Walter; Harold E. Garrett; John P. Dwyer

    2016-01-01

    Benefits of repeated air-root-pruning of seedlings when stepping up to progressively larger containers include excellent lateral root distribution immediately below the root collar and an exceptionally fibrous root ball. To evaluate long-term field performance of repeatedly air-root-pruned container stock, three plantings of swamp white oak (Quercus bicolor...

  10. Coarse and fine root plants affect pore size distributions differently

    OpenAIRE

    Bodner, G.; Leitner, D.; Kaul, H.-P.

    2014-01-01

    Aims Small scale root-pore interactions require validation of their impact on effective hydraulic processes at the field scale. Our objective was to develop an interpretative framework linking root effects on macroscopic pore parameters with knowledge at the rhizosphere scale. Methods A field experiment with twelve species from different families was conducted. Parameters of Kosugi?s pore size distribution (PSD) model were determined inversely from tension infiltrometer data. Measured root tr...

  11. Linking root hydraulic properties to carbon allocation patterns in annual plant

    Science.gov (United States)

    Hosseini, A.; Ewers, B. E.; Adjesiwor, A. T.; Kniss, A. R.

    2017-12-01

    Incorporation of root structure and function into biophysical models is an important tool to predict plant water and nutrient uptake from the soil, plant carbon (C) assimilation, partitioning and release to the soils. Most of the models describing root water uptake (RWU) are based on semi-empirical (i.e. built on physiological hypotheses, but still combined with empirical functions) approaches and hydraulic parameters involved are hardly available. Root conductance is essential to define the interaction between soil-to-root and canopy-to-atmosphere. Also root hydraulic limitations to water flow can impact gas exchange rates and plant biomass partitioning. In this study, sugar beet (B. vulgaris) seeds under two treatments, grass (Kentucky bluegrass) and no grass (control), were planted in 19 L plastic buckets in June 2016. Photosynthetic characteristics (e.g. gas exchange and chlorophyll fluorescence), leaf morphology and anatomy, root morphology and above and below ground biomass of the plants was monitored at 15, 30, 50, 70 and 90 days after planting (DAP). Further emphasis was placed on the limits to water flow by coupling of hydraulic conductance (k) whole root-system with water relation parameters and gas exchange rates in fully established plants.

  12. Exploring the transfer of recent plant photosynthates to soil microbes: mycorrhizal pathway vs direct root exudation

    Science.gov (United States)

    Kaiser, Christina; Kilburn, Matt R; Clode, Peta L; Fuchslueger, Lucia; Koranda, Marianne; Cliff, John B; Solaiman, Zakaria M; Murphy, Daniel V

    2015-01-01

    Plants rapidly release photoassimilated carbon (C) to the soil via direct root exudation and associated mycorrhizal fungi, with both pathways promoting plant nutrient availability. This study aimed to explore these pathways from the root's vascular bundle to soil microbial communities. Using nanoscale secondary ion mass spectrometry (NanoSIMS) imaging and 13C-phospho- and neutral lipid fatty acids, we traced in-situ flows of recently photoassimilated C of 13CO2-exposed wheat (Triticum aestivum) through arbuscular mycorrhiza (AM) into root- and hyphae-associated soil microbial communities. Intraradical hyphae of AM fungi were significantly 13C-enriched compared to other root-cortex areas after 8 h of labelling. Immature fine root areas close to the root tip, where AM features were absent, showed signs of passive C loss and co-location of photoassimilates with nitrogen taken up from the soil solution. A significant and exclusively fresh proportion of 13C-photosynthates was delivered through the AM pathway and was utilised by different microbial groups compared to C directly released by roots. Our results indicate that a major release of recent photosynthates into soil leave plant roots via AM intraradical hyphae already upstream of passive root exudations. AM fungi may act as a rapid hub for translocating fresh plant C to soil microbes. PMID:25382456

  13. Plant Functional Traits Associated with Mycorrhizal Root Foraging in Arbuscular Mycorrhizal and Ectomycorrhizal Trees

    Science.gov (United States)

    Eissenstat, D. M.; Chen, W.; Cheng, L.; Liu, B.; Koide, R. T.; Guo, D.

    2016-12-01

    Root foraging for nutrient "hot spots" is a key strategy by which some plants maximize nutrient gain from their carbon investment in root and mycorrhizal hyphae. Foraging strategies may depend on costs of root construction, with thick roots generally costing more per unit length than thin roots. Investment in mycorrhizal hyphae, which are considerably thinner than roots, may represent an alternative strategy for cost-effective nutrient foraging, especially for thick-root species. Type of mycorrhiza may matter, as ectomycorrhizal (EM) fungi are more associated with longer hyphae and ability to mineralize organic matter than arbuscular mycorrhizal (AM) fungi. Among AM trees in both subtropical forests in SE China and in temperate forests in central Pennsylvania, USA, we found that tree species with thin roots proliferated their roots in soil patches enriched with mineral nutrients to a greater extent than species with thick roots. In addition, thick-root species were consistently colonized more heavily with mycorrhizal fungi than thin root species, although nutrient addition tended to diminish colonization. In a common garden in central Pennsylvania of both AM and EM tree species, we found that nutrient patches enriched with organic materials resulted in greater root and mycorrhizal fungal proliferation compared to those enriched with inorganic nutrients and that thick-root species proliferated more with their mycorrhizal fungi whereas thin-root species proliferated more with their roots. We further examined with many more species, patterns of root and mycorrhizal fungal proliferation in organic-nutrient-enriched patches. Foraging precision, or the extent that roots or mycorrhizal hyphae grew in the enriched patch relative to the unenriched patch, was related to both root thickness and type of mycorrhiza. In both AM and EM trees, thick-root species were not selective foragers of either their roots or hyphae. In thin-root species, there was strong selectivity in

  14. Inoculation effects on root-colonizing arbuscular mycorrhizal fungal communities spread beyond directly inoculated plants.

    Directory of Open Access Journals (Sweden)

    Martina Janoušková

    Full Text Available Inoculation with arbuscular mycorrhizal fungi (AMF may improve plant performance at disturbed sites, but inoculation may also suppress root colonization by native AMF and decrease the diversity of the root-colonizing AMF community. This has been shown for the roots of directly inoculated plants, but little is known about the stability of inoculation effects, and to which degree the inoculant and the inoculation-induced changes in AMF community composition spread into newly emerging seedlings that were not in direct contact with the introduced propagules. We addressed this topic in a greenhouse experiment based on the soil and native AMF community of a post-mining site. Plants were cultivated in compartmented pots with substrate containing the native AMF community, where AMF extraradical mycelium radiating from directly inoculated plants was allowed to inoculate neighboring plants. The abundances of the inoculated isolate and of native AMF taxa were monitored in the roots of the directly inoculated plants and the neighboring plants by quantitative real-time PCR. As expected, inoculation suppressed root colonization of the directly inoculated plants by other AMF taxa of the native AMF community and also by native genotypes of the same species as used for inoculation. In the neighboring plants, high abundance of the inoculant and the suppression of native AMF were maintained. Thus, we demonstrate that inoculation effects on native AMF propagate into plants that were not in direct contact with the introduced inoculum, and are therefore likely to persist at the site of inoculation.

  15. Inoculation effects on root-colonizing arbuscular mycorrhizal fungal communities spread beyond directly inoculated plants

    Science.gov (United States)

    Krak, Karol; Vosátka, Miroslav; Püschel, David; Štorchová, Helena

    2017-01-01

    Inoculation with arbuscular mycorrhizal fungi (AMF) may improve plant performance at disturbed sites, but inoculation may also suppress root colonization by native AMF and decrease the diversity of the root-colonizing AMF community. This has been shown for the roots of directly inoculated plants, but little is known about the stability of inoculation effects, and to which degree the inoculant and the inoculation-induced changes in AMF community composition spread into newly emerging seedlings that were not in direct contact with the introduced propagules. We addressed this topic in a greenhouse experiment based on the soil and native AMF community of a post-mining site. Plants were cultivated in compartmented pots with substrate containing the native AMF community, where AMF extraradical mycelium radiating from directly inoculated plants was allowed to inoculate neighboring plants. The abundances of the inoculated isolate and of native AMF taxa were monitored in the roots of the directly inoculated plants and the neighboring plants by quantitative real-time PCR. As expected, inoculation suppressed root colonization of the directly inoculated plants by other AMF taxa of the native AMF community and also by native genotypes of the same species as used for inoculation. In the neighboring plants, high abundance of the inoculant and the suppression of native AMF were maintained. Thus, we demonstrate that inoculation effects on native AMF propagate into plants that were not in direct contact with the introduced inoculum, and are therefore likely to persist at the site of inoculation. PMID:28738069

  16. Inhibiting Cadmium Transport Process in Root Cells of Plants: A Review

    Directory of Open Access Journals (Sweden)

    ZHAO Yan-ling

    2016-05-01

    Full Text Available Cadmium(Cd is the most common element found in the heavy-metal contaminated soils in China. Roots of rice and vegetables can concentrate Cd from acid soils, and then transport Cd to above-ground parts. Cd in edible part of plants directly influences the food safety. Cellwall, plasma membrane and organells of root cells in plant can discriminate Cd from other elements. A lot of Cd can be fixed in root cells by precipitation, complexation, compartmentation, and so on, to inhibit its transport from roots to shoot and guarantee the physiological activities in above-ground parts carrying out normally. This paper summarized recent advance on inhibiting Cd transport process in subcellular fractions of root cells of plants, which is in advantage of exploring excellent germplasms and gene resources in the future.

  17. Sensitivity of root-knot nematodes to gamma irradiation, salinity and plant growth regulator, cycocel

    Energy Technology Data Exchange (ETDEWEB)

    Sweelam, M E [Econ. Entomology Dept., Fac. Agric. Menoufia University Shebin El-Kom, (Egypt)

    1995-10-01

    The experiment was carried out at the experimental station of the faculty of agriculture, Menoufia Univ. To determine the sensitivity of root-knot nematode, Meloidogyne Javanica infecting tomato plants exposed to different doses of gamma irradiation 0,20,40,60,80 Gy, salinity levels 0. 1000, 2000, 4000 ppm and the plant growth regulator cycocel 0,200 ppm. Treated seeds were planted clay pots and salinity levels and cycocel concentrations were applied. Fresh weights and nematode populations were computed 3 months after application. Results indicated that 20 Gy, 1000 ppm salinity and cycocel gave the highest fresh weight of shoots and roots. The developmental stages and egg-laying females of nematode decreased by the increasing of irradiation dose and salinity levels. Root-knot galls decreased with 40 and 60 Gy, while significant increase was observed with 0 and 80 Gy, salinity levels decreased root galls. Cycocel decreased nematode population, egg-lying females and root-knot galls.

  18. Sensitivity of root-knot nematodes to gamma irradiation, salinity and plant growth regulator, cycocel

    International Nuclear Information System (INIS)

    Sweelam, M.E.

    1995-01-01

    The experiment was carried out at the experimental station of the faculty of agriculture, Menoufia Univ. To determine the sensitivity of root-knot nematode, Meloidogyne Javanica infecting tomato plants exposed to different doses of gamma irradiation 0,20,40,60,80 Gy, salinity levels 0. 1000, 2000, 4000 ppm and the plant growth regulator cycocel 0,200 ppm. Treated seeds were planted clay pots and salinity levels and cycocel concentrations were applied. Fresh weights and nematode populations were computed 3 months after application. Results indicated that 20 Gy, 1000 ppm salinity and cycocel gave the highest fresh weight of shoots and roots. The developmental stages and egg-laying females of nematode decreased by the increasing of irradiation dose and salinity levels. Root-knot galls decreased with 40 and 60 Gy, while significant increase was observed with 0 and 80 Gy, salinity levels decreased root galls. Cycocel decreased nematode population, egg-lying females and root-knot galls

  19. A below-ground herbivore shapes root defensive chemistry in natural plant populations

    OpenAIRE

    Huber, Meret; Bont, Zoe; Fricke, Julia; Brillatz, Th?o; Aziz, Zohra; Gershenzon, Jonathan; Erb, Matthias

    2016-01-01

    Plants display extensive intraspecific variation in secondary metabolites. However, the selective forces shaping this diversity remain often unknown, especially below ground. Using Taraxacum officinale and its major native insect root herbivore Melolontha melolontha, we tested whether below-ground herbivores drive intraspecific variation in root secondary metabolites. We found that high M. melolontha infestation levels over recent decades are associated with high concentrations of major root ...

  20. Optical methods for creating delivery systems of chemical compounds to plant roots

    Science.gov (United States)

    Kuznetsov, Pavel E.; Rogacheva, Svetlana M.; Arefeva, Oksana A.; Minin, Dmitryi V.; Tolmachev, Sergey A.; Kupadze, Machammad S.

    2004-08-01

    Spectrophotometric and fluorescence methods have been used for creation and investigation of various systems of target delivery of chemical compounds to roots of plants. The possibility of using liposomes, incrusted by polysaccharides of the external surface of nitrogen-fixing rizospheric bacteria Azospirillum brasilense SP 245, and nanoparticles incrusted by polysaccharides of wheat roots, as the named systems has been shown. The important role of polysaccharide-polysaccharide interaction in the adsorption processes of bacteria on wheat roots has been demonstrated.

  1. Root herbivory indirectly affects above- and below-ground community members and directly reduces plant performance

    NARCIS (Netherlands)

    Barber, N.A.; Milano, N.J.; Kiers, E.T.; Theis, N.; Bartolo, V.; Hazzard, R.V.; Adler, L.S.

    2015-01-01

    There is a widespread recognition that above- and below-ground organisms are linked through their interactions with host plants that span terrestrial subsystems. In addition to direct effects on plants, soil organisms such as root herbivores can indirectly alter interactions between plants and other

  2. Root foraging increases performance of the clonal plant Potentilla reptans in heterogeneous nutrient environments.

    Science.gov (United States)

    Wang, Zhengwen; van Kleunen, Mark; During, Heinjo J; Werger, Marinus J A

    2013-01-01

    Plastic root-foraging responses have been widely recognized as an important strategy for plants to explore heterogeneously distributed resources. However, the benefits and costs of root foraging have received little attention. In a greenhouse experiment, we grew pairs of connected ramets of 22 genotypes of the stoloniferous plant Potentilla reptans in paired pots, between which the contrast in nutrient availability was set as null, medium and high, but with the total nutrient amount kept the same. We calculated root-foraging intensity of each individual ramet pair as the difference in root mass between paired ramets divided by the total root mass. For each genotype, we then calculated root-foraging ability as the slope of the regression of root-foraging intensity against patch contrast. For all genotypes, root-foraging intensity increased with patch contrast and the total biomass and number of offspring ramets were lowest at high patch contrast. Among genotypes, root-foraging intensity was positively related to production of offspring ramets and biomass in the high patch-contrast treatment, which indicates an evolutionary benefit of root foraging in heterogeneous environments. However, we found no significant evidence that the ability of plastic foraging imposes costs under homogeneous conditions (i.e. when foraging is not needed). Our results show that plants of P. reptans adjust their root-foraging intensity according to patch contrast. Moreover, the results show that the root foraging has an evolutionary advantage in heterogeneous environments, while costs of having the ability of plastic root foraging were absent or very small.

  3. In vitro ROOTING OF TENERA HYBRID OIL PALM (Elaeis guineensis Jacq. PLANTS1

    Directory of Open Access Journals (Sweden)

    Marlúcia Souza Souza Pádua

    2018-04-01

    Full Text Available ABSTRACT Oil palm is a woody monocot of economic importance due to high oil production from its fruits. Currently, the conventional method most used to propagate oil palm is seed germination, but success is limited by long time requirements and low germination percentage. An alternative for large-scale propagation of oil palm is the biotechnological technique of somatic embryogenesis. The rooting of plants germinated from somatic embryos is a difficult step, yet it is of great importance for later acclimatization and success in propagation. The aim of this study was to evaluate the effect of the auxins indole acetic acid (IAA and indole butyric acid (IBA on the rooting of somatic embryos of Tenera hybrid oil palm. Plants obtained by somatic embryogenesis were inoculated in modified MS medium with 10% sucrose and 0.6% agar and supplemented with IAA or IBA at concentrations of 5 µM, 10 µM, and 15 µM, and the absence of growth regulators. After 120 days, the presence of roots, root type, length of the longest root, number of roots, number of leaves, and shoot length were analyzed. Growth regulators were favorable to rooting; plants cultivated with IBA growth regulator at 15 µM showed higher rooting percentage (87% and better results for the parameters of number of roots (1.33 and shoot length (9.83.

  4. Improvement of date palm plant lets during rooting stage by silver ion

    International Nuclear Information System (INIS)

    Sharaf, M.M.; Khamis, M.A.; El Bana, A.; Abd El Galeil, L.M.; Zaid, Z.E.

    2012-01-01

    This study aim to promote growth plant lets of date palm cv. Zaghlool by decreasing ethylene production inside the containers during rooting stage. Data obtained declared that three silver thiosulphate (STS) levels added to one half strength MS rooting medium improved significantly three rooting measurements (rooting percentage; number and length of developed root lets). However, the lightest STS level (0.25 ml/L of 4 mM STS solution) was the superior, while highest one (1.0 ml/L) was the inferior from statistical point of view. Data obtained displayed that providing MS rooting medium with silver nitrate improved 3 rooting measurements (rooting %; number of root lets and their length) for Zaghloul date palm shoot lets proliferated from somatic embryos. However, the 0.50 mg/L AgNO 3 provided MS medium was the most preferable in this concern. Plant lets were transferred to capped tubes contained 1/4 liquid MS medium through 3 weeks in the growth chamber (under aseptic condition). Ventilation was allowed gradually by punching holes in aluminum foil caps during first five days of 2 nd week. After then, the plant lets were transplanted in acclimatization green house on mixture from (peat moss + perlite + vermiculite at 1:1:1) and survival percentage was 75% after three months.

  5. Thick root of cucumber: other susceptible plants and the effect of pH

    NARCIS (Netherlands)

    Gaag, van der D.J.; Paternotte, P.; Hamelink, R.

    2002-01-01

    Thick root is a relatively new disorder of cucumber grown in artificial substrates. Plants of cucumber, tomato, sweet pepper, lupin, anthurium, Cucurbita ficifolia, C. maxima and two lines from crosses between C. maxima and C. moschata were grown in thick root disease (TRD)-infested nutrient

  6. From lifting to planting: Root dip treatments affect survival of loblolly pine (Pinus taeda)

    Science.gov (United States)

    Tom E. Starkey; David B. South

    2009-01-01

    Hydrogels and clay slurries are the materials most commonly applied to roots of pines in the southern United States. Most nursery managers believe such applications offer a form of "insurance" against excessive exposure during planting. The objective of this study was to examine the ability of root dip treatments to: (1) support fungal growth; and (2) protect...

  7. Suberized transport barriers in Arabidopsis, barley and rice roots: From the model plant to crop species.

    Science.gov (United States)

    Kreszies, Tino; Schreiber, Lukas; Ranathunge, Kosala

    2018-02-07

    Water is the most important prerequisite for life and plays a major role during uptake and transport of nutrients. Roots are the plant organs that take up the major part of water, from the surrounding soil. Water uptake is related to the root system architecture, root growth, age and species dependent complex developmental changes in the anatomical structures. The latter is mainly attributed to the deposition of suberized barriers in certain layers of cell walls, such as endo- and exodermis. With respect to water permeability, changes in the suberization of roots are most relevant. Water transport or hydraulic conductivity of roots (Lp r ) can be described by the composite transport model and is known to be very variable between plant species and growth conditions and root developmental states. In this review, we summarize how anatomical structures and apoplastic barriers of roots can diversely affect water transport, comparing the model plant Arabidopsis with crop plants, such as barley and rice. Results comparing the suberin amounts and water transport properties indicate that the common assumption that suberin amount negatively correlates with water and solute transport through roots may not always be true. The composition, microstructure and localization of suberin may also have a great impact on the formation of efficient barriers to water and solutes. Copyright © 2018 The Authors. Published by Elsevier GmbH.. All rights reserved.

  8. Influence of plant root morphology and tissue composition on phenanthrene uptake: Stepwise multiple linear regression analysis

    International Nuclear Information System (INIS)

    Zhan, Xinhua; Liang, Xiao; Xu, Guohua; Zhou, Lixiang

    2013-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are contaminants that reside mainly in surface soils. Dietary intake of plant-based foods can make a major contribution to total PAH exposure. Little information is available on the relationship between root morphology and plant uptake of PAHs. An understanding of plant root morphologic and compositional factors that affect root uptake of contaminants is important and can inform both agricultural (chemical contamination of crops) and engineering (phytoremediation) applications. Five crop plant species are grown hydroponically in solutions containing the PAH phenanthrene. Measurements are taken for 1) phenanthrene uptake, 2) root morphology – specific surface area, volume, surface area, tip number and total root length and 3) root tissue composition – water, lipid, protein and carbohydrate content. These factors are compared through Pearson's correlation and multiple linear regression analysis. The major factors which promote phenanthrene uptake are specific surface area and lipid content. -- Highlights: •There is no correlation between phenanthrene uptake and total root length, and water. •Specific surface area and lipid are the most crucial factors for phenanthrene uptake. •The contribution of specific surface area is greater than that of lipid. -- The contribution of specific surface area is greater than that of lipid in the two most important root morphological and compositional factors affecting phenanthrene uptake

  9. Effects of contrasting rooting distribution patterns on plant transpiration along a precipitation gradient

    Science.gov (United States)

    Understanding and predicting ecosystem functioning in water limited ecosystems requires a thorough assessment of the role plant root systems. Widespread ecological phenomena such as shrub encroachment may drastically change root distribution in the soil profile affecting the uptake of water and nutr...

  10. Stimulation of vesicular-arbuscular mycorrhizal fungi by mycotrophic and nonmycotrophic plant root systems.

    Science.gov (United States)

    Schreiner, R P; Koide, R T

    1993-08-01

    Transformed root cultures of three nonmycotrophic and one mycotrophic plant species stimulated germination and hyphal growth of the vesicular-arbuscular mycorrhizal fungus Glomus etunicatum (Becker & Gerd.) in a gel medium. However, only roots of the mycotrophic species (carrot) supported continued hyphal exploration after 3 to 4 weeks and promoted appressoria formation by G. etunicatum.

  11. Stimulation of Vesicular-Arbuscular Mycorrhizal Fungi by Mycotrophic and Nonmycotrophic Plant Root Systems

    OpenAIRE

    Schreiner, R. Paul; Koide, Roger T.

    1993-01-01

    Transformed root cultures of three nonmycotrophic and one mycotrophic plant species stimulated germination and hyphal growth of the vesicular-arbuscular mycorrhizal fungus Glomus etunicatum (Becker & Gerd.) in a gel medium. However, only roots of the mycotrophic species (carrot) supported continued hyphal exploration after 3 to 4 weeks and promoted appressoria formation by G. etunicatum.

  12. Climate, soil and plant functional types as drivers of global fine-root trait variation

    NARCIS (Netherlands)

    Freschet, Grégoire T.; Valverde-Barrantes, Oscar J.; Tucker, Caroline M.; Craine, Joseph M.; McCormack, M. Luke; Violle, Cyrille; Fort, Florian; Blackwood, Christopher B.; Urban-Mead, Katherine R.; Iversen, Colleen M.; Bonis, Anne; Comas, Louise H.; Cornelissen, Johannes H.C.; Dong, Ming; Guo, Dali; Hobbie, Sarah E.; Holdaway, Robert J.; Kembel, Steven W.; Makita, Naoki; Onipchenko, Vladimir G.; Picon-Cochard, Catherine; Reich, Peter B.; de la Riva, Enrique G.; Smith, Stuart W.; Soudzilovskaia, Nadejda A.; Tjoelker, Mark G.; Wardle, David A.; Roumet, Catherine

    2017-01-01

    Ecosystem functioning relies heavily on below-ground processes, which are largely regulated by plant fine-roots and their functional traits. However, our knowledge of fine-root trait distribution relies to date on local- and regional-scale studies with limited numbers of species, growth forms and

  13. Effects of plant growth promoting rhizobacteria (PGPR on rooting and root growth of kiwifruit (Actinidia deliciosa stem cuttings

    Directory of Open Access Journals (Sweden)

    YASAR ERTURK

    2010-01-01

    Full Text Available The effects of plant growth promoting rhizobacteria (PGPR on the rooting and root growth of semi-hardwood and hardwood kiwifruit stem cuttings were investigated. The PGPR used were Bacillus RC23, Paenibacillus polymyxa RC05, Bacillus subtilis OSU142, Bacillus RC03, Comamonas acidovorans RC41, Bacillus megaterium RC01 and Bacillus simplex RC19. All the bacteria showed indole-3-acetic acid (IAA producing capacity. Among the PGPR used, the highest rooting ratios were obtained at 47.50% for semi-hardwood stem cuttings from Bacillus RC03 and Bacillus simplex RC19 treatments and 42.50% for hardwood stem cuttings from Bacillus RC03. As well, Comamonas acidovorans RC41 inoculations indicated higher value than control treatments. The results suggest that these PGPR can be used in organic nursery material production and point to the feasibility of synthetic auxin (IBA replacement by organic management based on PGPR.

  14. A plant microRNA regulates the adaptation of roots to drought stress

    KAUST Repository

    Chen, Hao; Li, Zhuofu; Xiong, Liming

    2012-01-01

    Plants tend to restrict their horizontal root proliferation in response to drought stress, an adaptive response mediated by the phytohormone abscisic acid (ABA) in antagonism with auxin through unknown mechanisms. Here, we found that stress

  15. Utilization of 15NO3− by nodulated soybean plants under conditions of root hypoxia

    OpenAIRE

    Nunes Menolli Lanza, Luciana; Ferreira Lanza, Daniel Carlos; Sodek, Ladaslav

    2014-01-01

    Waterlogging of soils is common in nature. The low availability of oxygen under these conditions leads to hypoxia of the root system impairing the development and productivity of the plant. The presence of nitrate under flooding conditions is regarded as being beneficial towards tolerance to this stress. However, it is not known how nodulated soybean plants, cultivated in the absence of nitrate and therefore not metabolically adapted to this compound, would respond to nitrate under root hypox...

  16. Iron Oxide and Titanium Dioxide Nanoparticle Effects on Plant Performance and Root Associated Microbes

    Directory of Open Access Journals (Sweden)

    David J. Burke

    2015-10-01

    Full Text Available In this study, we investigated the effect of positively and negatively charged Fe3O4 and TiO2 nanoparticles (NPs on the growth of soybean plants (Glycine max. and their root associated soil microbes. Soybean plants were grown in a greenhouse for six weeks after application of different amounts of NPs, and plant growth and nutrient content were examined. Roots were analyzed for colonization by arbuscular mycorrhizal (AM fungi and nodule-forming nitrogen fixing bacteria using DNA-based techniques. We found that plant growth was significantly lower with the application of TiO2 as compared to Fe3O4 NPs. The leaf carbon was also marginally significant lower in plants treated with TiO2 NPs; however, leaf phosphorus was reduced in plants treated with Fe3O4. We found no effects of NP type, concentration, or charge on the community structure of either rhizobia or AM fungi colonizing plant roots. However, the charge of the Fe3O4 NPs affected both colonization of the root system by rhizobia as well as leaf phosphorus content. Our results indicate that the type of NP can affect plant growth and nutrient content in an agriculturally important crop species, and that the charge of these particles influences the colonization of the root system by nitrogen-fixing bacteria.

  17. Trichoderma-Plant Root Colonization: Escaping Early Plant Defense Responses and Activation of the Antioxidant Machinery for Saline Stress Tolerance

    Science.gov (United States)

    Brotman, Yariv; Landau, Udi; Cuadros-Inostroza, Álvaro; Takayuki, Tohge; Fernie, Alisdair R.; Chet, Ilan; Viterbo, Ada; Willmitzer, Lothar

    2013-01-01

    Trichoderma spp. are versatile opportunistic plant symbionts which can colonize the apoplast of plant roots. Microarrays analysis of Arabidopsis thaliana roots inoculated with Trichoderma asperelloides T203, coupled with qPCR analysis of 137 stress responsive genes and transcription factors, revealed wide gene transcript reprogramming, proceeded by a transient repression of the plant immune responses supposedly to allow root colonization. Enhancement in the expression of WRKY18 and WRKY40, which stimulate JA-signaling via suppression of JAZ repressors and negatively regulate the expression of the defense genes FMO1, PAD3 and CYP71A13, was detected in Arabidopsis roots upon Trichoderma colonization. Reduced root colonization was observed in the wrky18/wrky40 double mutant line, while partial phenotypic complementation was achieved by over-expressing WRKY40 in the wrky18 wrky40 background. On the other hand increased colonization rate was found in roots of the FMO1 knockout mutant. Trichoderma spp. stimulate plant growth and resistance to a wide range of adverse environmental conditions. Arabidopsis and cucumber (Cucumis sativus L.) plants treated with Trichoderma prior to salt stress imposition show significantly improved seed germination. In addition, Trichoderma treatment affects the expression of several genes related to osmo-protection and general oxidative stress in roots of both plants. The MDAR gene coding for monodehydroascorbate reductase is significantly up-regulated and, accordingly, the pool of reduced ascorbic acid was found to be increased in Trichoderma treated plants. 1-Aminocyclopropane-1-carboxylate (ACC)-deaminase silenced Trichoderma mutants were less effective in providing tolerance to salt stress, suggesting that Trichoderma, similarly to ACC deaminase producing bacteria, can ameliorate plant growth under conditions of abiotic stress, by lowering ameliorating increases in ethylene levels as well as promoting an elevated antioxidative capacity

  18. Soil-to-plant halogens transfer studies 2. Root uptake of radiochlorine by plants

    Energy Technology Data Exchange (ETDEWEB)

    Kashparov, V. [Ukrainian Institute of Agricultural Radiology (UIAR), Mashinostroiteley Str.7, Chabany, Kiev Region 08162 (Ukraine); Colle, C. [Institute for Radioprotection and Nuclear Safety (IRSN/DEI/SECRE), Cadarache bat 159, BP 3, 13115 Saint Paul-lez-Durance (France)]. E-mail: claude.colle@irsn.fr; Zvarich, S. [Ukrainian Institute of Agricultural Radiology (UIAR), Mashinostroiteley Str.7, Chabany, Kiev Region 08162 (Ukraine); Yoschenko, V. [Ukrainian Institute of Agricultural Radiology (UIAR), Mashinostroiteley Str.7, Chabany, Kiev Region 08162 (Ukraine); Levchuk, S. [Ukrainian Institute of Agricultural Radiology (UIAR), Mashinostroiteley Str.7, Chabany, Kiev Region 08162 (Ukraine); Lundin, S. [Ukrainian Institute of Agricultural Radiology (UIAR), Mashinostroiteley Str.7, Chabany, Kiev Region 08162 (Ukraine)

    2005-07-01

    Long-term field experiments have been carried out in the Chernobyl exclusion zone in order to determine the parameters governing radiochlorine ({sup 36}Cl) transfer to plants from four types of soil, namely, podzoluvisol, greyzem, and typical and meadow chernozem. Radiochlorine concentration ratios (CR) in radish roots (15 {+-} 10), lettuce leaves (30 {+-} 15), bean pods (15 {+-} 11) and wheat seed (23 {+-} 11) and straw (210 {+-} 110) for fresh weight of plants were obtained. These values correlate well with stable chlorine values for the same plants. One year after injection, {sup 36}Cl reached a quasi-equilibrium with stable chlorine in the agricultural soils and its behavior in the soil-plant system mimicked the behavior of stable chlorine (this behavior was determined by soil moisture transport in the investigated soils). In the absence of intensive vertical migration, more than half of {sup 36}Cl activity in arable layer of soil passes into the radish, lettuce and the aboveground parts of wheat during a single vegetation period.

  19. Soil-to-plant halogens transfer studies 2. Root uptake of radiochlorine by plants

    International Nuclear Information System (INIS)

    Kashparov, V.; Colle, C.; Zvarich, S.; Yoschenko, V.; Levchuk, S.; Lundin, S.

    2005-01-01

    Long-term field experiments have been carried out in the Chernobyl exclusion zone in order to determine the parameters governing radiochlorine ( 36 Cl) transfer to plants from four types of soil, namely, podzoluvisol, greyzem, and typical and meadow chernozem. Radiochlorine concentration ratios (CR) in radish roots (15 ± 10), lettuce leaves (30 ± 15), bean pods (15 ± 11) and wheat seed (23 ± 11) and straw (210 ± 110) for fresh weight of plants were obtained. These values correlate well with stable chlorine values for the same plants. One year after injection, 36 Cl reached a quasi-equilibrium with stable chlorine in the agricultural soils and its behavior in the soil-plant system mimicked the behavior of stable chlorine (this behavior was determined by soil moisture transport in the investigated soils). In the absence of intensive vertical migration, more than half of 36 Cl activity in arable layer of soil passes into the radish, lettuce and the aboveground parts of wheat during a single vegetation period

  20. Dynamics of plant nutrient uptake as affected by biopore-associated root growth in arable subsoil

    DEFF Research Database (Denmark)

    Han, Eusun; Kautz, Timo; Huang, Ning

    2017-01-01

    %) precrops, respectively. On average root diameter and root dry mass of following crops were greater by 11 and 15 % after chicory than tall fescue. At anthesis chicory-barley treatment accumulated 10 % more K in comparison to tall fescue-barley treatment. P uptake of canola was greater (7 %) after tall...... fescue compared with chicory at the stage of fruit development. Conclusions: Our results suggest that the subsoil heterogenization by altered soil biopores hold relevance for plant root growth and overall crop performance. However, the effects depended on biopore size classes, root characteristics...

  1. Spatial distribution of root activity of Ganesh pomegranate (Punica granatum) plants

    International Nuclear Information System (INIS)

    Kotur, S.C.; Keshava Murthy, S.V.

    2003-01-01

    Information on the root activity pattern is invaluable while adopting appropriate time and method of fertilizer application, irrigation, planting distance and other cultural practices. The pattern of root activity distribution determined using the technique of soil injection of 32 P compares well with actual pattern ascertained by root excavation method. The isotopic technique is also non-destructive, quick and inexpensive. Root activity distribution pattern has been determined using this technique in citrus, grape, mango, guava and papaya. To generate the information on inbred Ganesh pomegranate seedlings, studies were undertaken and the results are reported in this paper. (author)

  2. Effect of different irrigation systems on root growth of maize and cowpea plants in sandy soil

    Directory of Open Access Journals (Sweden)

    Noha A. Mahgoub

    2017-10-01

    Full Text Available A field experiment was conducted at the Experimental Farm, Faculty of Agriculture, Suez Canal University to study the influence of different irrigation systems on root length density and specific root length of maize and cowpea plants cultivated in sandy soil. Three irrigation systems (Surface, drip and sprinkler irrigation were used in this study. The NPK fertilizers were applied as recommended doses for maize and cowpea. Root samples were collected from the soil profile below one plant (maize and cowpea which was irrigated by the three irrigation systems by using an iron box (30 cm× 20 cm which is divided into 24 small boxes each box is (5× 5 × 5 cm. At surface irrigation, root length density of cowpea reached to soil depth 30-40cm with lateral distances 5-10 cm and 15-20 cm. Vertical distribution of root length density of maize was increased with soil depth till 20-25 cm, and then it decreased till soil depth 35-40cm. Under drip irrigation, root length density of cowpea increased horizontally from 0-5cm to 10-15cm then it decreased till soil depth 25-30 cm and below this depth root length density disappeared. For the root length density and specific root length of maize under drip irrigation, the data showed that root length density and specific root length decreased with increasing in soil depth. The root length density of cowpea under sprinkler irrigation at 0-5cm disappeared from horizontal distance at 25-30 cm. The data showed that root length density of maize under sprinkler irrigation was higher at the soil top layers 0-5 cm and 5-10 cm than other layers from 10-40 cm.

  3. Effect of planting density on root lodging resistance and its relationship to nodal root growth characteristics in maize (Zea mays L.)

    DEFF Research Database (Denmark)

    Liu, Shengqun; Song, Fengbin; Liu, Fulai

    2012-01-01

    Increase of planting density has been widely used to increase grain yield in maize. However, it may lead to higher risk of root lodging hence causing significant yield loss of the crop. The objective of this study was to investigate the effect of planting density on maize nodal root growth...

  4. GAMMA IRRADIATION OF SUGAR BEET SEEDS INDUCED PLANT RESISTANCE TO ROOT-KNOT NEMATODE MELOIDOGYNE INCOGNITA

    International Nuclear Information System (INIS)

    ABD EL FATTAH, A.I.; KAMEL, H.A.; EL-NAGDI, W.M.A.

    2008-01-01

    The main objective of this study was to investigate the effect of irradiation of sugar beet seeds on the plant resistance to root-knot nematode Meloidogyne incognita infection in addition to some morphological parameters, biochemical components and root technological characters. Relative to control (non-irradiated seeds), the obtained data showed that, all doses except 10 Gy significantly increased root length of un inoculated plants and the most effective dose was 200 Gy. All doses significantly decreased root diameter except 50 and 100 Gy. The 10 and 400 Gy significantly reduced root fresh weight while 50, 100 and 200 Gy caused non-significant increase. All doses significantly increased root fresh weight/dry weight than control. There was non-significant effect on the morphological parameters of the plants germinated from gamma irradiated seeds and inoculated with Meloidogyne incognita. Total chlorophyll of seed irradiated and un inoculated plants were significantly reduced by all doses except 200 Gy. All doses of gamma radiation caused non-significant decrease in the total chlorophyll of the infected plants. In un inoculated plants, a significant reduction in the total phenol was occurred due to all doses of gamma radiation. In contrast, in inoculated plants, 10 and 25 Gy caused significant reduction in the total phenol while 50 and 400 Gy caused significant increase in the total phenol.Significant increase in sucrose % was observed due to 10 Gy in the un inoculated plants. The 400 Gy caused significant decrease while other doses caused non-significant decrease in the sucrose %. In the inoculated plants, 50, 100 and 400 Gy caused significant increase in sucrose %. All doses significantly increased total soluble salts percent (TSS %) of either inoculated or un inoculated plants. Purity % was increased by all doses in the inoculated plants.The number of galls and egg masses were reduced gradually by increasing gamma doses and 100 Gy caused the highest reduction 89

  5. Root strength of tropical plants - An investigation in the Western Ghats of Kerala, India

    Science.gov (United States)

    Lukose Kuriakose, S.; van Beek, L. P. H.; van Westen, C. J.

    2009-04-01

    Earlier research on debris flows in the Tikovil River basin of the Western Ghats concluded that root cohesion is significant in maintaining the overall stability of the region. In this paper we present the most recent results (December 2008) of root tensile strength tests conducted on nine species of plants that are commonly found in the region. They are 1) Rubber (Hevea Brasiliensis), 2) Coconut Palm (Cocos nucifera), 3) Jackfruit trees (Artocarpus heterophyllus), 4) Teak (Tectona grandis), 5) Mango trees (Mangifera indica), 6) Lemon grass (Cymbopogon citratus), 7) A variety of Tamarind (Garcinia gummigutta), 8) Coffee (Coffea Arabica) and Tea (Camellia sinensis). About 1500 samples were collected of which only 380 could be tested (in the laboratory) due to breakage of roots during the tests. In the successful tests roots failed in tension. Roots having diameters between 2 mm and 12 mm were tested. Each sample tested has a length of 15 cm. Results indicate that the roots of Coffee, Tamarind, Lemon grass and Jackfruit are the strongest of the nine plant types tested whereas Tea and Teak plants had the most fragile roots. Coconut roots behaved atypical to the others, as the bark of the roots was crushed and slipped from the clamp when tested whereas its internal fiber was the strongest of all tested. Root tensile strength decreases with increasing diameters, Rubber showing more ductile behaviour than Coffee and Tamarind that behaved more brittle, root tensile strength increasing exponentially for finer roots. Teak and Tea showed almost a constant root tensile strength over the range of diameters tested and little variability. Jack fruit and mango trees showed the largest variability, which may be explained by the presence of root nodules, preventing the derivation of an unequivocal relationship between root diameters and tensile strength. This results in uncertainty of root strength estimates that are applicable. These results provide important information to

  6. Soil Penetration by Earthworms and Plant Roots--Mechanical Energetics of Bioturbation of Compacted Soils.

    Directory of Open Access Journals (Sweden)

    Siul Ruiz

    Full Text Available We quantify mechanical processes common to soil penetration by earthworms and growing plant roots, including the energetic requirements for soil plastic displacement. The basic mechanical model considers cavity expansion into a plastic wet soil involving wedging by root tips or earthworms via cone-like penetration followed by cavity expansion due to pressurized earthworm hydroskeleton or root radial growth. The mechanical stresses and resulting soil strains determine the mechanical energy required for bioturbation under different soil hydro-mechanical conditions for a realistic range of root/earthworm geometries. Modeling results suggest that higher soil water content and reduced clay content reduce the strain energy required for soil penetration. The critical earthworm or root pressure increases with increased diameter of root or earthworm, however, results are insensitive to the cone apex (shape of the tip. The invested mechanical energy per unit length increase with increasing earthworm and plant root diameters, whereas mechanical energy per unit of displaced soil volume decreases with larger diameters. The study provides a quantitative framework for estimating energy requirements for soil penetration work done by earthworms and plant roots, and delineates intrinsic and external mechanical limits for bioturbation processes. Estimated energy requirements for earthworm biopore networks are linked to consumption of soil organic matter and suggest that earthworm populations are likely to consume a significant fraction of ecosystem net primary production to sustain their subterranean activities.

  7. Aboveground endophyte affects root volatile emission and host plant selection of a belowground insect.

    Science.gov (United States)

    Rostás, Michael; Cripps, Michael G; Silcock, Patrick

    2015-02-01

    Plants emit specific blends of volatile organic compounds (VOCs) that serve as multitrophic, multifunctional signals. Fungi colonizing aboveground (AG) or belowground (BG) plant structures can modify VOC patterns, thereby altering the information content for AG insects. Whether AG microbes affect the emission of root volatiles and thus influence soil insect behaviour is unknown. The endophytic fungus Neotyphodium uncinatum colonizes the aerial parts of the grass hybrid Festuca pratensis × Lolium perenne and is responsible for the presence of insect-toxic loline alkaloids in shoots and roots. We investigated whether endophyte symbiosis had an effect on the volatile emission of grass roots and if the root herbivore Costelytra zealandica was able to recognize endophyte-infected plants by olfaction. In BG olfactometer assays, larvae of C. zealandica were more strongly attracted to roots of uninfected than endophyte-harbouring grasses. Combined gas chromatography-mass spectrometry and proton transfer reaction-mass spectrometry revealed that endophyte-infected roots emitted less VOCs and more CO2. Our results demonstrate that symbiotic fungi in plants may influence soil insect distribution by changing their behaviour towards root volatiles. The well-known defensive mutualism between grasses and Neotyphodium endophytes could thus go beyond bioactive alkaloids and also confer protection by being chemically less apparent for soil herbivores.

  8. Root porosity and radial oxygen loss related to arsenic tolerance and uptake in wetland plants

    Energy Technology Data Exchange (ETDEWEB)

    Li, H. [State Key Laboratory for Bio-control, and School of Life Sciences, Sun Yat-sen University, Guangzhou 510006 (China); Croucher Institute for Environmental Sciences, and Department of Biology, Hong Kong Baptist University, Kowloon Tong (Hong Kong); Ye, Z.H., E-mail: lssyzhh@mail.sysu.edu.c [State Key Laboratory for Bio-control, and School of Life Sciences, Sun Yat-sen University, Guangzhou 510006 (China); Wei, Z.J. [School of Information and Technology, Guangdong University of Foreign Studies, Guangzhou 510275 (China); Wong, M.H., E-mail: mhwong@hkbu.edu.h [Croucher Institute for Environmental Sciences, and Department of Biology, Hong Kong Baptist University, Kowloon Tong (Hong Kong)

    2011-01-15

    The rates of radial oxygen loss (ROL), root porosity, concentrations of arsenic (As), iron (Fe) and manganese (Mn) in shoot and root tissues and on root surfaces, As tolerances, and their relationships in different wetland plants were investigated based on a hydroponic experiment (control, 0.8, 1.6 mg As L{sup -1}) and a soil pot trail (control, 60 mg As kg{sup -1}). The results revealed that wetland plants showed great differences in root porosity (9-64%), rates of ROL (55-1750 mmo1 O{sub 2} kg{sup -1} root d.w. d{sup -1}), As uptake (e.g., 8.8-151 mg kg{sup -1} in shoots in 0.8 mg As L{sup -1} treatment), translocation factor (2.1-47% in 0.8 mg As L{sup -1}) and tolerance (29-106% in 0.8 mg As L{sup -1}). Wetland plants with higher rates of ROL and root porosity tended to form more Fe/Mn plaque, possess higher As tolerance, higher concentrations of As on root surfaces and a lower As translocation factor so decreasing As toxicity. - Research highlights: There is significant correlation between the porosity of roots and rates of ROL. The rates of ROL are significantly correlated with tolerance indices and concentrations of As, Fe, Mn on root surface. The rates of ROL is negatively correlated with As translocation factor. - Wetland plants with high rates of ROL tended to form more Fe plaque on root surfaces and possess higher As tolerance.

  9. Effect of plant growth promoting rhizobacteria on root morphology of ...

    African Journals Online (AJOL)

    Jane

    2011-10-03

    Oct 3, 2011 ... Plant growth promoting rhizobacteria improve the plant growth by a variety of ways like ... preparing textile dye in the Far East, Central and. Northern Asia and ... The experiment was carried out in complete randomized design.

  10. Root bioactivity of corn and sunflower as evaluated by 75Se-plant injection technique

    International Nuclear Information System (INIS)

    Haak, E.; Paltineanu, I.C.

    1982-01-01

    A tracer technique was used for root studies under field conditions on a chernozemic soil in Romania. 75 Se was injected at the stem base and radioassayed for its presence in soil profiles with a gammasond lowered to different depths. Based on the assumption that 75 Se is preferably transferred within the root system to active root tissue of injected plants, the root bioactivity was estimated for corn at the knee high stage and just before tasseling, and for sunflower at early maturing, the crops being subjected to different N-fertilization and irigation treatments. The pattern of root bioactivity varied with crop, time and treatment applied. The technique, which is briefly described, seems to be a promising tool for delineation of root response to variation with depth in the soil profile of moisture and nutrient status and as shown in this pilote investigation for delineation of effects of irrigation and N-fertilization. (Authors)

  11. Non-invasive imaging of plant roots in different soils using magnetic resonance imaging (MRI

    Directory of Open Access Journals (Sweden)

    Daniel Pflugfelder

    2017-11-01

    Full Text Available Abstract Background Root systems are highly plastic and adapt according to their soil environment. Studying the particular influence of soils on root development necessitates the adaptation and evaluation of imaging methods for multiple substrates. Non-invasive 3D root images in soil can be obtained using magnetic resonance imaging (MRI. Not all substrates, however, are suitable for MRI. Using barley as a model plant we investigated the achievable image quality and the suitability for root phenotyping of six commercially available natural soil substrates of commonly occurring soil textures. The results are compared with two artificially composed substrates previously documented for MRI root imaging. Results In five out of the eight tested substrates, barley lateral roots with diameters below 300 µm could still be resolved. In two other soils, only the thicker barley seminal roots were detectable. For these two substrates the minimal detectable root diameter was between 400 and 500 µm. Only one soil did not allow imaging of the roots with MRI. In the artificially composed substrates, soil moisture above 70% of the maximal water holding capacity (WHCmax impeded root imaging. For the natural soil substrates, soil moisture had no effect on MRI root image quality in the investigated range of 50–80% WHCmax. Conclusions Almost all tested natural soil substrates allowed for root imaging using MRI. Half of these substrates resulted in root images comparable to our current lab standard substrate, allowing root detection down to a diameter of 300 µm. These soils were used as supplied by the vendor and, in particular, removal of ferromagnetic particles was not necessary. With the characterization of different soils, investigations such as trait stability across substrates are now possible using noninvasive MRI.

  12. Rotan manau intercropped with rubber: rate of root growth between three and four years after planting

    International Nuclear Information System (INIS)

    Wan Rashidah Kadir; Aminuddin Mohamad; Ahmad Sahali Mardi; Zaharah Abd Rahman

    1997-01-01

    Wan Rashidah, K., Aminuddin, M., Ahmad Sahali, M. & Zaharah, A.R. 1997. Rotan manau intercropped with rubber: rate of root growth between three and four years after planting. Efficient fertiliser management depends partly on understanding the active root distribution. In the present study, the active root distribution of 3- and 4-y-old plantation grown rotan manau (Calamus manan) was assessed using isotope tracer technique. For the 3-y-old rotan manau, three distances from the plant base (0.5, 1.0 and 1.5 m) at 5 and 30 cm depths were examined. For the 4-y-old plants, two distances, viz-a-viz at a centre between two rattan plants and another in the middle between two rattan plants and two rubber trees were studied. The isotope used was 32P, applied as a solution with KH2PO4. The rotan manau plants had been established under mature rubber plantation. High proportions of feeder roots were found at 0.5 and 1.0 m distances at the surface (5 cm depth) for the 3-y-old plants. Uptake of 32P was also observed for the application at 1.5 m distance for both depths but the counts were small. Statistical analysis gave a highly significant difference within the distances and within the different depths. For a better synchronisation between fertiliser application and plant uptake, it seems that application at approximately between 0.5 and 1.0 m distance around the plant is most appropriate at this age. At four years after planting, important uptake was obtained only for the two plants located near the application area. Anyhow, to some extent it reflected that roots had already extended for another 1 m compared to the 3-y-old plants

  13. Characterising root density of peach trees in a semi-arid Chernozem to increase plant density

    Science.gov (United States)

    Paltineanu, Cristian; Septar, Leinar; Gavat, Corina; Chitu, Emil; Oprita, Alexandru; Moale, Cristina; Calciu, Irina; Vizitiu, Olga; Lamureanu, Gheorghe

    2016-01-01

    The available information on root system in fully mature peach orchards in semi-arid regions is insufficient. This paper presents a study on the root system density in an irrigated peach orchard from Dobrogea, Romania, using the trench technique. The old orchard has clean cultivation in inter-row and in-row. The objectives of the study were to: test the hypothesis that the roots of fully mature peach trees occupy the whole soil volume; find out if root repulsive effect of adjacent plants occurred for the rootstocks and soil conditions; find relationships between root system and soil properties and analyse soil state trend. Some soil physical properties were significantly deteriorated in inter-row versus in-row, mainly due to soil compaction induced by technological traffic. Density of total roots was higher in-row than inter-row, but the differences were not significant. Root density decreased more intensely with soil depth than with distance from tree trunks. Root density correlated with some soil properties. No repulsive effect of the roots of adjacent peach trees was noted. The decrease of root density with distance from trunk can be used in optimising tree arrangement. The conclusions could also be used in countries with similar growth conditions.

  14. Evolutionary potential of root chemical defense: genetic correlations with shoot chemistry and plant growth.

    Science.gov (United States)

    Parker, J D; Salminen, J-P; Agrawal, Anurag A

    2012-08-01

    Root herbivores can affect plant fitness, and roots often contain the same secondary metabolites that act as defenses in shoots, but the ecology and evolution of root chemical defense have been little investigated. Here, we investigated genetic variance, heritability, and correlations among defensive phenolic compounds in shoot vs. root tissues of common evening primrose, Oenothera biennis. Across 20 genotypes, there were roughly similar concentrations of total phenolics in shoots vs. roots, but the allocation of particular phenolics to shoots vs. roots varied along a continuum of genotype growth rate. Slow-growing genotypes allocated 2-fold more of the potential pro-oxidant oenothein B to shoots than roots, whereas fast-growing genotypes had roughly equivalent above and belowground concentrations. Phenolic concentrations in both roots and shoots were strongly heritable, with mostly positive patterns of genetic covariation. Nonetheless, there was genotype-specific variation in the presence/absence of two major ellagitannins (oenothein A and its precursor oenothein B), indicating two different chemotypes based on alterations in this chemical pathway. Overall, the presence of strong genetic variation in root defenses suggests ample scope for the evolution of these compounds as defenses against root herbivores.

  15. Composite Phaseolus vulgaris plants with transgenic roots as ...

    African Journals Online (AJOL)

    SERVER

    2008-02-19

    Feb 19, 2008 ... ... important processes in the root system will be discussed. Key words: Genetic transformation, Phaseolus vulgaris, Agrobacterium rhizogenes. INTRODUCTION. Grain legumes are important agricultural crops, especially for developing countries, where they provide proteins in vegetarian or meat-poor diets.

  16. The Root-Associated Microbial Community of the World's Highest Growing Vascular Plants.

    Science.gov (United States)

    Angel, Roey; Conrad, Ralf; Dvorsky, Miroslav; Kopecky, Martin; Kotilínek, Milan; Hiiesalu, Inga; Schweingruber, Fritz; Doležal, Jiří

    2016-08-01

    Upward migration of plants to barren subnival areas is occurring worldwide due to raising ambient temperatures and glacial recession. In summer 2012, the presence of six vascular plants, growing in a single patch, was recorded at an unprecedented elevation of 6150 m.a.s.l. close to the summit of Mount Shukule II in the Western Himalayas (Ladakh, India). Whilst showing multiple signs of stress, all plants have managed to establish stable growth and persist for several years. To learn about the role of microbes in the process of plant upward migration, we analysed the root-associated microbial community of the plants (three individuals from each) using microscopy and tagged amplicon sequencing. No mycorrhizae were found on the roots, implying they are of little importance to the establishment and early growth of the plants. However, all roots were associated with a complex bacterial community, with richness and diversity estimates similar or even higher than the surrounding bare soil. Both soil and root-associated communities were dominated by members of the orders Sphingomonadales and Sphingobacteriales, which are typical for hot desert soils, but were different from communities of temperate subnival soils and typical rhizosphere communities. Despite taxonomic similarity on the order level, the plants harboured a unique set of highly dominant operational taxonomic units which were not found in the bare soil. These bacteria have been likely transported with the dispersing seeds and became part of the root-associated community following germination. The results indicate that developing soils act not only as a source of inoculation to plant roots but also possibly as a sink for plant-associated bacteria.

  17. Interplays between soil-borne plant viruses and RNA silencing-mediated antiviral defense in roots

    Directory of Open Access Journals (Sweden)

    Ida Bagus Andika

    2016-09-01

    Full Text Available Although the majority of plant viruses are transmitted by arthropod vectors and invade the host plants through the aerial parts, there is a considerable number of plant viruses that infect roots via soil-inhabiting vectors such as plasmodiophorids, chytrids, and nematodes. These soil-borne viruses belong to diverse families, and many of them cause serious diseases in major crop plants. Thus, roots are important organs for the life cycle of many viruses. Compared to shoots, roots have a distinct metabolism and particular physiological characteristics due to the differences in development, cell composition, gene expression patterns, and surrounding environmental conditions. RNA silencing is an important innate defense mechanism to combat virus infection in plants, but the specific information on the activities and molecular mechanism of RNA silencing-mediated viral defense in root tissue is still limited. In this review, we summarize and discuss the current knowledge regarding RNA silencing aspects of the interactions between soil-borne viruses and host plants. Overall, research evidence suggests that soil-borne viruses have evolved to adapt to the distinct mechanism of antiviral RNA silencing in roots.

  18. Genetic Control of Plant Root Colonization by the Biocontrol agent, Pseudomonas fluorescens

    Energy Technology Data Exchange (ETDEWEB)

    Cole, Benjamin J.; Fletcher, Meghan; Waters, Jordan; Wetmore, Kelly; Blow, Matthew J.; Deutschbauer, Adam M.; Dangl, Jeffry L.; Visel, Axel

    2015-03-19

    Plant growth promoting rhizobacteria (PGPR) are a critical component of plant root ecosystems. PGPR promote plant growth by solubilizing inaccessible minerals, suppressing pathogenic microorganisms in the soil, and directly stimulating growth through hormone synthesis. Pseudomonas fluorescens is a well-established PGPR isolated from wheat roots that can also colonize the root system of the model plant, Arabidopsis thaliana. We have created barcoded transposon insertion mutant libraries suitable for genome-wide transposon-mediated mutagenesis followed by sequencing (TnSeq). These libraries consist of over 105 independent insertions, collectively providing loss-of-function mutants for nearly all genes in the P.fluorescens genome. Each insertion mutant can be unambiguously identified by a randomized 20 nucleotide sequence (barcode) engineered into the transposon sequence. We used these libraries in a gnotobiotic assay to examine the colonization ability of P.fluorescens on A.thaliana roots. Taking advantage of the ability to distinguish individual colonization events using barcode sequences, we assessed the timing and microbial concentration dependence of colonization of the rhizoplane niche. These data provide direct insight into the dynamics of plant root colonization in an in vivo system and define baseline parameters for the systematic identification of the bacterial genes and molecular pathways using TnSeq assays. Having determined parameters that facilitate potential colonization of roots by thousands of independent insertion mutants in a single assay, we are currently establishing a genome-wide functional map of genes required for root colonization in P.fluorescens. Importantly, the approach developed and optimized here for P.fluorescens>A.thaliana colonization will be applicable to a wide range of plant-microbe interactions, including biofuel feedstock plants and microbes known or hypothesized to impact on biofuel-relevant traits including biomass productivity

  19. Ethylene sensitivity and relative air humidity regulate root hydraulic properties in tomato plants.

    Science.gov (United States)

    Calvo-Polanco, Monica; Ibort, Pablo; Molina, Sonia; Ruiz-Lozano, Juan Manuel; Zamarreño, Angel María; García-Mina, Jose María; Aroca, Ricardo

    2017-11-01

    The effect of ethylene and its precursor ACC on root hydraulic properties, including aquaporin expression and abundance, is modulated by relative air humidity and plant sensitivity to ethylene. Relative air humidity (RH) is a main factor contributing to water balance in plants. Ethylene (ET) is known to be involved in the regulation of root water uptake and stomatal opening although its role on plant water balance under different RH is not very well understood. We studied, at the physiological, hormonal and molecular levels (aquaporins expression, abundance and phosphorylation state), the plant responses to exogenous 1-aminocyclopropane-1-carboxylic acid (ACC; precursor of ET) and 2-aminoisobutyric acid (AIB; inhibitor of ET biosynthesis), after 24 h of application to the roots of tomato wild type (WT) plants and its ET-insensitive never ripe (nr) mutant, at two RH levels: regular (50%) and close to saturation RH. Highest RH induced an increase of root hydraulic conductivity (Lp o ) of non-treated WT plants, and the opposite effect in nr mutants. The treatment with ACC reduced Lp o in WT plants at low RH and in nr plants at high RH. The application of AIB increased Lp o only in nr plants at high RH. In untreated plants, the RH treatment changed the abundance and phosphorylation of aquaporins that affected differently both genotypes according to their ET sensitivity. We show that RH is critical in regulating root hydraulic properties, and that Lp o is affected by the plant sensitivity to ET, and possibly to ACC, by regulating aquaporins expression and their phosphorylation status. These results incorporate the relationship between RH and ET in the response of Lp o to environmental changes.

  20. Genotype and planting density effects on rooting traits and yield in cotton (Gossypium hirsutum L.)

    NARCIS (Netherlands)

    Zhang, L.Z.; Li, B.G.; Yan, G.T.; Werf, van der W.; Spiertz, J.H.J.; Zhang, S.P.

    2006-01-01

    Root density distribution of plants is a major indicator of competition between plants and determines resource capture from the soil. This experiment was conducted in 2005 at Anyang, located in the Yellow River region, Henan Province, China. Three cotton (Gossypium hirsutum L.) cultivars were

  1. A novel tracking tool for the analysis of plant-root tip movements

    International Nuclear Information System (INIS)

    Russino, A; Ascrizzi, A; Popova, L; Tonazzini, A; Mancuso, S; Mazzolai, B

    2013-01-01

    The growth process of roots consists of many activities, such as exploring the soil volume, mining minerals, avoiding obstacles and taking up water to fulfil the plant's primary functions, that are performed differently, depending on environmental conditions. Root movements are strictly related to a root decision strategy, which helps plants to survive under stressful conditions by optimizing energy consumption. In this work, we present a novel image-analysis tool to study the kinematics of the root tip (apex), named analyser for root tip tracks (ARTT). The software implementation combines a segmentation algorithm with additional software imaging filters in order to realize a 2D tip detection. The resulting paths, or tracks, arise from the sampled tip positions through the acquired images during the growth. ARTT allows work with no markers and deals autonomously with new emerging root tips, as well as handling a massive number of data relying on minimum user interaction. Consequently, ARTT can be used for a wide range of applications and for the study of kinematics in different plant species. In particular, the study of the root growth and behaviour could lead to the definition of novel principles for the penetration and/or control paradigms for soil exploration and monitoring tasks. The software capabilities were demonstrated by experimental trials performed with Zea mays and Oryza sativa. (paper)

  2. Phenotypic plasticity of fine root growth increases plant productivity in pine seedlings

    Directory of Open Access Journals (Sweden)

    Grissom James E

    2004-09-01

    Full Text Available Abstract Background The plastic response of fine roots to a changing environment is suggested to affect the growth and form of a plant. Here we show that the plasticity of fine root growth may increase plant productivity based on an experiment using young seedlings (14-week old of loblolly pine. We use two contrasting pine ecotypes, "mesic" and "xeric", to investigate the adaptive significance of such a plastic response. Results The partitioning of biomass to fine roots is observed to reduce with increased nutrient availability. For the "mesic" ecotype, increased stem biomass as a consequence of more nutrients may be primarily due to reduced fine-root biomass partitioning. For the "xeric" ecotype, the favorable influence of the plasticity of fine root growth on stem growth results from increased allocation of biomass to foliage and decreased allocation to fine roots. An evolutionary genetic analysis indicates that the plasticity of fine root growth is inducible, whereas the plasticity of foliage is constitutive. Conclusions Results promise to enhance a fundamental understanding of evolutionary changes of tree architecture under domestication and to design sound silvicultural and breeding measures for improving plant productivity.

  3. Culture Methodology for Experimental Investigations Involving Rooted Submersed Aquatic Plants.

    Science.gov (United States)

    1984-11-01

    stolons or runners are best planted as intact plants (Sculthorpe 1967). Many species can be propagated from seed in addition to the above methods...J. 1984. Growth response of Myriophyllwm spicatu and Hydrilla verticillata when exposed to continuous, low concentrations of fluridone . Tech. Rept. A...aquatic plants, water, and bottom sediments. Weed Sci. 20:482-486. Sastroutomo, S. S. 1980. Dormancy and germination in axillary turions of iijiilZla

  4. Woody plant roots fail to penetrate a clay-lined landfill: Managment implications

    Science.gov (United States)

    Robinson, George R.; Handel, Steven N.

    1995-01-01

    In many locations, regulatory agencies do not permit tree planting above landfills that are sealed with a capping clay, because roots might penetrate the clay barrier and expose landfill contents to leaching. We find, however, no empirical or theoretical basis for this restriction, and instead hypothesize that plant roots of any kind are incapable of penetrating the dense clays used to seal landfills. As a test, we excavated 30 trees and shrubs, of 12 species, growing over a clay-lined municipal sanitary landfill on Staten Island, New York. The landfill had been closed for seven years, and featured a very shallow (10 to 30-cm) soil layer over a 45-cm layer of compacted grey marl (Woodbury series) clay. The test plants had invaded naturally from nearby forests. All plants examined—including trees as tall as 6 m—had extremely shallow root plates, with deformed tap roots that grew entirely above and parallel to the clay layer. Only occasional stubby feeder roots were found in the top 1 cm of clay, and in clay cracks at depths to 6 cm, indicating that the primary impediment to root growth was physical, although both clay and the overlying soil were highly acidic. These results, if confirmed by experimental research should lead to increased options for the end use of many closed sanitary landfills.

  5. Plant regeneration via somatic embryogenesis from root explants of ...

    African Journals Online (AJOL)

    hope&shola

    2010-08-30

    Aug 30, 2010 ... 1Rubber Research Institute, Chinese Academy of Tropical Agricultural Sciences, State Center for Rubber Breeding, State. Engineering and ... established in this study will facilitate mass propagation and may be applied to culture the roots of .... cF-value of 2,4-D; dF-value of KT; eF-value of 6-BA. 6-BA but ...

  6. Plants : Adaptive behavior, root-brains, and minimal cognition

    NARCIS (Netherlands)

    Calvo Garzon, Paco; Keijzer, Fred

    Plant intelligence has gone largely unnoticed within the field of animal and human adaptive behavior. In this context, we will introduce current work on plant intelligence as a new set of relevant phenomena that deserves attention and also discuss its potential relevance for the study of adaptive

  7. [Induction and in vitro culture of hairy roots of Dianthus caryophyllus and its plant regeneration].

    Science.gov (United States)

    Shi, Heping; Zhu, Yuanfeng; Wang, Bei; Sun, Jiangbing; Huang, Shengqin

    2014-11-01

    To use Agrobacterium rhizogenes-induced hairy roots to create new germplasm of Dianthus caryophyllus, we transformed D. caryophyllus with A. rhizogenes by leaf disc for plant regeneration from hairy roots. The white hairy roots could be induced from the basal surface of leaf explants of D. caryophyllus 12 days after inoculation with A. rhizogenes ATCC15834. The percentage of the rooting leaf explants was about 90% 21 days after inoculation. The hairy roots could grow rapidly and autonomously in liquid or solid phytohormone-free MS medium. The transformation was confirmed by PCR amplification of rol gene of Ri plasmid and silica gel thin-layer chromatography of opines from D. caryophyllus hairy roots. Hairy roots could form light green callus after cultured on MS+6-BA 1.0-3.0 mg/L + NAA 0.1-0.2 mg/L for 15 days. The optimum medium for adventitious shoots formation was MS + 6-BA 2.0 mg/L + NAA 0.02 mg/L, where the rate of adventitious shoot induction was 100% after cultured for 6 weeks. The mean number of adventitious shoot per callus was 30-40. The adventitious shoots can form roots when cultured on phytohormone-free 1/2 MS or 1/2 MS +0.5 mg/L NAA for 10 days. When the rooted plantlets transplanted in the substrate mixed with perlite sand and peat (volume ratio of 1:2), the survival rate was above 95%.

  8. Gamma ray irradiation to roots of tea-plants and induced mutant system

    International Nuclear Information System (INIS)

    Takeda, Yoshiyuki; Nekaku, Koji; Wada, Mitsumasa

    1990-01-01

    In order to utilize the useful mutation which is induced by irradiation for the breeding of tea-plants, the gamma-ray irradiation to the roots of tea-plants was carried out. The samples were the roots of tea-plants of four varieties dug up in February, 1984, and were adjusted to about 20 cm, then, put in the cold storage at 5degC for 9 months till the time of irradiation in November, 1984. However, a part of them was taken out in August, and planted in a field for 76 days to germinate, thereafter, used as the samples. The gamma-ray from a Co-60 source was irradiated in the radiation breeding laboratory of Agriculture Bioresources Research Institute at the total dose of 1, 2 and 3 kR and the dose rate of 500 R/h. The irradiated roots were planted as they are or in the state of being cut, and the rate of germination, the number of buds and the induced mutation were examined. Clear difference was not observed in the rate of germination and the number of buds between the irradiated samples and those without irradiation. The long roots were superior to the short roots regarding these items. The types of the induced mutation were mostly thin leaves, and also yellowing, mottling, fascination and so on occurred. The mutant system lacking trichomes on the back of new leaves is considered to be strong against tea anthracnose, and is valuable. (K.I.)

  9. Gamma ray irradiation to roots of tea-plants and induced mutant system

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, Yoshiyuki; Nekaku, Koji; Wada, Mitsumasa (National Research Inst. of Vegetables, Ornamental Plants and Tea, Ano, Mie (Japan))

    1990-11-01

    In order to utilize the useful mutation which is induced by irradiation for the breeding of tea-plants, the gamma-ray irradiation to the roots of tea-plants was carried out. The samples were the roots of tea-plants of four varieties dug up in February, 1984, and were adjusted to about 20 cm, then, put in the cold storage at 5degC for 9 months till the time of irradiation in November, 1984. However, a part of them was taken out in August, and planted in a field for 76 days to germinate, thereafter, used as the samples. The gamma-ray from a Co-60 source was irradiated in the radiation breeding laboratory of Agriculture Bioresources Research Institute at the total dose of 1, 2 and 3 kR and the dose rate of 500 R/h. The irradiated roots were planted as they are or in the state of being cut, and the rate of germination, the number of buds and the induced mutation were examined. Clear difference was not observed in the rate of germination and the number of buds between the irradiated samples and those without irradiation. The long roots were superior to the short roots regarding these items. The types of the induced mutation were mostly thin leaves, and also yellowing, mottling, fascination and so on occurred. The mutant system lacking trichomes on the back of new leaves is considered to be strong against tea anthracnose, and is valuable. (K.I.).

  10. Swarms, swarming and entanglements of fungal hyphae and of plant roots

    Science.gov (United States)

    Barlow, Peter W.; Fisahn, Joachim

    2013-01-01

    There has been recent interest in the possibility that plant roots can show oriented collective motion, or swarming behavior. We examine the evidence supportive of root swarming and we also present new observations on this topic. Seven criteria are proposed for the definition of a swarm, whose application can help identify putative swarming behavior in plants. Examples where these criteria are fulfilled, at many levels of organization, are presented in relation to plant roots and root systems, as well as to the root-like mycelial cords (rhizomorphs) of fungi. The ideas of both an “active” swarming, directed by a signal which imposes a common vector on swarm element aggregation, and a “passive” swarming, where aggregation results from external constraint, are introduced. Active swarming is a pattern of cooperative behavior peculiar to the sporophyte generation of vascular plants and is the antithesis of the competitive behavior shown by the gametophyte generation of such plants, where passive swarming may be found. Fungal mycelial cords could serve as a model example of swarming in a multi-cellular, non-animal system. PMID:24255743

  11. Evaluation of allelopathic impact of aqueous extract of root and aerial root of Tinospora cordifolia (Willd. miers on some weed plants

    Directory of Open Access Journals (Sweden)

    K. M. Abdul RAOOF

    2012-05-01

    Full Text Available The present laboratory experimental study was conducted to evaluate the allelopathic potential of Tinospora cordifolia (Willd. Miers on seed germination and seedling growth of weed plants (Chenopodium album L. Chenopodium murale L., Cassia tora L. and Cassia sophera L.. Root and aerial root aqueous extracts of Tinospora at 0.5, 1.0, 2.0 and 4.0% concentrations were applied to determine their effect on seed germination and seedling growth of test plants under laboratory conditions. Germination was observed for 15 days after that the root length and shoot length was measured. Dry weight was measured after oven drying the seedlings. The aqueous extracts from root and aerial root had inhibitory effect on seed germination of test plants. Aqueous extracts from root and aerial root significantly inhibited not only germination and seedling growth but also reduced dry weight of the seedlings. Root length, shoot length of weed species decreased progressively when plants were exposed to increasing concentration (0.5, 1, 2 and 4%. Aqueous extract of aerial root shows the least inhibition. The pH of aqueous extracts of different parts of T. cordifolia does not show any major change when the concentration increases.

  12. Plant Invasions Associated with Change in Root-Zone Microbial Community Structure and Diversity.

    Directory of Open Access Journals (Sweden)

    Richard R Rodrigues

    Full Text Available The importance of plant-microbe associations for the invasion of plant species have not been often tested under field conditions. The research sought to determine patterns of change in microbial communities associated with the establishment of invasive plants with different taxonomic and phenetic traits. Three independent locations in Virginia, USA were selected. One site was invaded by a grass (Microstegium vimineum, another by a shrub (Rhamnus davurica, and the third by a tree (Ailanthus altissima. The native vegetation from these sites was used as reference. 16S rRNA and ITS regions were sequenced to study root-zone bacterial and fungal communities, respectively, in invaded and non-invaded samples and analyzed using Quantitative Insights Into Microbial Ecology (QIIME. Though root-zone microbial community structure initially differed across locations, plant invasion shifted communities in similar ways. Indicator species analysis revealed that Operational Taxonomic Units (OTUs closely related to Proteobacteria, Acidobacteria, Actinobacteria, and Ascomycota increased in abundance due to plant invasions. The Hyphomonadaceae family in the Rhodobacterales order and ammonia-oxidizing Nitrospirae phylum showed greater relative abundance in the invaded root-zone soils. Hyphomicrobiaceae, another bacterial family within the phyla Proteobacteria increased as a result of plant invasion, but the effect associated most strongly with root-zones of M. vimineum and R. davurica. Functional analysis using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt showed bacteria responsible for nitrogen cycling in soil increased in relative abundance in association with plant invasion. In agreement with phylogenetic and functional analyses, greater turnover of ammonium and nitrate was associated with plant invasion. Overall, bacterial and fungal communities changed congruently across plant invaders, and support the hypothesis that

  13. Protection of olive planting stocks against parasitism of root-knot nematodes by arbuscular mycorrhizal fungi

    OpenAIRE

    Castillo, Pablo; Nico, Andrés I.; Azcón González de Aguilar, Concepción; Río Rincón, C. del; Calvet, Cinta; Jiménez-Díaz, Rafael M.

    2006-01-01

    The effects were investigated, under controlled conditions, of single and joint inoculation of olive planting stocks cvs Arbequina and Picual with the arbuscular mycorrhizal fungi (AMF) Glomus intraradices, Glomus mosseae or Glomus viscosum, and the root-knot nematodes Meloidogyne incognita and Meloidogyne javanica, on plant performance and nematode infection. Establishment of the fungal symbiosis significantly increased growth of olive plants by 88·9% within a range of 11·9–214·0%, ...

  14. Plant Hormone Homeostasis, Signaling, and Function during Adventitious Root Formation in Cuttings

    OpenAIRE

    Druege, Uwe; Franken, Philipp; Hajirezaei, Mohammad R.

    2016-01-01

    Adventitious root (AR) formation in cuttings is a multiphase developmental process, resulting from wounding at the cutting site and isolation from the resource and signal network of the whole plant. Though, promotive effects of auxins are widely used for clonal plant propagation, the regulation and function of plant hormones and their intricate signaling networks during AR formation in cuttings are poorly understood. In this focused review, we discuss our recent publications on the involvemen...

  15. A plant microRNA regulates the adaptation of roots to drought stress

    KAUST Repository

    Chen, Hao

    2012-06-01

    Plants tend to restrict their horizontal root proliferation in response to drought stress, an adaptive response mediated by the phytohormone abscisic acid (ABA) in antagonism with auxin through unknown mechanisms. Here, we found that stress-regulated miR393-guided cleavage of the transcripts encoding two auxin receptors, TIR1 and AFB2, was required for inhibition of lateral root growth by ABA or osmotic stress. Unlike in the control plants, the lateral root growth of seedlings expressing miR393-resistant TIR1 or AFB2 was no longer inhibited by ABA or osmotic stress. Our results indicate that miR393-mediated attenuation of auxin signaling modulates root adaptation to drought stress. © 2012 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  16. Pectins, ROS homeostasis and UV-B responses in plant roots.

    Science.gov (United States)

    Yokawa, Ken; Baluška, František

    2015-04-01

    Light from the sun contains far-red, visible and ultra violet (UV) wavelength regions. Almost all plant species have been evolved under the light environment. Interestingly, several photoreceptors, expressing both in shoots and roots, process the light information during the plant life cycle. Surprisingly, Arabidopsis root apices express besides the UVR8 UV-B receptor, also root-specific UV-B sensing proteins RUS1 and RUS2 linked to the polar cell-cell transport of auxin. In this mini-review, we focus on reactive oxygen species (ROS) signaling and possible roles of pectins internalized via endocytic vesicle recycling system in the root-specific UV-B perception and ROS homeostasis. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Potential of Root Exudates from Wetland Plants and Their Potential Role for Denitrification and Allelopathic Interactions

    DEFF Research Database (Denmark)

    Zhai, Xu

    Root exudates from wetland plants have both positive and negative interactions among microbe, plants and ecosystems. Wetland species releasing organic carbon into the rhizosphere for providing energy to denitrifying bacteria fuel denitrification for removal nitrogen in subsurface flow constructed...... wetlands. Furthermore, environmental factors such as temperature and light-regime affect the photosynthetic carbon fixation, which continuously influence the compositions and quantity of root exudates released into rhizosphere. Conversely, root exudates from invasive species might contain some phytotoxic...... chemicals to suppress the growth of native species. Phragmites australis is recognized as the most invasive species in wetland ecosystems in North America, and allelopathy has been reported to be involved in the invasion success of the introduced exotic P. australis. The composition of the root exudates may...

  18. Germination and root elongation bioassays in six different plant species for testing Ni contamination in soil.

    Science.gov (United States)

    Visioli, Giovanna; Conti, Federica D; Gardi, Ciro; Menta, Cristina

    2014-04-01

    In vitro short-term chronic phytotoxicity germination and root elongation test were applied to test the effects of nickel (Ni) in seed germination and root elongation in six plants species: Cucumis sativus (Cucurbitaceae), Lepidium sativum and Brassica nigra (Brassicaceae), Trifolium alexandrinum and Medicago sativa (Fabaceae), Phacelia tanacetifolia (Boraginaceae). A naturally Ni rich soil was used to compare the results obtained. Unlike root elongation, germination was not affected by Ni in any of the six species tested. EC50 values, calculated on the root elongation, showed that Ni toxicity decreases in the following order: P. tanacetifolia > B. nigra > C. sativus > L. sativum > M. sativa > T. alexandrinum. The test conducted using soil elutriate revealed a significantly lower effect in both seed germination and root elongation when compared to the results obtained using untreated soil. Conversely, the test performed on soil confirmed the high sensitivity of C. sativus, P. tanacetifolia and L. sativum to Ni.

  19. Hydroponics--Studies in Plant Culture With Historical Roots.

    Science.gov (United States)

    Lopez, Luz Maria

    1981-01-01

    Presents methods for demonstrating and applying scientific principles by growing plants through water culture (hydroponics), including a review of the history of hydroponics, re-creating some early experiments, and setting up a modern hydroponic system. (CS)

  20. A mathematical model for investigating the effect of cluster roots on plant nutrient uptake

    KAUST Repository

    Zygalakis, K. C.

    2012-04-01

    Cluster roots are thought to play an important role in mediating nutrient uptake by plants. In this paper we develop a mathematical model for the transport and uptake of phosphate by a single root. Phosphate is assumed to diffuse in the soil fluid phase and can also solubilised due to citrate exudation. Using multiple scale homogenisation techniques we derive an effective model that accounts for the cumulative effect of citrate exudation and phosphate uptake by cluster roots whilst still retaining all the necessary information about the microscale geometry and effects. © 2012 EDP Sciences and Springer.

  1. Morphology and biomass variations in root system of young tomato plants (Solanum sp.)

    International Nuclear Information System (INIS)

    Álvarez Gil, Marta A.; Fernández, Ana Fita; Ruiz Sánchez, María del C.; Bolarín Jiménez, María del C.

    2016-01-01

    The scarce exploitation of genotypic variability present in plant roots is an attractive breeding choice with regard to abiotic stresses and supports the objective of this work, which is to identify genotypic variation in root system traits of tomato genotypes (Solanum sp.). Thus, five tomato genotypes were studied: the commercial hybrid cultivar Jaguar (S. lycopersicum), Pera, Volgogradiskij and PE-47 entry (S. pennellii), which were collected in Peru, and the interspecific hybrid PeraxPE-47. Plants were grown in hydroponics for 26 days since germination; their roots were extracted and images were digitalized on scanner to evaluate total length, average diameter, the projected area and root length, following the categories per diameter of the whole root system through software Win Rhizo Pro 2003. The dry mass of roots and aerial parts was also recorded. Results indicated that genotypes differed in morphology, length according to diameter, root system spatial configuration and biomass, mainly with respect to the wild salinity resistant species PE-47. The interspecific hybrid PxPE-47 could be used as a rootstock to increase salt tolerance of susceptible cultivars. (author)

  2. Composite Transport Model and Water and Solute Transport across Plant Roots: An Update

    Directory of Open Access Journals (Sweden)

    Yangmin X. Kim

    2018-02-01

    Full Text Available The present review examines recent experimental findings in root transport phenomena in terms of the composite transport model (CTM. It has been a well-accepted conceptual model to explain the complex water and solute flows across the root that has been related to the composite anatomical structure. There are three parallel pathways involved in the transport of water and solutes in roots – apoplast, symplast, and transcellular paths. The role of aquaporins (AQPs, which facilitate water flows through the transcellular path, and root apoplast is examined in terms of the CTM. The contribution of the plasma membrane bound AQPs for the overall water transport in the whole plant level was varying depending on the plant species, age of roots with varying developmental stages of apoplastic barriers, and driving forces (hydrostatic vs. osmotic. Many studies have demonstrated that the apoplastic barriers, such as Casparian bands in the primary anticlinal walls and suberin lamellae in the secondary cell walls, in the endo- and exodermis are not perfect barriers and unable to completely block the transport of water and some solute transport into the stele. Recent research on water and solute transport of roots with and without exodermis triggered the importance of the extension of conventional CTM adding resistances that arrange in series (epidermis, exodermis, mid-cortex, endodermis, and pericycle. The extension of the model may answer current questions about the applicability of CTM for composite water and solute transport of roots that contain complex anatomical structures with heterogeneous cell layers.

  3. Multi-walled carbon nanotubes can enhance root elongation of wheat (Triticum aestivum) plants

    Energy Technology Data Exchange (ETDEWEB)

    Wang Xiuping; Han Heyou, E-mail: hyhan@mail.hzau.edu.cn; Liu Xueqin; Gu Xiaoxu; Chen Kun; Lu Donglian [Huazhong Agricultural University, College of Science, State Key Laboratory of Agricultural Microbiology, Institute of Chemical Biology (China)

    2012-06-15

    The potential effects of oxidized multi-walled carbon nanotubes (o-MWCNTs) with a length ranging from 50 to 630 nm on the development and physiology of wheat plants were evaluated by examining their effects on seed germination, root elongation, stem length, and vegetative biomass at a concentration ranging from 10 to 160 {mu}g/mL in the plant. Results indicated that after 7 days of exposure to the o-MWCNTs medium, faster root growth and higher vegetative biomass were observed, but seed germination and stem length did not show any difference as compared with controls. Moreover, a physiological study was conducted at cellular level using a traditional physiological approach to evidence the possible alterations in morphology, the cell length of root zone, and the dehydrogenase activity of seedlings. Transmission electron microscopy images revealed that o-MWCNTs could penetrate the cell wall and enter the cytoplasm after being taken up by roots. The cell length of root zone for the seedlings germinated and grown in the o-MWCNTs (80 {mu}g/mL) medium increased by 1.4-fold and a significant concentration-dependent increase in the dehydrogenase activity for the o-MWCNT-treated wheat seedlings was detected. These findings suggest that o-MWCNTs can significantly promote cell elongation in the root system and increase the dehydrogenase activity, resulting in faster root growth and higher biomass production.

  4. Composite Transport Model and Water and Solute Transport across Plant Roots: An Update.

    Science.gov (United States)

    Kim, Yangmin X; Ranathunge, Kosala; Lee, Seulbi; Lee, Yejin; Lee, Deogbae; Sung, Jwakyung

    2018-01-01

    The present review examines recent experimental findings in root transport phenomena in terms of the composite transport model (CTM). It has been a well-accepted conceptual model to explain the complex water and solute flows across the root that has been related to the composite anatomical structure. There are three parallel pathways involved in the transport of water and solutes in roots - apoplast, symplast, and transcellular paths. The role of aquaporins (AQPs), which facilitate water flows through the transcellular path, and root apoplast is examined in terms of the CTM. The contribution of the plasma membrane bound AQPs for the overall water transport in the whole plant level was varying depending on the plant species, age of roots with varying developmental stages of apoplastic barriers, and driving forces (hydrostatic vs. osmotic). Many studies have demonstrated that the apoplastic barriers, such as Casparian bands in the primary anticlinal walls and suberin lamellae in the secondary cell walls, in the endo- and exodermis are not perfect barriers and unable to completely block the transport of water and some solute transport into the stele. Recent research on water and solute transport of roots with and without exodermis triggered the importance of the extension of conventional CTM adding resistances that arrange in series (epidermis, exodermis, mid-cortex, endodermis, and pericycle). The extension of the model may answer current questions about the applicability of CTM for composite water and solute transport of roots that contain complex anatomical structures with heterogeneous cell layers.

  5. Multi-walled carbon nanotubes can enhance root elongation of wheat (Triticum aestivum) plants

    International Nuclear Information System (INIS)

    Wang Xiuping; Han Heyou; Liu Xueqin; Gu Xiaoxu; Chen Kun; Lu Donglian

    2012-01-01

    The potential effects of oxidized multi-walled carbon nanotubes (o-MWCNTs) with a length ranging from 50 to 630 nm on the development and physiology of wheat plants were evaluated by examining their effects on seed germination, root elongation, stem length, and vegetative biomass at a concentration ranging from 10 to 160 μg/mL in the plant. Results indicated that after 7 days of exposure to the o-MWCNTs medium, faster root growth and higher vegetative biomass were observed, but seed germination and stem length did not show any difference as compared with controls. Moreover, a physiological study was conducted at cellular level using a traditional physiological approach to evidence the possible alterations in morphology, the cell length of root zone, and the dehydrogenase activity of seedlings. Transmission electron microscopy images revealed that o-MWCNTs could penetrate the cell wall and enter the cytoplasm after being taken up by roots. The cell length of root zone for the seedlings germinated and grown in the o-MWCNTs (80 μg/mL) medium increased by 1.4-fold and a significant concentration-dependent increase in the dehydrogenase activity for the o-MWCNT-treated wheat seedlings was detected. These findings suggest that o-MWCNTs can significantly promote cell elongation in the root system and increase the dehydrogenase activity, resulting in faster root growth and higher biomass production.

  6. The role of cell walls and pectins in cation exchange and surface area of plant roots.

    Science.gov (United States)

    Szatanik-Kloc, A; Szerement, J; Józefaciuk, G

    2017-08-01

    We aimed to assess role of cell walls in formation of cation exchange capacity, surface charge, surface acidity, specific surface, water adsorption energy and surface charge density of plant roots, and to find the input of the cell wall pectins to the above properties. Whole roots, isolated cell walls and the residue after the extraction of pectins from the cell walls of two Apiaceae L. species (celeriac and parsnip) were studied using potentiometric titration curves and water vapor adsorption - desorption isotherms. Total amount of surface charge, as well as the cation exchange capacity were markedly higher in roots than in their cell walls, suggesting large contribution of other cell organelles to the binding of cations by the whole root cells. Significantly lower charge of the residues after removal of pectins was noted indicating that pectins play the most important role in surface charge formation of cell walls. The specific surface was similar for all of the studied materials. For the separated cell walls it was around 10% smaller than of the whole roots, and it increased slightly after the removal of pectins. The surface charge density and water vapor adsorption energy were the highest for the whole roots and the lowest for the cell walls residues after removal of pectins. The results indicate that the cell walls and plasma membranes are jointly involved in root ion exchange and surface characteristics and their contribution depends upon the plant species. Copyright © 2017 Elsevier GmbH. All rights reserved.

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

    Directory of Open Access Journals (Sweden)

    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.

  8. Sensitivity of greenhouse summer dryness to changes in plant rooting characteristics

    Science.gov (United States)

    Milly, P.C.D.

    1997-01-01

    A possible consequence of increased concentrations of greenhouse gases in Earth's atmosphere is "summer dryness," a decrease of summer plant-available soil water in middle latitudes, caused by increased availability of energy to drive evapotranspiration. Results from a numerical climate model indicate that summer dryness and related changes of land-surface water balances are highly sensitive to possible concomitant changes of plant-available water-holding capacity of soil, which depends on plant rooting depth and density. The model suggests that a 14% decrease of the soil volume whose water is accessible to plant roots would generate the same summer dryness, by one measure, as an equilibrium doubling of atmospheric carbon dioxide. Conversely, a 14% increase of that soil volume would be sufficient to offset the summer dryness associated with carbon-dioxide doubling. Global and regional changes in rooting depth and density may result from (1) plant and plant-community responses to greenhouse warming, to carbon-dioxide fertilization, and to associated changes in the water balance and (2) anthropogenic deforestation and desertification. Given their apparently critical role, heretofore ignored, in global hydroclimatic change, such changes of rooting characteristics should be carefully evaluated using ecosystem observations, theory, and models.

  9. Extracellular Trapping of Soil Contaminants by Root Border Cells: New Insights into Plant Defense

    Directory of Open Access Journals (Sweden)

    Martha C. Hawes

    2016-01-01

    Full Text Available Soil and water pollution by metals and other toxic chemicals is difficult to measure and control, and, as such, presents an ongoing global threat to sustainable agriculture and human health. Efforts to remove contaminants by plant-mediated pathways, or “phytoremediation”, though widely studied, have failed to yield consistent, predictable removal of biological and chemical contaminants. Emerging research has revealed that one major limitation to using plants to clean up the environment is that plants are programmed to protect themselves: Like white blood cells in animals, border cells released from plant root tips carry out an extracellular trapping process to neutralize threats and prevent injury to the host. Variability in border cell trapping has been found to be correlated with variation in sensitivity of roots to aluminum, and removal of border cell results in increased Al uptake into the root tip. Studies now have implicated border cells in responses of diverse plant roots to a range of heavy metals, including arsenic, copper, cadmium, lead, mercury, iron, and zinc. A better understanding of border cell extracellular traps and their role in preventing toxin uptake may facilitate efforts to use plants as a nondestructive approach to neutralize environmental threats.

  10. Breeding crop plants with deep roots: their role in sustainable carbon, nutrient and water sequestration

    Science.gov (United States)

    Kell, Douglas B.

    2011-01-01

    Background The soil represents a reservoir that contains at least twice as much carbon as does the atmosphere, yet (apart from ‘root crops’) mainly just the above-ground plant biomass is harvested in agriculture, and plant photosynthesis represents the effective origin of the overwhelming bulk of soil carbon. However, present estimates of the carbon sequestration potential of soils are based more on what is happening now than what might be changed by active agricultural intervention, and tend to concentrate only on the first metre of soil depth. Scope Breeding crop plants with deeper and bushy root ecosystems could simultaneously improve both the soil structure and its steady-state carbon, water and nutrient retention, as well as sustainable plant yields. The carbon that can be sequestered in the steady state by increasing the rooting depths of crop plants and grasses from, say, 1 m to 2 m depends significantly on its lifetime(s) in different molecular forms in the soil, but calculations (http://dbkgroup.org/carbonsequestration/rootsystem.html) suggest that this breeding strategy could have a hugely beneficial effect in stabilizing atmospheric CO2. This sets an important research agenda, and the breeding of plants with improved and deep rooting habits and architectures is a goal well worth pursuing. PMID:21813565

  11. Iron absorption by roots of fruit plants : some characteristics of the phenomena

    International Nuclear Information System (INIS)

    Bindra, A.S.

    1979-01-01

    Using young plants of peach, plum and almond growing in water culture, study was undertaken on the absorption and translocation of labelled iron. When peach plants deficient in this element were supplied with it, they tended to absorb it very rapidly, especially during the first 30 minutes. This absorption was not a superficial adsorption. Iron absorption was found to be linked to the length of non-lignified roots. Of the three species, almond absorbed more iron than peach but less than olum. No significant varietal difference was found regarding the iron absorption capacity of roots of different varieties of peach. Removal of foliage did not influence the absorption of iron by roots of peach plants in the early stages. (auth.)

  12. Water movement through plant roots - exact solutions of the water flow equation in roots with linear or exponential piecewise hydraulic properties

    Science.gov (United States)

    Meunier, Félicien; Couvreur, Valentin; Draye, Xavier; Zarebanadkouki, Mohsen; Vanderborght, Jan; Javaux, Mathieu

    2017-12-01

    In 1978, Landsberg and Fowkes presented a solution of the water flow equation inside a root with uniform hydraulic properties. These properties are root radial conductivity and axial conductance, which control, respectively, the radial water flow between the root surface and xylem and the axial flow within the xylem. From the solution for the xylem water potential, functions that describe the radial and axial flow along the root axis were derived. These solutions can also be used to derive root macroscopic parameters that are potential input parameters of hydrological and crop models. In this paper, novel analytical solutions of the water flow equation are developed for roots whose hydraulic properties vary along their axis, which is the case for most plants. We derived solutions for single roots with linear or exponential variations of hydraulic properties with distance to root tip. These solutions were subsequently combined to construct single roots with complex hydraulic property profiles. The analytical solutions allow one to verify numerical solutions and to get a generalization of the hydric behaviour with the main influencing parameters of the solutions. The resulting flow distributions in heterogeneous roots differed from those in uniform roots and simulations led to more regular, less abrupt variations of xylem suction or radial flux along root axes. The model could successfully be applied to maize effective root conductance measurements to derive radial and axial hydraulic properties. We also show that very contrasted root water uptake patterns arise when using either uniform or heterogeneous root hydraulic properties in a soil-root model. The optimal root radius that maximizes water uptake under a carbon cost constraint was also studied. The optimal radius was shown to be highly dependent on the root hydraulic properties and close to observed properties in maize roots. We finally used the obtained functions for evaluating the impact of root maturation

  13. Water movement through plant roots – exact solutions of the water flow equation in roots with linear or exponential piecewise hydraulic properties

    Directory of Open Access Journals (Sweden)

    F. Meunier

    2017-12-01

    Full Text Available In 1978, Landsberg and Fowkes presented a solution of the water flow equation inside a root with uniform hydraulic properties. These properties are root radial conductivity and axial conductance, which control, respectively, the radial water flow between the root surface and xylem and the axial flow within the xylem. From the solution for the xylem water potential, functions that describe the radial and axial flow along the root axis were derived. These solutions can also be used to derive root macroscopic parameters that are potential input parameters of hydrological and crop models. In this paper, novel analytical solutions of the water flow equation are developed for roots whose hydraulic properties vary along their axis, which is the case for most plants. We derived solutions for single roots with linear or exponential variations of hydraulic properties with distance to root tip. These solutions were subsequently combined to construct single roots with complex hydraulic property profiles. The analytical solutions allow one to verify numerical solutions and to get a generalization of the hydric behaviour with the main influencing parameters of the solutions. The resulting flow distributions in heterogeneous roots differed from those in uniform roots and simulations led to more regular, less abrupt variations of xylem suction or radial flux along root axes. The model could successfully be applied to maize effective root conductance measurements to derive radial and axial hydraulic properties. We also show that very contrasted root water uptake patterns arise when using either uniform or heterogeneous root hydraulic properties in a soil–root model. The optimal root radius that maximizes water uptake under a carbon cost constraint was also studied. The optimal radius was shown to be highly dependent on the root hydraulic properties and close to observed properties in maize roots. We finally used the obtained functions for evaluating the impact

  14. Actin Cytoskeleton-Based Plant Synapse as Gravitransducer in the Transition Zone of the Root Apex

    Science.gov (United States)

    Baluska, Frantisek; Barlow, Peter; Volkmann, Dieter; Mancuso, Stefano

    The actin cytoskeleton was originally proposed to act as the signal transducer in the plant gravity sensory-motoric circuit. Surprisingly, however, several studies have documented that roots perfom gravisensing and gravitropism more effectively if exposed to diverse anti-F-actin drugs. Our study, using decapped maize root apices, has revealed that depolymerization of F-actin stimulates gravity perception in cells of the transition zone where root gravitropism is initiated (Mancuso et al. 2006). It has been proposed (Balǔka et al. 2005, 2009a) that s the non-growing adhesive end-poles, enriched with F-actin and myosin VIII, and active in endocytic recycling of both PIN transporters and cell wall pectins cross-linked with calcium and boron, act as the gravisensing domains, and that these impinge directly upon the root motoric responses via control of polar auxin transport. This model suggests that mechanical asymmetry at these plant synapses determines vectorial gravity-controlled auxin transport. Due to the gravity-imposed mechanical load upon the protoplast, a tensional stress is also imposed upon the plasma membrane of the physically lower synaptic cell pole. This stress is then relieved by shifting the endocytosis-exocytosis balance towards exocytosis (Balǔka et al. s 2005, 2009a,b). This `Synaptic Auxin Secretion' hypothesis does not conflict with the `Starch Statolith' hypothesis, which is based on amyloplast sedimentation. In fact, the `Synaptic Auxin Secretion' hypothesis has many elements which allow its unification with the Starch-Statolith model (Balǔka et al. 2005, 2009a,b). s References Balǔka F, Volkmann D, Menzel D (2005) Plant synapses: actin-based adhesion s domains for cell-to-cell communication. Trends Plant Sci 10: 106-111 Balǔka F, Schlicht M, s Wan Y-L, Burbach C, Volkmann D (2009a) Intracellular domains and polarity in root apices: from synaptic domains to plant neurobiology. Nova Acta Leopoldina 96: 103-122 Balǔka s F, Mancuso S

  15. Effect of Root-Zone Moisture Variations on Growth of Lettuce and Pea Plants

    Science.gov (United States)

    Ilieva, Iliana; Ivanova, Tania

    2008-06-01

    Variations in substrate moisture lead to changes in water and oxygen availability to plant roots. Ground experiments were carried out in the laboratory prototype of SVET-2 Space Greenhouse to study the effect of variation of root-zone moisture conditions on growth of lettuce and pea plants. The effect of transient increase (for 1 day) and drastic increase (waterlogging for 10 days) of substrate moisture was studied with 16-day old pea and 21-day old lettuce plants respectively. Pea height and fresh biomass accumulation were not affected by transient substrate moisture increase. Net photosynthetic rate (Pn) of pea plants showed fast response to substrate moisture variation, while chlorophyll content did not change. Drastic change of substrate moisture suppressed lettuce Pn, chlorophyll biosynthesis and plant growth. These parameters slowly recovered after termination of waterlogging treatment but lettuce yield was greatly affected. The results showed that the most sensitive physiological parameter to substrate moisture variations is photosynthesis.

  16. Plant root proliferation in nitrogen-rich patches confers competitive advantage

    Science.gov (United States)

    Robinson, D.; Hodge, A.; Griffiths, B. S.; Fitter, A. H.

    1999-01-01

    Plants respond strongly to environmental heterogeneity, particularly below ground, where spectacular root proliferations in nutrient-rich patches may occur. Such 'foraging' responses apparently maximize nutrient uptake and are now prominent in plant ecological theory. Proliferations in nitrogen-rich patches are difficult to explain adaptively, however. The high mobility of soil nitrate should limit the contribution of proliferation to N capture. Many experiments on isolated plants show only a weak relation between proliferation and N uptake. We show that N capture is associated strongly with proliferation during interspecific competition for finite, locally available, mixed N sources, precisely the conditions under which N becomes available to plants on generally infertile soils. This explains why N-induced root proliferation is an important resource-capture mechanism in N-limited plant communities and suggests that increasing proliferation by crop breeding or genetic manipulation will have a limited impact on N capture by well-fertilized monocultures.

  17. Molecular responses in root-associative rhizospheric bacteria to variations in plant exudates

    Science.gov (United States)

    Abdoun, Hamid; McMillan, Mary; Pereg, Lily

    2015-04-01

    Plant exudates are a major factor in the interface of plant-soil-microbe interactions and it is well documented that the microbial community structure in the rhizosphere is largely influenced by the particular exudates excreted by various plants. Azospirillum brasilense is a plant growth promoting rhizobacterium that is known to interact with a large number of plants, including important food crops. The regulatory gene flcA has an important role in this interaction as it controls morphological differentiation of the bacterium that is essential for attachment to root surfaces. Being a response regulatory gene, flcA mediates the response of the bacterial cell to signals from the surrounding rhizosphere. This makes this regulatory gene a good candidate for analysis of the response of bacteria to rhizospheric alterations, in this case, variations in root exudates. We will report on our studies on the response of Azospirillum, an ecologically, scientifically and agriculturally important bacterial genus, to variations in the rhizosphere.

  18. Physiological conditions and uptake of inorganic carbon-14 by plant roots

    International Nuclear Information System (INIS)

    Amiro, B.D.; Ewing, L.L.

    1992-01-01

    The uptake of inorganic 14 C by bean plant roots was measured. The plants were grown in a nutrient solution culture at pH 6 and a NaH 14 CO 3 tracer was added to the growth medium. Photosynthesis and transpiration were varied by exposing the aerial portions of the plants to different atmospheric CO 2 concentrations, humidities and light levels in a cuvette system. Leaf concentrations of 14 C were measured at the end of the experiments using liquid scintillation counting. Plant uptake of 14 C via the roots was independent of the photosynthetic rate and, in most cases, could be predicted by knowing the transpiration rate and the nutrient solution concentration. However, when a less efficient root-medium aeration system was used, 14 C uptake was greater than that predicted using transpiration, a phenomenon observed by other researchers. This contrasted to results of another experiment where the measured uptake of iodine was much slower than that predicted using transpiration. Knowledge of transpiration rates is useful in predicting inorganic carbon uptake via the roots and in estimating 14 C transport from contaminated soils to biota. Also, the independence of the uptake from photosynthesis and ambient CO 2 concentrations suggests that future increases in atmospheric CO 2 concentrations may not have a direct effect on root uptake of soil carbon. (author)

  19. The roots of defense: plant resistance and tolerance to belowground herbivory.

    Directory of Open Access Journals (Sweden)

    Sean M Watts

    2011-04-01

    Full Text Available There is conclusive evidence that there are fitness costs of plant defense and that herbivores can drive selection for defense. However, most work has focused on above-ground interactions, even though belowground herbivory may have greater impacts on individual plants than above-ground herbivory. Given the role of belowground plant structures in resource acquisition and storage, research on belowground herbivores has much to contribute to theories on the evolution of plant defense. Pocket gophers (Geomyidae provide an excellent opportunity to study root herbivory. These subterranean rodents spend their entire lives belowground and specialize on consuming belowground plant parts.We compared the root defenses of native forbs from mainland populations (with a history of gopher herbivory to island populations (free from gophers for up to 500,000 years. Defense includes both resistance against herbivores and tolerance of herbivore damage. We used three approaches to compare these traits in island and mainland populations of two native California forbs: 1 Eschscholzia californica populations were assayed to compare alkaloid deterrents, 2 captive gophers were used to test the palatability of E. californica roots and 3 simulated root herbivory assessed tolerance to root damage in Deinandra fasciculata and E. californica. Mainland forms of E. californica contained 2.5 times greater concentration of alkaloids and were less palatable to gophers than island forms. Mainland forms of D. fasciculata and, to a lesser extent, E. californica were also more tolerant of root damage than island conspecifics. Interestingly, undamaged island individuals of D. fasciculata produced significantly more fruit than either damaged or undamaged mainland individuals.These results suggest that mainland plants are effective at deterring and tolerating pocket gopher herbivory. Results also suggest that both forms of defense are costly to fitness and thus reduced in the absence of

  20. CEP genes regulate root and shoot development in response to environmental cues and are specific to seed plants.

    Science.gov (United States)

    Delay, Christina; Imin, Nijat; Djordjevic, Michael A

    2013-12-01

    The manifestation of repetitive developmental programmes during plant growth can be adjusted in response to various environmental cues. During root development, this means being able to precisely control root growth and lateral root development. Small signalling peptides have been found to play roles in many aspects of root development. One member of the CEP (C-TERMINALLY ENCODED PEPTIDE) gene family has been shown to arrest root growth. Here we report that CEP genes are widespread among seed plants but are not present in land plants that lack true branching roots or root vasculature. We have identified 10 additional CEP genes in Arabidopsis. Expression analysis revealed that CEP genes are regulated by environmental cues such as nitrogen limitation, increased salt levels, increased osmotic strength, and increased CO2 levels in both roots and shoots. Analysis of synthetic CEP variants showed that both peptide sequence and modifications of key amino acids affect CEP biological activity. Analysis of several CEP over-expression lines revealed distinct roles for CEP genes in root and shoot development. A cep3 knockout mutant showed increased root and shoot growth under a range of abiotic stress, nutrient, and light conditions. We demonstrate that CEPs are negative regulators of root development, slowing primary root growth and reducing lateral root formation. We propose that CEPs are negative regulators that mediate environmental influences on plant development.

  1. [Difference of anti-fracture mechanical characteristics between lateral-root branches and adjacent upper straight roots of four plant species in vigorous growth period].

    Science.gov (United States)

    Liu, Peng-fei; Liu, Jing; Zhu, Hong-hui; Zhang, Xin; Zhang, Ge; Li, You-fang; Su, Yu; Wang, Chen-jia

    2016-01-01

    Taking four plant species, Caragana korshinskii, Salix psammophila, Hippophae rhamnides and Artemisia sphaerocephala, which were 3-4 years old and in vigorous growth period, as test materials, the anti-fracture forces of lateral-root branches and adjacent upper straight roots were measured with the self-made fixture and the instrument of TY 8000. The lateral-root branches were vital and the diameters were 1-4 mm. The results showed that the anti-fracture force and anti-fracture strength of lateral-root branches were lesser than those of the adjacent upper straight roots even though the average diameter of lateral-root branches was greater. The ratios of anti-fracture strength of lateral-root branches to the adjacent upper straight roots were 71.5% for C. korshinskii, 62.9% for S. psammophila, 45.4% for H. rhamnides and 35.4% for A. sphaerocephala. For the four plants, the anti-fracture force positively correlated with the diameter in a power function, while the anti-fracture strength negatively correlated with diameter in a power function. The anti-fracture strengths of lateral-root branches and adjacent upper straight roots for the four species followed the sequence of C. korshinskii (33.66 and 47.06 MPa) > S. psammophila (17.31 and 27.54 MPa) > H. rhamnides (3.97 and 8.75 MPa) > A. sphaerphala (2.18 and 6.15 MPa).

  2. Cadmium uptake from solution by plants and its transport from roots to shoots

    Energy Technology Data Exchange (ETDEWEB)

    Jarvis, S.C.; Jones, L.H.P.; Hopper, M.J.

    1976-02-01

    The uptake of cadmium by the roots of plants, and its transport to shoots was examined using solution culture. Uptake by the roots of perennial ryegrass over a period of 4 hours from an aqueous solution containing 0.25 ppm cadmium as CdCl/sub 2/ was (i) enhanced by killing the roots and (ii) depressed when Ca/sup 2 +/, Mn/sup 2 +/ or Zn/sup 2 +/ were added to the solution. The distribution of cadmium between the roots and shoots of 23 species was examined at 4 days after a single, 3-day exposure to a nutrient solution containing 0.01 ppm added Cd. In all except 3 species, i.e. kale, lettuce and watercress, more than 50% of that taken up was retained in the shoot, and in fibrous roots of fodder beet, parsnip, carrot and radish it was greater than in the swollen storage roots. When perennial ryegrass was similarly exposed to solutions containing 0.01, 0.05, and 0.25 ppm added cadmium, uptake, as measured at 3 days after adding cadmium, increased with increasing rates of addition, but the proportion retained in the roots was constant (approximately 88%). There was no further transport from roots to shoots during the next 21 days, with the result that the concentration in the shoots decreased progressively with increasing growth. It is concluded that although the roots of several species can take up large quantities of cadmium from solution there are mechanisms which may restrict the movement of cadmium through plants, and thus to animals. 21 references, 7 tables.

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

    Directory of Open Access Journals (Sweden)

    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.

  4. Metabolic analysis of the increased adventitious rooting mutant of Artemisia annua reveals a role for the plant monoterpene borneol in adventitious root formation.

    Science.gov (United States)

    Tian, Na; Liu, Shuoqian; Li, Juan; Xu, Wenwen; Yuan, Lin; Huang, Jianan; Liu, Zhonghua

    2014-08-01

    Adventitious root (AR) formation is a critical process for plant clonal propagation. The role of plant secondary metabolites in AR formation is still poorly understood. Chemical and physical mutagenesis in combination with somatic variation were performed on Artemisia annua in order to obtain a mutant with changes in adventitious rooting and composition of plant secondary metabolites. Metabolic and morphological analyses of the iar (increased adventitious rooting) mutant coupled with in vitro assays were used to elucidate the relationship between plant secondary metabolites and AR formation. The only detected differences between the iar mutant and wild-type were rooting capacity and borneol/camphor content. Consistent with this, treatment with borneol in vitro promoted adventitious rooting in wild-type. The enhanced rooting did not continue upon removal of borneol. The iar mutant displayed no significant differences in AR formation upon treatment with camphor. Together, our results suggest that borneol promotes adventitious rooting whereas camphor has no effect on AR formation. © 2013 Scandinavian Plant Physiology Society.

  5. Online condition monitoring to enable extended operation of nuclear power plants

    International Nuclear Information System (INIS)

    Meyer, Ryan Michael; Bond, Leonard John; Ramuhalli, Pradeep

    2012-01-01

    Safe, secure, and economic operation of nuclear power plants will remain of strategic significance. New and improved monitoring will likely have increased significance in the post-Fukushima world. Prior to Fukushima, many activities were already underway globally to facilitate operation of nuclear power plants beyond their initial licensing periods. Decisions to shut down a nuclear power plant are mostly driven by economic considerations. Online condition monitoring is a means to improve both the safety and economics of extending the operating lifetimes of nuclear power plants, enabling adoption of proactive aging management. With regard to active components (e.g., pumps, valves, motors, etc.), significant experience in other industries has been leveraged to build the science base to support adoption of online condition-based maintenance and proactive aging management in the nuclear industry. Many of the research needs are associated with enabling proactive management of aging in passive components (e.g., pipes, vessels, cables, containment structures, etc.). This paper provides an overview of online condition monitoring for the nuclear power industry with an emphasis on passive components. Following the overview, several technology/knowledge gaps are identified, which require addressing to facilitate widespread online condition monitoring of passive components. (author)

  6. Root phosphatase activity, plant growth and phosphorus accumulation of maize genotypes

    Directory of Open Access Journals (Sweden)

    Machado Cynthia Torres de Toledo

    2004-01-01

    Full Text Available The activity of the enzyme phosphatase (P-ase is a physiological characteristic related to plant efficiency in relation to P acquisition and utilization, and is genetically variable. As part of a study on maize genotype characterization in relation to phosphorus (P uptake and utilization efficiency, two experiments were set up to measure phosphatase (P-ase activity in intact roots of six local and improved maize varieties and two sub-populations. Plants were grown at one P level in nutrient solution (4 mg L-1 and the P-ase activity assay was run using 17-day-old plants for varieties and 24-day-old plants for subpopulations. Shoot and root dry matter yields and P concentrations and contents in plant parts were determined, as well as P-efficiency indexes. Root P-ase activity differed among varieties, and highest enzimatic activities were observed in two local varieties -'Catetão' and 'Caiano' -and three improved varieties -'Sol da Manhã', 'Nitrodente' and 'BR 106'. 'Carioca', a local variety, had the lowest activity. Between subpopulations, 'ND2', with low yielding and poorly P-efficient plants, presented higher root P-ase activity as compared to 'ND10', high yielding and highly P-efficient plants. In general, subpopulations presented lower P-ase activities as compared to varieties. Positive and/or negative correlations were obtained between P-ase activity and P-efficiency characteristics, specific for the genotypes, not allowing inference on a general and clear association between root-secreted phosphatase and dry matter production or P acquisition. Genotypic variability must be known and considered before using P-ase activity as an indicator of P nutritional status, or P tolerance, adaptation and efficiency under low P conditions.

  7. Arbuscular mycorrhizal assemblages in native plant roots change in the presence of invasive exotic grasses

    Science.gov (United States)

    Hawkes, C.V.; Belnap, J.; D'Antonio, C.; Firestone, M.K.

    2006-01-01

    Plant invasions have the potential to significantly alter soil microbial communities, given their often considerable aboveground effects. We examined how plant invasions altered the arbuscular mycorrhizal fungi of native plant roots in a grassland site in California and one in Utah. In the California site, we used experimentally created plant communities composed of exotic (Avena barbata, Bromus hordeaceus) and native (Nassella pulchra, Lupinus bicolor) monocultures and mixtures. In the Utah semi-arid grassland, we took advantage of invasion by Bromus tectorum into long-term plots dominated by either of two native grasses, Hilaria jamesii or Stipa hymenoides. Arbuscular mycorrhizal fungi colonizing roots were characterized with PCR amplification of the ITS region, cloning, and sequencing. We saw a significant effect of the presence of exotic grasses on the diversity of mycorrhizal fungi colonizing native plant roots. In the three native grasses, richness of mycorrhizal fungi decreased; in the native forb at the California site, the number of fungal RFLP patterns increased in the presence of exotics. The exotic grasses also caused the composition of the mycorrhizal community in native roots to shift dramatically both in California, with turnover of Glomus spp., and Utah, with replacement of Glomus spp. by apparently non-mycorrhizal fungi. Invading plants may be able to influence the network of mycorrhizal fungi in soil that is available to natives through either earlier root activity or differential carbon provision compared to natives. Alteration of the soil microbial community by plant invasion can provide a mechanism for both successful invasion and the resulting effects of invaders on the ecosystem. ?? Springer 2006.

  8. The symbiosis with the arbuscular mycorrhizal fungus Rhizophagus irregularis drives root water transport in flooded tomato plants.

    Science.gov (United States)

    Calvo-Polanco, Monica; Molina, Sonia; Zamarreño, Angel María; García-Mina, Jose María; Aroca, Ricardo

    2014-05-01

    It is known that the presence of arbuscular mycorrhizal fungi within the plant roots enhances the tolerance of the host plant to different environmental stresses, although the positive effect of the fungi in plants under waterlogged conditions has not been well studied. Tolerance of plants to flooding can be achieved through different molecular, physiological and anatomical adaptations, which will affect their water uptake capacity and therefore their root hydraulic properties. Here, we investigated the root hydraulic properties under non-flooded and flooded conditions in non-mycorrhizal tomato plants and plants inoculated with the arbuscular mycorrhizal fungus Rhizophagus irregularis. Only flooded mycorrhizal plants increased their root hydraulic conductivity, and this effect was correlated with a higher expression of the plant aquaporin SlPIP1;7 and the fungal aquaporin GintAQP1. There was also a higher abundance of the PIP2 protein phoshorylated at Ser280 in mycorrhizal flooded plants. The role of plant hormones (ethylene, ABA and IAA) in root hydraulic properties was also taken into consideration, and it was concluded that, in mycorrhizal flooded plants, ethylene has a secondary role regulating root hydraulic conductivity whereas IAA may be the key hormone that allows the enhancement of root hydraulic conductivity in mycorrhizal plants under low oxygen conditions.

  9. Evaluation of allelopathic impact of aqueous extract of root and aerial root of Tinospora cordifolia (Willd.) miers on some weed plants

    OpenAIRE

    K. M. Abdul RAOOF; M. Badruzzaman SIDDIQUI

    2012-01-01

    The present laboratory experimental study was conducted to evaluate the allelopathic potential of Tinospora cordifolia (Willd.) Miers on seed germination and seedling growth of weed plants (Chenopodium album L. Chenopodium murale L., Cassia tora L. and Cassia sophera L.). Root and aerial root aqueous extracts of Tinospora at 0.5, 1.0, 2.0 and 4.0% concentrations were applied to determine their effect on seed germination and seedling growth of test plants under laboratory conditions. Germinati...

  10. Snake venom neutralization by Indian medicinal plants (Vitex negundo and Emblica officinalis) root extracts.

    Science.gov (United States)

    Alam, M I; Gomes, A

    2003-05-01

    The methanolic root extracts of Vitex negundo Linn. and Emblica officinalis Gaertn. were explored for the first time for antisnake venom activity. The plant (V. negundo and E. officinalis) extracts significantly antagonized the Vipera russellii and Naja kaouthia venom induced lethal activity both in in vitro and in vivo studies. V. russellii venom-induced haemorrhage, coagulant, defibrinogenating and inflammatory activity was significantly neutralized by both plant extracts. No precipitating bands were observed between the plant extract and snake venom. The above observations confirmed that the plant extracts possess potent snake venom neutralizing capacity and need further investigation.

  11. Towards systems biology of the gravity response of higher plants -multiscale analysis of Arabidopsis thaliana root growth

    Science.gov (United States)

    Palme, Klaus; Aubry, D.; Bensch, M.; Schmidt, T.; Ronneberger, O.; Neu, C.; Li, X.; Wang, H.; Santos, F.; Wang, B.; Paponov, I.; Ditengou, F. A.; Teale, W. T.; Volkmann, D.; Baluska, F.; Nonis, A.; Trevisan, S.; Ruperti, B.; Dovzhenko, A.

    Gravity plays a fundamental role in plant growth and development. Up to now, little is known about the molecular organisation of the signal transduction cascades and networks which co-ordinate gravity perception and response. By using an integrated systems biological approach, a systems analysis of gravity perception and the subsequent tightly-regulated growth response is planned in the model plant Arabidopsis thaliana. This approach will address questions such as: (i) what are the components of gravity signal transduction pathways? (ii) what are the dynamics of these components? (iii) what is their spatio-temporal regulation in different tis-sues? Using Arabidopsis thaliana as a model-we use root growth to obtain insights in the gravity response. New techniques enable identification of the individual genes affected by grav-ity and further integration of transcriptomics and proteomics data into interaction networks and cell communication events that operate during gravitropic curvature. Using systematic multiscale analysis we have identified regulatory networks consisting of transcription factors, the protein degradation machinery, vesicle trafficking and cellular signalling during the gravire-sponse. We developed approach allowing to incorporate key features of the root system across all relevant spatial and temporal scales to describe gene-expression patterns and correlate them with individual gene and protein functions. Combination of high-resolution microscopy and novel computational tools resulted in development of the root 3D model in which quantitative descriptions of cellular network properties and of multicellular interactions important in root growth and gravitropism can be integrated for the first time.

  12. Plant clinics must take root in poor countries

    DEFF Research Database (Denmark)

    Danielsen, Solveig; Matsiko, Frank

    2010-01-01

    Food security, the production of safe food and the provision of quality products for domestic and export markets are all dependent on the ability to grow healthy plants. But pests and diseases destroy millions of tons of crops every year across the world, preventing families, communities and nati...... and responsive system, so the clinics need to be well integrated with other services, including technology and knowledge providers. The biggest challenges to achieving this are overcoming the 'project mentality' and the limits imposed by constraining institutional structures.......Food security, the production of safe food and the provision of quality products for domestic and export markets are all dependent on the ability to grow healthy plants. But pests and diseases destroy millions of tons of crops every year across the world, preventing families, communities...... and nations from fully exploiting their potential to produce food and create wealth. Timely access to information and advice about how to manage plant health problems can make the difference between success and failure. Since 2003, 12 countries in Africa, Asia and Latin America, have introduced community...

  13. Root Canal Irrigation: Chemical Agents and Plant Extracts Against Enterococcus faecalis

    Science.gov (United States)

    Borzini, Letizia; Condò, Roberta; De Dominicis, Paolo; Casaglia, Adriano; Cerroni, Loredana

    2016-01-01

    Background: There are various microorganisms related to intra and extra-radicular infections and many of these are involved in persistent infections. Bacterial elimination from the root canal is achieved by means of the mechanical action of instruments and irrigation as well as the antibacterial effects of the irrigating solutions. Enterococcus faecalis can frequently be isolated from root canals in cases of failed root canal treatments. Antimicrobial agents have often been developed and optimized for their activity against endodontic bacteria. An ideal root canal irrigant should be biocompatible, because of its close contact with the periodontal tissues during endodontic treatment. Sodium hypoclorite (NaOCl) is one of the most widely recommended and used endodontic irrigants but it is highly toxic to periapical tissues. Objectives: To analyze the literature on the chemotherapeutic agent and plant extracts studied as root canal irrigants. In particularly, the study is focused on their effect on Enterococcus faecalis. Method: Literature search was performed electronically in PubMed (PubMed Central, MEDLINE) for articles published in English from 1982 to April 2015. The searched keywords were “endodontic irrigants” and “Enterococcus faecalis” and “essential oil” and “plant extracts”. Results: Many of the studied chemotherapeutic agents and plant extracts have shown promising results in vitro. Conclusion: Some of the considered phytotherapic substances, could be a potential alternative to NaOCl for the biomechanical treatment of the endodontic space. PMID:28217184

  14. Spatial distribution of enzyme activities along the root and in the rhizosphere of different plants

    Science.gov (United States)

    Razavi, Bahar S.; Zarebanadkouki, Mohsen; Blagodatskaya, Evgenia; Kuzyakov, Yakov

    2015-04-01

    Extracellular enzymes are important for decomposition of many biological macromolecules abundant in soil such as cellulose, hemicelluloses and proteins. Activities of enzymes produced by both plant roots and microbes are the primary biological drivers of organic matter decomposition and nutrient cycling. So far acquisition of in situ data about local activity of different enzymes in soil has been challenged. That is why there is an urgent need in spatially explicit methods such as 2-D zymography to determine the variation of enzymes along the roots in different plants. Here, we developed further the zymography technique in order to quantitatively visualize the enzyme activities (Spohn and Kuzyakov, 2013), with a better spatial resolution We grew Maize (Zea mays L.) and Lentil (Lens culinaris) in rhizoboxes under optimum conditions for 21 days to study spatial distribution of enzyme activity in soil and along roots. We visualized the 2D distribution of the activity of three enzymes:β-glucosidase, leucine amino peptidase and phosphatase, using fluorogenically labelled substrates. Spatial resolution of fluorescent images was improved by direct application of a substrate saturated membrane to the soil-root system. The newly-developed direct zymography shows different pattern of spatial distribution of enzyme activity along roots and soil of different plants. We observed a uniform distribution of enzyme activities along the root system of Lentil. However, root system of Maize demonstrated inhomogeneity of enzyme activities. The apical part of an individual root (root tip) in maize showed the highest activity. The activity of all enzymes was the highest at vicinity of the roots and it decreased towards the bulk soil. Spatial patterns of enzyme activities as a function of distance from the root surface were enzyme specific, with highest extension for phosphatase. We conclude that improved zymography is promising in situ technique to analyze, visualize and quantify

  15. Influence of plant roots on electrical resistivity measurements of cultivated soil columns

    Science.gov (United States)

    Maloteau, Sophie; Blanchy, Guillaume; Javaux, Mathieu; Garré, Sarah

    2016-04-01

    Electrical resistivity methods have been widely used for the last 40 years in many fields: groundwater investigation, soil and water pollution, engineering application for subsurface surveys, etc. Many factors can influence the electrical resistivity of a media, and thus influence the ERT measurements. Among those factors, it is known that plant roots affect bulk electrical resistivity. However, this impact is not yet well understood. The goals of this experiment are to quantify the effect of plant roots on electrical resistivity of the soil subsurface and to map a plant roots system in space and time with ERT technique in a soil column. For this research, it is assumed that roots system affect the electrical properties of the rhizosphere. Indeed the root activity (by transporting ions, releasing exudates, changing the soil structure,…) will modify the rhizosphere electrical conductivity (Lobet G. et al, 2013). This experiment is included in a bigger research project about the influence of roots system on geophysics measurements. Measurements are made on cylinders of 45 cm high and a diameter of 20 cm, filled with saturated loam on which seeds of Brachypodium distachyon (L.) Beauv. are sowed. Columns are equipped with electrodes, TDR probes and temperature sensors. Experiments are conducted at Gembloux Agro-Bio Tech, in a growing chamber with controlled conditions: temperature of the air is fixed to 20° C, photoperiod is equal to 14 hours, photosynthetically active radiation is equal to 200 μmol m-2s-1, and air relative humidity is fixed to 80 %. Columns are fully saturated the first day of the measurements duration then no more irrigation is done till the end of the experiment. The poster will report the first results analysis of the electrical resistivity distribution in the soil columns through space and time. These results will be discussed according to the plant development and other controlled factors. Water content of the soil will also be detailed

  16. A below-ground herbivore shapes root defensive chemistry in natural plant populations.

    Science.gov (United States)

    Huber, Meret; Bont, Zoe; Fricke, Julia; Brillatz, Théo; Aziz, Zohra; Gershenzon, Jonathan; Erb, Matthias

    2016-03-30

    Plants display extensive intraspecific variation in secondary metabolites. However, the selective forces shaping this diversity remain often unknown, especially below ground. Using Taraxacum officinale and its major native insect root herbivore Melolontha melolontha, we tested whether below-ground herbivores drive intraspecific variation in root secondary metabolites. We found that high M. melolontha infestation levels over recent decades are associated with high concentrations of major root latex secondary metabolites across 21 central European T. officinale field populations. By cultivating offspring of these populations, we show that both heritable variation and phenotypic plasticity contribute to the observed differences. Furthermore, we demonstrate that the production of the sesquiterpene lactone taraxinic acid β-D-glucopyranosyl ester (TA-G) is costly in the absence, but beneficial in the presence of M. melolontha, resulting in divergent selection of TA-G. Our results highlight the role of soil-dwelling insects for the evolution of plant defences in nature. © 2016 The Author(s).

  17. Rooting of Mugo pine (Pinus mugo) cuttings as affected by IBA, NAA and planting substrate

    Energy Technology Data Exchange (ETDEWEB)

    Sedaghathoor, S.; Kayghobadi, S.; Tajva, Y.

    2016-07-01

    Aim of the study. The effect of planting substrate and concentrations of indole-3-butyric acid (Ia) and naphthaleneacetic acid (Naca) hormones was studied on the rooting of mugo pine cuttings. Area of study: The research was carried out in Rasht city, Guilan province, Iran. Material and Methods: Both hormones (IBA and NAA) were applied at four concentrations of 0, 1000, 2000 and 4000 mg/l. Planting substrates included sand, perlite, cocopeat, sand + perlite, and sand + cocopeat (1:1). Main results: The highest rooting percentage (55%) was obtained under the trilateral treatment a2b4c1 (sand × 4000 mg/l NAA × 1000 mg/l IBA). Sand + cocopeat was found to be the best rooting substrate. Research highlights: It is recommended to apply sand with 4000 mg/l and 1000mg/l concentration of experimental hormones (NAA and IBA, respectively). (Author)

  18. Root Differentiation of Agricultural Plant Cultivars and Proveniences Using FTIR Spectroscopy

    Directory of Open Access Journals (Sweden)

    Nicole Legner

    2018-06-01

    Full Text Available The differentiation of roots of agricultural species is desired for a deeper understanding of the belowground root interaction which helps to understand the complex interaction in intercropping and crop-weed systems. The roots can be reliably differentiated via Fourier transform infrared spectroscopy with attenuated total reflection (FTIR-ATR. In two replicated greenhouse experiments, six pea cultivars, five oat cultivars as well as seven maize cultivars and five barnyard grass proveniences (n = 10 plants/cultivar or provenience were grown under controlled conditions. One root of each plant was harvested and five different root segments of each root were separated, dried and measured with FTIR-ATR spectroscopy. The results showed that, firstly, the root spectra of single pea and single oat cultivars as well as single maize and single barnyard grass cultivars/proveniences separated species-specific in cluster analyses. In the majority of cases the species separation was correct, but in a few cases, the spectra of the root tips had to be omitted to ensure the precise separation between the species. Therefore, species differentiation is possible regardless of the cultivar or provenience. Consequently, all tested cultivars of pea and oat spectra were analyzed together and separated within a cluster analysis according to their affiliated species. The same result was found in a cluster analysis with maize and barnyard grass spectra. Secondly, a cluster analysis with all species (pea, oat, maize and barnyard grass was performed. The species split up species-specific and formed a dicotyledonous pea cluster and a monocotyledonous cluster subdivided in oat, maize and barnyard grass subclusters. Thirdly, cultivar or provenience differentiations within one species were possible in one of the two replicated experiments. But these separations were less resilient.

  19. AGROBACTERIUM-MEDIATED TRANSFORMATION OF COMPOSITAE PLANTS. I. CONSTRUCTION OF TRANSGENIC PLANTS AND «HAIRY» ROOTS WITH NEW PROPERTIES

    Directory of Open Access Journals (Sweden)

    N. A.Matvieieva

    2013-02-01

    Full Text Available The review explores some of the recent advances and the author's own researchs concerning biotechnological approaches for Agrobacterium tumefaciens- and A. rhizogenes-mediated transformation of Compositae family plants. This paper reviews the results of genetic transformation of Compositae plants, including edible (Cichorium intybus, Lactuca sativa, oil (Helianthus annuus, decorative (Gerbera hybrida, medical (Bidens pilosa, Artemisia annua, Artemisia vulgaris, Calendula officinalis, Withania somnifera etc. plant species. Some Compositae genetic engineering areas are considered including creation of plants, resistant to pests, diseases and herbicides, to the effect of abiotic stress factors as well as plants with altered phenotype. The article also presents the data on the development of biotechnology for Compositae plants Cynara cardunculus, Arnica montana, Cichorium intybus, Artemisia annua "hairy" roots construction.

  20. Agrobacterium rhizogenes - based transformation of soybean roots to form composite plants

    Science.gov (United States)

    Composite plants are a powerful tool to rapidly analyze the effects of gene overexpression, gene silencing, and examine test promoter expression in transgenic roots. No sterile tissue culture is needed. This avoids loss of valuable material due to contamination of sterile cultures. This method uses ...

  1. Detect thy neighbor: Identity recognition at the root level in plants

    NARCIS (Netherlands)

    Chen, B.J.W.; During, H.J.; Anten, N.P.R.

    2012-01-01

    Some plant species increase root allocation at the expense of reproduction in the presence of non-self and non-kin neighbors, indicating the capacity of neighbor-identityrecognition at the rootlevel. Yet in spite of the potential consequences of rootidentityrecognition for the relationship between

  2. Spatial Regulation of Root Growth: Placing the Plant TOR Pathway in a Developmental Perspective

    Science.gov (United States)

    Barrada, Adam; Montané, Marie-Hélène; Robaglia, Christophe; Menand, Benoît

    2015-01-01

    Plant cells contain specialized structures, such as a cell wall and a large vacuole, which play a major role in cell growth. Roots follow an organized pattern of development, making them the organs of choice for studying the spatio-temporal regulation of cell proliferation and growth in plants. During root growth, cells originate from the initials surrounding the quiescent center, proliferate in the division zone of the meristem, and then increase in length in the elongation zone, reaching their final size and differentiation stage in the mature zone. Phytohormones, especially auxins and cytokinins, control the dynamic balance between cell division and differentiation and therefore organ size. Plant growth is also regulated by metabolites and nutrients, such as the sugars produced by photosynthesis or nitrate assimilated from the soil. Recent literature has shown that the conserved eukaryotic TOR (target of rapamycin) kinase pathway plays an important role in orchestrating plant growth. We will summarize how the regulation of cell proliferation and cell expansion by phytohormones are at the heart of root growth and then discuss recent data indicating that the TOR pathway integrates hormonal and nutritive signals to orchestrate root growth. PMID:26295391

  3. Calonectria spp. causing leaf spot, crown and root rot of ornamental plants in Tunisia

    NARCIS (Netherlands)

    Lombard, L.; Polizzi, G.; Guarnaccia, V.; Vitale, A.; Crous, P.W.

    2011-01-01

    Calonectria spp. are important pathogens of ornamental plants in nurseries, especially in the Northern Hemisphere. They are commonly associated with a wide range of disease symptoms of roots, leaves and shoots. During a recent survey in Tunisia, a number of Calonectria spp. were isolated from

  4. Calonectria spp. causing leaf spot, crown and root rot of ornamental plants in Tunisia

    NARCIS (Netherlands)

    Lombard, L.; Polizzi, G.; Guarnaccia, V.; Vitale, A.; Crous, P.W.

    2012-01-01

    Calonectria spp. are important pathogens of ornamental plants in nurseries, especially in the Northern Hemisphere. They are commonly associated with a wide range of disease symptoms of roots, leaves and shoots. During a recent survey in Tunisia, a number of Calonectria spp. were isolated from

  5. Direct and indirect plant defenses are not suppressed by endosymbionts of a specialist root herbivore

    Science.gov (United States)

    Insect endosymbionts influence many important metabolic and developmental processes of their host. It has been speculated that they may also help to manipulate and suppress plant defenses to the benefit of herbivores. Recently, endosymbionts of the root herbivore Diabrotica virgifera virgifera have ...

  6. Utilization of (15)NO3 (-) by nodulated soybean plants under conditions of root hypoxia.

    Science.gov (United States)

    Nunes Menolli Lanza, Luciana; Ferreira Lanza, Daniel Carlos; Sodek, Ladaslav

    2014-07-01

    Waterlogging of soils is common in nature. The low availability of oxygen under these conditions leads to hypoxia of the root system impairing the development and productivity of the plant. The presence of nitrate under flooding conditions is regarded as being beneficial towards tolerance to this stress. However, it is not known how nodulated soybean plants, cultivated in the absence of nitrate and therefore not metabolically adapted to this compound, would respond to nitrate under root hypoxia in comparison with non-nodulated plants grown on nitrate. A study was conducted with (15)N labelled nitrate supplied on waterlogging for a period of 48 h using both nodulated and non-nodulated plants of different physiological ages. Enrichment of N was found in roots and leaves with incorporation of the isotope in amino acids, although to a much smaller degree under hypoxia than normoxia. This demonstrates that nitrate is taken up under hypoxic conditions and assimilated into amino acids, although to a much lesser extent than for normoxia. The similar response obtained with nodulated and non-nodulated plants indicates the rapid metabolic adaptation of nodulated plants to the presence of nitrate under hypoxia. Enrichment of N in nodules was very much weaker with a distinct enrichment pattern of amino acids (especially asparagine) suggesting that labelling arose from a tissue source external to the nodule rather than through assimilation in the nodule itself.

  7. Discrimination of plant root zone water status in greenhouse production based on phenotyping and machine learning techniques

    OpenAIRE

    Guo, Doudou; Juan, Jiaxiang; Chang, Liying; Zhang, Jingjin; Huang, Danfeng

    2017-01-01

    Plant-based sensing on water stress can provide sensitive and direct reference for precision irrigation system in greenhouse. However, plant information acquisition, interpretation, and systematical application remain insufficient. This study developed a discrimination method for plant root zone water status in greenhouse by integrating phenotyping and machine learning techniques. Pakchoi plants were used and treated by three root zone moisture levels, 40%, 60%, and 80% relative water content...

  8. The influence of arbuscular mycorrhizae on root precision nutrient foraging of two pioneer plant species during early reclamation

    Science.gov (United States)

    Boldt-Burisch, Katja; Naeth, M. Anne

    2017-04-01

    On many post mining sites in the Lusatian Mining District (East Germany) soil heterogeneity consists of sandy soil with embedded clay-silt fragments. Those clays silt fragments might act as nutrient hotspots. Arbuscular mycorrhizal fungi in an infertile ecosystem could enhance a plant's ability to selectively forage for those nutrients and thus to improve plants nutrient supply. In our study we investigated whether silt-clay fragments within a sandy soil matrix induced preferential root growth of Lotus corniculatus and Calamagrostis epigeios, whether arbuscular mycorrhizae influenced root foraging patterns, and to what extent selective rooting in clay silt fragments influenced plant growth were addressed in this research. Soil types were sterile and non-sterile sandy soil and clay-silt fragments. Treatments were with and without arbuscular mycorrhizae, with and without soil solution, and soil solution and mycorrhizal inoculum combined. Root biomass, root density and intraradical fungal alkaline phosphatase activity and frequency were determined in fragments relative to sandy soil. Furthermore, temporal relationship of number of roots in fragments and plant height was assessed. Lotus corniculatus showed strong selective rooting into fragments especially with those plants treated with commercial cultivated arbuscular mycorrhizae; Calamagrostis epigeios did not. Without arbuscular mycorrhizae, L. corniculatus growth was significantly reduced and selective rooting did not occur. Selective rooting induced significant growth spurts of L. corniculatus. Roots in fragments had higher fungal alkaline phosphatase activity suggesting that mycorrhizal efficiency and related plants phosphorus supply is enhanced in roots in fragments. The application of cultivated arbuscular mycorrhizal fungi significantly and quickly influenced root foraging patterns, especially those of L. corniculatus, suggesting mycorrhizae may also enhance the ability of other plants to selectively forage

  9. Composite potato plants with transgenic roots on non-transgenic shoots: a model system for studying gene silencing in roots

    DEFF Research Database (Denmark)

    Horn, Patricia; Santala, Johanna; Nielsen, Steen Lykke

    2014-01-01

    induced phenotypically normal roots which, however, showed a reduced response to cytokinin as compared with non-transgenic roots. Nevertheless, both types of roots were infected to a similar high rate with the zoospores of Spongospora subterranea, a soilborne potato pathogen. The transgenic roots...

  10. Microscopic processes ruling the bioavailability of Zn to roots of Euphorbia pithyusa L. pioneer plant.

    Science.gov (United States)

    Medas, Daniela; De Giudici, Giovanni; Casu, Maria Antonietta; Musu, Elodia; Gianoncelli, Alessandra; Iadecola, Antonella; Meneghini, Carlo; Tamburini, Elena; Sprocati, Anna Rosa; Turnau, Katarzyna; Lattanzi, Pierfranco

    2015-02-03

    Euphorbia pithyusa L. was used in a plant growth-promoting assisted field trial experiment. To unravel the microscopic processes at the interface, thin slices of E. pithyusa roots were investigated by micro-X-ray fluorescence mapping. Roots and rhizosphere materials were examined by X-ray absorption spectroscopy at the Zn K-edge, X-ray diffraction, and scanning electron microscopy. Results indicate some features common to all the investigated samples. (i) In the rhizosphere of E. pithyusa, Zn was found to exist in different phases. (ii) Si and Al are mainly concentrated in a rim at the epidermis of the roots. (iii) Zn is mostly stored in root epidermis and does not appear to be coordinated to organic molecules but mainly occurs in mineral phases such as Zn silicates. We interpreted that roots of E. pithyusa significantly promote mineral evolution in the rhizosphere. Concomitantly, the plant uses Si and Al extracted by soil minerals to build a biomineralization rim, which can capture Zn. This Zn silicate biomineralization has relevant implications for phytoremediation techniques and for further biotechnology development, which can be better designed and developed after specific knowledge of molecular processes ruling mineral evolution and biomineralization processes has been gained.

  11. A novel growing device inspired by plant root soil penetration behaviors.

    Directory of Open Access Journals (Sweden)

    Ali Sadeghi

    Full Text Available Moving in an unstructured environment such as soil requires approaches that are constrained by the physics of this complex medium and can ensure energy efficiency and minimize friction while exploring and searching. Among living organisms, plants are the most efficient at soil exploration, and their roots show remarkable abilities that can be exploited in artificial systems. Energy efficiency and friction reduction are assured by a growth process wherein new cells are added at the root apex by mitosis while mature cells of the root remain stationary and in contact with the soil. We propose a new concept of root-like growing robots that is inspired by these plant root features. The device penetrates soil and develops its own structure using an additive layering technique: each layer of new material is deposited adjacent to the tip of the device. This deposition produces both a motive force at the tip and a hollow tubular structure that extends to the surface of the soil and is strongly anchored to the soil. The addition of material at the tip area facilitates soil penetration by omitting peripheral friction and thus decreasing the energy consumption down to 70% comparing with penetration by pushing into the soil from the base of the penetration system. The tubular structure provides a path for delivering materials and energy to the tip of the system and for collecting information for exploratory tasks.

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

    Science.gov (United States)

    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.

  13. Concept for Sustained Plant Production on ISS Using VEGGIE Capillary Mat Rooting System

    Science.gov (United States)

    Stutte, Gary W.; Newsham, Gerard; Morrow, Robert M.; Wheeler, Raymond M.

    2011-01-01

    Plant growth in microgravity presents unique challenges associated with maintaining appropriate conditions for seed germination, seedling establishment, maturation and harvest. They include maintaining appropriate soil moisture content, nutrient balance, atmospheric mixing and containment. Sustained production imposes additional challenges of harvesting, replanting, and safety. The VEGGIE is a deployable (collapsible) plant growth chamber developed as part of a NASA SBIR Phase II by Orbitec, Madison, WI. The intent of VEGGIE is to provide a low-resource system to produce fresh vegetables for the crew on long duration missions. The VEGGIE uses and LED array for lighting, an expandable bellows for containment, and a capillary matting system for nutrient and water delivery. The project evaluated a number of approaches to achieve sustained production, and repeated plantings, using the capillary rooting system. A number of different root media, seed containment, and nutrient delivery systems were evaluated and effects on seed germination and growth were evaluated. A number of issues limiting sustained production, such as accumulation of nutrients, uniform water, elevated vapor pressure deficit, and media containment were identified. A concept using pre-planted rooting packs shown to effectively address a number of those issues and is a promising approach for future development as a planting system for microgravity conditions.

  14. Incorporation of plant materials in the control of root pathogens in muskmelon

    Directory of Open Access Journals (Sweden)

    Andréa Mirne de Macêdo Dantas

    2013-12-01

    Full Text Available The effect of plant materials[Sunn Hemp (Crotalaria juncea, Castor Bean (Ricinus communis L., Cassava (Manihot esculenta Crantz and Neem (Azadirachta indica] and the times of incorporation of these materials in regards to the incidence of root rot in melon was evaluated in Ceará state, Brazil. The experiment was conducted in a commercial area with a history of root pathogens in cucurbitaceae. The randomized block design was used, in a 5 x 3 factorial arrangement with four repetitions. The treatments consisted of a combination of four plant materials (sunn hemp, castor beans, cassava and neem and a control with no soil incorporation of plant material and three times of incorporation (28, 21, and 14 days before the transplanting of the seedlings. Lower incidence of root rot was observed in practically all of the treatments where materials were incorporated at different times, with variation between the materials, corresponding with the time of incorporation, in relation to the soil without plant material. The pathogens isolated from the symptomatic muskmelon plants were Fusarium solani, Macrophomina phaseolina, Monosporascus cannonballus and Rhizoctonia solani, F. solani being encountered most frequently.

  15. Invasive clonal plant species have a greater root-foraging plasticity than non-invasive ones.

    Science.gov (United States)

    Keser, Lidewij H; Dawson, Wayne; Song, Yao-Bin; Yu, Fei-Hai; Fischer, Markus; Dong, Ming; van Kleunen, Mark

    2014-03-01

    Clonality is frequently positively correlated with plant invasiveness, but which aspects of clonality make some clonal species more invasive than others is not known. Due to their spreading growth form, clonal plants are likely to experience spatial heterogeneity in nutrient availability. Plasticity in allocation of biomass to clonal growth organs and roots may allow these plants to forage for high-nutrient patches. We investigated whether this foraging response is stronger in species that have become invasive than in species that have not. We used six confamilial pairs of native European clonal plant species differing in invasion success in the USA. We grew all species in large pots under homogeneous or heterogeneous nutrient conditions in a greenhouse, and compared their nutrient-foraging response and performance. Neither invasive nor non-invasive species showed significant foraging responses to heterogeneity in clonal growth organ biomass or in aboveground biomass of clonal offspring. Invasive species had, however, a greater positive foraging response in terms of root and belowground biomass than non-invasive species. Invasive species also produced more total biomass. Our results suggest that the ability for strong root foraging is among the characteristics promoting invasiveness in clonal plants.

  16. Combined DECS Analysis and Next-Generation Sequencing Enable Efficient Detection of Novel Plant RNA Viruses

    Directory of Open Access Journals (Sweden)

    Hironobu Yanagisawa

    2016-03-01

    Full Text Available The presence of high molecular weight double-stranded RNA (dsRNA within plant cells is an indicator of infection with RNA viruses as these possess genomic or replicative dsRNA. DECS (dsRNA isolation, exhaustive amplification, cloning, and sequencing analysis has been shown to be capable of detecting unknown viruses. We postulated that a combination of DECS analysis and next-generation sequencing (NGS would improve detection efficiency and usability of the technique. Here, we describe a model case in which we efficiently detected the presumed genome sequence of Blueberry shoestring virus (BSSV, a member of the genus Sobemovirus, which has not so far been reported. dsRNAs were isolated from BSSV-infected blueberry plants using the dsRNA-binding protein, reverse-transcribed, amplified, and sequenced using NGS. A contig of 4,020 nucleotides (nt that shared similarities with sequences from other Sobemovirus species was obtained as a candidate of the BSSV genomic sequence. Reverse transcription (RT-PCR primer sets based on sequences from this contig enabled the detection of BSSV in all BSSV-infected plants tested but not in healthy controls. A recombinant protein encoded by the putative coat protein gene was bound by the BSSV-antibody, indicating that the candidate sequence was that of BSSV itself. Our results suggest that a combination of DECS analysis and NGS, designated here as “DECS-C,” is a powerful method for detecting novel plant viruses.

  17. Toward Self-Growing Soft Robots Inspired by Plant Roots and Based on Additive Manufacturing Technologies.

    Science.gov (United States)

    Sadeghi, Ali; Mondini, Alessio; Mazzolai, Barbara

    2017-09-01

    In this article, we present a novel class of robots that are able to move by growing and building their own structure. In particular, taking inspiration by the growing abilities of plant roots, we designed and developed a plant root-like robot that creates its body through an additive manufacturing process. Each robotic root includes a tubular body, a growing head, and a sensorized tip that commands the robot behaviors. The growing head is a customized three-dimensional (3D) printer-like system that builds the tubular body of the root in the format of circular layers by fusing and depositing a thermoplastic material (i.e., polylactic acid [PLA] filament) at the tip level, thus obtaining movement by growing. A differential deposition of the material can create an asymmetry that results in curvature of the built structure, providing the possibility of root bending to follow or escape from a stimulus or to reach a desired point in space. Taking advantage of these characteristics, the robotic roots are able to move inside a medium by growing their body. In this article, we describe the design of the growing robot together with the modeling of the deposition process and the description of the implemented growing movement strategy. Experiments were performed in air and in an artificial medium to verify the functionalities and to evaluate the robot performance. The results showed that the robotic root, with a diameter of 50 mm, grows with a speed of up to 4 mm/min, overcoming medium pressure of up to 37 kPa (i.e., it is able to lift up to 6 kg) and bending with a minimum radius of 100 mm.

  18. Wild plant species growing closely connected in a subalpine meadow host distinct root-associated bacterial communities

    Directory of Open Access Journals (Sweden)

    Kristin Aleklett

    2015-02-01

    Full Text Available Plant roots are known to harbor large and diverse communities of bacteria. It has been suggested that plant identity can structure these root-associated communities, but few studies have specifically assessed how the composition of root microbiota varies within and between plant species growing under natural conditions. We assessed the community composition of endophytic and epiphytic bacteria through high throughput sequencing using 16S rDNA derived from root tissues collected from a population of a wild, clonal plant (Orange hawkweed–Pilosella aurantiaca as well as two neighboring plant species (Oxeye daisy–Leucanthemum vulgare and Alsike clover–Trifolium hybridum. Our first goal was to determine if plant species growing in close proximity, under similar environmental conditions, still hosted unique root microbiota. Our results showed that plants of different species host distinct bacterial communities in their roots. In terms of community composition, Betaproteobacteria (especially the family Oxalobacteraceae were found to dominate in the root microbiota of L. vulgare and T. hybridum samples, whereas the root microbiota of P. aurantiaca had a more heterogeneous distribution of bacterial abundances where Gammaproteobacteria and Acidobacteria occupied a larger portion of the community. We also explored the extent of individual variance within each plant species investigated, and found that in the plant species thought to have the least genetic variance among individuals (P. aurantiaca still hosted just as diverse microbial communities. Whether all plant species host their own distinct root microbiota and plants more closely related to each other share more similar bacterial communities still remains to be fully explored, but among the plants examined in this experiment there was no trend that the two species belonging to the same family shared more similarities in terms of bacterial community composition.

  19. Degradation kinetics of chlorinated aliphatic hydrocarbons by methane oxidizers naturally-associated with wetland plant roots

    Science.gov (United States)

    Powell, C. L.; Goltz, M. N.; Agrawal, A.

    2014-12-01

    Chlorinated aliphatic hydrocarbons (CAHs) are common groundwater contaminants that can be removed from the environment by natural attenuation processes. CAH biodegradation can occur in wetland environments by reductive dechlorination as well as oxidation pathways. In particular, CAH oxidation may occur in vegetated wetlands, by microorganisms that are naturally associated with the roots of wetland plants. The main objective of this study was to evaluate the cometabolic degradation kinetics of the CAHs, cis-1,2-dichloroethene (cisDCE), trichloroethene (TCE), and 1,1,1-trichloroethane (1,1,1TCA), by methane-oxidizing bacteria associated with the roots of a typical wetland plant in soil-free system. Laboratory microcosms with washed live roots investigated aerobic, cometabolic degradation of CAHs by the root-associated methane-oxidizing bacteria at initial aqueous [CH4] ~ 1.9 mg L- 1, and initial aqueous [CAH] ~ 150 μg L- 1; cisDCE and TCE (in the presence of 1,1,1TCA) degraded significantly, with a removal efficiency of approximately 90% and 46%, respectively. 1,1,1TCA degradation was not observed in the presence of active methane oxidizers. The pseudo first-order degradation rate-constants of TCE and cisDCE were 0.12 ± 0.01 and 0.59 ± 0.07 d- 1, respectively, which are comparable to published values. However, their biomass-normalized degradation rate constants obtained in this study were significantly smaller than pure-culture studies, yet they were comparable to values reported for biofilm systems. The study suggests that CAH removal in wetland plant roots may be comparable to processes within biofilms. This has led us to speculate that the active biomass may be on the root surface as a biofilm. The cisDCE and TCE mass losses due to methane oxidizers in this study offer insight into the role of shallow, vegetated wetlands as an environmental sink for such xenobiotic compounds.

  20. Effect of root temperature on the uptake and metabolism of anions by the root system of Zea mays L. I. Uptake of sulphate by resistant and non-resistant plants

    Energy Technology Data Exchange (ETDEWEB)

    Holobrada, M; Mistrik, I; Kolek, J [Institute of Experimental Biology and Ecology of the Slovak Academy of Sciences, Bratislava (Czechoslovakia)

    1980-01-01

    The effect of root temperature upon the uptake of /sup 35/S-sulfate by intact 21 days old maize roots was discussed. The plant roots grown at 20 degC were cooled in steps down to 15 degC or 5 degC. The rate of /sup 35/S uptake was studied both in the whole root system and separately in the individual roots (primary seminal root, seminal adventitious roots and nodal roots). Differences were ascertained at lower uptakes by various root samples from resistant and nonresistant maize cultivars.

  1. A Bacillus subtilis Sensor Kinase Involved in Triggering Biofilm Formation on the Roots of Tomato Plants

    Science.gov (United States)

    Chen, Yun; Cao, Shugeng; Chai, Yunrong; Clardy, Jon; Kolter, Roberto; Guo, Jian-hua; Losick, Richard

    2012-01-01

    SUMMARY The soil bacterium Bacillus subtilis is widely used in agriculture as a biocontrol agent able to protect plants from a variety of pathogens. Protection is thought to involve the formation of bacterial communities - biofilms - on the roots of the plants. Here we used confocal microscopy to visualize biofilms on the surface of the roots of tomato seedlings and demonstrated that biofilm formation requires genes governing the production of the extracellular matrix that holds cells together. We further show that biofilm formation was dependent on the sensor histidine kinase KinD and in particular on an extracellular CACHE domain implicated in small molecule sensing. Finally, we report that exudates of tomato roots strongly stimulated biofilm formation ex planta and that an abundant small molecule in the exudates, l-malic acid, was able to stimulate biofilm formation at high concentrations in a manner that depended on the KinD CACHE domain. We propose that small signaling molecules released by the roots of tomato plants are directly or indirectly recognized by KinD, triggering biofilm formation. PMID:22716461

  2. Gaseous release of radioactive iodine from decaying plants. I. Release following foliar and root uptake

    International Nuclear Information System (INIS)

    Saas, Arsene; Grauby, Andre

    1975-12-01

    Iodine uptake by plants is a significant link in the contamination of the food chain. Long half-live iodine was studied considering foliar and root uptake, loss by rain scavenging, residue decay or outgassing in order to assess two aspects of the problem: the importance of outgassing and the effect of the route of transfer on iodine losses. It appeared that iodine release was a function of the vegetal type, there were differences according to the pattern of absorption (via leaf or root) and the processes of iodine release were usually related to biochemical mechanisms [fr

  3. Effects of rare earth oxide nanoparticles on root elongation of plants.

    Science.gov (United States)

    Ma, Yuhui; Kuang, Linglin; He, Xiao; Bai, Wei; Ding, Yayun; Zhang, Zhiyong; Zhao, Yuliang; Chai, Zhifang

    2010-01-01

    The phytotoxicity of four rare earth oxide nanoparticles, nano-CeO(2), nano-La(2)O(3), nano-Gd(2)O(3) and nano-Yb(2)O(3) on seven higher plant species (radish, rape, tomato, lettuce, wheat, cabbage, and cucumber) were investigated in the present study by means of root elongation experiments. Their effects on root growth varied greatly between different nanoparticles and plant species. A suspension of 2000 mg L(-1) nano-CeO(2) had no effect on the root elongation of six plants, except lettuce. On the contrary, 2000 mg L(-1) suspensions of nano-La(2)O(3), nano-Gd(2)O(3) and nano-Yb(2)O(3) severely inhibited the root elongation of all the seven species. Inhibitory effects of nano-La(2)O(3), nano-Gd(2)O(3), and nano-Yb(2)O(3) also differed in the different growth process of plants. For wheat, the inhibition mainly took place during the seed incubation process, while lettuce and rape were inhibited on both seed soaking and incubation process. The fifty percent inhibitory concentrations (IC(50)) for rape were about 40 mg L(-1) of nano-La(2)O(3), 20mg L(-1) of nano-Gd(2)O(3), and 70 mg L(-1) of nano-Yb(2)O(3), respectively. In the concentration ranges used in this study, the RE(3+) ion released from the nanoparticles had negligible effects on the root elongation. These results are helpful in understanding phytotoxicity of rare earth oxide nanoparticles. Copyright 2009 Elsevier Ltd. All rights reserved.

  4. The impact of solarisation integrated with plant bio-fermentation on root knot nematodes

    International Nuclear Information System (INIS)

    Ibrahim, S. K.; Traboulsi, A. F.

    2009-01-01

    The impact of different freshly/dried chopped medicinal or aromatic plant materials as an organic amendment in pot cultures, as well as integrated with solarisation under greenhouse conditions on the root knot nematodes population was evaluated. Results indicated that application of solarisation alone gave good control (72%) but when integrated with different plant materials, the control level increased to 95% with Allium sativum and 90% with Mentha microphylla and slightly less with other plant materials which ranged from75 to 80%. The results of pot experiments revealed that the most significant effect on the number of nematodes was achieved with Tagetes patula followed by Pimpinella anisum, Melia azadirach and Origanium syriacum reaching 0.0, 1.2, 1.2 and 2.5/g of roots, respectively. Total control was obtained with Allium sativum. Origanium syriacum contained the highest amount of essential oil (6%). Results obtained indicated that integrated approach using solarisation combined with plant materials could be the best alternative control for the root-knot nematodes. (author)

  5. Effect of IAA on in vitro growth and colonization of Nostoc in plant roots

    Science.gov (United States)

    Hussain, Anwar; Shah, Syed T.; Rahman, Hazir; Irshad, Muhammad; Iqbal, Amjad

    2015-01-01

    Nostoc is widely known for its ability to fix atmospheric nitrogen and the establishment of symbiotic relationship with a wide range of plants from various taxonomic groups. Several strains of Nostoc produce phytohormones that promote growth of its plant partners. Nostoc OS-1 was therefore selected for study because of the presence of putative ipdC gene that encodes a key enzyme to produce Indole-3-acetic acid (IAA). The results indicated that both cellular and released IAA was found high with increasing incubation time and reached to a peak value (i.e., 21 pmol mg-1ch-a) on the third week as determined by UPLC-ESI-MS/MS. Also the Nostoc OS-1 strain efficiently colonized the roots and promoted the growth of rice as well as wheat under axenic conditions and induced ipdC gene that suggested the possible involvement of IAA in these phenotypes. To confirm the impact of IAA on root colonization efficiency and plant promoting phenotypes of Nostoc OS-1, an ipdC knockout mutant was generated by homologous recombinant method. The amount of releasing IAA, in vitro growth, root colonization, and plant promoting efficiency of the ipdC knockout mutant was observed significantly lower than wild type strain under axenic conditions. Importantly, these phenotypes were restored to wild-type levels when the ipdC knockout mutant was complemented with wild type ipdC gene. These results together suggested that ipdC and/or synthesized IAA of Nostoc OS-1 is required for its efficient root colonization and plant promoting activity. PMID:25699072

  6. Somatic embryogenesis and plant regeneration in Carica papaya L. tissue culture derived from root explants.

    Science.gov (United States)

    Chen, M H; Wang, P J; Maeda, E

    1987-10-01

    The regeneration potential of shoot tip, stem, leaf, cotyledon and root explants of two papaya cultivars (Carica papaya cv. 'Solo' and cv. 'Sunrise') were studed. Callus induction of these two cultivars of papaya showed that the shoot tips and stems are most suitable for forming callus, while leaves, cotyledons and roots are comparatively difficult to induce callus. Callus induction also varied with the varities. Somatic embryogenesis was obtained from 3-month-old root cultures. A medium containing half strength of MS inorganic salts, 160 mg/l adenine sulfate, 1.0 mg/1 NAA, 0.5 mg/1 kinetin and 1.0 mg/1 GA3 was optimal for embryogenesis. The callus maintained high regenerative capacity after two years of culture on this medium. Plants derived from somatic embryos were obtained under green-house conditions.

  7. Cadmium stress antioxidant responses and root-to-shoot communication in grafted tomato plants.

    Science.gov (United States)

    Gratão, Priscila Lupino; Monteiro, Carolina Cristina; Tezotto, Tiago; Carvalho, Rogério Falleiros; Alves, Letícia Rodrigues; Peters, Leila Priscila; Azevedo, Ricardo Antunes

    2015-10-01

    Many aspects related to ROS modulation of signaling networks and biological processes that control stress responses still remain unanswered. For this purpose, the grafting technique may be a powerful tool to investigate stress signaling and specific responses between plant organs during stress. In order to gain new insights on the modulation of antioxidant stress responses mechanisms, gas-exchange measurements, lipid peroxidation, H2O2 content, proline, superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), ascorbate peroxidase (APX) and guaiacol peroxidase (GPOX) were analyzed in Micro-Tom grafted plants submitted to cadmium (Cd). The results observed revealed that higher amounts of Cd accumulated mainly in the roots and rootstocks when compared to leaves and scions. Macronutrients uptake (Ca, S, P and Mg) decreased in non-grafted plants, but differed among plant parts in all grafted plants. The results showed that the accumulation of proline observed in scions of grafted plants could be associated to the lower MDA contents in the scions of grafted plants. In the presence of Cd, non-grafted plants displayed increased CAT, GR, GPOX and APX activities for both tissues, whilst grafted plants revealed distinct trends that clearly indicate signaling responses from the rootstocks, allowing sufficient time to activate defense mechanisms in shoot. The information available concerning plants subjected to grafting can provide a better understanding of the mechanisms of Cd detoxification involving root-to-shoot signaling, opening new possibilities on strategies which can be used to manipulate heavy metal tolerance, since antioxidant systems are directly involved in such mechanism.

  8. Root and leaf abscisic acid concentration impact on gas exchange in tomato (Lycopersicon esculentum Mill plants subjected to partial root-zone drying

    Directory of Open Access Journals (Sweden)

    Maria Valerio

    2017-03-01

    Full Text Available Partial root-zone drying (PRD is a deficit irrigation technique with great potential for water saving. A split-root experiment was conducted on tomato in controlled environment in order to test the response of two long-time storage cultivars to PRD. Ponderosa tomato, a cultivar with yellow fruits, was compared to Giallo tondo di Auletta, a local cultivar from southern Campania (Italy. Plants were subjected to three irrigation treatments: plants receiving an amount of water equivalent to 100% of plant evapotranspiration (V100; plants in which 50% of the amount of water given to V100 was supplied (V50; and plants where one root compartment was irrigated at 50% of water requirements and the other compartment was allowed to dry, and thereafter every side was rewetted alternatively (PRD. The highest levels of leaf abscisic acid (ABA [on average equal to 104 ng g–1 fresh weight FW] were measured in PRD and V50, at 70 days after transplantation. Root ABA concentration in both PRD and V50 reached mean values of 149 ng g–1 FW. There were differences for the irrigation regime in root ABA biosynthesis and accumulation under partial root-zone drying and conventional deficit irrigation (V50. Assimilation rate, stomatal conductance and intercellular CO2 concentration decreased in relation to the irrigation regime by 22, 36 and 12%, respectively, in PRD, V50 and V100 at 50 days after transplantation. Ponderosa variety accumulated 20% more dry matter than Auletta and significant differences were observed in leaf area. In both PRD and V50 of the two varieties, it was possible to save on average 46% of water. Our results indicate that there is still space to optimise the PRD strategy, to further improve the cumulative physiological effects of the root-sourced signaling system.

  9. In vitro evaluation of the root canal cleaning ability of plant extracts and their antimicrobial action

    Directory of Open Access Journals (Sweden)

    Edja Maria Melo de Brito Costa

    2012-06-01

    Full Text Available This in vitro study evaluated both the antimicrobial activity and the root canal cleaning ability of plant extracts used in irrigation solutions. The antimicrobial activities of the aroeira-da-praia (Schinus terebintifolius Raddi and the quixabeira (Syderoxylum obtusifolium Roem & Schult hydroalcoholic extracts, of 2.5% sodium hypochlorite (NaOCl and of 0.12% chlorhexidine (positive control against Enterococcus faecalis were tested with the agar well diffusion method. The level of root canal cleanliness was examined by scanning electron microscopy (SEM. Twenty one single-rooted human teeth were divided into three groups according to the irrigation solution applied: 1 50% aroeira-da-praia; 2 50% quixabeira and 3 a combination of 2.5% sodium hypochlorite + 17% EDTA. All solutions tested demonstrated antimicrobial activity against Enterococcus faecalis. The SEM analysis revealed that higher and lower degrees of surface cleaning were observed, in the three groups, respectively for the coronal and apical thirds, in that quixabeira showed the greatest efficiency in removing the smear layer in the apical third. All the agents tested presented antimicrobial activity against E. faecalis. None, however, was able to completely remove the smear layer of the dentinal surface in the different thirds of the root canal. The results suggest that the analyzed plant extracts may represent a new therapeutic option in the list of alternative agents available for endodontic treatment.

  10. Translocation of metal ions from soil to tobacco roots and their concentration in the plant parts.

    Science.gov (United States)

    da Silva, Cleber Pinto; de Almeida, Thiago E; Zittel, Rosimara; de Oliveira Stremel, Tatiana R; Domingues, Cinthia E; Kordiak, Januário; de Campos, Sandro Xavier

    2016-12-01

    This paper presents a study on the translocation factors (TFs) and bioconcentration factors (BCFs) of copper (Cu), manganese (Mn), zinc (Zn), cobalt (Co), chromium (Cr), cadmium (Cd), lead (Pb), iron (Fe), nickel (Ni), and arsenic (As) ions in roots, stems, and leaves of tobacco. The results revealed that during the tobacco growth, the roots are able to increase the sensitiveness of the physiological control, reducing the translocation of the metals Ni (0.38) and Pb (0.48) to the leaves. Cd and Zn presented factors TF and BCF >1 in the three tissues under analysis, which indicates the high potential for transportation and accumulation of these metals in all plant tissues. The TF values for Cr (0.65) and As (0.63) revealed low translocation of these ions to the aerial parts, indicating low mobility of ions from the roots. Therefore, tobacco can be considered an efficient accumulator of Ni, Cr, As and Pb in roots and Cd and Zn in all plant parts.

  11. Arbuscular mycorrhizal fungal hyphae contribute to the uptake of polycyclic aromatic hydrocarbons by plant roots.

    Science.gov (United States)

    Gao, Yanzheng; Cheng, Zhaoxia; Ling, Wanting; Huang, Jing

    2010-09-01

    The arbuscular mycorrhizal (AM) hyphae-mediated uptake of polycyclic aromatic hydrocarbons (PAHs) by the roots of ryegrass (Lolium multiflorum Lam.) was investigated using three-compartment systems. Glomus mosseae and Glomus etunicatum were chosen, and fluorene and phenanthrene were used as representative PAHs. When roots were grown in un-spiked soils, AM hyphae extended into PAH-spiked soil and clearly absorbed and transported PAHs to roots, resulting in high concentrations of fluorene and phenanthrene in roots. This was further confirmed by the batch equilibration experiment, which revealed that the partition coefficients (K(d)) of tested PAHs by mycorrhizal hyphae were 270-356% greater than those by roots, suggesting the great potential of hyphae to absorb PAHs. Because of fluorene's lower molecular weight and higher water solubility, its translocation by hyphae was greater than that of phenanthrene. These results provide new perspectives on the AM hyphae-mediated uptake by plants of organic contaminants from soil. Copyright 2010 Elsevier Ltd. All rights reserved.

  12. A fungal root symbiont modifies plant resistance to an insect herbivore.

    Science.gov (United States)

    Borowicz, Victoria A

    1997-11-01

    Vesicular-arbuscular mycorrhizal (VAM) fungi are common root-colonizing symbionts that affect nutrient uptake by plants and can alter plant susceptibility to herbivores. I conducted a factorial experiment to test the hypotheses that colonization by VAM fungi (1) improves soybean (Glycine max) tolerance to grazing by folivorous Mexican bean beetle (Epilachna varivestis), and (2) indirectly affects herbivores by increasing host resistance. Soybean seedlings were inoculated with the VAM fungus Glomus etunicatum or VAM-free filtrate and fertilized with high-[P] or low-[P] fertilizer. After plants had grown for 7 weeks first-instar beetle larvae were placed on bagged leaves. Growth of soybean was little affected by grazing larvae, and no effects of treatments on tolerance of soybeans to herbivores were evident. Colonization by VAM fungus doubled the size of phosphorus-stressed plants but these plants were still half the size of plants given adequate phosphorus. High-[P] fertilizer increased levels of phosphorus and soluble carbohydrates, and decreased levels of soluble proteins in leaves of grazed plants. Colonization of grazed plants by VAM fungus had no significant effect on plant soluble carbohydrates, but increased concentration of phosphorus and decreased levels of proteins in phosphorus-stressed plants to concentrations similar to those of plants given adequate phosphorus. Mexican bean beetle mass at pupation, pupation rate, and survival to eclosion were greatest for beetles reared on phosphorus-stressed, VAM-colonized plants, refuting the hypothesis that VAM colonization improves host plant resistance. VAM colonization indirectly affected performance of Mexician bean beetle larvae by improving growth and nutrition of the host plant.

  13. Petroleum Contamination and Plant Identity Influence Soil and Root Microbial Communities While AMF Spores Retrieved from the Same Plants Possess Markedly Different Communities

    OpenAIRE

    Iffis, Bachir; St-Arnaud, Marc; Hijri, Mohamed

    2017-01-01

    Phytoremediation is a promising in situ green technology based on the use of plants to cleanup soils from organic and inorganic pollutants. Microbes, particularly bacteria and fungi, that closely interact with plant roots play key roles in phytoremediation processes. In polluted soils, the root-associated microbes contribute to alleviation of plant stress, improve nutrient uptake and may either degrade or sequester a large range of soil pollutants. Therefore, improving the efficiency of phyto...

  14. Root-induced decomposer growth and plant N uptake are not positively associated among a set of grassland plants

    DEFF Research Database (Denmark)

    Saj, S.; Mikola, J.; Ekelund, Flemming

    2008-01-01

    It is known that plant species can induce development of different soil decomposer communities and that they differ in their influence on organic matter decomposition and N mineralization in soil. However, no study has so far assessed whether these two observations are related to each other. Base...... that plant traits such as competitive ability for soil mineral N were more important for plant uptake of litter-N than those that directly affected the growth of soil decomposers.......It is known that plant species can induce development of different soil decomposer communities and that they differ in their influence on organic matter decomposition and N mineralization in soil. However, no study has so far assessed whether these two observations are related to each other. Based...... on the hypothesis that root-induced growth of soil decomposers leads to accelerated decomposition of SOM and increased plant N availability in soil, we predicted that (1) among a set of grassland plants the abundance of soil decomposers in the plant rhizosphere is positively associated with plant N uptake from soil...

  15. Plant-Microbe Communication Enhances Auxin Biosynthesis by a Root-Associated Bacterium, Bacillus amyloliquefaciens SQR9.

    Science.gov (United States)

    Liu, Yunpeng; Chen, Lin; Zhang, Nan; Li, Zunfeng; Zhang, Guishan; Xu, Yu; Shen, Qirong; Zhang, Ruifu

    2016-04-01

    Mechanisms by which beneficial rhizobacteria promote plant growth include tryptophan-dependent indole-3-acetic acid (IAA) synthesis. The abundance of tryptophan in the rhizosphere, however, may influence the level of benefit provided by IAA-producing rhizobacteria. This study examined the cucumber-Bacillus amyloliquefaciens SQR9 system and found that SQR9, a bacterium previously shown to enhance the growth of cucumber, increased root secretion of tryptophan by three- to fourfold. Using a split-root system, SQR9 colonization of roots in one chamber not only increased tryptophan secretion from the noninoculated roots but also increased the expression of the cucumber tryptophan transport gene but not the anthranilate synthesis gene in those roots. The increased tryptophan in isolated rhizosphere exudates was sufficient to support increased IAA production by SQR9. Moreover, SQR9 colonization of roots in one chamber in the split-root system resulted in sufficient tryptophan production by the other roots to upregulate SQR9 IAA biosynthesis genes, including a 27-fold increase in the indole-3-acetonitrilase gene yhcX during subsequent colonization of those roots. Deletion of yhcX eliminated SQR9-mediated increases in root surface area, likely by reducing IAA-stimulated lateral root growth. This study demonstrates a chemical dialogue between B. amyloliquefaciens and cucumber in which this communication contributes to bacteria-mediated plant-growth enhancement.

  16. archiDART v3.0: A new data analysis pipeline allowing the topological analysis of plant root systems.

    Science.gov (United States)

    Delory, Benjamin M; Li, Mao; Topp, Christopher N; Lobet, Guillaume

    2018-01-01

    Quantifying plant morphology is a very challenging task that requires methods able to capture the geometry and topology of plant organs at various spatial scales. Recently, the use of persistent homology as a mathematical framework to quantify plant morphology has been successfully demonstrated for leaves, shoots, and root systems. In this paper, we present a new data analysis pipeline implemented in the R package archiDART to analyse root system architectures using persistent homology. In addition, we also show that both geometric and topological descriptors are necessary to accurately compare root systems and assess their natural complexity.

  17. Root activity studies of guava plants (Psidium Quajava, L) using 32P radioisotope

    International Nuclear Information System (INIS)

    Ahmad Sahali Mardi; Bajuri Kadmin; Khairuddin, A. Rahim

    1988-01-01

    The study was conducted on two year old guava plants (Psidium guajava L.) grown on Bungor series soil (Typic paleudult) at the UTN Agricultural Experimental Plot, Bangi, Selangor. The active roots of these guava plants were found to be present in abundance at about 100 cm away from the base of the tree at a depth of 10 cm. Fertilizers could be applied in that area. Sampling of every fourth leaf (for young trees) for counting, to represent the 32 P counts in the leaves can be used in future studies. The leaves and branches (green parts) of guava also have a more consistent P contents, as compared to other parts. (author)

  18. Synergistic and individual effect of glomus etunicatum root colonization and acetyl salicylic acid on root activity and architecture of tomato plants under moderate nacl stress

    International Nuclear Information System (INIS)

    Ghanzanfar, B.; Cheng, Z.; Ahmad, I.; Khan, A. R.; Hanqiang, L.; Haiyan, D.; Fang, C.

    2015-01-01

    A pot based experiment in plastic tunnel was conducted to investigate the changes in root morphology and root activity of the tomato plants grown under moderate NaCl stress (100 mM), pretreated with arbuscular mycorrhizal fungus AMF (Glomus etunicatum) root colonization and acetyl salicylic acid (ASA) as salinity ameliorative agents. The results revealed that both AMF and ASA treatments significantly enhanced the fresh root weight and root morphological parameters; net length, surface area, volume, mean diameter, nodal count and number of tips to different extents as compared to those of sole salinity treatment at 90 days after transplantation. Both treatments; AMF alone and in combination with ASA significantly enhanced the root activity level in terms of triphenyl tetrazolium chloride (TTC) reduction (2.37 and 2.40 mg g /sup -1/ h /sup -1/ respectively) as compared to the sole salinity treatment (0.40 mg g /sup -1/ h /sup -1/ ) as well as the salt free control (1.69 mg g /sup -1/ h /sup -1/) On the other hand, ASA treatment alone also uplifted root activity (1.53 mg g /sup -1/ h /sup -1/ ) which was significantly higher than that of sole salt treatment. It was inferred that under moderate saline conditions (100 mM NaCl), AMF (Glomus etunicatum) and ASA (individually or in combination) confer protective effect on plant growth by enhanced root activity and improved root architecture. Therefore, synergistic use of AMF (G. etunicatum) and ASA can be eco-friendly and economically feasible option for tomato production in marginally salt affected lands and suggests further investigations. (author)

  19. Benzo[a]pyrene co-metabolism in the presence of plant root extracts and exudates: Implications for phytoremediation

    Energy Technology Data Exchange (ETDEWEB)

    Rentz, Jeremy A [Civil and Environmental Engineering, University of Iowa, Iowa City, IA 52242 (United States); Alvarez, Pedro J.J. [Civil and Environmental Engineering, Rice University, Houston, TX 77251 (United States); Schnoor, Jerald L [Civil and Environmental Engineering, University of Iowa, Iowa City, IA 52242 (United States)

    2005-08-15

    Benzo[a]pyrene, a high molecular weight (HMW) polycyclic aromatic hydrocarbon (PAH) was removed from solution by Sphingomonas yanoikuyae JAR02 while growing on root products as a primary carbon and energy source. Plant root extracts of osage orange (Maclura pomifera), hybrid willow (Salix albaxmatsudana), or kou (Cordia subcordata), or plant root exudates of white mulberry (Morus alba) supported 15-20% benzo[a]pyrene removal over 24 h that was similar to a succinate grown culture and an unfed acetonitrile control. No differences were observed between the different root products tested. Mineralization of {sup 14}C-7-benzo[a]pyrene by S. yanoikuyae JAR02 yielded 0.2 to 0.3% {sup 14}CO{sub 2} when grown with plant root products. Collectively, these observations were consistent with field observations of enhanced phytoremediation of HMW PAH and corroborated the hypothesis that co-metabolism may be a plant/microbe interaction important to rhizoremediation. However, degradation and mineralization was much less for root product-exposed cultures than salicylate-induced cultures, and suggested the rhizosphere may not be an optimal environment for HMW PAH degradation by Sphingomonas yanoikuyae JAR02. - Bacterial benzo[a]pyrene cometabolism, a plant-microbe interaction affecting polycyclic aromatic hydrocarbon phytoremediation was demonstrated with Sphingomonas yanoikuyae JAR02 that utilized plant root extracts and exudates as primary substrates.

  20. Benzo[a]pyrene co-metabolism in the presence of plant root extracts and exudates: Implications for phytoremediation

    International Nuclear Information System (INIS)

    Rentz, Jeremy A.; Alvarez, Pedro J.J.; Schnoor, Jerald L.

    2005-01-01

    Benzo[a]pyrene, a high molecular weight (HMW) polycyclic aromatic hydrocarbon (PAH) was removed from solution by Sphingomonas yanoikuyae JAR02 while growing on root products as a primary carbon and energy source. Plant root extracts of osage orange (Maclura pomifera), hybrid willow (Salix albaxmatsudana), or kou (Cordia subcordata), or plant root exudates of white mulberry (Morus alba) supported 15-20% benzo[a]pyrene removal over 24 h that was similar to a succinate grown culture and an unfed acetonitrile control. No differences were observed between the different root products tested. Mineralization of 14 C-7-benzo[a]pyrene by S. yanoikuyae JAR02 yielded 0.2 to 0.3% 14 CO 2 when grown with plant root products. Collectively, these observations were consistent with field observations of enhanced phytoremediation of HMW PAH and corroborated the hypothesis that co-metabolism may be a plant/microbe interaction important to rhizoremediation. However, degradation and mineralization was much less for root product-exposed cultures than salicylate-induced cultures, and suggested the rhizosphere may not be an optimal environment for HMW PAH degradation by Sphingomonas yanoikuyae JAR02. - Bacterial benzo[a]pyrene cometabolism, a plant-microbe interaction affecting polycyclic aromatic hydrocarbon phytoremediation was demonstrated with Sphingomonas yanoikuyae JAR02 that utilized plant root extracts and exudates as primary substrates

  1. Response of root fungi in Pisum sativum to plant and soil environmental factors

    DEFF Research Database (Denmark)

    Yu, Lingling

    and nutritional status of the plant and soil environments. However, limited information is available about the richness and composition of most of these root-associated fungi as studies of fungal communities remain a challenge because of below-ground high taxonomic and ecological diversity. In the present study......; thus obligate biotrophic fungi and saprotrophic fungi were markedly increased with organic fertilizer dosages, while root pathogenic fungi were decreased with organic amendments. In conclusion, the present work has shown that root-associated fungal community structure relate to plant and soil...... environmental factors. The obtained knowledge from this study can provide novel information of communities of root-associated fungi; thus improving the basic understanding of plant-root fungi-environment interactions in agroecosystems....

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

    NARCIS (Netherlands)

    Pangesti, N.P.D.; Pineda Gomez, A.M.; Pieterse, C.M.J.; Dicke, M.; Loon, van J.J.A.

    2013-01-01

    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

  3. The Integration of Electrical Signals Originating in the Root of Vascular Plants

    Directory of Open Access Journals (Sweden)

    Javier Canales

    2018-01-01

    Full Text Available Plants have developed different signaling systems allowing for the integration of environmental cues to coordinate molecular processes associated to both early development and the physiology of the adult plant. Research on systemic signaling in plants has traditionally focused on the role of phytohormones as long-distance signaling molecules, and more recently the importance of peptides and miRNAs in building up this communication process has also been described. However, it is well-known that plants have the ability to generate different types of long-range electrical signals in response to different stimuli such as light, temperature variations, wounding, salt stress, or gravitropic stimulation. Presently, it is unclear whether short or long-distance electrical communication in plants is linked to nutrient uptake. This review deals with aspects of sensory input in plant roots and the propagation of discrete signals to the plant body. We discuss the physiological role of electrical signaling in nutrient uptake and how nutrient variations may become an electrical signal propagating along the plant.

  4. Petroleum Contamination and Plant Identity Influence Soil and Root Microbial Communities While AMF Spores Retrieved from the Same Plants Possess Markedly Different Communities.

    Science.gov (United States)

    Iffis, Bachir; St-Arnaud, Marc; Hijri, Mohamed

    2017-01-01

    Phytoremediation is a promising in situ green technology based on the use of plants to cleanup soils from organic and inorganic pollutants. Microbes, particularly bacteria and fungi, that closely interact with plant roots play key roles in phytoremediation processes. In polluted soils, the root-associated microbes contribute to alleviation of plant stress, improve nutrient uptake and may either degrade or sequester a large range of soil pollutants. Therefore, improving the efficiency of phytoremediation requires a thorough knowledge of the microbial diversity living in the rhizosphere and in close association with plant roots in both the surface and the endosphere. This study aims to assess fungal ITS and bacterial 16S rRNA gene diversity using high-throughput sequencing in rhizospheric soils and roots of three plant species ( Solidago canadensis, Populus balsamifera , and Lycopus europaeus ) growing spontaneously in three petroleum hydrocarbon polluted sedimentation basins. Microbial community structures of rhizospheric soils and roots were compared with those of microbes associated with arbuscular mycorrhizal fungal (AMF) spores to determine the links between the root and rhizosphere communities and those associated with AMF. Our results showed a difference in OTU richness and community structure composition between soils and roots for both bacteria and fungi. We found that petroleum hydrocarbon pollutant (PHP) concentrations have a significant effect on fungal and bacterial community structures in both soils and roots, whereas plant species identity showed a significant effect only on the roots for bacteria and fungi. Our results also showed that the community composition of bacteria and fungi in soil and roots varied from those associated with AMF spores harvested from the same plants. This let us to speculate that in petroleum hydrocarbon contaminated soils, AMF may release chemical compounds by which they recruit beneficial microbes to tolerate or degrade the

  5. Petroleum Contamination and Plant Identity Influence Soil and Root Microbial Communities While AMF Spores Retrieved from the Same Plants Possess Markedly Different Communities

    Directory of Open Access Journals (Sweden)

    Bachir Iffis

    2017-08-01

    Full Text Available Phytoremediation is a promising in situ green technology based on the use of plants to cleanup soils from organic and inorganic pollutants. Microbes, particularly bacteria and fungi, that closely interact with plant roots play key roles in phytoremediation processes. In polluted soils, the root-associated microbes contribute to alleviation of plant stress, improve nutrient uptake and may either degrade or sequester a large range of soil pollutants. Therefore, improving the efficiency of phytoremediation requires a thorough knowledge of the microbial diversity living in the rhizosphere and in close association with plant roots in both the surface and the endosphere. This study aims to assess fungal ITS and bacterial 16S rRNA gene diversity using high-throughput sequencing in rhizospheric soils and roots of three plant species (Solidago canadensis, Populus balsamifera, and Lycopus europaeus growing spontaneously in three petroleum hydrocarbon polluted sedimentation basins. Microbial community structures of rhizospheric soils and roots were compared with those of microbes associated with arbuscular mycorrhizal fungal (AMF spores to determine the links between the root and rhizosphere communities and those associated with AMF. Our results showed a difference in OTU richness and community structure composition between soils and roots for both bacteria and fungi. We found that petroleum hydrocarbon pollutant (PHP concentrations have a significant effect on fungal and bacterial community structures in both soils and roots, whereas plant species identity showed a significant effect only on the roots for bacteria and fungi. Our results also showed that the community composition of bacteria and fungi in soil and roots varied from those associated with AMF spores harvested from the same plants. This let us to speculate that in petroleum hydrocarbon contaminated soils, AMF may release chemical compounds by which they recruit beneficial microbes to tolerate

  6. Petroleum Contamination and Plant Identity Influence Soil and Root Microbial Communities While AMF Spores Retrieved from the Same Plants Possess Markedly Different Communities

    Science.gov (United States)

    Iffis, Bachir; St-Arnaud, Marc; Hijri, Mohamed

    2017-01-01

    Phytoremediation is a promising in situ green technology based on the use of plants to cleanup soils from organic and inorganic pollutants. Microbes, particularly bacteria and fungi, that closely interact with plant roots play key roles in phytoremediation processes. In polluted soils, the root-associated microbes contribute to alleviation of plant stress, improve nutrient uptake and may either degrade or sequester a large range of soil pollutants. Therefore, improving the efficiency of phytoremediation requires a thorough knowledge of the microbial diversity living in the rhizosphere and in close association with plant roots in both the surface and the endosphere. This study aims to assess fungal ITS and bacterial 16S rRNA gene diversity using high-throughput sequencing in rhizospheric soils and roots of three plant species (Solidago canadensis, Populus balsamifera, and Lycopus europaeus) growing spontaneously in three petroleum hydrocarbon polluted sedimentation basins. Microbial community structures of rhizospheric soils and roots were compared with those of microbes associated with arbuscular mycorrhizal fungal (AMF) spores to determine the links between the root and rhizosphere communities and those associated with AMF. Our results showed a difference in OTU richness and community structure composition between soils and roots for both bacteria and fungi. We found that petroleum hydrocarbon pollutant (PHP) concentrations have a significant effect on fungal and bacterial community structures in both soils and roots, whereas plant species identity showed a significant effect only on the roots for bacteria and fungi. Our results also showed that the community composition of bacteria and fungi in soil and roots varied from those associated with AMF spores harvested from the same plants. This let us to speculate that in petroleum hydrocarbon contaminated soils, AMF may release chemical compounds by which they recruit beneficial microbes to tolerate or degrade the

  7. Determination of Cu, Fe, Zn Elements in Soil, Root Tea Plants, Tea Leaves, and Tea Beverage

    International Nuclear Information System (INIS)

    Supriyanto; Zainul-Kamal

    2006-01-01

    One of the causes of land quality damage was due to the pollution of Cu, Fe, and Zn so that it could directly and also indirectly cause the occurrence of pollution of plants which is growing on it for example tea plant that has been used by society for making of tea beverage. The sampling of soil, root tea plants, tea leaves and tea beverage samples were done in June, 2005 at sub district of Keparakan, Temanggung, Central Java. The purpose of research was to determine the content of Cu, Fe and Zn in soil, root tea plants, tea leaves and tea beverage. The research was done by digesting the sample with nitric acid until the clear solution was obtained, then it was added by aquabidest until 10.0 ml. Determination of Cu, Fe and Zn content used AAS instrument. The average concentration of Cu Fe and Zn obtained in deep soil samples area 0.155 ± 0.005 ppm, 127.16 ± 2.65 ppm, and 0.68 ± 0.02 ppm respectively, in surface soil samples are 0.355 ± 0.025 ppm, 360.59 ± 13.17 ppm and 0.78 ± 0.01 ppm respectively, in root of tea plants samples area 0.241 ± 0.098 ppm, 13.16 ± 1.34 ppm and 2.64 ± 0.06 ppm respectively, in tea leaves are 0.211 ± 0.013 ppm, 3.35 ± 0.886 ppm, and 0.795 ± 0.016 ppm respectively and in tea beverage 0.142 ± 0.086 ppm, 6.11 ± 0.35 ppm and 0.66 ± 0.02 ppm respectively. (author)

  8. A conserved fungal glycosyltransferase facilitates pathogenesis of plants by enabling hyphal growth on solid surfaces.

    Directory of Open Access Journals (Sweden)

    Robert King

    2017-10-01

    Full Text Available Pathogenic fungi must extend filamentous hyphae across solid surfaces to cause diseases of plants. However, the full inventory of genes which support this is incomplete and many may be currently concealed due to their essentiality for the hyphal growth form. During a random T-DNA mutagenesis screen performed on the pleomorphic wheat (Triticum aestivum pathogen Zymoseptoria tritici, we acquired a mutant unable to extend hyphae specifically when on solid surfaces. In contrast "yeast-like" growth, and all other growth forms, were unaffected. The inability to extend surface hyphae resulted in a complete loss of virulence on plants. The affected gene encoded a predicted type 2 glycosyltransferase (ZtGT2. Analysis of >800 genomes from taxonomically diverse fungi highlighted a generally widespread, but discontinuous, distribution of ZtGT2 orthologues, and a complete absence of any similar proteins in non-filamentous ascomycete yeasts. Deletion mutants of the ZtGT2 orthologue in the taxonomically un-related fungus Fusarium graminearum were also severely impaired in hyphal growth and non-pathogenic on wheat ears. ZtGT2 expression increased during filamentous growth and electron microscopy on deletion mutants (ΔZtGT2 suggested the protein functions to maintain the outermost surface of the fungal cell wall. Despite this, adhesion to leaf surfaces was unaffected in ΔZtGT2 mutants and global RNAseq-based gene expression profiling highlighted that surface-sensing and protein secretion was also largely unaffected. However, ΔZtGT2 mutants constitutively overexpressed several transmembrane and secreted proteins, including an important LysM-domain chitin-binding virulence effector, Zt3LysM. ZtGT2 likely functions in the synthesis of a currently unknown, potentially minor but widespread, extracellular or outer cell wall polysaccharide which plays a key role in facilitating many interactions between plants and fungi by enabling hyphal growth on solid matrices.

  9. A conserved fungal glycosyltransferase facilitates pathogenesis of plants by enabling hyphal growth on solid surfaces

    Science.gov (United States)

    Plummer, Amy; Halsey, Kirstie; Lovegrove, Alison; Hammond-Kosack, Kim

    2017-01-01

    Pathogenic fungi must extend filamentous hyphae across solid surfaces to cause diseases of plants. However, the full inventory of genes which support this is incomplete and many may be currently concealed due to their essentiality for the hyphal growth form. During a random T-DNA mutagenesis screen performed on the pleomorphic wheat (Triticum aestivum) pathogen Zymoseptoria tritici, we acquired a mutant unable to extend hyphae specifically when on solid surfaces. In contrast “yeast-like” growth, and all other growth forms, were unaffected. The inability to extend surface hyphae resulted in a complete loss of virulence on plants. The affected gene encoded a predicted type 2 glycosyltransferase (ZtGT2). Analysis of >800 genomes from taxonomically diverse fungi highlighted a generally widespread, but discontinuous, distribution of ZtGT2 orthologues, and a complete absence of any similar proteins in non-filamentous ascomycete yeasts. Deletion mutants of the ZtGT2 orthologue in the taxonomically un-related fungus Fusarium graminearum were also severely impaired in hyphal growth and non-pathogenic on wheat ears. ZtGT2 expression increased during filamentous growth and electron microscopy on deletion mutants (ΔZtGT2) suggested the protein functions to maintain the outermost surface of the fungal cell wall. Despite this, adhesion to leaf surfaces was unaffected in ΔZtGT2 mutants and global RNAseq-based gene expression profiling highlighted that surface-sensing and protein secretion was also largely unaffected. However, ΔZtGT2 mutants constitutively overexpressed several transmembrane and secreted proteins, including an important LysM-domain chitin-binding virulence effector, Zt3LysM. ZtGT2 likely functions in the synthesis of a currently unknown, potentially minor but widespread, extracellular or outer cell wall polysaccharide which plays a key role in facilitating many interactions between plants and fungi by enabling hyphal growth on solid matrices. PMID:29020037

  10. The Essential Oils of Rhaponticum carthamoides Hairy Roots and Roots of Soil-Grown Plants: Chemical Composition and Antimicrobial, Anti-Inflammatory, and Antioxidant Activities

    Science.gov (United States)

    Rijo, Patrícia; Garcia, Catarina; Kalemba, Danuta; Toma, Monika; Szemraj, Janusz; Pytel, Dariusz; Śliwiński, Tomasz

    2016-01-01

    The essential oils were isolated by hydrodistillation from the hairy roots (HR) and roots of soil-grown plants (SGR) of Rhaponticum carthamoides and were analyzed by GC-MS method. In the both essential oils 62 compounds were identified. The root essential oils showed the differences in the qualitative and quantitative composition. The sesquiterpene hydrocarbons (55–62%) dominated in both essential oils. The major compounds of HR essential oil were cyperene, 13-norcypera-1(5),11(12)-diene, and cadalene while aplotaxene, nardosina-1(10),11-diene, and dauca-4(11),8-diene dominated in SGR essential oil. Both essential oils showed antibacterial activity especially against Enterococcus faecalis (ATCC 29212) and Pseudomonas aeruginosa (ATCC 27853) (MIC value = 125 µg/mL). HR and SGR essential oils also decreased the expression of IL-1β, IL-6, and TNF-α and the ROS level in LPS-treatment astrocytes. This is the first report to describe the chemical composition of R. carthamoides essential oil from hairy roots, its protective effect against LPS-induced inflammation and ROS production in astrocytes, and its antimicrobial potential. The results show that R. carthamoides hairy roots may be a valuable source of the essential oil and may be an alternative to the roots of soil-grown plants. PMID:28074117

  11. The Essential Oils of Rhaponticum carthamoides Hairy Roots and Roots of Soil-Grown Plants: Chemical Composition and Antimicrobial, Anti-Inflammatory, and Antioxidant Activities.

    Science.gov (United States)

    Skała, Ewa; Rijo, Patrícia; Garcia, Catarina; Sitarek, Przemysław; Kalemba, Danuta; Toma, Monika; Szemraj, Janusz; Pytel, Dariusz; Wysokińska, Halina; Śliwiński, Tomasz

    2016-01-01

    The essential oils were isolated by hydrodistillation from the hairy roots (HR) and roots of soil-grown plants (SGR) of Rhaponticum carthamoides and were analyzed by GC-MS method. In the both essential oils 62 compounds were identified. The root essential oils showed the differences in the qualitative and quantitative composition. The sesquiterpene hydrocarbons (55-62%) dominated in both essential oils. The major compounds of HR essential oil were cyperene, 13-norcypera-1(5),11(12)-diene, and cadalene while aplotaxene, nardosina-1(10),11-diene, and dauca-4(11),8-diene dominated in SGR essential oil. Both essential oils showed antibacterial activity especially against Enterococcus faecalis (ATCC 29212) and Pseudomonas aeruginosa (ATCC 27853) (MIC value = 125  µ g/mL). HR and SGR essential oils also decreased the expression of IL-1 β , IL-6, and TNF- α and the ROS level in LPS-treatment astrocytes. This is the first report to describe the chemical composition of R. carthamoides essential oil from hairy roots, its protective effect against LPS-induced inflammation and ROS production in astrocytes, and its antimicrobial potential. The results show that R. carthamoides hairy roots may be a valuable source of the essential oil and may be an alternative to the roots of soil-grown plants.

  12. An efficient soil penetration strategy for explorative robots inspired by plant root circumnutation movements.

    Science.gov (United States)

    Del Dottore, Emanuela; Mondini, Alessio; Sadeghi, Ali; Mattoli, Virgilio; Mazzolai, Barbara

    2017-11-10

    This paper presents a comparative analysis in terms of energy required by an artificial probe to penetrate soil implementing two different strategies: a straight penetration movement; and a circumnutation, which is a peculiar root movement in plants. The role of circumnutations in plant roots is still reason of debate. We hypothesized that circumnutation movements can help roots in penetrating soil and we validated our assumption testing the probe at three distinct soil densities and using various combinations of circumnutation amplitude and period for each soil. The comparison was based on the total work done by the system while circumnutating at its tip level respect that showed by the same system in straight penetration. The total energy evaluation confirmed an improvement obtained by circumnutations up to 33%. We also proposed a fitting model for our experimental data that was used to estimate energy needed by the probe to penetrate soil at different dimensions and circumnutation amplitudes. Results show the existence of a trade-off among penetration velocity, circumnutation period and amplitude towards an energy consumption optimization, expressed by the lead angle of the helical path that should stay in the range between 46° and 65°. Moreover, circumnutations with appropriate amplitude (~10°) and period (~80 s) values are more efficient than straight penetration also at different probe tip dimensions up to a threshold diameter (from 2 mm to 55 mm). Based on the obtained results, we speculated that circumnutations can represent a strategy used by plant roots to reduce pressure and energy needed to penetrate soil. In perspective, the translation of this biological feature in robotic systems will allow improving their energetic efficiency in digging capabilities and thus opening new scenarios of use in search and rescue, environmental monitoring and soil exploration. Creative Commons Attribution license.

  13. 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.

  14. Selective laser melting of titanium alloy enables osseointegration of porous multi-rooted implants in a rabbit model.

    Science.gov (United States)

    Peng, Wei; Xu, Liangwei; You, Jia; Fang, Lihua; Zhang, Qing

    2016-07-21

    Osseointegration refers to the direct connection between living bone and the surface of a load-bearing artificial implant. Porous implants with well-controlled porosity and pore size can enhance osseointegration. However, until recently implants were produced by machining solid core titanium rods. The aim of this study was to develop a multi-rooted dental implant (MRI) with a connected porous surface structure to facilitate osseointegration. MRIs manufactured by selective laser melting (SLM) and commercial implants with resorbable blasting media (RBM)-treated surfaces were inserted into the hind limbs of New Zealand white rabbits. Osseointegration was evaluated periodically over 12 weeks by micro-computerized tomography (CT) scanning, histological analysis, mechanical push-out tests, and torque tests. Bone volume densities were consistently higher in the MRI group than in the RBM group throughout the study period, ultimately resulting in a peak value of 48.41 % for the MRI group. Histological analysis revealed denser surrounding bone growth in the MRIs; after 4 and 8 weeks, bone tissue had grown into the pore structures and root bifurcation areas, respectively. Biomechanics tests indicated binding of the porous MRIs to the neobone tissues, as push-out forces strengthened from 294.7 to 446.5 N and maximum mean torque forces improved from 81.15 to 289.57 N (MRI), versus 34.79 to 87.8 N in the RBM group. MRIs manufactured by SLM possess a connected porous surface structure that improves the osteogenic characteristics of the implant surface.

  15. Metabolism of carbamazepine in plant roots and endophytic rhizobacteria isolated from Phragmites australis.

    Science.gov (United States)

    Sauvêtre, Andrés; May, Robert; Harpaintner, Rudolf; Poschenrieder, Charlotte; Schröder, Peter

    2018-01-15

    Carbamazepine (CBZ) is a pharmaceutical frequently categorized as a recalcitrant pollutant in the aquatic environment. Endophytic bacteria previously isolated from reed plants have shown the ability to promote growth of their host and to contribute to CBZ metabolism. In this work, a horseradish (Armoracia rusticana) hairy root (HR) culture has been used as a plant model to study the interactions between roots and endophytic bacteria in response to CBZ exposure. HRs could remove up to 5% of the initial CBZ concentration when they were grown in spiked Murashige and Skoog (MS) medium. Higher removal rates were observed when HRs were inoculated with the endophytic bacteria Rhizobium radiobacter (21%) and Diaphorobacter nitroreducens (10%). Transformation products resulting from CBZ degradation were identified using liquid chromatography-ultra high-resolution quadrupole time of flight mass spectrometry (LC-UHR-QTOF-MS). CBZ metabolism could be divided in four pathways. Metabolites involving GSH conjugation and 2,3-dihydroxylation, as well as acridine related compounds are described in plants for the first time. This study presents strong evidence that xenobiotic metabolism and degradation pathways in plants can be modulated by the interaction with their endophytic community. Hence it points to plausible applications for the elimination of recalcitrant compounds such as CBZ from wastewater in CWs. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Two-photon Photoactivation to Measure Histone Exchange Dynamics in Plant Root Cells.

    Science.gov (United States)

    Rosa, Stefanie; Shaw, Peter

    2015-10-20

    Chromatin-binding proteins play a crucial role in chromatin structure and gene expression. Direct binding of chromatin proteins both maintains and regulates transcriptional states. It is therefore important to study the binding properties of these proteins in vivo within the natural environment of the nucleus. Photobleaching, photoactivation and photoconversion (photoswitching) can provide a non-invasive experimental approach to study dynamic properties of living cells and organisms. We used photoactivation to determine exchange dynamics of histone H2B in plant stem cells of the root (Rosa et al. , 2014). The stem cells of the root are located in the middle of the tissue, which made it impossible to carry out photoactivation of sufficiently small and well-defined sub-cellular regions with conventional laser illumination in the confocal microscope, mainly because scattering and refraction effects within the root tissue dispersed the focal spot and caused photoactivation of too large a region. We therefore used 2-photon activation, which has much better inherent resolution of the illuminated region. This is because the activation depends on simultaneous absorption of two or more photons, which in turns depends on the square (or higher power) of the intensity-a much sharper peak. In this protocol we will describe the experimental procedure to perform two-photon photoactivation experiments and the corresponding image analysis. This protocol can be used for nuclear proteins tagged with photoactivable GFP (PA-GFP) expressed in root tissues.

  17. Fungal root symbionts of high-altitude vascular plants in the Himalayas.

    Science.gov (United States)

    Kotilínek, Milan; Hiiesalu, Inga; Košnar, Jiří; Šmilauerová, Marie; Šmilauer, Petr; Altman, Jan; Dvorský, Miroslav; Kopecký, Martin; Doležal, Jiří

    2017-07-26

    Arbuscular mycorrhizal fungi (AMF) and dark septate endophytes (DSE) form symbiotic relationships with plants influencing their productivity, diversity and ecosystem functions. Only a few studies on these fungi, however, have been conducted in extreme elevations and none over 5500 m a.s.l., although vascular plants occur up to 6150 m a.s.l. in the Himalayas. We quantified AMF and DSE in roots of 62 plant species from contrasting habitats along an elevational gradient (3400-6150 m) in the Himalayas using a combination of optical microscopy and next generation sequencing. We linked AMF and DSE communities with host plant evolutionary history, ecological preferences (elevation and habitat type) and functional traits. We detected AMF in elevations up to 5800 m, indicating it is more constrained by extreme conditions than the host plants, which ascend up to 6150 m. In contrast, DSE were found across the entire gradient up to 6150 m. AMF diversity was unimodally related to elevation and positively related to the intensity of AMF colonization. Mid-elevation steppe and alpine plants hosted more diverse AMF communities than plants from deserts and the subnival zone. Our results bring novel insights to the abiotic and biotic filters structuring AMF and DSE communities in the Himalayas.

  18. Foliar or root exposures to smelter particles: Consequences for lead compartmentalization and speciation in plant leaves

    International Nuclear Information System (INIS)

    Schreck, Eva; Dappe, Vincent; Sarret, Géraldine; Sobanska, Sophie; Nowak, Dorota; Nowak, Jakub; Stefaniak, Elżbieta Anna; Magnin, Valérie; Ranieri, Vincent; Dumat, Camille

    2014-01-01

    In urban areas with high fallout of airborne particles, metal uptake by plants mainly occurs by foliar pathways and can strongly impact crop quality. However, there is a lack of knowledge on metal localization and speciation in plants after pollution exposure, especially in the case of foliar uptake. In this study, two contrasting crops, lettuce (Lactuca sativa L.) and rye-grass (Lolium perenne L.), were exposed to Pb-rich particles emitted by a Pb-recycling factory via either atmospheric or soil application. Pb accumulation in plant leaves was observed for both ways of exposure. The mechanisms involved in Pb uptake were investigated using a combination of microscopic and spectroscopic techniques (electron microscopy, laser ablation, Raman microspectroscopy, and X-ray absorption spectroscopy). The results show that Pb localization and speciation are strongly influenced by the type of exposure (root or shoot pathway) and the plant species. Foliar exposure is the main pathway of uptake, involving the highest concentrations in plant tissues. Under atmospheric fallouts, Pb-rich particles were strongly adsorbed on the leaf surface of both plant species. In lettuce, stomata contained Pb-rich particles in their apertures, with some deformations of guard cells. In addition to PbO and PbSO 4 , chemical forms that were also observed in pristine particles, new species were identified: organic compounds (minimum 20%) and hexagonal platy crystals of PbCO 3 . In rye-grass, the changes in Pb speciation were even more egregious: Pb–cell wall and Pb–organic acid complexes were the major species observed. For root exposure, identified here as a minor pathway of Pb transfer compared to foliar uptake, another secondary species, pyromorphite, was identified in rye-grass leaves. Finally, combining bulk and spatially resolved spectroscopic techniques permitted both the overall speciation and the minor but possibly highly reactive lead species to be determined in order to better

  19. Foliar or root exposures to smelter particles: Consequences for lead compartmentalization and speciation in plant leaves

    Energy Technology Data Exchange (ETDEWEB)

    Schreck, Eva [Université de Toulouse, INP, UPS, EcoLab (Laboratoire Ecologie Fonctionnelle et Environnement), ENSAT, Avenue de l' Agrobiopole, 31326 Castanet-Tolosan (France); CNRS, EcoLab, 31326 Castanet-Tolosan (France); Géosciences Environnement Toulouse (GET), Observatoire Midi Pyrénées, Université de Toulouse, CNRS, IRD, 14 Avenue E. Belin, F-31400 Toulouse (France); Dappe, Vincent [LASIR (UMR CNRS 8516), Université de Lille 1, Bât. C5, 59655 Villeneuve d' Ascq Cedex (France); Sarret, Géraldine [ISTerre, UMR 5275, Université Grenoble I, CNRS, F-38041 Grenoble (France); Sobanska, Sophie [LASIR (UMR CNRS 8516), Université de Lille 1, Bât. C5, 59655 Villeneuve d' Ascq Cedex (France); Nowak, Dorota; Nowak, Jakub; Stefaniak, Elżbieta Anna [Department of Chemistry, John Paul II Catholic University of Lublin, Al. Kraśnicka 102, 20-718 Lublin (Poland); Magnin, Valérie [ISTerre, UMR 5275, Université Grenoble I, CNRS, F-38041 Grenoble (France); Ranieri, Vincent [CEA-INAC, 17 rue des Martyrs, 38054 Grenoble Cedex 9 (France); Dumat, Camille, E-mail: camille.dumat@ensat.fr [Université de Toulouse, INP, UPS, EcoLab (Laboratoire Ecologie Fonctionnelle et Environnement), ENSAT, Avenue de l' Agrobiopole, 31326 Castanet-Tolosan (France); CNRS, EcoLab, 31326 Castanet-Tolosan (France)

    2014-04-01

    In urban areas with high fallout of airborne particles, metal uptake by plants mainly occurs by foliar pathways and can strongly impact crop quality. However, there is a lack of knowledge on metal localization and speciation in plants after pollution exposure, especially in the case of foliar uptake. In this study, two contrasting crops, lettuce (Lactuca sativa L.) and rye-grass (Lolium perenne L.), were exposed to Pb-rich particles emitted by a Pb-recycling factory via either atmospheric or soil application. Pb accumulation in plant leaves was observed for both ways of exposure. The mechanisms involved in Pb uptake were investigated using a combination of microscopic and spectroscopic techniques (electron microscopy, laser ablation, Raman microspectroscopy, and X-ray absorption spectroscopy). The results show that Pb localization and speciation are strongly influenced by the type of exposure (root or shoot pathway) and the plant species. Foliar exposure is the main pathway of uptake, involving the highest concentrations in plant tissues. Under atmospheric fallouts, Pb-rich particles were strongly adsorbed on the leaf surface of both plant species. In lettuce, stomata contained Pb-rich particles in their apertures, with some deformations of guard cells. In addition to PbO and PbSO{sub 4}, chemical forms that were also observed in pristine particles, new species were identified: organic compounds (minimum 20%) and hexagonal platy crystals of PbCO{sub 3}. In rye-grass, the changes in Pb speciation were even more egregious: Pb–cell wall and Pb–organic acid complexes were the major species observed. For root exposure, identified here as a minor pathway of Pb transfer compared to foliar uptake, another secondary species, pyromorphite, was identified in rye-grass leaves. Finally, combining bulk and spatially resolved spectroscopic techniques permitted both the overall speciation and the minor but possibly highly reactive lead species to be determined in order to

  20. Arbuscular Mycorrhiza Improves Substrate Hydraulic Conductivity in the Plant Available Moisture Range Under Root Growth Exclusion.

    Science.gov (United States)

    Bitterlich, Michael; Franken, Philipp; Graefe, Jan

    2018-01-01

    Arbuscular mycorrhizal fungi (AMF) proliferate in soils and are known to affect soil structure. Although their contribution to structure is extensively investigated, the consequences of those processes for soil water extractability and transport has, so far, gained surprisingly little attention. Therefore we asked, whether AMF can affect water retention and unsaturated hydraulic conductivity under exclusion of root ingrowth, in order to minimize plant driven effects. We carried out experiments with tomato inoculated with Rhizoglomus irregulare in a soil substrate with sand and vermiculite that created variation in colonization by mixed pots with wild type (WT) plants and mycorrhiza resistant (RMC) mutants. Sampling cores were introduced and used to assess substrate moisture retention dynamics and modeling of substrate water retention and hydraulic conductivity. AMF reduced the saturated water content and total porosity, but maintained air filled porosity in soil spheres that excluded root ingrowth. The water content between field capacity and the permanent wilting point (6-1500 kPa) was only reduced in mycorrhizal substrates that contained at least one RMC mutant. Plant available water contents correlated positively with soil protein contents. Soil protein contents were highest in pots that possessed the strongest hyphal colonization, but not significantly affected. Substrate conductivity increased up to 50% in colonized substrates in the physiologically important water potential range between 6 and 10 kPa. The improvements in hydraulic conductivity are restricted to substrates where at least one WT plant was available for the fungus, indicating a necessity of a functional symbiosis for this effect. We conclude that functional mycorrhiza alleviates the resistance to water movement through the substrate in substrate areas outside of the root zone.

  1. The nucleus of differentiated root plant cells: modifications induced by arbuscular mycorrhizal fungi

    Directory of Open Access Journals (Sweden)

    G Lingua

    2009-12-01

    Full Text Available The nuclei of plant cells show marked differences in chromatin organisation, related to their DNA content, which ranges from the type with large strands of condensed chromatin (reticulate or chromonematic nuclei to one with mostly decondensed chromatin (chromocentric or diffuse nuclei. A loosening of the chromatin structure generally occurs in actively metabolising cells, such as differentiating and secretory cells, in relation to their high transcriptional activity. Endoreduplication may occur, especially in plants with a small genome, which increases the availability of nuclear templates, the synthesis of DNA, and probably regulates gene expression. Here we describe structural and quantitative changes of the chromatin and their relationship with transcription that occur in differentiated cells following an increase of their metabolism. The nuclei of root cortical cells of three plants with different 2C DNA content (Allium porrum, Pisum sativum and Lycopersicon esculentm and their modifications induced by arbuscular mycorrhization, which strongly increase the metabolic activity of colonised cells, are taken as examples.

  2. Absence of Hg transpiration by shoot after Hg uptake by roots of six terrestrial plant species

    International Nuclear Information System (INIS)

    Greger, Maria; Wang Yaodong; Neuschuetz, Clara

    2005-01-01

    In this paper we investigated if, and to what extent, six different plant species accumulate, translocate and emit mercury (Hg) into the air. The Hg uptake by roots, distribution of Hg to the shoot and release of Hg via shoots of garden pea, spring wheat, sugar beet, oil-seed rape, white clover and willow were investigated in a transpiration chamber. The airborne Hg was trapped in a Hopcalite trap or a gold trap. Traps and plant materials were analysed for content of Hg by CVAAS. The results show that all plant species were able to take up Hg to a large extent from a nutrient solution containing 200 μg L -1 Hg. However, the Hg translocation to the shoot was low (0.17-2.5%) and the Hg that reached the leaves was trapped and no release of the absorbed Hg to the air was detected. - Mercury translocation to shoots was low

  3. Tall or short? Slender or thick? A plant strategy for regulating elongation growth of roots by low concentrations of gibberellin.

    Science.gov (United States)

    Tanimoto, Eiichi

    2012-07-01

    Since the plant hormone gibberellin (GA) was discovered as a fungal toxin that caused abnormal elongation of rice shoots, the physiological function of GA has mainly been investigated in relation to the regulation of plant height. However, an indispensable role for GA in root growth has been elucidated by using severely GA-depleted plants, either with a gene mutation in GA biosynthesis or which have been treated by an inhibitor of GA biosynthesis. The molecular sequence of GA signalling has also been studied to understand GA functions in root growth. This review addresses research progress on the physiological functions of GA in root growth. Concentration-dependent stimulation of elongation growth by GA is important for the regulation of plant height and root length. Thus the endogenous level of GA and/or the GA sensitivity of shoots and roots plays a role in determining the shoot-to-root ratio of the plant body. Since the shoot-to-root ratio is an important parameter for agricultural production, control of GA production and GA sensitivity may provide a strategy for improving agricultural productivity. The sequence of GA signal transduction has recently been unveiled, and some component molecules are suggested as candidate in planta regulatory sites and as points for the artificial manipulation of GA-mediated growth control. This paper reviews: (1) the breakthrough dose-response experiments that show that root growth is regulated by GA in a lower concentration range than is required for shoot growth; (2) research on the regulation of GA biosynthesis pathways that are known predominantly to control shoot growth; and (3) recent research on GA signalling pathways, including GA receptors, which have been suggested to participate in GA-mediated growth regulation. This provides useful information to suggest a possible strategy for the selective control of shoot and root growth, and to explain how GA plays a role in rosette and liana plants with tall or short, and slender

  4. Plant root transcriptome profiling reveals a strain-dependent response during Azospirillum-rice cooperation

    Directory of Open Access Journals (Sweden)

    Benoît eDrogue

    2014-11-01

    Full Text Available Cooperation involving Plant Growth-Promoting Rhizobacteria results in improvements of plant growth and health. While pathogenic and symbiotic interactions are known to induce transcriptional changes for genes related to plant defence and development, little is known about the impact of phytostimulating rhizobacteria on plant gene expression. This study aims at identifying genes significantly regulated in rice roots upon Azospirillum inoculation, considering possible favored interaction between a strain and its original host cultivar. Genome-wide analyses of Oryza sativa japonica cultivars Cigalon and Nipponbare were performed, by using microarrays, seven days post inoculation with A. lipoferum 4B (isolated from Cigalon or Azospirillum sp. B510 (isolated from Nipponbare and compared to the respective non-inoculated condition. A total of 7,384 genes were significantly regulated, which represent about 16 % of total rice genes. A set of 34 genes is regulated by both Azospirillum strains in both cultivars, including a gene orthologous to PR10 of Brachypodium, and these could represent plant markers of Azospirillum-rice interactions. The results highlight a strain-dependent response of rice, with 83 % of the differentially expressed genes being classified as combination-specific. Whatever the combination, most of the differentially expressed genes are involved in primary metabolism, transport, regulation of transcription and protein fate. When considering genes involved in response to stress and plant defence, it appears that strain B510, a strain displaying endophytic properties, leads to the repression of a wider set of genes than strain 4B. Individual genotypic variations could be the most important driving force of rice roots gene expression upon Azospirillum inoculation. Strain-dependent transcriptional changes observed for genes related to auxin and ethylene signalling highlight the complexity of hormone signalling networks in the Azospirillum

  5. Longevity of contributions to SOC stocks from roots and aboveground plant litter below a Miscanthus plantation

    Science.gov (United States)

    Robertson, Andrew; Smith, Pete; Davies, Christian; Bottoms, Emily; McNamara, Niall

    2013-04-01

    Miscanthus is a lignocellulosic crop that uses the Hatch-Slack (C4) photosynthetic pathway as opposed to most C3 vegetation native to the UK. Miscanthus can be grown for a number of practical end-uses but recently interest has increased in its viability as a bioenergy crop; both providing a renewable source of energy and helping to limit climate change by improving the carbon (C) budgets associated with energy generation. Recent studies have shown that Miscanthus plantations may increase stocks of soil organic carbon (SOC), however the longevity and origin of this 'new' SOC must be assessed. Consequently, we combined an input manipulation experiment with physio-chemical soil fractionation to quantify new SOC and CO2 emissions from Miscanthus roots, decomposing plant litter and soil individually. Further, fractionation of SOC from the top 30 cm gave insight into the longevity of that SOC. In January 2009 twenty-five 2 m2 plots were set up in a three-year old 11 hectare Miscanthus plantation in Lincolnshire, UK; with five replicates of five treatments. These treatments varied plant input to the soil by way of controlled exclusion techniques. Treatments excluded roots only ("No Roots"), surface litter only ("No Litter"), both roots and surface litter ("No Roots or Litter") or had double the litter amount added to the soil surface ("Double Litter"). A fifth treatment was a control with undisturbed roots and an average amount of litter added. Monthly measurements of CO2 emissions were taken at the soil surface from each treatment between March 2009 and March 2013, and soil C from the top 30 cm was monitored in all plots over the same period. Miscanthus-derived SOC was determined using the isotopic discrimination between C4 plant matter and C3 soil, and soil fractionation was then used to establish the longevity of that Miscanthus-derived SOC. Ongoing results for CO2 emissions indicate a strong seasonal variation; litter decomposition forms a large portion of the CO2

  6. Concentration of petroleum-hydrocarbon contamination shapes fungal endophytic community structure in plant roots

    Directory of Open Access Journals (Sweden)

    Guillaume eBourdel

    2016-05-01

    Full Text Available Plant-root inhabiting fungi are a universal phenomenon found in all ecosystems where plants are able to grow, even in harsh environments. Interactions between fungi and plant roots can vary widely from mutualism to parasitism depending on many parameters. The role of fungal endophytes in phytoremediation of polluted sites, and characterization of the endophytic diversity and community assemblages in contaminated areas remain largely unexplored. In this study, we investigated the composition of endophytic fungal communities in the roots of two plant species growing spontaneously in petroleum-contaminated sedimentation basins of a former petro-chemical plant. The three adjacent basins showed a highly heterogeneous patterns of pollutant concentrations. We combined a culture-based isolation approach with the pyrosequencing of fungal ITS ribosomal DNA. We selected two species, Eleocharis erythropoda Steud. and Populus balsamifera L., and sampled three individuals of each species from each of three adjacent basins, each with a different concentration of petroleum hydrocarbons. We found that contamination level significantly shaped endophytic fungal diversity and community composition in E. erythropoda, with only 9.9% of these fungal Operational Taxonomic Units (OTUs retrieved in all three basins. However, fungal community structure associated with P. balsamifera remained unaffected by the contamination level with 28.2% of fungal OTUs shared among all three basins. This could be explained by the smaller differences of pollutant concentrations in the soil around our set of P. balsamifera sampless compared to that around our set of E. erythropoda samples. Our culture-based approach allowed isolation of 11 and 30 fungal endophytic species from surface-sterilized roots of E. erythropoda and P. balsamifera, respectively. These isolates were ribotyped using ITS, and all were found in pyrosequensing datasets. Our results demonstrate that extreme levels of

  7. Root uptake of uranium by a higher plant model (Phaseolus vulgaris) bioavailability from soil solution

    Energy Technology Data Exchange (ETDEWEB)

    Laroche, L.; Henner, P.; Camilleri, V.; Garnier-Laplace, J. [CEA Cadarache (DEI/SECRE/LRE), Laboratory of Radioecology and Ecotoxicology, Institute for Radioprotection and Nuclear Safety, 13 - Saint-Paul-lez-Durance (France)

    2004-07-01

    Uranium behaviour in soils is controlled by actions and interactions between physicochemical and biological processes that also determine its bioavailability. In soil solution, uranium(+VI) aqueous speciation undergoes tremendous changes mainly depending on pH, carbonates, phosphates and organic matter. In a first approach to identify bioavailable species of U to plants, cultures were performed using hydroponics, to allow an easy control of the composition of the exposure media. The latter, here an artificial soil solution, was designed to control the uranium species in solution. The geochemical speciation code JCHESS using a database compiled from the OECD/NEA thermochemical database project and verified was used to perform the solution speciation calculations. On this theoretical basis, three domains were defined for short-duration well-defined laboratory experiments in simplified conditions: pH 4.9, 5.8 and 7 where predicted dominant species are uranyl ions, hydroxyl complexes and carbonates respectively. For these domains, biokinetics and characterization of transmembrane transport according to a classical Michaelis Menten approach were investigated. The Free Ion Model (or its derived Biotic Ligand Model) was tested to determine if U uptake is governed by the free uranyl species or if other metal complexes can be assimilated. The effect of different variables on root assimilation efficiency and phyto-toxicity was explored: presence of ligands such as phosphates or carbonates and competitive ions such as Ca{sup 2+} at the 3 pH. According to previous experiments, uranium was principally located in roots whatever the pH and no difference in uranium uptake was evidenced between the main growth stages of the plant. Within the 3 studied chemical domains, results from short-term kinetics evidenced a linear correlation between total uranium concentration in bean roots and that in exposure media, suggesting that total uranium in soil solution could be a good predictor

  8. Root uptake of uranium by a higher plant model (Phaseolus vulgaris) bioavailability from soil solution

    International Nuclear Information System (INIS)

    Laroche, L.; Henner, P.; Camilleri, V.; Garnier-Laplace, J.

    2004-01-01

    Uranium behaviour in soils is controlled by actions and interactions between physicochemical and biological processes that also determine its bioavailability. In soil solution, uranium(+VI) aqueous speciation undergoes tremendous changes mainly depending on pH, carbonates, phosphates and organic matter. In a first approach to identify bioavailable species of U to plants, cultures were performed using hydroponics, to allow an easy control of the composition of the exposure media. The latter, here an artificial soil solution, was designed to control the uranium species in solution. The geochemical speciation code JCHESS using a database compiled from the OECD/NEA thermochemical database project and verified was used to perform the solution speciation calculations. On this theoretical basis, three domains were defined for short-duration well-defined laboratory experiments in simplified conditions: pH 4.9, 5.8 and 7 where predicted dominant species are uranyl ions, hydroxyl complexes and carbonates respectively. For these domains, biokinetics and characterization of transmembrane transport according to a classical Michaelis Menten approach were investigated. The Free Ion Model (or its derived Biotic Ligand Model) was tested to determine if U uptake is governed by the free uranyl species or if other metal complexes can be assimilated. The effect of different variables on root assimilation efficiency and phyto-toxicity was explored: presence of ligands such as phosphates or carbonates and competitive ions such as Ca 2+ at the 3 pH. According to previous experiments, uranium was principally located in roots whatever the pH and no difference in uranium uptake was evidenced between the main growth stages of the plant. Within the 3 studied chemical domains, results from short-term kinetics evidenced a linear correlation between total uranium concentration in bean roots and that in exposure media, suggesting that total uranium in soil solution could be a good predictor for

  9. Rooting of hybrid clones of Populus tremula L. x P. tremuloides Michx. by stem cuttings derived from micropropagated plants

    Energy Technology Data Exchange (ETDEWEB)

    Qibin Yu [Univ. of Helsinki (Finland). Dept. of Plant Biology; Maentylae, N. [Univ. of Turku (Finland). Dept. of Biology, Plant Physiology and Molecular Biology; Salonen, M. [Finnish Forest Research Inst., Laeyliaeinen (Finland). Haapastensyrjae Breeding Station

    2001-07-01

    Propagation costs could be cut by replacing part of the micropropagation process with steps involving more traditional techniques. This study explored possibilities for improving existing vegetative propagation techniques for aspen using stem cuttings obtained from micropropagated plants. Vegetative propagation through stem cuttings was studied in 10 micropropagated hybrid aspen clones (Populus tremula L. x P. tremuloides Michx). Cuttings containing one axillary bud were harvested from the same donor plants twice during the growing season: the first harvest in May and the second harvest in July. Rooting percentage was correlated positively with root length, number of roots and height of cutting plant but negatively with length of rooting. The average rooting percentage was 53% in the first harvest and 27% in second harvest. Indole-3-butyric acid treatments (1.2 mM) significantly improved rooting in the second harvest, but not in the first harvest, suggesting different endogenous auxin levels in the cuttings. A significant variation for most traits related to rooting ability was found among the clones, indicating that clonal effects play an important role in the propagation of aspen. Thus, clones with a good response in shoot growth and rooting could be exploited in large-scale propagation using stem cuttings.

  10. Hospitability of ornamental and medicinal plants to root-knot nematode (Meloidogyne incognita race 2

    Directory of Open Access Journals (Sweden)

    Francisco José Carvalho Moreira

    2017-10-01

    Full Text Available The correct identification of species and genus of nematodes that affect a particular culture is of great importance to form a quantity of information that will be useful to laboratories for diagnosis and control of these pathogens. Because of the increase in the production of ornamental and medicinal plants in the of Cear. á State, the agricultural importance of the genus Meloidogyne and the scarcity of information on the hospitability this pathogen in these species, in that it was to evaluate the susceptibility testing of 30 species, and 20 ornamental (Antirrhimum majus, Gazania ringens, Carthamus tinctorius, Bryophyllum cayicinum, Ceasalpinia pulcherrima, Thumbergia alata, Petunia hibryda, Exacum affine, Catharanthus roseus, Opuntia sp., Sansevieria trifasciata, Asparagus densiflorus, Hibiscus mutabilis-roreus, Impatiens balsamiana, Celosia spicata, Antirrhimum sp., Dianthus chinensis, Zinnia elegans, Tagetes patula, Capsicum annuum and 10 medicinal (Peumus boldus, Ocimum gratissimum, Mentha arvensis var. piperascens, Mentha x Vilosa, Plectranthus amboinicus, Ocimum bassilicum, Rosmarinus officinalis, Cymbopogon citratus, Lippia alba, Cymbopogon winterianus. The test was conducted in a greenhouse, of the Phytosanitary Sector, Department of Plant Science, Federal University of Ceará. The inoculation was conducted with 4,000 eggs/J2 for pot. Evaluation of the plants gave to 60 days after inoculation. Evaluated is the reaction of the plants, measuring up: number of galls and eggs, egg mass index, reproduction factor and reduce the reproduction factor. From these variables it was classified the reaction of plants to the nematode by means of five criterions. Of ownership of the results, it was verified that of the ornamental plants only species T. patula didn’t presented galls in your root system. Concerning medicinal species M. vilosa, C. citrates, L. alba, C. winterianus and P. boldus showed no galls in their root systems. Thus, concluded

  11. The influence of flooding on soil proportion and plant growth. 1. The influence on root development and growth of barley

    International Nuclear Information System (INIS)

    Sisworo, E.L.

    1975-01-01

    An experiment has been carried out to study the extent of root and shoot of barley exposed to flooding at various time of flooding. Several parameters were used in the experiment, namely the percentage of 86 Rb in the root system, dry weight of root as well as shoot, increase of leaf size, number of leaves and tillers and nitrogen content in leaf tissue. Radioactive 86 Rb-Cl was used in the experiment and injected into the plant 24 hours before harvest. The plants were harvested 2, 6, and 20 days after flooding. From the result obtained, it turned out that flooding conditions apparently reduced root development in the lower part of soil layer, while in the top layer a proper development of root was concentrated. Injury symptoms were mainly observed in the shoot; where leaf yellowing occured and started with the first leaf five days after flooding and subsequently reduced the number of leaves and tillers. (author)

  12. Confirmation and quantification of strigolactones, germination stimulants for root parasitic plants Striga and Orobanche, produced by cotton.

    Science.gov (United States)

    Sato, Daisuke; Awad, Ayman A; Takeuchi, Yasutomo; Yoneyama, Koichi

    2005-01-01

    The germination stimulants for root parasitic plants Striga and Orobanche produced by cotton (Gossypium hirsutum L.) were examined in detail. Seeds of cotton were germinated and grown on glass wool wetted with sterile distilled water in sterile filter units. The root exudate was collected daily and extracted with ethyl acetate. Each of these ethyl acetate extracts was analyzed directly by high-performance liquid chromatography linked with tandem mass spectrometry (LC/MS/MS). The results demonstrate that cotton roots exuded strigol and strigyl acetate, but no other known strigolactones such as orobanchol and alectrol. The production of strigol was detected even in the root exudate collected during the first 24 h of incubation and reached a maximum 5-7 days later. The average exudation of strigol and strigyl acetate during the incubation period was ca. 15 and 2 pg/plant/day, respectively, indicating that strigol mainly contributed to germination stimulation by the cotton root exudate.

  13. A maize root tip system to study DNA replication programmes in somatic and endocycling nuclei during plant development.

    Science.gov (United States)

    Bass, Hank W; Wear, Emily E; Lee, Tae-Jin; Hoffman, Gregg G; Gumber, Hardeep K; Allen, George C; Thompson, William F; Hanley-Bowdoin, Linda

    2014-06-01

    The progress of nuclear DNA replication is complex in both time and space, and may reflect several levels of chromatin structure and 3-dimensional organization within the nucleus. To understand the relationship between DNA replication and developmental programmes, it is important to examine replication and nuclear substructure in different developmental contexts including natural cell-cycle progressions in situ. Plant meristems offer an ideal opportunity to analyse such processes in the context of normal growth of an organism. Our current understanding of large-scale chromosomal DNA replication has been limited by the lack of appropriate tools to visualize DNA replication with high resolution at defined points within S phase. In this perspective, we discuss a promising new system that can be used to visualize DNA replication in isolated maize (Zea mays L.) root tip nuclei after in planta pulse labelling with the thymidine analogue, 5-ethynyl-2'-deoxyuridine (EdU). Mixed populations of EdU-labelled nuclei are then separated by flow cytometry into sequential stages of S phase and examined directly using 3-dimensional deconvolution microscopy to characterize spatial patterns of plant DNA replication. Combining spatiotemporal analyses with studies of replication and epigenetic inheritance at the molecular level enables an integrated experimental approach to problems of mitotic inheritance and cellular differentiation. © 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.

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

    Science.gov (United States)

    Picard, Christine; Bosco, Marco

    2008-01-01

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

  15. Co-ordinated growth between aerial and root systems in young apple plants issued from in vitro culture.

    Science.gov (United States)

    Costes, E; García-Villanueva, E; Jourdan, C; Regnard, J L; Guédon, Y

    2006-01-01

    In several species exhibiting a rhythmic aerial growth, the existence of an alternation between root and shoot growth has been demonstrated. The present study aims to investigate the respective involvement of the emergence of new organs and their elongation in relation to this phenomenon and its possible genotypic variation in young apple plants. Two apple varieties, X6407 (recently named 'Ariane') and X3305 ('Chantecler' x 'Baujade'), were compared. Five plants per variety, issued from in vitro culture, were observed in minirhizotrons over 4 months. For each plant, root emergence and growth were observed twice per week. Growth rates were calculated for all roots with more than two segments and the branching density was calculated on primary roots. On the aerial part, the number of leaves, leaf area and total shoot length were observed weekly. No significant difference was observed between varieties in any of the final characteristics of aerial growth. Increase in leaf area and shoot length exhibited a 3-week rhythm in X3305 while a weaker signal was observed in Ariane. The primary root growth rate was homogeneous between the plants and likewise between the varieties, while their branching density differed significantly. Secondary roots emerged rhythmically, with a 3-week and a 2-week rhythm, respectively, in X3305 and 'Ariane'. Despite a high intra-variety variability, significant differences were observed between varieties in the secondary root life span and mean length. A synchronism between leaf emergence and primary root growth was highlighted in both varieties, while an opposition phase was observed between leaf area increments and secondary root emergence in X3305 only. A biological model of dynamics that summarizes the interactions between processes and includes the assumption of a feedback effect of lateral root emergence on leaf emergence is proposed.

  16. Physiological behavior of hydrogen sulfide in rice plant. Part 5. Effect of hydrogen sulfide on respiration of rice roots

    Energy Technology Data Exchange (ETDEWEB)

    Okajima, H; Takagi, S

    1955-01-01

    The inhibitory effects of hydrogen sulfide on the respiration of rice plant roots were investigated using Warburg's manometory technique. Hydrogen sulfide inhibited not only aerobic respiration but anaerobic respiration process of roots. Inhibitory action of hydrogen sulfide and potassium cyanide on the respiration were apparently reversible, but the style of recovery reaction from inhibition was somewhat different in each case. Oxygen consumption of roots was increased by addition of ammonium salts, but the same effects were not recognized by the addition of any other salt examined (except nitrate salts). There was close relationship between respiration of roots and assimilation of nitrogen by roots. The increased oxygen uptake by addition of ammonium salt was also inhibited by hydrogen sulfide. The reactivation of this reaction occurred with the recovery of endogenous respiration of roots. 19 references, 8 figures, 3 tables.

  17. Root inoculation with Pseudomonas putida KT2440 induces transcriptional and metabolic changes and systemic resistance in maize plants

    Directory of Open Access Journals (Sweden)

    Chantal ePlanchamp

    2015-01-01

    Full Text Available Pseudomonas putida KT2440 (KT2440 rhizobacteria colonize a wide range of plants. They have been extensively studied for their capacity to adhere to maize seeds, to tolerate toxic secondary metabolites produced by maize roots and to be attracted by maize roots. However, the response of maize plants to KT2440 colonization has not been investigated yet. Maize roots were inoculated with KT2440 and the local (roots and systemic (leaves early plant responses were investigated. The colonization behavior of KT2440 following application to maize seedlings was investigated and transcriptional analysis of stress- and defense-related genes as well as metabolite profiling of local and systemic maize tissues of KT2440-inoculated were performed. The local and systemic responses differed and more pronounced changes were observed in roots compared to leaves. Early in the interaction roots responded via jasmonic acid- and abscisic acid-dependent signaling. Interestingly, during later steps, the salicylic acid pathway was suppressed. Metabolite profiling revealed the importance of plant phospholipids in KT2440-maize interactions. An additional important maize secondary metabolite, a form of benzoxazinone, was also found to be differently abundant in roots three days after KT2440 inoculation. However, the transcriptional and metabolic changes observed in bacterized plants early during the interaction were minor and became even less pronounced with time, indicating an accommodation state of the plant to the presence of KT2440. Since the maize plants reacted to the presence of KT2440 in the rhizosphere, we also investigated the ability of these bacteria to trigger induced systemic resistance (ISR against the maize anthracnose fungus Colletotrichum graminicola. The observed resistance was expressed as strongly reduced leaf necrosis and fungal development in infected bacterized plants compared to non-bacterized controls, showing the potential of KT2440 to act as

  18. Root exudates and leaf leachates of 19 medicinal plants of pakistan exhibit allelopathic potential

    International Nuclear Information System (INIS)

    Syed, S.; Ahmed, Z.I.; Razzaq, A.

    2014-01-01

    Laboratory experiments were conducted to evaluate the allelopathic potential of root exudates and leaf leachates of 19 medicinal plants commonly used in Pakistan by plant box and sandwich methods, respectively. In sandwich method, lettuce seedlings were grown with the dry leaf leachates of the selected plant species in a growing media at the rate of 5, 10 and 50 mg dish-1 in a completely randomized design with three replications. Their effects on hypocotyl and radicle growth of the lettuce were recorded as a percentage of untreated control. Data was subjected for analysis of variance and treatment means were compared by Tukey's HSD test at p<0.05. Results indicated that allelopathic effects of the leaf leachates of all selected plant species on the hypocotyl and radicle elongations of the lettuce varied significantly in all concentrations used in experiments. The hypocotyl growth of the lettuce seedlings was affected from promotion (6.71% inhibition) caused by Phlaris minor to inhibition (78.40%) by Withania somnifera. Both species suppressed the radicle length from 33.69-93.30%. Leachates of W. somnifera and Sarcococca saligna exhibited strong inhibitory results in a concentration dependant manner. After the growth period of 50 days, root exudates of S. saligna appeared most detrimental (78.00% inhibition) to radicle growth of the lettuce seedling followed by W. somnifera (75.00%) when tested by plant box method. The results presented can be utilized as benchmark information for further joint research on the elucidation of chemicals involved in the allelopathy in nature and in the development of new and potent bioherbicides to combat environmental risk. (author)

  19. Affects N fertilization intensity and composition of root exudation from two plant species differing in their exploitation strategy?

    Science.gov (United States)

    Kotas, Petr; Kastovska, Eva

    2017-04-01

    The rhizosphere represents one of the most important hotspots of microbial activity in soil. As such, it controls soil element cycling and significantly contributes to important ecosystem processes like C and N sequestration. The close plant-microbe-soil interactions in the rhizosphere are mediated by the input of labile exudates into the surroundings of plant roots. Thus microbial performance is constrained by the intensity and composition of root exudation. However, it is poorly understood how closely root exudation corresponds with the plant metabolome and how it is related to plant traits and changing environmental conditions. To fill this gap, we determined the composition of the root metabolic pool and root exudates in two plant species differing in their exploitation type (conservative Carex acuta versus competitive Glyceria maxima) grown for two months in controlled conditions and treated weekly by two levels of foliar N fertilization. Based on previous studies, we knew that Glyceria has, compared to Carex, a lower tissue C:N ratio, higher photosynthetic rate, higher allocation belowground and also larger investment to exudation. Prior to extraction, the roots were cleaned by water and immediately frozen in liquid N2. The root exudates were collected from carefully cleaned roots of living plants encased in glass vials with water and subsequently lyophilised. Both sample types were silylated and analysed for their metabolic profiles using GC-MS/MS. Our results revealed that the metabolite content in root tissue (DW basis) of Glyceria was on average lower compared to Carex, but increased with fertilization, while the root tissue of Carex was characterized by significantly higher metabolite content in the low intensity fertilization treatment compared to both the control and high N fertilization intensity. In contrast, the amount of exuded compounds was much higher in Glyceria compared to Carex in the control plants, but decreased for Glyceria and increased

  20. Infestation of the banana root borer among different banana plant genotypes

    Directory of Open Access Journals (Sweden)

    Fernando Teixeira de Oliveira

    Full Text Available ABSTRACT: In this study, we aimed to investigate Cosmopolites sordidus (Coleoptera: Dryophthoridae infestation among different banana genotypes in a commercial banana orchard over the course of 30 months. Banana root borer infestation was compared in 20 banana genotypes, including five varieties and 15 hybrids. Overall, we observed that 94.17% of pest infestation cases occurred in the cortex region, and only 5.83% occurred in the central cylinder. Genotypes least sensitive to infestation were the Prata Anã (AAB and Pacovan (AAB varieties, where no damage was recorded. Among the hybrid genotypes, PV 9401 and BRS Fhia 18 showed intermediate levels of sensitivity, while BRS Tropical hybrids (AAAB, PA 9401 (AAAB, BRS Vitoria (AAAB, YB 4203 (AAAB, and Bucaneiro (AAAA were the most sensitive to attack by banana root borer. This study demonstrated that the infestation of the banana root borer varies according banana plant genotype, and the utilization of less susceptible genotypes could reduce infestation rates of C. sordidus.

  1. The incidence of Pyrenochaeta terrestris in root of different plant species in Serbia

    Directory of Open Access Journals (Sweden)

    Lević Jelena T.

    2013-01-01

    Full Text Available Root samples of cereals (oats, wheat, barley, maize and sorghum, vegetables (garlic, onion, pepper, cucumber, pumpkin, carrot and tomato, industrial plant (soya bean and weeds (Johnson grass, barnyard grass and green bristle-grass collected in different agroecological conditions in Serbia were analysed for the presence of Pyrenochaeta terrestris. The fungus was found in 42 out of 51 samples (82.4%, while the incidence varied from 2.5 to 72.5%. The highest incidence was detected in cereals (average 30.3%, and then in weeds of the Poaceae family (average 14.2%. Considering single species, maize (up to 72.5% in root and Johnson grass (up to 37.5% were mostly attacked by this fungus. The lowest incidence of the fungus was determined in vegetable crops (average 6.7%. Red to reddish discoloration of root was correlated with the incidence of the fungus. Obtained data indicate that P. terrestris is widespread in Serbia and conditions for its development are favourable. [Projekat Ministarstva nauke Republike Srbije, br. TR-31023

  2. Sodium bicarbonate absorption and anabolism by detatched root of young paddy rice, corn and wheat plants

    International Nuclear Information System (INIS)

    Yamakawa, Takeo; Yamada, Yoshio

    1985-01-01

    This work is aimed at investigating species-to-species difference in the capability of absorption and anabolism through the root and examining the effects of sodium bicarbonate on the capability. Roots detatched from young plants of paddy rice, corn and wheat are used as the samples. The respiratory rate and anabolic rate of the detatched roots are measured by using the 14 C tracer. It is found that paddy rice whows the greatest initial anabolic rate, while the rates of corn and wheat are 14 - 30 % of that of paddy rice. The initial anabolic rate is almost independent of the concentration of sodium bicarbonate. The initial absorption rate is greatest in paddy rice, followed by corn (30 - 78 %) and wheat (16 - 21 %). It is also shown that paddy rice has the greatest capability both in anabolism and absorption. The anabolism and absorption capabilities of corn are 17 - 29 % and 31 - 80 % of those of paddy rice, respectively. The corresponding values of wheat are 16 - 38 % and 24 - 66 %. Sidium bicarbonate has little effect on the anabolism capability, while the absorption capability is affected above a high concentration of 50 mM. (Nogami, K.)

  3. Impact of soil salinity on the plant-growth – promoting and biological control abilities of root associated bacteria

    Directory of Open Access Journals (Sweden)

    Dilfuza Egamberdieva

    2017-11-01

    Full Text Available The effectiveness of plant growth – promoting bacteria is variable under different biotic and abiotic conditions. Abiotic factors may negatively affect the beneficial properties and efficiency of the introduced PGPR inoculants. The aim of this study was to evaluate the effect of plant growth – promoting rhizobacteria on plant growth and on the control of foot and root rot of tomatoes caused by Fusarium solani under different soil salinity conditions. Among the five tested strains, only Pseudomonas chlororaphis TSAU13, and Pseudomonas extremorientalis TSAU20 were able to stimulate plant growth and act as biological controls of foot and root rot disease of tomato. The soil salinity did not negatively affect the beneficial impacts of these strains, as they were able to colonize and survive on the roots of tomato plants under both saline and non-saline soil conditions. The improved plant height and fruit yield of tomato was also observed for plants inoculated with P. extremorientalis TSAU20. Our results indicated that, saline condition is not crucial factor in obtaining good performance with respect to the plant growth stimulating and biocontrol abilities of PGPR strains. The bacterial inoculant also enhanced antioxidant enzymes activities thereby preventing ROS induced oxidative damage in plants, and the proline concentrations in plant tissue that play an important role in plant stress tolerance.

  4. Leaf Senescence, Root Morphology, and Seed Yield of Winter Oilseed Rape (Brassica napus L. at Varying Plant Densities

    Directory of Open Access Journals (Sweden)

    Ming Li

    2017-01-01

    Full Text Available In this study, the yield and yield components were studied using a conventional variety Zhongshuang 11 (ZS 11 and a hybrid variety Zhongyouza 12 (ZYZ 12 at varying plant densities. The increase in plant density led to an initial increase in seed yield and pod numbers per unit area, followed by a decrease. The optimal plant density was 58.5 × 104 plants ha−1 in both ZS 11 and ZYZ 12. The further researches on physiological traits showed a rapid decrease in the green leaf area index (GLAI and chlorophyll content and a remarkable increase in malondialdehyde content in high plant density (HPD population than did the low plant density (LPD population, which indicated the rapid leaf senescence. However, HPD had higher values in terms of pod area index (PAI, pod photosynthesis, and radiation use efficiency (RUE after peak anthesis. A significantly higher level of dry matter accumulation and nitrogen utilization efficiency were observed, which resulted in higher yield. HPD resulted in a rapid decrease in root morphological parameters (root length, root tips, root surface area, and root volume. These results suggested that increasing the plant density within a certain range was a promising option for high seed yield in winter rapeseed in China.

  5. A plant economics spectrum in Mediterranean forests along environmental gradients: is there coordination among leaf, stem and root traits?

    NARCIS (Netherlands)

    Riva, de la E.G.; Tosto, A.; Perez-Ramos, I.M.; Navarro-Fernandez, C.M.; Olmos, M.; Anten, N.P.R.; Maranon, T.; Villar, R.

    2016-01-01

    Questions: Is there any evidence of coordination among leaf, stem and root traits, and thereby of the existence of a plant economics spectrum at the species and community level in Mediterranean forests? Are these traits related to plant size and seedmass? Location: Mediterranean forests and

  6. Plant Hormone Homeostasis, Signaling, and Function during Adventitious Root Formation in Cuttings.

    Science.gov (United States)

    Druege, Uwe; Franken, Philipp; Hajirezaei, Mohammad R

    2016-01-01

    Adventitious root (AR) formation in cuttings is a multiphase developmental process, resulting from wounding at the cutting site and isolation from the resource and signal network of the whole plant. Though, promotive effects of auxins are widely used for clonal plant propagation, the regulation and function of plant hormones and their intricate signaling networks during AR formation in cuttings are poorly understood. In this focused review, we discuss our recent publications on the involvement of polar auxin transport (PAT) and transcriptional regulation of auxin and ethylene action during AR formation in petunia cuttings in a broad context. Integrating new findings on cuttings of other plant species and general models on plant hormone networks, a model on the regulation and function of auxin, ethylene, and jasmonate in AR formation of cuttings is presented. PAT and cutting off from the basipetal auxin drain are considered as initial principles generating early accumulation of IAA in the rooting zone. This is expected to trigger a self-regulatory process of auxin canalization and maximization to responding target cells, there inducing the program of AR formation. Regulation of auxin homeostasis via auxin influx and efflux carriers, GH3 proteins and peroxidases, of flavonoid metabolism, and of auxin signaling via AUX/IAA proteins, TOPLESS, ARFs, and SAUR-like proteins are postulated as key processes determining the different phases of AR formation. NO and H2O2 mediate auxin signaling via the cGMP and MAPK cascades. Transcription factors of the GRAS-, AP2/ERF-, and WOX-families link auxin signaling to cell fate specification. Cyclin-mediated governing of the cell cycle, modifications of sugar metabolism and microtubule and cell wall remodeling are considered as important implementation processes of auxin function. Induced by the initial wounding and other abiotic stress factors, up-regulation of ethylene biosynthesis, and signaling via ERFs and early accumulation of

  7. Plant hormone homeostasis, signaling and function during adventitious root formation in cuttings

    Directory of Open Access Journals (Sweden)

    Uwe eDruege

    2016-03-01

    Full Text Available Adventitious root (AR formation in cuttings is a multiphase developmental process, resulting from wounding at the cutting site and isolation from the resource and signal network of the whole plant. Though promotive effects of auxins are widely used for clonal plant propagation, the regulation and function of plant hormones and their intricate signaling networks during AR formation in cuttings are poorly understood. In this focused review, we discuss our recent publications on the involvement of polar auxin transport (PAT and transcriptional regulation of auxin and ethylene action during AR formation in petunia cuttings in a broad context. Integrating new findings on cuttings of other plant species and general models on plant hormone networks, a model on the regulation and function of auxin, ethylene and jasmonate in AR formation of cuttings is presented. PAT and cutting off from the basipetal auxin drain are considered as initial principles generating early accumulation of IAA in the rooting zone. This is expected to trigger a self-regulatory process of auxin canalization and maximization to responding target cells, there inducing the program of AR formation. Regulation of auxin homeostasis via auxin influx and efflux carriers, GH3 proteins and peroxidases, of flavonoid metabolism and of auxin signaling via AUX/IAA proteins, TOPLESS, ARFs and SAUR-like proteins are postulated as key processes determining the different phases of AR formation. NO and H2O2 mediate auxin signaling via the cGMP and MAPK cascades. Transcription factors of the GRAS-, AP2/ERF- and WOX-families link auxin signaling to cell fate specification. Cyclin-mediated governing of the cell cycle, modifications of sugar metabolism and microtubule and cell wall remodeling are considered as important implementation processes of auxin function. Induced by the initial wounding and other abiotic stress factors, up-regulation of ethylene biosynthesis and signaling via ERFs and early

  8. Root morphology, hydraulic conductivity and plant water relations of high-yielding rice grown under aerobic conditions.

    Science.gov (United States)

    Kato, Yoichiro; Okami, Midori

    2011-09-01

    Increasing physical water scarcity is a major constraint for irrigated rice (Oryza sativa) production. 'Aerobic rice culture' aims to maximize yield per unit water input by growing plants in aerobic soil without flooding or puddling. The objective was to determine (a) the effect of water management on root morphology and hydraulic conductance, and (b) their roles in plant-water relationships and stomatal conductance in aerobic culture. Root system development, stomatal conductance (g(s)) and leaf water potential (Ψ(leaf)) were monitored in a high-yielding rice cultivar ('Takanari') under flooded and aerobic conditions at two soil moisture levels [nearly saturated (> -10 kPa) and mildly dry (> -30 kPa)] over 2 years. In an ancillary pot experiment, whole-plant hydraulic conductivity (soil-leaf hydraulic conductance; K(pa)) was measured under flooded and aerobic conditions. Adventitious root emergence and lateral root proliferation were restricted even under nearly saturated conditions, resulting in a 72-85 % reduction in total root length under aerobic culture conditions. Because of their reduced rooting size, plants grown under aerobic conditions tended to have lower K(pa) than plants grown under flooded conditions. Ψ(leaf) was always significantly lower in aerobic culture than in flooded culture, while g(s) was unchanged when the soil moisture was at around field capacity. g(s) was inevitably reduced when the soil water potential at 20-cm depth reached -20 kPa. Unstable performance of rice in water-saving cultivations is often associated with reduction in Ψ(leaf). Ψ(leaf) may reduce even if K(pa) is not significantly changed, but the lower Ψ(leaf) would certainly occur in case K(pa) reduces as a result of lower water-uptake capacity under aerobic conditions. Rice performance in aerobic culture might be improved through genetic manipulation that promotes lateral root branching and rhizogenesis as well as deep rooting.

  9. Trans-specific gene silencing of acetyl-CoA carboxylase in a root-parasitic plant.

    Science.gov (United States)

    Bandaranayake, Pradeepa C G; Yoder, John I

    2013-05-01

    Parasitic species of the family Orobanchaceae are devastating agricultural pests in many parts of the world. The control of weedy Orobanchaceae spp. is challenging, particularly due to the highly coordinated life cycles of the parasite and host plants. Although host genetic resistance often provides the foundation of plant pathogen management, few genes that confer resistance to root parasites have been identified and incorporated into crop species. Members of the family Orobanchaceae acquire water, nutrients, macromolecules, and oligonucleotides from host plants through haustoria that connect parasite and host plant roots. We are evaluating a resistance strategy based on using interfering RNA (RNAi) that is made in the host but inhibitory in the parasite as a parasite-derived oligonucleotide toxin. Sequences from the cytosolic acetyl-CoA carboxylase (ACCase) gene from Triphysaria versicolor were cloned in hairpin conformation and introduced into Medicago truncatula roots by Agrobacterium rhizogenes transformation. Transgenic roots were recovered for four of five ACCase constructions and infected with T. versicolor against parasitic weeds. In all cases, Triphysaria root viability was reduced up to 80% when parasitizing a host root bearing the hairpin ACCase. Triphysaria root growth was recovered by exogenous application of malonate. Reverse-transcriptase polymerase chain reaction (RT-PCR) showed that ACCase transcript levels were dramatically decreased in Triphysaria spp. parasitizing transgenic Medicago roots. Northern blot analysis identified a 21-nucleotide, ACCase-specific RNA in transgenic M. truncatula and in T. versicolor attached to them. One hairpin ACCase construction was lethal to Medicago spp. unless grown in media supplemented with malonate. Quantitative RT-PCR showed that the Medicago ACCase was inhibited by the Triphysaria ACCase RNAi. This work shows that ACCase is an effective target for inactivation in parasitic plants by trans-specific gene

  10. Antioxidant activity, phenolic and flavonoid content of wild Alhagi maurorum root plant extracts

    Directory of Open Access Journals (Sweden)

    Fuad AL-RIMAWI

    2016-11-01

    Full Text Available Alhagi maurorum, belonging to family Leguminosae, is a highly branched spiny shrub. Roots may reach up to the depth of 15 meters. Alhagi maurorum is used in folk medicine, as a purgative, diaphoretic, expectorant and diuretic used to treat piles, migraine, warts and rheumatism. Samples of the root of Alhagi maurorum plant grown wild in Palestine were extracted with different solvents; water, 80% ethanol, and 100% ethanol. The extracts were analyzed for their total phenolic content (TPC, total flavonoid content (TFC, and antioxidant activity (AA. Four different antioxidant assays were used to evaluate AA of the extracts: two measures the reducing power of the extracts (ferric reducing antioxidant power (FRAP and Cupric reducing antioxidant power (CUPRAC, while two other assays measure the scavenging ability of the extracts (2,2-azino-di-(3-ethylbenzothialozine-sulphonic acid (ABTS, and 2,2-diphenyl-1-picrylhydrazyl (DPPH.The results revealed that the polarity of the extraction solvent affects the TPC, TFC, and AA. It was found that both TPC and AA are highest for plant extracted with 80% ethanol, followed by water, and finally with 100% ethanol. TFC however was highest in the following order: 80% ethanol >100% ethanol >water

  11. Association of plant growth-promoting Serratia spp. with the root nodules of chickpea.

    Science.gov (United States)

    Zaheer, Ahmad; Mirza, Babur S; Mclean, Joan E; Yasmin, Sumera; Shah, Tariq Mahmud; Malik, Kauser A; Mirza, M Sajjad

    2016-01-01

    Serratia species-affiliated DNA sequences have recently been discovered in the root nodules of two chickpea cultivars; however, little is known about their potential influence on chickpea plant growth. All Serratia-affiliated sequences (1136) could be grouped into two clusters at 98% DNA similarity. The major cluster, represented by 96% of sequences, was closely associated with Serratia marcescens sequences from GenBank. In the current study, we isolated two Serratia strains, 5D and RTL100, from root nodules of a field-grown Desi cultivar from Faisalabad and Thal areas, respectively. In vitro, strain 5D showed significantly higher phosphate (P) solubilization and lactic acid production than RTL100, whereas a comparable concentration of phytohormone was produced by both isolates. The application of Serratia strain 5D as an inoculum resulted in 25.55% and 30.85% increases in the grain yield of crops grown on fertile soil in irrigated areas and nutrient-deficient soil in rainfed areas, respectively, compared to the non-inoculated control. Results of plant inoculations indicated that Serratia sp. 5D and RTL100 can serve as effective microbial inoculants, particularly in nutrient-deficient soils in rainfed areas, where chickpea is the only major crop grown during the entire year. Copyright © 2016 Institut Pasteur. All rights reserved.

  12. Transport of plutonium, americium, and curium from soils into plants by roots

    International Nuclear Information System (INIS)

    Pimpl, M.; Schuettelkopf, H.

    1979-12-01

    For assessing the dose from radionuclides in agricultural products by ingestion it is necessary to know the soil to plant transfer factors. The literature was entirely investigated, in order to judge the size of the soil to plant transfer factors. In total, 92 publications - from 1948 to 1978 -have been evaluated. As result, transfer factors from 10 -9 to 10 -3 have been found for Plutonium, and from 10 -6 to 1 for Americium. For Curium only few data are available in literature. The considerable variation of the measured transfer factors is based on the dependence of these transfer factors from the ion exchange capacity of soils, from the amount of organic materials, from the pH-value, and from the mode of contamination. There are, in any case, contradictory data, although there has been detected a dependence of the transfer factors from these parameters. Chelating agenst increase the transfer factors to approximately 1300. As well, fertilizers have an influence on the size of the transfer factors - however, the relationships have been scarcely investigated. The distribution of actinides within the individual parts of plants has been investigated. The highest concentrations are in the roots; in the plant parts above ground the concentration of actinides decreases considerably. The most inferior transfer factors were measured for the respective seed or fruits. The soil to plant transfer factors of actinides are more dependend on the age of the plants within one growing period. At the beginning of the period, the transfer factor is considerably higher than at the end of this period. With respect to plants with a growing period of several years, correlations are unknown. (orig.) [de

  13. Roles of Arbuscular Mycorrhizas in Plant Phosphorus Nutrition: Interactions between Pathways of Phosphorus Uptake in Arbuscular Mycorrhizal Roots Have Important Implications for Understanding and Manipulating Plant Phosphorus Acquisition

    DEFF Research Database (Denmark)

    Smith, S.E.; Jakobsen, Iver; Grønlund, Mette

    2011-01-01

    In this Update, we review new findings about the roles of the arbuscular mycorrhizas (mycorrhiza = fungus plus root) in plant growth and phosphorus (P) nutrition. We focus particularly on the function of arbuscular mycorrhizal (AM) symbioses with different outcomes for plant growth (from positive...

  14. Physiological and Biochemical Responses to Aluminum Stress in the Root of a Biodiesel Plant Jatropha curcas L.

    Directory of Open Access Journals (Sweden)

    RADITE TISTAMA

    2012-03-01

    Full Text Available We investigated J. curcas responses to aluminum stress, histochemically and biochemically. Histochemical stainings were observed to analysis aluminum accumulation, lipid peroxidation and the loss of plasma membrane integrity on the surface and tissue of the root apex. Enzymatic analysis was conducted to measure malate content in leaf, root and malate efflux in the medium. We used M. malabathricum as a comparison for Al-tolerance plant. J. curcas root elongation was inhibited by 0.4 mM AlCl3, while M. malabathricum root elongation was inhibited by 0.8 mM AlCl3 treatment. Inhibition of root elongation has high correlation with Al accumulation in the root apex, which caused lipid degradation and cell death. Generally, malate content in J. curcas leaf and root was higher than that in M. malabathricum. In the contrary malate efflux from the root into the medium was lower. J. curcas root has a different pattern compared to M. malabathricum in malate synthesis and malate secretion when treated with a different Al concentration. We categorized J. curcas acc IP3 as more sensitive to aluminum than M. malabathricum.

  15. Root hydraulic vulnerability regulation of whole-plant conductance along hillslope gradients within subalpine and montane forests

    Science.gov (United States)

    Beverly, D.; Speckman, H. N.; Ewers, B. E.

    2017-12-01

    Ecosystem-scale models often rely on root vulnerability or whole-plant conductance for simulating seasonal evapotranspiration declines via constraints of water uptake and vegetation mortality. Further, many of these ecosystem models rely on single, unvarying, hydraulic parameter estimates for modeling large areas. Ring-porous species have shown seasonal variability in root vulnerability (percent loss of conductivity; PLC) and whole-plant conductance (Kw) but simulations of coniferous forest typically rely on point measurements. This assumption for coniferous forest is not likely true because of seasonal variability caused by phenology and environmental stresses and the potential for cavitation fatigue is not considered. Moreover, many of these dynamics have only been considered for stems even though roots are often the most vulnerable segments of the pathway for conifers. We hypothesized that seasonally dynamic whole-plant conductance along hillslope gradients in coniferous forests are regulated by cavitation fatigue within the roots resulting in seasonal increases in vulnerability. To test the hypothesis, a subalpine mixed forest (3000 m.a.s.l) and montane forest (2550 m.a.s.l.) were monitored between 2015-2017 to quantify PLC and Kw along the hillslope gradients of 300 m and 50 m, respectively. Forest plots were instrumented with 35 Granier-type sapflow sensors. Seasonal sampling campaigns occurred to quantify PLC through centrifuge techniques and Kw through Darcy's law approximations with pre-dawn and diurnal leaf water potentials. Downslope roots exhibit a 33% decrease in maximal conductivity corresponding to the approximately 50% decrease in whole-plant conductance suggesting seasonal soil dry-down limitations within the downslope stands. Upslope stands had no to little change in root vulnerability or decrease in whole-plant conductance as soil water limitations occur immediately following snowmelt, thus limiting hydraulic conductance throughout the growing

  16. The plant natriuretic peptide receptor is a guanylyl cyclase and enables cGMP-dependent signaling

    KAUST Repository

    Turek, Ilona; Gehring, Christoph A

    2016-01-01

    and water balance and responses to biotrophic plant pathogens. Although there is increasing understanding of the complex roles of PNPs in plant responses at the systems level, little is known about the underlying signaling mechanisms. Here we report

  17. Fungi colonizing the soil and roots of tomato (Lycopersicum esculentum Mill. plants treated with biological control agents

    Directory of Open Access Journals (Sweden)

    Bożena Cwalina-Ambroziak

    2012-12-01

    Full Text Available Tomato plants, cv. Rumba Ożarowska, grown in the greenhouse of the University of Warmia and Mazury, were protected in the form of alternate spraying (twice and watering (twice with 5% aqueous extracts of the following plant species: Aloe vulgaris Lam., Achillea millefolium L., Mentha piperita L., Polygonum aviculare L., Equisetum arvense L., Juglans regia L. and Urtica dioica L. Plants not treated with the extracts served as control. After fruit harvest, samples of roots and soil were collected. The roots were disinfected and next placed on PDA medium. Soil-colonizing fungi were cultured on Martin medium. Fungi were identified microscopically after incubation. Pathogenic fungal species, Colletotrichum coccodes, Fusarium equiseti, F. oxysporum and F. poae, accounted for over 60% of all isolates obtained from the roots of tomato plants. The soil fungal community was dominated by yeast-like fungi (75.4%, whereas pathogenic fungi were present in low numbers. The applied 5% aqueous plant extracts effectively reduced the abundance of fungi, including pathogenic species, colonizing tomato plants and soil. The extract from P. aviculare showed the highest efficacy, while the extract from J. regia was least effective. Fungi showing antagonistic activity against pathogens (Paecilomyces roseum and species of the genus Trichoderma were isolated in greatest abundance from the soil and the roots of tomato plants treated with A. millefolium, M. piperita and U. dioica extracts.

  18. Influence of plant genotype on the cultivable fungi associated to tomato rhizosphere and roots in different soils.

    Science.gov (United States)

    Poli, Anna; Lazzari, Alexandra; Prigione, Valeria; Voyron, Samuele; Spadaro, Davide; Varese, Giovanna Cristina

    2016-01-01

    Rhizosphere and root-associated microbiota are crucial in determining plant health and in increasing productivity of agricultural crops. To date, research has mainly focused on the bacterial dimension of the microbiota. However, interest in the mycobiota is increasing, since fungi play a key role in soil ecosystems. We examined the effect of plant genotype, soil, and of Fusarium oxysporum f. sp. lycopersici (Fol) on the cultivable component of rhizosphere and root-associated mycobiota of tomato. Resistant and susceptible varieties were cultivated on two different soils (A and B), under glasshouse conditions. Isolated fungi were identified by morphological and molecular approaches. Differences were found between the rhizosphere and the roots, which in general displayed a lower number of species. The structure of the mycobiota was significantly affected by the soil type in the rhizosphere as well as by the plant genotype within the roots (NPERMANOVA, p fungi. Overall, the results indicated that i) soil type and plant genotype affect the fungal communities; ii) plant roots select few species from the rhizosphere; and iii) the fungal community structure is influenced by Fol. Copyright © 2016 British Mycological Society. Published by Elsevier Ltd. All rights reserved.

  19. Water Status Related Root-to-Shoot Communication Regulates the Chilling Tolerance of Shoot in Cucumber (Cucumis sativus L.) Plants.

    Science.gov (United States)

    Zhang, Zi-Shan; Liu, Mei-Jun; Gao, Hui-Yuan; Jin, Li-Qiao; Li, Yu-Ting; Li, Qing-Ming; Ai, Xi-Zhen

    2015-10-16

    Although root-to-shoot communication has been intensively investigated in plants under drought, few studies have examined root-to-shoot communication under chilling. Here we explored whether root-to-shoot communication contributes to the chilling-light tolerance of cucumber shoots and clarified the key signal involves in this communication. After leaf discs chilling-light treatment, the photoinhibitions of Photosystem I (PSI) and Photosystem II (PSII) were similar in leaf discs of two cucumber varieties (JY-3 and JC-4). When the whole plants, including roots, were chilled under light, the photosynthetic performances in JC-4 leaves decreased more seriously than that in JY-3 leaves. However, when the water status of leaves was maintained by warming roots or floating the attached leaves on water, the PSII activity and amount of PSI in the leaves of the two varieties were similar after chilling-light treatment. In addition, the differences of PSII activities and amount of PSI between the two varieties under whole plant chilling-light treatment were independent of ABA pretreatment. Above results indicate that (1) the better water status in leaves under chilling contributes to the higher chilling tolerance of JY-3; (2) the water status, rather than an ABA signal, dominates root-to-shoot communication under chilling and the chilling tolerance of cucumber shoot.

  20. Nitrogen-15 uptake by whole plants and root callus cultures of inbred maize lines and their F1 hybrids

    International Nuclear Information System (INIS)

    Mladenova, Y.; Karadimova, M.

    1981-01-01

    The uptake of nitrogen-15 by 3 maize genotypes was investigated. Comparative analysis of N15 assimilation and distribution in the organs of intact plants of two self-pollinated lines and their F1 hybrid and also in a callus tissue of roots of the same genotypes was made. From the results the conclusion is drawn that the N-use efficiency of the female line is higher than that of the male line both in intact plants and callus tissues from roots. This fact indicates that the N-use efficiency is determined not only by the functions of the cells in the shoots, suggesting the participation of the photosynthetic carboxylases but also by the functions of cells without a photosynthesizing apparatus. The N-use efficiency in the F1 hybrid manifests ''heterosis'', in spite of the intact plants or root callus tissues are being studied. (author)

  1. Genes of the most conserved WOX clade in plants affect root and flower development in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Moreau Hervé

    2008-10-01

    Full Text Available Abstract Background The Wuschel related homeobox (WOX family proteins are key regulators implicated in the determination of cell fate in plants by preventing cell differentiation. A recent WOX phylogeny, based on WOX homeodomains, showed that all of the Physcomitrella patens and Selaginella moellendorffii WOX proteins clustered into a single orthologous group. We hypothesized that members of this group might preferentially share a significant part of their function in phylogenetically distant organisms. Hence, we first validated the limits of the WOX13 orthologous group (WOX13 OG using the occurrence of other clade specific signatures and conserved intron insertion sites. Secondly, a functional analysis using expression data and mutants was undertaken. Results The WOX13 OG contained the most conserved plant WOX proteins including the only WOX detected in the highly proliferating basal unicellular and photosynthetic organism Ostreococcus tauri. A large expansion of the WOX family was observed after the separation of mosses from other land plants and before monocots and dicots have arisen. In Arabidopsis thaliana, AtWOX13 was dynamically expressed during primary and lateral root initiation and development, in gynoecium and during embryo development. AtWOX13 appeared to affect the floral transition. An intriguing clade, represented by the functional AtWOX14 gene inside the WOX13 OG, was only found in the Brassicaceae. Compared to AtWOX13, the gene expression profile of AtWOX14 was restricted to the early stages of lateral root formation and specific to developing anthers. A mutational insertion upstream of the AtWOX14 homeodomain sequence led to abnormal root development, a delay in the floral transition and premature anther differentiation. Conclusion Our data provide evidence in favor of the WOX13 OG as the clade containing the most conserved WOX genes and established a functional link to organ initiation and development in Arabidopsis, most

  2. Comparative effects of partial root-zone irrigation and deficit irrigation on phosphorus uptake in tomato plants

    DEFF Research Database (Denmark)

    Wang, Yaosheng; Liu, Fulai; Jensen, Christian Richardt

    2012-01-01

    The comparative effects of partial root-zone irrigation (PRI) and deficit irrigation (DI) on phosphorus (P) uptake in tomato (Lycopersicon esculentum Mill.) plants were investigated in a split-root pot experiment. The results showed that PRI treatment improved water-use efficiency (WUE) compared...... to the DI treatment. PRI-treated plants accumulated significantly higher amounts of P in their shoots than DI plants under organic maize straw N fertilisation, whereas similar levels of shoot P accumulation were observed under mineral N fertilisation. Thus, the form of N fertiliser, and thereby...... the different plant N status, affected the accumulation of P in shoots, as reflected by a higher plant N:P ratio following mineral N fertilisation than after organic N fertilisation. Compared to the DI treatment, PRI significantly increased both the physiological and agronomic efficiencies of P-use under...

  3. Plant density-dependent variations in bioactive markers and root yield in Australian-grown Salvia miltiorrhiza Bunge.

    Science.gov (United States)

    Li, Chun Guang; Sheng, Shu Jun; Pang, Edwin C K; May, Brian; Xue, Charlie Chang Li

    2011-04-01

    The plant density-dependent variations in the root yield and content, and the yield of biomarkers in Australian grown Salvia miltiorrhiza Bunge, a commonly used Chinese medicinal herb for the treatment of cardiovascular diseases, were investigated in a field trial involving six different plant densities. The key biomarker compounds cryptotanshinone, tanshinone I, tanshinone IIA, and salvianolic acid B were quantified by a validated RP-HPLC method, and the root yields were determined per plant pair or unit area. There were significant variations (pplant densities. Positive linear correlations were observed between the contents of the three tanshinones, whereas negative linear correlations were revealed between the contents of the tanshinones and salvianolic acid B. The highest root yield per plant pair was achieved when the plants were grown at 45×30 cm or 45×40 cm, whereas the highest root production par unit area was obtained for a plant density of 30×30 cm. The highest contents of the three tanshinones and the most abundant production of these tanshinones per unit area were achieved when the plants were grown at 30×30 cm. However, the highest content of salvianolic acid B was found for a density of 45×40 cm, while its highest yield per unit area was obtained for densities of 30×40 cm or 45×30 cm. The findings suggest that the plant density distinctly affects the root yield and content and the yield of tanshinones and salvianolic acid B in Australian grown S. miltiorrhiza, which may be used as a guide for developing optimal agricultural procedures for cultivating this herb. Copyright © 2011 Verlag Helvetica Chimica Acta AG, Zürich.

  4. Root causes and impacts of severe accidents at large nuclear power plants.

    Science.gov (United States)

    Högberg, Lars

    2013-04-01

    The root causes and impacts of three severe accidents at large civilian nuclear power plants are reviewed: the Three Mile Island accident in 1979, the Chernobyl accident in 1986, and the Fukushima Daiichi accident in 2011. Impacts include health effects, evacuation of contaminated areas as well as cost estimates and impacts on energy policies and nuclear safety work in various countries. It is concluded that essential objectives for reactor safety work must be: (1) to prevent accidents from developing into severe core damage, even if they are initiated by very unlikely natural or man-made events, and, recognizing that accidents with severe core damage may nevertheless occur; (2) to prevent large-scale and long-lived ground contamination by limiting releases of radioactive nuclides such as cesium to less than about 100 TBq. To achieve these objectives the importance of maintaining high global standards of safety management and safety culture cannot be emphasized enough. All three severe accidents discussed in this paper had their root causes in system deficiencies indicative of poor safety management and poor safety culture in both the nuclear industry and government authorities.

  5. Plant-microbe rhizosphere interactions mediated by Rehmannia glutinosa root exudates under consecutive monoculture

    Science.gov (United States)

    Wu, Linkun; Wang, Juanying; Huang, Weimin; Wu, Hongmiao; Chen, Jun; Yang, Yanqiu; Zhang, Zhongyi; Lin, Wenxiong

    2015-10-01

    Under consecutive monoculture, the biomass and quality of Rehmannia glutinosa declines significantly. Consecutive monoculture of R. glutinosa in a four-year field trial led to significant growth inhibition. Most phenolic acids in root exudates had cumulative effects over time under sterile conditions, but these effects were not observed in the rhizosphere under monoculture conditions. It suggested soil microbes might be involved in the degradation and conversion of phenolic acids from the monocultured plants. T-RFLP and qPCR analysis demonstrated differences in both soil bacterial and fungal communities during monoculture. Prolonged monoculture significantly increased levels of Fusarium oxysporum, but decreased levels of Pseudomonas spp. Abundance of beneficial Pseudomonas spp. with antagonistic activity against F. oxysporum was lower in extended monoculture soils. Phenolic acid mixture at a ratio similar to that found in the rhizosphere could promote mycelial growth, sporulation, and toxin (3-Acetyldeoxynivalenol, 15-O-Acetyl-4-deoxynivalenol) production of pathogenic F. oxysporum while inhibiting growth of the beneficial Pseudomonas sp. W12. This study demonstrates that extended monoculture can alter the microbial community of the rhizosphere, leading to relatively fewer beneficial microorganisms and relatively more pathogenic and toxin-producing microorganisms, which is mediated by the root exudates.

  6. Root Causes and Impacts of Severe Accidents at Large Nuclear Power Plants

    International Nuclear Information System (INIS)

    Hoegberg, Lars

    2013-01-01

    The root causes and impacts of three severe accidents at large civilian nuclear power plants are reviewed: the Three Mile Island accident in 1979, the Chernobyl accident in 1986, and the Fukushima Daiichi accident in 2011. Impacts include health effects, evacuation of contaminated areas as well as cost estimates and impacts on energy policies and nuclear safety work in various countries. It is concluded that essential objectives for reactor safety work must be: (1) to prevent accidents from developing into severe core damage, even if they are initiated by very unlikely natural or man-made events, and, recognizing that accidents with severe core damage may nevertheless occur; (2) to prevent large-scale and long lived ground contamination by limiting releases of radioactive nuclides such as cesium to less than about 100 TBq. To achieve these objectives the importance of maintaining high global standards of safety management and safety culture cannot be emphasized enough. All three severe accidents discussed in this paper had their root causes in system deficiencies indicative of poor safety management and poor safety culture in both the nuclear industry and government authorities

  7. Root Causes and Impacts of Severe Accidents at Large Nuclear Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    Hoegberg, Lars

    2013-04-15

    The root causes and impacts of three severe accidents at large civilian nuclear power plants are reviewed: the Three Mile Island accident in 1979, the Chernobyl accident in 1986, and the Fukushima Daiichi accident in 2011. Impacts include health effects, evacuation of contaminated areas as well as cost estimates and impacts on energy policies and nuclear safety work in various countries. It is concluded that essential objectives for reactor safety work must be: (1) to prevent accidents from developing into severe core damage, even if they are initiated by very unlikely natural or man-made events, and, recognizing that accidents with severe core damage may nevertheless occur; (2) to prevent large-scale and long lived ground contamination by limiting releases of radioactive nuclides such as cesium to less than about 100 TBq. To achieve these objectives the importance of maintaining high global standards of safety management and safety culture cannot be emphasized enough. All three severe accidents discussed in this paper had their root causes in system deficiencies indicative of poor safety management and poor safety culture in both the nuclear industry and government authorities.

  8. A preliminary evaluation of some soil and plant parameters that influence root uptake of arsenic, cadmium, cooper, and zinc

    International Nuclear Information System (INIS)

    Hattemer-Frey, H.A.; Krieger, G.R.; Lau, V.

    1994-01-01

    In the absence of site-specific data, the concentration of metals in plants is typically estimated by multiplying the total concentration of metal in soil by a metal-specific soil-to-root bioconcentration factor (BCF). However, this approach does not account for various soil properties, such as pH, organic matter content, and cation exchange capacity, that are known to influence root uptake of some metals. For risk assessment purposes, a simple, predictive method for estimating root uptake of metals that is based on site-specific soil and crop data is needed so that the importance of the produce ingestion pathway and subsequent influence on human exposure can be quantitatively assessed. An easy-to-use method is necessary since collecting site-specific data on the concentration of metals in home-grown produce is often time-consuming and costly. Ideally, it should be possible to develop a statistically-reliable relationship between plant and soil metals levels that includes appropriate weighing factors for various soil properties. Multiple linear regression analyses were used to develop simple, predictive models for estimating the concentration of metals in plants via root uptake using site-specific soil data. This paper presents preliminary predictive equations for estimating root uptake of arsenic, cadmium, copper, and zinc in fruiting, root, and all vegetables combined (i.e., fruiting and root crop data were combined). Results show that by using data on additional soil parameters (other than relying solely on the concentration of metals in soil), the concentration of metals in fruiting and root vegetables can be more confidently predicted

  9. Growth of bean and tomato plants as affected by root absorbed growth substances and atmospheric carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Tognoni, F; Halevy, A H; Wittwer, S H

    1967-01-01

    Bean and tomato plants were grown in solution culture root media containing pre-determined concentrations of gibberellin A/sub 3/ (GA), 1-naphthalene-acetic acid (NAA), N/sup 6/-benzyladenine (BA), (2-chloroethyl)trimethylammonium chloride (CCC), and at atmospheric levels of 300 and 1000 ppm of CO/sub 2/. Net assimilation rates (NAR), relative growth rates (RGR), leaf area ratios (LAR), root to top dry weight ratios (R/T) and changes in dry weight, size, and form of each organ were recorded. Gibberellin had no effect on RGR of either plant species but increased the NAR of tomatoes at 1000 ppm CO/sub 2/. Total dry weight was only slightly affected by GA but root growth and R/T were markedly depressed. CCC had no effect on NAR, but decreased RGR and LAR. Root growth of beans and R/T in both plants were promoted by CCC. NAR and RGR were strongly inhibited by BA and NAA. Inhibition of stem and leaf growth by CCC and NAA was greater than that for roots; thus, R/T ratios were increased. Root branching was promoted by NAA. High (1000 ppm), compared to the low (300 ppm), atmospheric levels of CO/sub 2/ generally promoted root growth and produced an increase in the R/T, both in the absence and presence of chemical treatment. The multiplicity of effects of the root-absorbed chemical growth substances and CO/sub 2/ on growth and photosynthesis is discussed.

  10. The iPlant collaborative: cyberinfrastructure for enabling data to discovery for the life sciences

    Science.gov (United States)

    The iPlant Collaborative provides life science research communities access to comprehensive, scalable, and cohesive computational infrastructure for data management; identify management; collaboration tools; and cloud, high-performance, high-throughput computing. iPlant provides training, learning m...

  11. Proteogenomics data for deciphering Frankia coriariae interactions with root exudates from three host plants

    Directory of Open Access Journals (Sweden)

    Guylaine Miotello

    2017-10-01

    Full Text Available Frankia coriariae BMG5.1 cells were incubated with root exudates derived from compatible (Coriaria myrtifolia, incompatible (Alnus glutinosa and non-actinorhizal (Cucumis melo host plants. Bacteria cells and their exoproteomes were analyzed by high-throughput proteomics using a Q-Exactive HF high resolution tandem mass spectrometer incorporating an ultra-high-field orbitrap analyzer. MS/MS spectra were assigned with two protein sequence databases derived from the closely-related genomes from strains BMG5.1 andDg1, the Frankia symbiont of Datisca glomerata. The tandem mass spectrometry data accompanying the manuscript describing the database searches and comparative analysis (Ktari et al., 2017, doi.org/10.3389/fmicb.2017.00720 [1] have been deposited to the ProteomeXchange with identifiers PXD005979 (whole cell proteomes and PXD005980 (exoproteome data.

  12. Assimilation of 15N-labelled urea nitrogen and ammonium nitrate nitrogen by plants in case of root and non-root fertilization

    International Nuclear Information System (INIS)

    Muravin, Eh.A.; Kozhemyachko, V.A.; Vernichenko, I.V.

    1974-01-01

    Assimilation of 15 N labeled urea and ammonium nitrate in root and foliar application by spring wheat and barley has been studied during 1970-1973 period in a series of vegetative experiments at the Department of Agrochemistry, Timiryazev Agricultural Academy, and at D.N. Pryanishnikov Experimental Agrochemical Station. Additional fertilizer nitrogen applied at later ontogenesis stages (flowering and milky ripeness) is utilized mostly for protein synthesis in developing grains, thus leading to a significant increase in the relative grain protein content. A transfer of a part of nitrogen from the main ortion of fertilizer at later stages of nitrition results, at the same time, in a lower yield. Nitrogen utilization degree of urea and ammonium nitrate, when introduced before sowing or at the flowering stage is similar but in the latter case, however, additional assimilation of soil nitrogen is lower. The assimilation rate of nitrogen in root application is the lower the later the fertilizer is applied. When ammonium nitrate is additionally applied as nutrition to barley at the milky ripeness stage, ammonia and nitrate nitrogen are assimilated at the same rate and to the same extent but ammonia nitrogen is more rapidly used for protein synthesis and the rate of its transfer to the developing grains is higher. The rate of nitrogen assimilation at plant is much higher in foliar than in root application. Wheat utilizes more urea nitrogen at the flowering stage when root application is used but at the milky ripeness stage foliar application is more effective

  13. Assimilation of /sup 15/N-labelled urea nitrogen and ammonium nitrate nitrogen by plants in case of root and non-root fertilization

    Energy Technology Data Exchange (ETDEWEB)

    Muravin, E A; Kozhemyachko, V A; Vernichenko, I V

    1974-01-01

    Assimilation of /sup 15/N labeled urea and ammonium nitrate in root and foliar application by spring wheat and barley has been studied during 1970-1973 period in a series of vegetative experiments at the Department of Agrochemistry, Timiryazev Agricultural Academy, and at D.N. Pryanishnikov Experimental Agrochemical Station. Additional fertilizer nitrogen applied at later ontogenesis stages (flowering and milky ripeness) is utilized mostly for protein synthesis in developing grains, thus leading to a significant increase in the relative grain protein content. A transfer of a part of nitrogen from the main portion of fertilizer at later stages of nitrition results, at the same time, in a lower yield. Nitrogen utilization degree of urea and ammonium nitrate, when introduced before sowing or at the flowering stage is similar but in the latter case, however, additional assimilation of soil nitrogen is lower. The assimilation rate of nitrogen in root application is the lower the later the fertilizer is applied. When ammonium nitrate is additionally applied as nutrition to barley at the milky ripeness stage, ammonia and nitrate nitrogen are assimilated at the same rate and to the same extent but ammonia nitrogen is more rapidly used for protein synthesis and the rate of its transfer to the developing grains is higher. The rate of nitrogen assimilation at plant is much higher in foliar than in root application. Wheat utilizes more urea nitrogen at the flowering stage when root application is used but at the milky ripeness stage foliar application is more effective.

  14. Seed priming with extracts of Acacia nilotica (L.) Willd. ex Delile and Sapindus mukorossi (L.) plant parts in the control of root rot fungi and growth of plants

    International Nuclear Information System (INIS)

    Rafi, H.; Dawar, S.; Zaki, M.J.

    2015-01-01

    Seed priming with plant extracts and chemicals has been used as an important growth enhancement tool in crop plants. In this research, an attempt was made to understand the mechanism of various seed priming treatments on greenhouse-grown okra (Abelmoschus esculentus (L.) Moench.), sunflower (Helianthus annuus L.), peanut (Arachis hypogaea L.) and chickpea (Cicer arietinum L.) for the control of root infecting fungi like Rhizoctonia solani (Kn), Fusarium spp. and Macrophomina phaseolina (Tassi) Goid by plant parts extracts (stem, leaves and seeds) of Acacia nilotica (L.) Willd. ex Delile and Sapindus mukorossi (L) at different time intervals (5, 10, 20, 40 minutes). Results showed significant suppression of root rot fungi and significantly enhanced the growth parameters like shoot length, root length, shoot weight and root weight. Seed-priming with A. nilotica and S. mukorossi leaves extract for 10 minutes time interval was found to be effective for the control of root rot fungi and growth of all tested leguminous and non-leguminous plants. (author)

  15. Plants influence on arsenic availability and speciation in the rhizosphere, roots and shoots of three different vegetables

    International Nuclear Information System (INIS)

    Bergqvist, Claes; Herbert, Roger; Persson, Ingmar; Greger, Maria

    2014-01-01

    The toxicity of arsenic (As) in the environment is controlled by its concentration, availability and speciation. The aims of the study were to evaluate the accumulation and speciation of As in carrot, lettuce and spinach cultivated in soils with various As concentrations and to estimate the concomitant health risks associated with the consumption of the vegetables. Arsenic concentration and speciation in plant tissues and soils was analysed by HPLC, AAS and XANES spectroscopy. To estimate the plants influence in the rhizosphere, organic acids in lettuce root exudates were analysed by ion chromatography. The results showed that the As accumulation was higher in plants cultivated in soil with higher As extractability. Arsenate predominated in the soils, rhizosphere and root exudates of lettuce. Succinic acid was the major organic acid in lettuce root exudates. Ingestion of the tested vegetables may result in an intake of elevated levels of inorganic As. -- Highlights: • In soils with higher arsenic extractability, accumulation in plants was higher. • Arsenate predominated in the soils, rhizosphere and root exudates of lettuce. • Arsenite predominated in the shoots of healthy looking vegetables. -- Regardless of the initial level of extractable As in the soil, the plants almost doubled the extractable As in the rhizosphere soil

  16. Synchronous high-resolution phenotyping of leaf and root growth in Nicotiana tabacum over 24-h periods with GROWMAP-plant

    Directory of Open Access Journals (Sweden)

    Ruts Tom

    2013-01-01

    Full Text Available Abstract Background Root growth is highly responsive to temporal changes in the environment. On the contrary, diel (24 h leaf expansion in dicot plants is governed by endogenous control and therefore its temporal pattern does not strictly follow diel changes in the environment. Nevertheless, root and shoot are connected with each other through resource partitioning and changing environments for one organ could affect growth of the other organ, and hence overall plant growth. Results We developed a new technique, GROWMAP-plant, to monitor growth processes synchronously in leaf and root of the same plant with a high resolution over the diel period. This allowed us to quantify treatment effects on the growth rates of the treated and non-treated organ and the possible interaction between them. We subjected the root system of Nicotiana tabacum seedlings to three different conditions: constant darkness at 22°C (control, constant darkness at 10°C (root cooling, and 12 h/12 h light–dark cycles at 22°C (root illumination. In all treatments the shoot was kept under the same 12 h/12 h light–dark cycles at 22°C. Root growth rates were found to be constant when the root-zone environment was kept constant, although the root cooling treatment significantly reduced root growth. Root velocity was decreased after light-on and light-off events of the root illumination treatment, resulting in diel root growth rhythmicity. Despite these changes in root growth, leaf growth was not affected substantially by the root-zone treatments, persistently showing up to three times higher nocturnal growth than diurnal growth. Conclusion GROWMAP-plant allows detailed synchronous growth phenotyping of leaf and root in the same plant. Root growth was very responsive to the root cooling and root illumination, while these treatments altered neither relative growth rate nor diel growth pattern in the seedling leaf. Our results that were obtained simultaneously in growing

  17. Monitoring plant water status and rooting depth for precision irrigation in the vineyards of Classic Karst

    Science.gov (United States)

    Savi, Tadeja; Moretti, Elisa; Dal Borgo, Anna; Petruzzellis, Francesco; Stenni, Barbara; Bertoncin, Paolo; Dreossi, Giuliano; Zini, Luca; Martellos, Stefano; Nardini, Andrea

    2017-04-01

    The extreme summer drought and heat waves that occurred in South-Europe in 2003 and 2012 have led to the loss of more than 50% of winery production in the Classic Karst (NE Italy). The irrigation of vineyards in this area is not appropriately developed and, when used, it does not consider the actual water status and needs of plants, posing risks of inappropriate or useless usage of large water volumes. The predicted future increase in frequency and severity of extreme climate events poses at serious risk the local agriculture based on wine business. We monitored seasonal trends of pre-dawn (Ψpd) and minimum (Ψmin) leaf water potential, and stomatal conductance (gL) of 'Malvasia' grapevine in one mature (MV, both in 2015 and 2016) and one young vineyard (YV, in 2016). Moreover, we extracted xylem sap form plant stems and soil water from samples collected in nearby caves, by cryo-vacuum distillation. We also collected precipitation and irrigation water in different months. Oxygen isotope composition (δ18O) of atmospheric, plant, soil and irrigation water was analyzed to get information about rooting depth. In 2015, at the peak of summer aridity, two irrigation treatments were applied according to traditional management practices. The treatments were performed in a sub-area of the MV, followed by physiological analysis and yield measurements at grape harvest. In 2016, the soil water potential (Ψsoil) at 50 cm depth was also monitored throughout the season. Under harsh environmental conditions the apparently deep root system ensured relatively favorable plant water status in both MV and YV and during both growing seasons. The Ψsoil at 50 cm depth gradually decreased as drought progressed, reaching a minimum value of about -1.7 MPa, far more negative than Ψpd recorded in plants (about -0.5 MPa). In July, significant stomatal closure was observed, but Ψmin never surpassed the critical threshold of -1.3 MPa, indicating that irrigation was not needed. The xylem sap

  18. Phosphorus acquisition by citrate- and phytase-exuding Nicotiana tabacum plant mixtures depends on soil phosphorus availability and root intermingling.

    Science.gov (United States)

    Giles, Courtney D; Richardson, Alan E; Cade-Menun, Barbara J; Mezeli, Malika M; Brown, Lawrie K; Menezes-Blackburn, Daniel; Darch, Tegan; Blackwell, Martin Sa; Shand, Charles A; Stutter, Marc I; Wendler, Renate; Cooper, Patricia; Lumsdon, David G; Wearing, Catherine; Zhang, Hao; Haygarth, Philip M; George, Timothy S

    2018-03-02

    Citrate and phytase root exudates contribute to improved phosphorus (P) acquisition efficiency in Nicotiana tabacum (tobacco) when both exudates are produced in a P deficient soil. To test the importance of root intermingling in the interaction of citrate and phytase exudates, Nicotiana tabacum plant-lines with constitutive expression of heterologous citrate (Cit) or fungal phytase (Phy) exudation traits were grown under two root treatments (roots separated or intermingled) and in two soils with contrasting soil P availability. Complementarity of plant mixtures varying in citrate efflux rate and mobility of the expressed phytase in soil was determined based on plant biomass and P accumulation. Soil P composition was evaluated using solution 31 P NMR spectroscopy. In the soil with limited available P, positive complementarity occurred in Cit+Phy mixtures with roots intermingled. Root separation eliminated positive interactions in mixtures expressing the less mobile phytase (Aspergillus niger PhyA) whereas positive complementarity persisted in mixtures that expressed the more mobile phytase (Peniophora lycii PhyA). Soils from Cit+Phy mixtures contained less inorganic P and more organic P compared to monocultures. Exudate-specific strategies for the acquisition of soil P were most effective in P-limited soil and depended on citrate efflux rate and the relative mobility of the expressed phytase in soil. Plant growth and soil P utilization in plant systems with complementary exudation strategies are expected to be greatest where exudates persist in soil and are expressed synchronously in space and time. This article is protected by copyright. All rights reserved.

  19. The iPlant Collaborative: Cyberinfrastructure for Enabling Data to Discovery for the Life Sciences.

    Science.gov (United States)

    Merchant, Nirav; Lyons, Eric; Goff, Stephen; Vaughn, Matthew; Ware, Doreen; Micklos, David; Antin, Parker

    2016-01-01

    The iPlant Collaborative provides life science research communities access to comprehensive, scalable, and cohesive computational infrastructure for data management; identity management; collaboration tools; and cloud, high-performance, high-throughput computing. iPlant provides training, learning material, and best practice resources to help all researchers make the best use of their data, expand their computational skill set, and effectively manage their data and computation when working as distributed teams. iPlant's platform permits researchers to easily deposit and share their data and deploy new computational tools and analysis workflows, allowing the broader community to easily use and reuse those data and computational analyses.

  20. The iPlant Collaborative: Cyberinfrastructure for Enabling Data to Discovery for the Life Sciences.

    Directory of Open Access Journals (Sweden)

    Nirav Merchant

    2016-01-01

    Full Text Available The iPlant Collaborative provides life science research communities access to comprehensive, scalable, and cohesive computational infrastructure for data management; identity management; collaboration tools; and cloud, high-performance, high-throughput computing. iPlant provides training, learning material, and best practice resources to help all researchers make the best use of their data, expand their computational skill set, and effectively manage their data and computation when working as distributed teams. iPlant's platform permits researchers to easily deposit and share their data and deploy new computational tools and analysis workflows, allowing the broader community to easily use and reuse those data and computational analyses.

  1. Extracellular peptidase hunting for improvement of protein production in plant cells and roots

    Directory of Open Access Journals (Sweden)

    Jérôme eLallemand

    2015-02-01

    Full Text Available Plant-based recombinant protein production systems have gained an extensive interest over the past few years, because of their reduced cost and relative safety. Although the first products are now reaching the market, progress are still needed to improve plant hosts and strategies for biopharming. Targeting recombinant proteins toward the extracellular space offers several advantages in terms of protein folding and purification, but degradation events are observed, due to endogenous peptidases. This paper focuses on the analysis of extracellular proteolytic activities in two production systems: cell cultures and root-secretion (rhizosecretion, in Arabidopsis thaliana and Nicotiana tabacum. Proteolytic activities of extracellular proteomes (secretomes were evaluated in vitro against two substrate proteins: bovine serum albumin (BSA and human serum immunoglobulins G (hIgGs. Both targets were found to be degraded by the secretomes, BSA being more prone to proteolysis than hIgGs. The analysis of the proteolysis pH-dependence showed that target degradation was mainly dependent upon the production system: rhizosecretomes contained more peptidase activity than extracellular medium of cell suspensions, whereas variations due to plant species were smaller. Using class-specific peptidase inhibitors, serine and metallopeptidases were found to be responsible for degradation of both substrates. An in-depth in silico analysis of genomic and transcriptomic data from Arabidopsis was then performed and led to the identification of a limited number of serine and metallo-peptidases that are consistently expressed in both production systems. These peptidases should be prime candidates for further improvement of plant hosts by targeted silencing.

  2. Mechanisms behind pH changes by plant roots and shoots caused by elevated concentration of toxic elements

    OpenAIRE

    Javed, Muhammad Tariq

    2011-01-01

    Toxic elements are present in polluted water from mines, industrial outlets, storm water etc. Wetland plants take up toxic elements and increase the pH of the medium. In this thesis was investigated how the shoots of submerged plants and roots of emergent plants affected the pH of the surrounding water in the presence of free toxic ions. The aim was to clarify the mechanisms by which these plants change the surrounding water pH in the presence of toxic ions. The influence of Elodea canadensis...

  3. A synthetic glycan microarray enables epitope mapping of plant cell wall glycan-directed antibodies

    DEFF Research Database (Denmark)

    Ruprecht, Colin; Bartetzko, Max P; Senf, Deborah

    2017-01-01

    In the last three decades, more than 200 monoclonal antibodies have been raised against most classes of plant cell wall polysaccharides by different laboratories world-wide. These antibodies are widely used to identify differences in plant cell wall components in mutants, organ and tissue types......, and developmental stages. Despite their importance and broad use, the precise binding epitope for only a few of these antibodies has been determined. Here, we use a plant glycan microarray equipped with 88 synthetic oligosaccharides to comprehensively map the epitopes of plant cell wall glycan-directed antibodies....... Our results reveal the binding epitopes for 78 arabinogalactan-, rhamnogalacturonan-, xylan-, and xyloglucan-directed antibodies. We demonstrate that, with knowledge of the exact epitopes recognized by individual antibodies, specific glycosyl hydrolases can be implemented into immunological cell wall...

  4. Plants know where it hurts: root and shoot jasmonic acid induction elicit differential responses in Brassica oleracea.

    Directory of Open Access Journals (Sweden)

    Tom O G Tytgat

    Full Text Available Plants respond to herbivore attack by rapidly inducing defenses that are mainly regulated by jasmonic acid (JA. Due to the systemic nature of induced defenses, attack by root herbivores can also result in a shoot response and vice versa, causing interactions between above- and belowground herbivores. However, little is known about the molecular mechanisms underlying these interactions. We investigated whether plants respond differently when roots or shoots are induced. We mimicked herbivore attack by applying JA to the roots or shoots of Brassica oleracea and analyzed molecular and chemical responses in both organs. In shoots, an immediate and massive change in primary and secondary metabolism was observed. In roots, the JA-induced response was less extensive and qualitatively different from that in the shoots. Strikingly, in both roots and shoots we also observed differential responses in primary metabolism, development as well as defense specific traits depending on whether the JA induction had been below- or aboveground. We conclude that the JA response is not only tissue-specific but also dependent on the organ that was induced. Already very early in the JA signaling pathway the differential response was observed. This indicates that both organs have a different JA signaling cascade, and that the signal eliciting systemic responses contains information about the site of induction, thus providing plants with a mechanism to tailor their responses specifically to the organ that is damaged.

  5. How changing root system architecture can help tackle a reduction in soil phosphate (P) levels for better plant P acquisition

    KAUST Repository

    HEPPELL, J.

    2014-06-24

    © 2014 John Wiley & Sons Ltd. The readily available global rock phosphate (P) reserves may run out within the next 50-130 years, causing soils to have a reduced P concentration which will affect plant P uptake. Using a combination of mathematical modelling and experimental data, we investigated potential plant-based options for optimizing crop P uptake in reduced soil P environments. By varying the P concentration within a well-mixed agricultural soil, for high and low P (35.5-12.5mgL-1 respectively using Olsen\\'s P index), we investigated branching distributions within a wheat root system that maximize P uptake. Changing the root branching distribution from linear (evenly spaced branches) to strongly exponential (a greater number of branches at the top of the soil) improves P uptake by 142% for low-P soils when root mass is kept constant between simulations. This causes the roots to emerge earlier and mimics topsoil foraging. Manipulating root branching patterns, to maximize P uptake, is not enough on its own to overcome the drop in soil P from high to low P. Further mechanisms have to be considered to fully understand the impact of P reduction on plant development.

  6. A dynamic growth model of vegetative soya bean plants: model structure and behaviour under varying root temperature and nitrogen concentration

    Science.gov (United States)

    Lim, J. T.; Wilkerson, G. G.; Raper, C. D. Jr; Gold, H. J.

    1990-01-01

    A differential equation model of vegetative growth of the soya bean plant (Glycine max (L.) Merrill cv. Ransom') was developed to account for plant growth in a phytotron system under variation of root temperature and nitrogen concentration in nutrient solution. The model was tested by comparing model outputs with data from four different experiments. Model predictions agreed fairly well with measured plant performance over a wide range of root temperatures and over a range of nitrogen concentrations in nutrient solution between 0.5 and 10.0 mmol NO3- in the phytotron environment. Sensitivity analyses revealed that the model was most sensitive to changes in parameters relating to carbohydrate concentration in the plant and nitrogen uptake rate.

  7. Arbuscules of vesicular-arbuscular mycorrhizal fungi inhabit an acidic compartment within plant roots.

    Science.gov (United States)

    Guttenberger, M

    2000-08-01

    The most widespread type of mycorrhiza is the so-called vesicular-arbuscular mycorrhiza. In this endomycorrhiza, fungal hyphae penetrate plant cell walls in the root cortex. There they form densely branched arbuscules. Fungus and plant plasma membrane are separated by a common interfacial apoplast. The pH of the compartment between the symbionts is of pivotal importance for nutrient transfer. Histochemical experiments were conducted to check for an acidic nature of the interface in the model system Glomus versiforme (Karst.) Berch-Allium porrum L. Two chemically different acidotropic dyes (neutral red and LysoSensor Green DND-189) stained the arbuscules intensely. The staining of arbuscules could be eliminated by addition of the protonophore carbonylcyanide m-chlorophenylhydrazone (CCCP) or treatments leading to membrane rupture. Therefore, the staining of the arbuscules was based on the ion-trap mechanism, which indicates acidic, membrane-bound compartments. Microscopic examination of stained arbuscules at high optical resolution revealed a peripheral accumulation of the dye. Since plasmolysis rapidly destained the arbuscules, it is concluded that the dyes accumulate in the arbuscular interface, indicating the highly acidic nature of this compartment. The findings are discussed with respect to their relevance for the nutrient transfer in mycorrhizas. In addition, evidence for a discontinuity in the arbuscular interface between the stem and the branches of the arbuscule is given.

  8. Tomato root growth and phosphorus absorption kinetics by tomato plants as affected by phosphorus concentration in nutrient solution

    International Nuclear Information System (INIS)

    Fontes, P.C.R.; Barber, S.A.

    1984-01-01

    To evaluate the effects P concentrations in nutrient solution on root growth and on root physiological characteristics involved in P uptake by tomato Lycopersicon esculentum Mill plants, six seedlings were grown in nutrient solution at initial concentrations of 48.5, 97, 194 and 388 μMP until one day before harvest. They were then transferred to solutions with P at 20 μM and 30 μM, and the depletion curves and Michaelis-Menten parameters were determined. The conclusions were that as P supply increased and as the plant P contents are sufficient for maximum growth, the rate of P uptake tends to be lower. The results also indicate that total P uptake by tomato seedlings depends on the amount of root surface area exposed to P. (M.A.C.) [pt

  9. Differential metabolic responses of Beauveria bassiana cultured in pupae extracts, root exudates and its interactions with insect and plant.

    Science.gov (United States)

    Luo, Feifei; Wang, Qian; Yin, Chunlin; Ge, Yinglu; Hu, Fenglin; Huang, Bo; Zhou, Hong; Bao, Guanhu; Wang, Bin; Lu, Ruili; Li, Zengzhi

    2015-09-01

    Beauveria bassiana is a kind of world-wide entomopathogenic fungus and can also colonize plant rhizosphere. Previous researches showed differential expression of genes when entomopathogenic fungi are cultured in insect or plant materials. However, so far there is no report on metabolic alterations of B. bassiana in the environments of insect or plant. The purpose of this paper is to address this problem. Herein, we first provide the metabolomic analysis of B. bassiana cultured in insect pupae extracts (derived from Euproctis pseudoconspersa and Bombyx mori, EPP and BMP), plant root exudates (derived from asparagus and carrot, ARE and CRE), distilled water and minimal media (MM), respectively. Principal components analysis (PCA) shows that mycelia cultured in pupae extracts and root exudates are evidently separated and individually separated from MM, which indicates that fungus accommodates to insect and plant environments by different metabolic regulation mechanisms. Subsequently, orthogonal projection on latent structure-discriminant analysis (OPLS-DA) identifies differential metabolites in fungus under three environments relative to MM. Hierarchical clustering analysis (HCA) is performed to cluster compounds based on biochemical relationships, showing that sphingolipids are increased in BMP but are decreased in EPP. This observation further implies that sphingolipid metabolism may be involved in the adaptation of fungus to different hosts. In the meantime, sphingolipids are significantly decreased in root exudates but they are not decreased in distilled water, suggesting that some components of the root exudates can suppress sphingolipid to down-regulate sphingolipid metabolism. Pathway analysis finds that fatty acid metabolism is maintained at high level but non-ribosomal peptides (NRP) synthesis is unaffected in mycelia cultured in pupae extracts. In contrast, fatty acid metabolism is not changed but NRP synthesis is high in mycelia cultured in root exudates

  10. Virtual Plants Need Water Too: Functional-Structural Root System Models in the Context of Drought Tolerance Breeding.

    Science.gov (United States)

    Ndour, Adama; Vadez, Vincent; Pradal, Christophe; Lucas, Mikaël

    2017-01-01

    Developing a sustainable agricultural model is one of the great challenges of the coming years. The agricultural practices inherited from the Green Revolution of the 1960s show their limits today, and new paradigms need to be explored to counter rising issues such as the multiplication of climate-change related drought episodes. Two such new paradigms are the use of functional-structural plant models to complement and rationalize breeding approaches and a renewed focus on root systems as untapped sources of plant amelioration. Since the late 1980s, numerous functional and structural models of root systems were developed and used to investigate the properties of root systems in soil or lab-conditions. In this review, we focus on the conception and use of such root models in the broader context of research on root-driven drought tolerance, on the basis of root system architecture (RSA) phenotyping. Such models result from the integration of architectural, physiological and environmental data. Here, we consider the different phenotyping techniques allowing for root architectural and physiological study and their limits. We discuss how QTL and breeding studies support the manipulation of RSA as a way to improve drought resistance. We then go over the integration of the generated data within architectural models, how those architectural models can be coupled with functional hydraulic models, and how functional parameters can be measured to feed those models. We then consider the assessment and validation of those hydraulic models through confrontation of simulations to experimentations. Finally, we discuss the up and coming challenges facing root systems functional-structural modeling approaches in the context of breeding.

  11. Virtual Plants Need Water Too: Functional-Structural Root System Models in the Context of Drought Tolerance Breeding

    Directory of Open Access Journals (Sweden)

    Adama Ndour

    2017-09-01

    Full Text Available Developing a sustainable agricultural model is one of the great challenges of the coming years. The agricultural practices inherited from the Green Revolution of the 1960s show their limits today, and new paradigms need to be explored to counter rising issues such as the multiplication of climate-change related drought episodes. Two such new paradigms are the use of functional-structural plant models to complement and rationalize breeding approaches and a renewed focus on root systems as untapped sources of plant amelioration. Since the late 1980s, numerous functional and structural models of root systems were developed and used to investigate the properties of root systems in soil or lab-conditions. In this review, we focus on the conception and use of such root models in the broader context of research on root-driven drought tolerance, on the basis of root system architecture (RSA phenotyping. Such models result from the integration of architectural, physiological and environmental data. Here, we consider the different phenotyping techniques allowing for root architectural and physiological study and their limits. We discuss how QTL and breeding studies support the manipulation of RSA as a way to improve drought resistance. We then go over the integration of the generated data within architectural models, how those architectural models can be coupled with functional hydraulic models, and how functional parameters can be measured to feed those models. We then consider the assessment and validation of those hydraulic models through confrontation of simulations to experimentations. Finally, we discuss the up and coming challenges facing root systems functional-structural modeling approaches in the context of breeding.

  12. Nitrogen dynamics in the soil-plant system under deficit and partial root-zone drying irrigation strategies in potatoes

    DEFF Research Database (Denmark)

    Shahnazari, Ali; Ahmadi, Seyed Hamid; Lærke, Poul Erik

    2008-01-01

    Experiments were conducted in lysimeters with sandy soil under an automatic rain-out shelter to study the effects of subsurface drip irrigation treatments, full irrigation (FI), deficit irrigation (DI) and partial root-zone drying (PRD), on nitrogen (N) dynamics in the soil-plant system of potatoes...

  13. Passive restoration augments active restoration in deforested landscapes: the role of root suckering adjacent to planted stands of Acacia koa

    Science.gov (United States)

    Paul G. Scowcroft; Justin T. Yeh

    2013-01-01

    Active forest restoration in Hawaii’s Hakalau Forest National Wildlife Refuge has produced a network of Acacia koa tree corridors and islands in deforested grasslands. Passive restoration by root suckering has potential to expand tree cover and close gaps between planted stands. This study documents rates of encroachment into grassland, clonal...

  14. Spatial and temporal dynamics of water in the root environment of potted plants on a flooded bench fertigation system

    NARCIS (Netherlands)

    Otten, W.; Raats, P.A.C.; Baas, R.; Challa, H.; Kabat, P.

    1999-01-01

    The relationship between evapotranspiration of potted Ficus benjamina plants on a flooded bench fertigation system and the distribution of water in the root zone was studied in detail for a range of fertigation schedules. The physical characteristics of the peat-based potting medium were described

  15. Exogenous glucosinolate produced by Arabidopsis thaliana has an impact on microbes in the rhizosphere and plant roots.

    Science.gov (United States)

    Bressan, Mélanie; Roncato, Marie-Anne; Bellvert, Floriant; Comte, Gilles; Haichar, Feth Zahar; Achouak, Wafa; Berge, Odile

    2009-11-01

    A specificity of Brassicaceous plants is the production of sulphur secondary metabolites called glucosinolates that can be hydrolysed into glucose and biocidal products. Among them, isothiocyanates are toxic to a wide range of microorganisms and particularly soil-borne pathogens. The aim of this study was to investigate the role of glucosinolates and their breakdown products as a factor of selection on rhizosphere microbial community associated with living Brassicaceae. We used a DNA-stable isotope probing approach to focus on the active microbial populations involved in root exudates degradation in rhizosphere. A transgenic Arabidopsis thaliana line producing an exogenous glucosinolate and the associated wild-type plant associated were grown under an enriched (13)CO(2) atmosphere in natural soil. DNA from the rhizospheric soil was separated by density gradient centrifugation. Bacterial (Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria and Acidobacteria), Archaea and fungal community structures were analysed by DGGE fingerprints of amplified 16S and 18S rRNA gene sequences. Specific populations were characterized by sequencing DGGE fragments. Roots of the transgenic plant line presented an altered profile of glucosinolates and other minor additional modifications. These modifications significantly influenced microbial community on roots and active populations in the rhizosphere. Alphaproteobacteria, particularly Rhizobiaceae, and fungal communities were mainly impacted by these Brassicaceous metabolites, in both structure and composition. Our results showed that even a minor modification in plant root could have important repercussions for soil microbial communities.

  16. Arbuscular Mycorrhizal Symbiosis with Arundo donax Decreases Root Respiration and Increases Both Photosynthesis and Plant Biomass Accumulation.

    Science.gov (United States)

    Romero-Munar, Antònia; Del-Saz, Néstor Fernández; Ribas-Carbó, Miquel; Flexas, Jaume; Baraza, Elena; Florez-Sarasa, Igor; Fernie, Alisdair Robert; Gulías, Javier

    2017-07-01

    The effect of arbuscular mycorrhiza (AM) symbiosis on plant growth is associated with the balance between costs and benefits. A feedback regulation loop has been described in which the higher carbohydrate cost to plants for AM symbiosis is compensated by increases in their photosynthetic rates. Nevertheless, plant carbon balance depends both on photosynthetic carbon uptake and respiratory carbon consumption. The hypothesis behind this research was that the role of respiration in plant growth under AM symbiosis may be as important as that of photosynthesis. This hypothesis was tested in Arundo donax L. plantlets inoculated with Rhizophagus irregularis and Funneliformis mosseae. We tested the effects of AM inoculation on both photosynthetic capacity and in vivo leaf and root respiration. Additionally, analyses of the primary metabolism and ion content were performed in both leaves and roots. AM inoculation increased photosynthesis through increased CO 2 diffusion and electron transport in the chloroplast. Moreover, respiration decreased only in AM roots via the cytochrome oxidase pathway (COP) as measured by the oxygen isotope technique. This decline in the COP can be related to the reduced respiratory metabolism and substrates (sugars and tricarboxylic acid cycle intermediates) observed in roots. © 2017 John Wiley & Sons Ltd.

  17. Root isolations of Metarhizium spp. from crops reflect diversity in the soil and indicate no plant specificity

    DEFF Research Database (Denmark)

    Steinwender, Bernhardt M.; Enkerli, Jürg; Widmer, Franco

    2015-01-01

    elongation factor 1-alpha and characterized by simple sequence repeat (SSR) analysis of 14 different loci. Metarhizium brunneum was the most common species isolated from plant roots (84.1% of all isolates), while M. robertsii (11.1%) and M. majus (4.8%) comprised the remainder. The SSR analysis revealed...

  18. Rooting of cuttings of vanilla plant (Orchidaceae / Enraizamento de estacas da baunilheira (Orchidaceae

    Directory of Open Access Journals (Sweden)

    Aparecida Gomes de Araujo

    2009-07-01

    Full Text Available The vanilla plant (Vanilla planifolia could have a higher commercial production but there are problems in the efficiency of propagation. The present work was conducted with the aim of studying the effect of different substrates, in the adventitious rooting of cuttings taken at five heights in the plant stem. The cuttings were 20cm long and had two buds and one leaf and were planted in: 1 Liquid medium formed by Clark’s nutrient added of 2.5mg L-1 of IBA placed in plastic foam box with a capacity of 1.5L lined inside with transparent plastic bag and lidded with proper lid. 2 Solid substrate formed by the mixture of sand, carbonized rice husk, soil and cured cow manure in equal proportions of volume, they being placed in rigid polypropylene with a capacity of 0.28L. 3 Pre-rooting of the cuttings in liquid medium (20 days before planting, and later transferred into seedling tubes containing solid substrate. The cuttings planted in the solid substrate were maintained under intermittent mist condition controlled by a timer. After 90 days, the percentage of rooting was of 98-100%, regardless of the treatment. Larger and more vigorous sproutings were obtained from cuttings planted directly into solid substrate. Adventitious rooting of cuttings and formation of new vanilla cuttings occurred, when the cuttings were obtained from position P2 (ranging between 20 to 40cm in stem height and planted in solid substrate in greenhouse with intermittent misting system. A baunilheira (Vanilla planifolia é uma planta pouco explorada comercialmente, devido ao emprego de tecnologias de baixa eficiência para a produção de mudas. Assim sendo, realizou-se o presente trabalho com o objetivo de estudar o efeito de diferentes substratos, no enraizamento adventício de estacas retiradas de diferentes posições na planta. Estacas com 20cm de comprimento, duas gemas e uma folha, tomadas na haste da planta, em cinco posições subseqüentes, a partir do ápice caulinar

  19. A test system to quantify inoculum in runoff from Phytophthora ramorum-infected plant roots

    Science.gov (United States)

    Nina. Shishkoff

    2010-01-01

    Foliar hosts of Phytophthora ramorum are often susceptible to root infection, but the epidemiological significance of such infections is unknown. We used a standardized test system to study inoculum in runoff from root-infected Viburnum tinus cuttings.

  20. 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.

  1. Salt and genotype impact on plant physiology and root proteome variations in tomato.

    Science.gov (United States)

    Manaa, Arafet; Ben Ahmed, Hela; Valot, Benoît; Bouchet, Jean-Paul; Aschi-Smiti, Samira; Causse, Mathilde; Faurobert, Mireille

    2011-05-01

    To evaluate the genotypic variation of salt stress response in tomato, physiological analyses and a proteomic approach have been conducted in parallel on four contrasting tomato genotypes. After a 14 d period of salt stress in hydroponic conditions, the genotypes exhibited different responses in terms of plant growth, particularly root growth, foliar accumulation of Na(+), and foliar K/Na ratio. As a whole, Levovil appeared to be the most tolerant genotype while Cervil was the most sensitive one. Roma and Supermarmande exhibited intermediary behaviours. Among the 1300 protein spots reproducibly detected by two-dimensional electrophoresis, 90 exhibited significant abundance variations between samples and were submitted to mass spectrometry for identification. A common set of proteins (nine spots), up- or down-regulated by salt-stress whatever the genotype, was detected. But the impact of the tomato genotype on the proteome variations was much higher than the salt effect: 33 spots that were not variable with salt stress varied with the genotype. The remaining number of variable spots (48) exhibited combined effects of the genotype and the salt factors, putatively linked to the degrees of genotype tolerance. The carbon metabolism and energy-related proteins were mainly up-regulated by salt stress and exhibited most-tolerant versus most-sensitive abundance variations. Unexpectedly, some antioxidant and defence proteins were also down-regulated, while some proteins putatively involved in osmoprotectant synthesis and cell wall reinforcement were up-regulated by salt stress mainly in tolerant genotypes. The results showed the effect of 14 d stress on the tomato root proteome and underlined significant genotype differences, suggesting the importance of making use of genetic variability.

  2. Dispersal strategy of cyst nematodes (Heterodera arenaria) in the plant root zone of mobile dunes and consequences for emergence, survival and reproductive success

    NARCIS (Netherlands)

    Stoel, C.D.; Putten, van der W.H.

    2006-01-01

    Root-feeding nematodes may play an important role in generating spatial and temporal variation in natural plant communities, but little is known about the performance of the nematodes in the plant root zone. We studied the emergence, survival and reproductive success of the cyst nematode Heterodera

  3. Dispersal strategy of cyst nematodes (Heterodera Arenaria) in the plant root zone of mobile dunes and consequences for emergence, survival and reproductive success

    NARCIS (Netherlands)

    Van der Stoel, C.D.; Van der Putten, W.H.

    2006-01-01

    Root-feeding nematodes may play an important role in generating spatial and temporal variation in natural plant communities, but little is known about the performance of the nematodes in the plant root zone. We studied the emergence, survival and reproductive success of the cyst nematode Heterodera

  4. Functional diversity of carbohydrate-active enzymes enabling a bacterium to ferment plant biomass.

    Science.gov (United States)

    Boutard, Magali; Cerisy, Tristan; Nogue, Pierre-Yves; Alberti, Adriana; Weissenbach, Jean; Salanoubat, Marcel; Tolonen, Andrew C

    2014-11-01

    Microbial metabolism of plant polysaccharides is an important part of environmental carbon cycling, human nutrition, and industrial processes based on cellulosic bioconversion. Here we demonstrate a broadly applicable method to analyze how microbes catabolize plant polysaccharides that integrates carbohydrate-active enzyme (CAZyme) assays, RNA sequencing (RNA-seq), and anaerobic growth screening. We apply this method to study how the bacterium Clostridium phytofermentans ferments plant biomass components including glucans, mannans, xylans, galactans, pectins, and arabinans. These polysaccharides are fermented with variable efficiencies, and diauxies prioritize metabolism of preferred substrates. Strand-specific RNA-seq reveals how this bacterium responds to polysaccharides by up-regulating specific groups of CAZymes, transporters, and enzymes to metabolize the constituent sugars. Fifty-six up-regulated CAZymes were purified, and their activities show most polysaccharides are degraded by multiple enzymes, often from the same family, but with divergent rates, specificities, and cellular localizations. CAZymes were then tested in combination to identify synergies between enzymes acting on the same substrate with different catalytic mechanisms. We discuss how these results advance our understanding of how microbes degrade and metabolize plant biomass.

  5. Genome sequences of Phytophthora enable translational plant disease management and accelerate research

    Science.gov (United States)

    Niklaus J. Grünwald

    2012-01-01

    Whole and partial genome sequences are becoming available at an ever-increasing pace. For many plant pathogen systems, we are moving into the era of genome resequencing. The first Phytophthora genomes, P. ramorum and P. sojae, became available in 2004, followed shortly by P. infestans...

  6. The plant natriuretic peptide receptor is a guanylyl cyclase and enables cGMP-dependent signaling

    KAUST Repository

    Turek, Ilona

    2016-03-05

    The functional homologues of vertebrate natriuretic peptides (NPs), the plant natriuretic peptides (PNPs), are a novel class of peptidic hormones that signal via guanosine 3′,5′-cyclic monophosphate (cGMP) and systemically affect plant salt and water balance and responses to biotrophic plant pathogens. Although there is increasing understanding of the complex roles of PNPs in plant responses at the systems level, little is known about the underlying signaling mechanisms. Here we report isolation and identification of a novel Leucine-Rich Repeat (LRR) protein that directly interacts with A. thaliana PNP, AtPNP-A. In vitro binding studies revealed that the Arabidopsis AtPNP-A binds specifically to the LRR protein, termed AtPNP-R1, and the active region of AtPNP-A is sufficient for the interaction to occur. Importantly, the cytosolic part of the AtPNP-R1, much like in some vertebrate NP receptors, harbors a catalytic center diagnostic for guanylyl cyclases and the recombinant AtPNP-R1 is capable of catalyzing the conversion of guanosine triphosphate to cGMP. In addition, we show that AtPNP-A causes rapid increases of cGMP levels in wild type (WT) leaf tissue while this response is significantly reduced in the atpnp-r1 mutants. AtPNP-A also causes cGMP-dependent net water uptake into WT protoplasts, and hence volume increases, whereas responses of the protoplasts from the receptor mutant are impaired. Taken together, our results suggest that the identified LRR protein is an AtPNP-A receptor essential for the PNP-dependent regulation of ion and water homeostasis in plants and that PNP- and vertebrate NP-receptors and their signaling mechanisms share surprising similarities. © 2016 Springer Science+Business Media Dordrecht

  7. Invasive plants and their escape from root herbivory: a worldwide comparison of the root-feeding nematode communities of the dune grass Ammophila arenaria in natural and introduced ranges

    NARCIS (Netherlands)

    Putten, van der W.H.; Yeates, G.W.; Duyts, H.; Schreck Reis, C.; Karssen, G.

    2005-01-01

    Invasive plants generally have fewer aboveground pathogens and viruses in their introduced range than in their natural range, and they also have fewer pathogens than do similar plant species native to the introduced range. However, although plant abundance is strongly controlled by root herbivores

  8. Diversity and distribution patterns of root-associated fungi on herbaceous plants in alpine meadows of southwestern China.

    Science.gov (United States)

    Gao, Qian; Yang, Zhu L

    2016-01-01

    The diversity of root-associated fungi associated with four ectomycorrhizal herbaceous species, Kobresia capillifolia, Carex parva, Polygonum macrophyllum and Potentilla fallens, collected in three sites of alpine meadows in southwestern China, was estimated based on internal transcribed spacer (ITS) rDNA sequence analysis of root tips. Three hundred seventy-seven fungal sequences sorted to 154 operational taxonomical units (sequence similarity of ≥ 97% across the ITS) were obtained from the four plant species across all three sites. Similar taxa (in GenBank with ≥ 97% similarity) were not found in GenBank and/or UNITE for most of the OTUs. Ectomycorrhiz a made up 64% of the fungi operational taxonomic units (OTUs), endophytes constituted 4% and the other 33% were unidentified root-associated fungi. Fungal OTUs were represented by 57% basidiomycetes and 43% ascomycetes. Inocybe, Tomentella/Thelophora, Sebacina, Hebeloma, Pezizomycotina, Cenococcum geophilum complex, Cortinarius, Lactarius and Helotiales were OTU-rich fungal lineages. Across the sites and host species the root-associated fungal communities generally exhibited low host and site specificity but high host and sampling site preference. Collectively our study revealed noteworthy diversity and endemism of root-associated fungi of alpine plants in this global biodiversity hotspot. © 2016 by The Mycological Society of America.

  9. Discrimination of plant root zone water status in greenhouse production based on phenotyping and machine learning techniques.

    Science.gov (United States)

    Guo, Doudou; Juan, Jiaxiang; Chang, Liying; Zhang, Jingjin; Huang, Danfeng

    2017-08-15

    Plant-based sensing on water stress can provide sensitive and direct reference for precision irrigation system in greenhouse. However, plant information acquisition, interpretation, and systematical application remain insufficient. This study developed a discrimination method for plant root zone water status in greenhouse by integrating phenotyping and machine learning techniques. Pakchoi plants were used and treated by three root zone moisture levels, 40%, 60%, and 80% relative water content. Three classification models, Random Forest (RF), Neural Network (NN), and Support Vector Machine (SVM) were developed and validated in different scenarios with overall accuracy over 90% for all. SVM model had the highest value, but it required the longest training time. All models had accuracy over 85% in all scenarios, and more stable performance was observed in RF model. Simplified SVM model developed by the top five most contributing traits had the largest accuracy reduction as 29.5%, while simplified RF and NN model still maintained approximately 80%. For real case application, factors such as operation cost, precision requirement, and system reaction time should be synthetically considered in model selection. Our work shows it is promising to discriminate plant root zone water status by implementing phenotyping and machine learning techniques for precision irrigation management.

  10. Instrumentation enabling study of plant physiological response to elevated night temperature

    Directory of Open Access Journals (Sweden)

    Tarpley Lee

    2009-06-01

    Full Text Available Abstract Background Global climate warming can affect functioning of crops and plants in the natural environment. In order to study the effects of global warming, a method for applying a controlled heating treatment to plant canopies in the open field or in the greenhouse is needed that can accept either square wave application of elevated temperature or a complex prescribed diurnal or seasonal temperature regime. The current options are limited in their accuracy, precision, reliability, mobility or cost and scalability. Results The described system uses overhead infrared heaters that are relatively inexpensive and are accurate and precise in rapidly controlling the temperature. Remote computer-based data acquisition and control via the internet provides the ability to use complex temperature regimes and real-time monitoring. Due to its easy mobility, the heating system can randomly be allotted in the open field or in the greenhouse within the experimental setup. The apparatus has been successfully applied to study the response of rice to high night temperatures. Air temperatures were maintained within the set points ± 0.5°C. The incorporation of the combination of air-situated thermocouples, autotuned proportional integrative derivative temperature controllers and phase angled fired silicon controlled rectifier power controllers provides very fast proportional heating action (i.e. 9 ms time base, which avoids prolonged or intense heating of the plant material. Conclusion The described infrared heating system meets the utilitarian requirements of a heating system for plant physiology studies in that the elevated temperature can be accurately, precisely, and reliably controlled with minimal perturbation of other environmental factors.

  11. Nano titania aided clustering and adhesion of beneficial bacteria to plant roots to enhance crop growth and stress management

    Science.gov (United States)

    Palmqvist, N. G. M.; Bejai, S.; Meijer, J.; Seisenbaeva, G. A.; Kessler, V. G.

    2015-05-01

    A novel use of Titania nanoparticles as agents in the nano interface interaction between a beneficial plant growth promoting bacterium (Bacillus amyloliquefaciens UCMB5113) and oilseed rape plants (Brassica napus) for protection against the fungal pathogen Alternaria brassicae is presented. Two different TiO2 nanoparticle material were produced by the Sol-Gel approach, one using the patented Captigel method and the other one applying TiBALDH precursor. The particles were characterized by transmission electron microscopy, thermogravimetric analysis, X-ray diffraction, dynamic light scattering and nano particle tracking analysis. Scanning electron microscopy showed that the bacterium was living in clusters on the roots and the combined energy-dispersive X-ray spectroscopy analysis revealed that titanium was present in these cluster formations. Confocal laser scanning microscopy further demonstrated an increased bacterial colonization of Arabidopsis thaliana roots and a semi-quantitative microscopic assay confirmed an increased bacterial adhesion to the roots. An increased amount of adhered bacteria was further confirmed by quantitative fluorescence measurements. The degree of infection by the fungus was measured and quantified by real-time-qPCR. Results showed that Titania nanoparticles increased adhesion of beneficial bacteria on to the roots of oilseed rape and protected the plants against infection.

  12. Advanced nutrient root feeding system for conveyer-type cylindrical plant growth facilities developed for microgravity

    Science.gov (United States)

    Berkovich, Yuliy A.; Smolyanina, Svetlana O.; Krivobok, Anna; Krivobok, Nikolay

    A new brand of cylindrical conveyer-type space plant growth facilities (PGF) has been created to improve of cosmonauts’ diet in the microgravity conditions. Up to date several ground prototypes of the space PGF have been made and tested: “Phytocycle”, “Vitacycle”, “Phytocycle-LED”, “Phytoconveyer”; now the space PGF “Vitacycle-T” for the Russian segment of the ISS is under developing. In the PGFs the ion-exchange salt-saturated fibrous artificial soil (AS) is used as a root medium. We have proposed the system for enrichment of irrigation water by nutrients to decrease of the AS store required for PGF working during the long space mission. The system includes root modules filled in fibrous ion-exchange AS, the enrichment column with crumble salt-saturation ion-exchange resin and the cassette with slow releasing fertilizer (SRF). Both substrates (ion-exchange resin and SRF) are necessary because of the SRF contains mostly N, P and K but another three essential elements S, Ca, Mg are provided by the ion-exchange resin. In the system water goes throw the enrichment column with ion-exchange resin fertilizing by the nutrients and comes into the mixer cell fertilize equipped with the electrical conductivity sensor. When the signal of the conductivity sensor is coming to the controller it turns on the pump directed the water flow throw the cassette with SRF until the electric conductivity of the solution in the mixer cell will reach the setpoint. The nutrient root feeding system was tested during 88 days when Chinese cabbage grew in PGF “Phytocycle-LED”. The crop has been continuously illuminated by red and blue LEDs in the PPF ratio 7 to 1; an integral PPF level has been (240 ± 10) µmol/(m2×s). There was no renewal of the used fibrous AS during the experiment. The PGF total electric power consumption was of 0,45 kW. The average fresh biomass productivity of the PGF during steady state working mode was equal 135×g/day per m2 of the illuminated

  13. The bean rhizosphere Pseudomonas aeruginosa strain RZ9 strongly reduces Fusarium culmorum growth and infectiveness of plant roots

    Energy Technology Data Exchange (ETDEWEB)

    Haddoudi, I.; Sendi, Y.; Batnini, M.; Romdhane, S.B.; Mhadhbi, H.; Mrabet, M.

    2017-07-01

    A faba bean rhizospheric Pseudomonas aeruginosa isolate RZ9 was used for studying its antifungal activity and protecting effects of faba bean and common bean against the root pathogen Fusarium culmorum strain MZB47. The dual culture tests showed that RZ9 inhibits MZB47 in vitro growth by 56%. When mixing RZ9 cell suspension with MZB47 macroconidia at equal proportion, the macroconidia viability was reduced with 70%. Pathogenicity tests conducted in sterile conditions showed that MZB47 caused an intense root rotting in faba bean ‘Aquadulce’ plantlets and a slight level in common bean ‘Coco blanc’. This was associated to significant decreases in plant growth only in ‘Aquadulce’, reducing shoot dry weight (DW) by 82% and root DW by 70%. In soil samples, MZB47 caused severe root rotting and induced significant decreases in shoot DW (up to 51%) and root DW (up to 60%) for both beans. It was associated to a decrease in nodule number by 73% and 52% for faba bean and common bean, respectively. Biocontrol assays revealed that the inoculation of RZ9 to MZB47-treated plantlets enhanced shoot DWs (25% and 110%) and root DWs (29% and 67%), in faba bean and common bean, respectively. Moreover, root rotting levels decreased and nodule number increased in treated compared to untreated plantlets. Collected data highlighted the disease severity of F. culmorum and demonstrated the potential of using RZ9 in controlling Fusaria root diseases in beans. Thereby, the current study represents the first report on the biocontrol effectiveness of P. aeruginosa against F. culmorum in beans.

  14. The bean rhizosphere Pseudomonas aeruginosa strain RZ9 strongly reduces Fusarium culmorum growth and infectiveness of plant roots

    Directory of Open Access Journals (Sweden)

    Imen Haddoudi

    2017-07-01

    Full Text Available A faba bean rhizospheric Pseudomonas aeruginosa isolate RZ9 was used for studying its antifungal activity and protecting effects of faba bean and common bean against the root pathogen Fusarium culmorum strain MZB47. The dual culture tests showed that RZ9 inhibits MZB47 in vitro growth by 56%. When mixing RZ9 cell suspension with MZB47 macroconidia at equal proportion, the macroconidia viability was reduced with 70%. Pathogenicity tests conducted in sterile conditions showed that MZB47 caused an intense root rotting in faba bean ‘Aquadulce’ plantlets and a slight level in common bean ‘Coco blanc’. This was associated to significant decreases in plant growth only in ‘Aquadulce’, reducing shoot dry weight (DW by 82% and root DW by 70%. In soil samples, MZB47 caused severe root rotting and induced significant decreases in shoot DW (up to 51% and root DW (up to 60% for both beans. It was associated to a decrease in nodule number by 73% and 52% for faba bean and common bean, respectively. Biocontrol assays revealed that the inoculation of RZ9 to MZB47-treated plantlets enhanced shoot DWs (25% and 110% and root DWs (29% and 67%, in faba bean and common bean, respectively. Moreover, root rotting levels decreased and nodule number increased in treated compared to untreated plantlets. Collected data highlighted the disease severity of F. culmorum and demonstrated the potential of using RZ9 in controlling Fusaria root diseases in beans. Thereby, the current study represents the first report on the biocontrol effectiveness of P. aeruginosa against F. culmorum in beans.

  15. Abscisic Acid Regulation of Root Hydraulic Conductivity and Aquaporin Gene Expression Is Crucial to the Plant Shoot Growth Enhancement Caused by Rhizosphere Humic Acids.

    Science.gov (United States)

    Olaetxea, Maite; Mora, Verónica; Bacaicoa, Eva; Garnica, María; Fuentes, Marta; Casanova, Esther; Zamarreño, Angel M; Iriarte, Juan C; Etayo, David; Ederra, Iñigo; Gonzalo, Ramón; Baigorri, Roberto; García-Mina, Jose M

    2015-12-01

    The physiological and metabolic mechanisms behind the humic acid-mediated plant growth enhancement are discussed in detail. Experiments using cucumber (Cucumis sativus) plants show that the shoot growth enhancement caused by a structurally well-characterized humic acid with sedimentary origin is functionally associated with significant increases in abscisic acid (ABA) root concentration and root hydraulic conductivity. Complementary experiments involving a blocking agent of cell wall pores and water root transport (polyethylenglycol) show that increases in root hydraulic conductivity are essential in the shoot growth-promoting action of the model humic acid. Further experiments involving an inhibitor of ABA biosynthesis in root and shoot (fluridone) show that the humic acid-mediated enhancement of both root hydraulic conductivity and shoot growth depended on ABA signaling pathways. These experiments also show that a significant increase in the gene expression of the main root plasma membrane aquaporins is associated with the increase of root hydraulic conductivity caused by the model humic acid. Finally, experimental data suggest that all of these actions of model humic acid on root functionality, which are linked to its beneficial action on plant shoot growth, are likely related to the conformational structure of humic acid in solution and its interaction with the cell wall at the root surface. © 2015 American Society of Plant Biologists. All Rights Reserved.

  16. Comparison of direct deposition and root uptake results after the Fukushima Daiichi Nuclear Power Plant accident

    International Nuclear Information System (INIS)

    Tagami, Keiko; Uchida, Shigeo

    2012-01-01

    Field horsetail(Equisetum arvense) is a kind of fern, and the fertile shoots are eaten as vegetables in Japan in the spring. Since fern species tend to concentrate radiocaesium from soil, concentrations and distribution patterns of radiocaesium in the fertile shoots are of interest. In this study, distribution and food processing results were compared using samples collected in 2011(n=1) and 2012(n=3); the sample collected in 2011 received direct deposition from the Fukushima Daiichi Nuclear Power Plant accident while those collected in 2012 included radiocaesium mainly taken up from soil. About 200-300 shoots were collected at each sampling time. The 137 Cs concentration in samples collected in 2012 decreased by 100-200 times compared to that in 2011. The radiocaesium distribution patterns in strobili, leaves and stems of 2012 samples were almost the same as those of 2011; however, the patterns were different from those of potassium. The radiocaesium removal percentage by food processing (washing + boiling for 2.5min) was 70% in 2011, while that for 2012 samples was 32-72%; the effect of direct deposition and root uptake was not clear. (author)

  17. Hybridization and polyploidy enable genomic plasticity without sex in the most devastating plant-parasitic nematodes.

    Directory of Open Access Journals (Sweden)

    Romain Blanc-Mathieu

    2017-06-01

    Full Text Available Root-knot nematodes (genus Meloidogyne exhibit a diversity of reproductive modes ranging from obligatory sexual to fully asexual reproduction. Intriguingly, the most widespread and devastating species to global agriculture are those that reproduce asexually, without meiosis. To disentangle this surprising parasitic success despite the absence of sex and genetic exchanges, we have sequenced and assembled the genomes of three obligatory ameiotic and asexual Meloidogyne. We have compared them to those of relatives able to perform meiosis and sexual reproduction. We show that the genomes of ameiotic asexual Meloidogyne are large, polyploid and made of duplicated regions with a high within-species average nucleotide divergence of ~8%. Phylogenomic analysis of the genes present in these duplicated regions suggests that they originated from multiple hybridization events and are thus homoeologs. We found that up to 22% of homoeologous gene pairs were under positive selection and these genes covered a wide spectrum of predicted functional categories. To biologically assess functional divergence, we compared expression patterns of homoeologous gene pairs across developmental life stages using an RNAseq approach in the most economically important asexually-reproducing nematode. We showed that >60% of homoeologous gene pairs display diverged expression patterns. These results suggest a substantial functional impact of the genome structure. Contrasting with high within-species nuclear genome divergence, mitochondrial genome divergence between the three ameiotic asexuals was very low, signifying that these putative hybrids share a recent common maternal ancestor. Transposable elements (TE cover a ~1.7 times higher proportion of the genomes of the ameiotic asexual Meloidogyne compared to the sexual relative and might also participate in their plasticity. The intriguing parasitic success of asexually-reproducing Meloidogyne species could be partly explained by

  18. Automated Root Tracking with "Root System Analyzer"

    Science.gov (United States)

    Schnepf, Andrea; Jin, Meina; Ockert, Charlotte; Bol, Roland; Leitner, Daniel

    2015-04-01

    Crucial factors for plant development are water and nutrient availability in soils. Thus, root architecture is a main aspect of plant productivity and needs to be accurately considered when describing root processes. Images of root architecture contain a huge amount of information, and image analysis helps to recover parameters describing certain root architectural and morphological traits. The majority of imaging systems for root systems are designed for two-dimensional images, such as RootReader2, GiA Roots, SmartRoot, EZ-Rhizo, and Growscreen, but most of them are semi-automated and involve mouse-clicks in each root by the user. "Root System Analyzer" is a new, fully automated approach for recovering root architectural parameters from two-dimensional images of root systems. Individual roots can still be corrected manually in a user interface if required. The algorithm starts with a sequence of segmented two-dimensional images showing the dynamic development of a root system. For each image, morphological operators are used for skeletonization. Based on this, a graph representation of the root system is created. A dynamic root architecture model helps to determine which edges of the graph belong to an individual root. The algorithm elongates each root at the root tip and simulates growth confined within the already existing graph representation. The increment of root elongation is calculated assuming constant growth. For each root, the algorithm finds all possible paths and elongates the root in the direction of the optimal path. In this way, each edge of the graph is assigned to one or more coherent roots. Image sequences of root systems are handled in such a way that the previous image is used as a starting point for the current image. The algorithm is implemented in a set of Matlab m-files. Output of Root System Analyzer is a data structure that includes for each root an identification number, the branching order, the time of emergence, the parent

  19. Root bacterial endophytes confer drought resistance and enhance expression and activity of a vacuolar H+ -pumping pyrophosphatase in pepper plants.

    Science.gov (United States)

    Vigani, Gianpiero; Rolli, Eleonora; Marasco, Ramona; Dell'Orto, Marta; Michoud, Grégoire; Soussi, Asma; Raddadi, Noura; Borin, Sara; Sorlini, Claudia; Zocchi, Graziano; Daffonchio, Daniele

    2018-05-22

    It has been previously shown that the transgenic overexpression of the plant root vacuolar proton pumps H + -ATPase (V-ATPase) and H + -PPase (V-PPase) confer tolerance to drought. Since plant-root endophytic bacteria can also promote drought tolerance, we hypothesize that such promotion can be associated to the enhancement of the host vacuolar proton pumps expression and activity. To test this hypothesis, we selected two endophytic bacteria endowed with an array of in vitro plant growth promoting traits. Their genome sequences confirmed the presence of traits previously shown to confer drought resistance to plants, such as the synthesis of nitric oxide and of organic volatile organic compounds. We used the two strains on pepper (Capsicuum annuum L.) because of its high sensitivity to drought. Under drought conditions, both strains stimulated a larger root system and enhanced the leaves' photosynthetic activity. By testing the expression and activity of the vacuolar proton pumps, H + -ATPase (V-ATPase) and H + -PPase (V-PPase), we found that bacterial colonization enhanced V-PPase only. We conclude that the enhanced expression and activity of V-PPase can be favoured by the colonization of drought-tolerance-inducing bacterial endophytes. This article is protected by copyright. All rights reserved. © 2018 Society for Applied Microbiology and John Wiley & Sons Ltd.

  20. The Mechanism Forming the Cell Surface of Tip-Growing Rooting Cells Is Conserved among Land Plants.

    Science.gov (United States)

    Honkanen, Suvi; Jones, Victor A S; Morieri, Giulia; Champion, Clement; Hetherington, Alexander J; Kelly, Steve; Proust, Hélène; Saint-Marcoux, Denis; Prescott, Helen; Dolan, Liam

    2016-12-05

    To discover mechanisms that controlled the growth of the rooting system in the earliest land plants, we identified genes that control the development of rhizoids in the liverwort Marchantia polymorpha. 336,000 T-DNA transformed lines were screened for mutants with defects in rhizoid growth, and a de novo genome assembly was generated to identify the mutant genes. We report the identification of 33 genes required for rhizoid growth, of which 6 had not previously been functionally characterized in green plants. We demonstrate that members of the same orthogroup are active in cell wall synthesis, cell wall integrity sensing, and vesicle trafficking during M. polymorpha rhizoid and Arabidopsis thaliana root hair growth. This indicates that the mechanism for constructing the cell surface of tip-growing rooting cells is conserved among land plants and was active in the earliest land plants that existed sometime more than 470 million years ago [1, 2]. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  1. Colonization on root surface by a phenanthrene-degrading endophytic bacterium and its application for reducing plant phenanthrene contamination.

    Directory of Open Access Journals (Sweden)

    Juan Liu

    Full Text Available A phenanthrene-degrading endophytic bacterium, Pn2, was isolated from Alopecurus aequalis Sobol grown in soils contaminated with polycyclic aromatic hydrocarbons (PAHs. Based on morphology, physiological characteristics and the 16S rRNA gene sequence, it was identified as Massilia sp. Strain Pn2 could degrade more than 95% of the phenanthrene (150 mg · L(-1 in a minimal salts medium (MSM within 48 hours at an initial pH of 7.0 and a temperature of 30 °C. Pn2 could grow well on the MSM plates with a series of other PAHs, including naphthalene, acenaphthene, anthracene and pyrene, and degrade them to different degrees. Pn2 could also colonize the root surface of ryegrass (Lolium multiflorum Lam, invade its internal root tissues and translocate into the plant shoot. When treated with the endophyte Pn2 under hydroponic growth conditions with 2 mg · L(-1 of phenanthrene in the Hoagland solution, the phenanthrene concentrations in ryegrass roots and shoots were reduced by 54% and 57%, respectively, compared with the endophyte-free treatment. Strain Pn2 could be a novel and useful bacterial resource for eliminating plant PAH contamination in polluted environments by degrading the PAHs inside plants. Furthermore, we provide new perspectives on the control of the plant uptake of PAHs via endophytic bacteria.

  2. GROWTH AND ARCHITECTURE OF ROOT SYSTEMS OF PLANTS OF Eucalyptus camaldulensis, E. GRANDIS AND E. PELLITA WERE EVALUATED AFTER THE PLANTING

    Directory of Open Access Journals (Sweden)

    Paulo Sérgio dos Santos Leles

    2001-01-01

    Full Text Available The seedlings were produced according to two methodologies: pressed blocks and stiff plastic tubes. A mixture of decomposed sugar-cane bagasse (60% and industrial sugar-cane plant residues (40% were used as substrate. The blocks were made by pressing the humid substrate in metallic moulds with the dimensions of 60 x 40 x 20 cm (lenght, width and height and pressure of 10 kgf/cm2 for 15 minutes. Under this load the blocks height was reduced to 10 cm. They were placed in wooden boxes with screen bottom. The stiff plastic tubes had circular section 12 cm high, with volume capacity of 50 cm3. The seeds were sown in the blocks 5 cm apart, by means of a spatula. At the end of nursey phase, the seedlings were planted the field. After 2, 6 and 10 months of planting, the height and the diameter at the ground level were evaluated. At the age of 10 months it was also evaluated the number of laterals root and deformatiom cofficient the three plants for treatment. Two months after planting, the plants originated from the pressed blocks showed growth highly signifficant in relation to those of the stiff plastic tubes. At 10 months, of age only Eucalyptus grandis seedlings showed significant difference concerning to height and diameter at the ground level between plants produced by pressed blocks and stiff plastic tubes. For the three species, the pressed blocks seedling showed higher number of lateral roots and smaller number of root deformation coefficents in comparision to the plants from the stiff tubes.

  3. Primary physical mechanism of different magnetic fields action on roots of some plants

    Directory of Open Access Journals (Sweden)

    N. V. Sheykina

    2017-12-01

    Full Text Available Background: Though the magnetic field action on biological object is proved now by many experiments it cannot be explained. The counterarguments are the small value of magnetic induction, that is effective for static magnetic field and the small value of ions free path length for ion cyclotron resonance presence.   Objectives of the article were to generalize all the results that had been obtained before in static, alternative and combined magnetic fields and to explain all results by one and the same primary physical mechanism. Materials and methods that were used to obtain experimental results were based on the using of well reproducible magnetic conditions. For this purpose 3 lays µ-metal shield and superconductive shield with warm volume were used. The artificial magnetic field was created in the shield. The objects of the investigation were roots of cress, maize and pea. Their gravitropic reaction was studied. Results and discussion: All experimental results were compared with the theories and calculations maid before and following from the three mechanisms proposed below.  It was shown that there were three physical primary mechanisms that could lead to effect of low frequency alternative and combined magnetic fields and permanent magnetic field on gravitropic reaction in plants. All of them depended on the relative location of roots, gravity and components of permanent and alternative magnetic fields between themselves. The first mechanism is based on the classic model of the rotation of ions in the plane that is perpendicular to the magnetic field direction or precession of magnetic moments round the direction of magnetic field vector. The second mechanism is connected with the piezoelectric properties of starch grain (porous piezoelectricity. This property of starch may create the change in the moving of starch grains in alternative and combined magnetic fields, and even in static one. The third mechanism is caused by the phase

  4. Mapping soil deformation around plant roots using in vivo 4D X-ray Computed Tomography and Digital Volume Correlation.

    Science.gov (United States)

    Keyes, S D; Gillard, F; Soper, N; Mavrogordato, M N; Sinclair, I; Roose, T

    2016-06-14

    The mechanical impedance of soils inhibits the growth of plant roots, often being the most significant physical limitation to root system development. Non-invasive imaging techniques have recently been used to investigate the development of root system architecture over time, but the relationship with soil deformation is usually neglected. Correlative mapping approaches parameterised using 2D and 3D image data have recently gained prominence for quantifying physical deformation in composite materials including fibre-reinforced polymers and trabecular bone. Digital Image Correlation (DIC) and Digital Volume Correlation (DVC) are computational techniques which use the inherent material texture of surfaces and volumes, captured using imaging techniques, to map full-field deformation components in samples during physical loading. Here we develop an experimental assay and methodology for four-dimensional, in vivo X-ray Computed Tomography (XCT) and apply a Digital Volume Correlation (DVC) approach to the data to quantify deformation. The method is validated for a field-derived soil under conditions of uniaxial compression, and a calibration study is used to quantify thresholds of displacement and strain measurement. The validated and calibrated approach is then demonstrated for an in vivo test case in which an extending maize root in field-derived soil was imaged hourly using XCT over a growth period of 19h. This allowed full-field soil deformation data and 3D root tip dynamics to be quantified in parallel for the first time. This fusion of methods paves the way for comparative studies of contrasting soils and plant genotypes, improving our understanding of the fundamental mechanical processes which influence root system development. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Roles for root iron plaque in sequestration and uptake of heavy metals and metalloids in aquatic and wetland plants.

    Science.gov (United States)

    Tripathi, Rudra D; Tripathi, Preeti; Dwivedi, Sanjay; Kumar, Amit; Mishra, Aradhana; Chauhan, Puneet S; Norton, Gareth J; Nautiyal, Chandra S

    2014-10-01

    Toxic metal(loid) contamination of soil and sediment poses long term risk to soil and human health through plant-human or plant-animal-human food chain pathways. Iron plaque (IP) formation is frequent in aquatic and wetland plant species and is responsible for the sequestration of various metal(loids). The presence of IP may act as a buffer or barrier and may thus enhance or reduce the uptake of potentially phytotoxic metals and metalloids by plants. If IP acts as a barrier, then low IP producing macrophytes/aquatic plants may be better accumulators of toxic metals and may find use in constructed wetlands for remediation of pollutants, while high IP forming edible plant species could be safer for human consumption. Conversely, if IP acts as a buffer for mineral nutrients and toxic elements then those cultivars may be rich in nutrients, but may also cause toxicity. However, an ecotoxicological risk is also inevitable if IP rich macrophyte roots containing heavy metals are consumed by herbivores. In this review, we summarize the current understanding about the role of IP in metal and metalloid sequestration, uptake, and transport. Furthermore, we will address the role of root IP in Oryza sativa for arsenic (As) sequestration leading to lower grain As translocation, reducing the risk of human exposure.

  6. Chromosomal abnormalities in roots of aquatic plant Elodea canadensis as a tool for testing genotoxicity of bottom sediments.

    Science.gov (United States)

    Zotina, Tatiana; Medvedeva, Marina; Trofimova, Elena; Alexandrova, Yuliyana; Dementyev, Dmitry; Bolsunovsky, Alexander

    2015-12-01

    Submersed freshwater macrophytes are considered as relevant indicators for use in bulk bottom sediment contact tests. The purpose of this study was to estimate the validity of endpoints of aquatic plant Elodea canadensis for laboratory genotoxicity testing of natural bottom sediments. The inherent level of chromosome abnormalities (on artificial sediments) in roots of E. canadensis under laboratory conditions was lower than the percentage of abnormal cells in bulk sediments from the Yenisei River. The percentage of abnormal cells in roots of E. canadensis was more sensitive to the presence of genotoxic agents in laboratory contact tests than in the natural population of the plant. The spectra of chromosomal abnormalities that occur in roots of E. canadensis under natural conditions in the Yenisei River and in laboratory contact tests on the bulk bottom sediments from the Yenisei River were similar. Hence, chromosome abnormalities in roots of E. canadensis can be used as a relevant and sensitive genotoxicity endpoint in bottom sediment-contact tests. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Biomass production and control of nutrient leaching of willows using different planting methods with special emphasis on an appraisal of the electrical impedance for roots

    Energy Technology Data Exchange (ETDEWEB)

    Yang Cao

    2011-07-01

    Willow reproduction can be achieved through vertically or horizontally planted cuttings. Conventionally, plantations are established by inserting cuttings vertically into the soil. There is, however, a lack of information about the biomass production and nutrient leaching of plantations established through horizontally planted cuttings. A greenhouse experiment and a field trial were carried out to investigate whether horizontally planted Salix schwerinii cuttings have a positive effect on stem yield, root distribution and nutrient leaching in comparison with vertically planted cuttings with different planting densities. The shoots' height of horizontally planted cuttings was significantly smaller than that of vertically planted cuttings during the first two weeks after planting in the pot experiment. Thereafter, no significant effect of planting orientation on the stem biomass was observed in the two conducted experiments. In both experiments the total stem biomass increased with the planting density. It was also found that the fine root biomass and the specific root length were not affected by the planting orientation or density, while the fine root surface area and the absorbing root surface area (ARSA) were affected only by the planting density. The planting orientation did not affect the nutrient concentrations in the soil leachate, apart from SO{sub 4}-S and PO{sub 4}-P in the pot experiment. The ARSA in the pot experiment was assessed by using the earth impedance method. The applicability of this method was evaluated in a hydroponic study of willow cuttings where root and stem were measured independently. Electrical resistance had a good correlation with the contact area of the roots with the solution. However, the resistance depended strongly on the contact area of the stem with the solution, which caused a bias in the evaluation of root surface area. A similar experimental set-up with electrical impedance spectroscopy was employed to study the

  8. Dissecting host plant manipulation by cyst and root-knot nematodes

    NARCIS (Netherlands)

    Karczmarek, A.

    2006-01-01

    Cyst ( Globodera spp. and Heterodera spp.) and root-knot nematodes ( Meloidogyne spp.), one of the most damaging crop pests, are a perfect example of highly adapted, sophisticated root parasites. These nematodes induces specialized feeding structures (cyst

  9. Simulating the partitioning of biomass and nitrogen between roots and shoot in crop and grass plants

    NARCIS (Netherlands)

    Yin, X.; Schapendonk, A.H.C.M.

    2004-01-01

    Quantification of the assimilate partitioning between roots and shoot has been one of the components that need improvement in crop growth models. In this study we derived two equations for root-shoot partitioning of biomass and nitrogen (N) that hold for crops grown under steady-state conditions.

  10. A root-bound index for evaluating planting stock quality of container ...

    African Journals Online (AJOL)

    Pot-binding can adversely affect the performance of container-grown stock. One factor that affects potbinding is the size of the root system in relation to the size of the container. The aim of this study was to determine if an objective root-bound index (RBI) would be useful when evaluating the quality of pines grown in various ...

  11. Elucidation of in-vitro anti-inflammatory bioactive compounds isolated from Jatropha curcas L. plant root.

    Science.gov (United States)

    Othman, Ahmad Razi; Abdullah, Norhani; Ahmad, Syahida; Ismail, Intan Safinar; Zakaria, Mohamad Pauzi

    2015-02-05

    The Jatropha curcas plant or locally known as "Pokok Jarak" has been widely used in traditional medical applications. This plant is used to treat various conditions such as arthritis, gout, jaundice, wound and inflammation. However, the nature of compounds involved has not been well documented. Hence, this study was conducted to investigate the anti-inflammatory activity of different parts of J. curcas plant and to identify the active compounds involved. In this study, methanol (80%) extraction of four different parts (leaves, fruits, stem and root) of J. curcas plant was carried out. Phenolic content of each part was determined by using Folin-Ciocalteau reagent. Gallic acid was used as the phenol standard. Each plant part was screened for anti-inflammatory activity using cultured macrophage RAW 264.7 cells. The active plant part was then partitioned with hexane, chloroform, ethyl acetate and water. Each partition was again screened for anti-inflammatory activity. The active partition was then fractionated using an open column chromatography system. Single spots isolated from column chromatography were assayed for anti-inflammatory and cytotoxicity activities. Spots that showed activity were subjected to gas chromatography mass spectrophotometry (GC-MS) analysis for identification of active metabolites. The hexane partition from root extract showed the highest anti-inflammatory activity. However, it also showed high cytotoxicity towards RAW 264.7 cells at 1 mg/mL. Fractionation process using column chromatography showed five spots. Two spots labeled as H-4 and H-5 possessed anti-inflammatory activity, without cytotoxicity activity. Analysis of both spots by GC-MS showed the presence of hexadecanoic acid methyl ester, octadecanoic acid methyl ester and octadecanoic acid. This finding suggests that hexadecanoic acid methyl ester, octadecanoic acid methyl ester and octadecanoic acid could be responsible for the anti-inflammatory activity of the J. curcas root extract.

  12. Shoot to root communication is necessary to control the expression of iron-acquisition genes in Strategy I plants.

    Science.gov (United States)

    García, María J; Romera, Francisco J; Stacey, Minviluz G; Stacey, Gary; Villar, Eduardo; Alcántara, Esteban; Pérez-Vicente, Rafael

    2013-01-01

    Previous research showed that auxin, ethylene, and nitric oxide (NO) can activate the expression of iron (Fe)-acquisition genes in the roots of Strategy I plants grown with low levels of Fe, but not in plants grown with high levels of Fe. However, it is still an open question as to how Fe acts as an inhibitor and which pool of Fe (e.g., root, phloem, etc.) in the plant acts as the key regulator for gene expression control. To further clarify this, we studied the effect of the foliar application of Fe on the expression of Fe-acquisition genes in several Strategy I plants, including wild-type cultivars of Arabidopsis [Arabidopsis thaliana (L.) Heynh], pea [Pisum sativum L.], tomato [Solanum lycopersicon Mill.], and cucumber [Cucumis sativus L.], as well as mutants showing constitutive expression of Fe-acquisition genes when grown under Fe-sufficient conditions [Arabidopsis opt3-2 and frd3-3, pea dgl and brz, and tomato chln (chloronerva)]. The results showed that the foliar application of Fe blocked the expression of Fe-acquisition genes in the wild-type cultivars and in the frd3-3, brz, and chln mutants, but not in the opt3-2 and dgl mutants, probably affected in the transport of a Fe-related repressive signal in the phloem. Moreover, the addition of either ACC (ethylene precursor) or GSNO (NO donor) to Fe-deficient plants up-regulated the expression of Fe-acquisition genes, but this effect did not occur in Fe-deficient plants sprayed with foliar Fe, again suggesting the existence of a Fe-related repressive signal moving from leaves to roots.

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

    Directory of Open Access Journals (Sweden)

    Ramona Marasco

    2013-01-01

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

  14. Computational investigation of small RNAs in the establishment of root nodules and arbuscular mycorrhiza in leguminous plants.

    Science.gov (United States)

    Jin, Danfeng; Meng, Xianwen; Wang, Yue; Wang, Jingjing; Zhao, Yuhua; Chen, Ming

    2018-01-03

    Many small RNAs have been confirmed to play important roles in the development of root nodules and arbuscular mycorrhiza. In this study, we carried out the identification of certain small RNAs in leguminous plants (Medicago truncatula, soybean, peanut and common bean), such as miRNAs, tRFs and srRNAs, as well as the computational investigation of their regulations. Thirty miRNAs were predicted to be involved in establishing root nodules and mycorrhiza, and 12 of them were novel in common bean and peanut. The generation of tRFs in M. truncatula was not associated with tRNA gene frequencies and codon usage. Six tRFs exhibited different expressions in mycorrhiza and root nodules. Moreover, srRNA 5.8S in M. truncatula was generated from the regions with relatively low conservation at the rRNA 3' terminal. The protein-protein interactions between the proteins encoded by the target genes of miRNAs, tRFs and srRNAs were computed. The regulation of these three types of sRNAs in the symbiosis between leguminous plants and microorganisms is not a single regulation of certain signaling or metabolic pathways but a global regulation for the plants to own growth or specific events in symbiosis.

  15. An in vivo root hair assay for determining rates of apoptotic-like programmed cell death in plants

    Directory of Open Access Journals (Sweden)

    Hogg Bridget V

    2011-12-01

    Full Text Available Abstract In Arabidopsis thaliana we demonstrate that dying root hairs provide an easy and rapid in vivo model for the morphological identification of apoptotic-like programmed cell death (AL-PCD in plants. The model described here is transferable between species, can be used to investigate rates of AL-PCD in response to various treatments and to identify modulation of AL-PCD rates in mutant/transgenic plant lines facilitating rapid screening of mutant populations in order to identify genes involved in AL-PCD regulation.

  16. Root system markup language: toward a unified root architecture description language.

    Science.gov (United States)

    Lobet, Guillaume; Pound, Michael P; Diener, Julien; Pradal, Christophe; Draye, Xavier; Godin, Christophe; Javaux, Mathieu; Leitner, Daniel; Meunier, Félicien; Nacry, Philippe; Pridmore, Tony P; Schnepf, Andrea

    2015-03-01

    The number of image analysis tools supporting the extraction of architectural features of root systems has increased in recent years. These tools offer a handy set of complementary facilities, yet it is widely accepted that none of these software tools is able to extract in an efficient way the growing array of static and dynamic features for different types of images and species. We describe the Root System Markup Language (RSML), which has been designed to overcome two major challenges: (1) to enable portability of root architecture data between different software tools in an easy and interoperable manner, allowing seamless collaborative work; and (2) to provide a standard format upon which to base central repositories that will soon arise following the expanding worldwide root phenotyping effort. RSML follows the XML standard to store two- or three-dimensional image metadata, plant and root properties and geometries, continuous functions along individual root paths, and a suite of annotations at the image, plant, or root scale at one or several time points. Plant ontologies are used to describe botanical entities that are relevant at the scale of root system architecture. An XML schema describes the features and constraints of RSML, and open-source packages have been developed in several languages (R, Excel, Java, Python, and C#) to enable researchers to integrate RSML files into popular research workflow. © 2015 American Society of Plant Biologists. All Rights Reserved.

  17. Use of ex vitro composite plants to study the interaction of cowpea (Vigna unguiculata L.) with the root parasitic angiosperm Striga gesnerioides

    Science.gov (United States)

    2012-01-01

    Background Cowpea (Vigna unguiculata L.) is an important grain and forage legume grown throughout sub-Saharan Africa primarily by subsistence farmers on poor, drought prone soils. Genetic improvement of the crop is being actively pursued and numerous functional genomics studies are underway aimed at characterizing gene controlling key agronomic characteristics for disease and pest resistances. Unfortunately, similar to other legumes, efficient plant transformation technology is a rate-limiting step in analysis of gene function in cowpea. Results Here we describe an optimized protocol for the rapid generation of transformed hairy roots on ex vitro composite plants of cowpea using Agrobacterium rhizogenes. We further demonstrate the applicability of cowpea composite plants to study gene expression involved in the resistance response of the plant roots to attack by the root parasitic weed, Striga gesnerioides. The utility of the new system and critical parameters of the method are described and discussed herein. Conclusions Cowpea composite plants offer a rapid alternative to methods requiring stable transformation and whole plant regeneration for studying gene expression in resistance or susceptibility responses to parasitic weeds. Their use can likely be readily adapted to look at the effects of both ectopic gene overexpression as well as gene knockdown of root associated defense responses and to the study of a broader range of root associated physiological and aphysiological processes including root growth and differentiation as well as interactions with other root pests, parasites, and symbionts. PMID:22741546

  18. Physiological, vascular and nanomechanical assessment of hybrid poplar leaf traits in micropropagated plants and plants propagated from root cuttings: A contribution to breeding programs.

    Science.gov (United States)

    Ďurkovič, Jaroslav; Husárová, Hana; Javoříková, Lucia; Čaňová, Ingrid; Šuleková, Miriama; Kardošová, Monika; Lukáčik, Ivan; Mamoňová, Miroslava; Lagaňa, Rastislav

    2017-09-01

    Micropropagated plants experience significant stress from rapid water loss when they are transferred from an in vitro culture to either greenhouse or field conditions. This is caused both by inefficient stomatal control of transpiration and the change to a higher light intensity and lower humidity. Understanding the physiological, vascular and biomechanical processes that allow micropropagated plants to modify their phenotype in response to environmental conditions can help to improve both field performance and plant survival. To identify changes between the hybrid poplar [Populus tremula × (Populus × canescens)] plants propagated from in vitro tissue culture and those from root cuttings, we assessed leaf performance for any differences in leaf growth, photosynthetic and vascular traits, and also nanomechanical properties of the tracheary element cell walls. The micropropagated plants showed significantly higher values for leaf area, leaf length, leaf width and leaf dry mass. The greater leaf area and leaf size dimensions resulted from the higher transpiration rate recorded for this stock type. Also, the micropropagated plants reached higher values for chlorophyll a fluorescence parameters and for the nanomechanical dissipation energy of tracheary element cell walls which may indicate a higher damping capacity within the primary xylem tissue under abiotic stress conditions. The performance of the plants propagated from root cuttings was superior for instantaneous water-use efficiency which signifies a higher acclimation capacity to stressful conditions during a severe drought particularly for this stock type. Similarities were found among the majority of the examined leaf traits for both vegetative plant origins including leaf mass per area, stomatal conductance, net photosynthetic rate, hydraulic axial conductivity, indicators of leaf midrib vascular architecture, as well as for the majority of cell wall nanomechanical traits. This research revealed that

  19. Expression of Arabidopsis genes AtNPR1 and AtTGA2 in transgenic soybean roots of composite plants confers resistance to root-knot nematode (Meloidogyne incognita)

    Science.gov (United States)

    Root-knot nematodes (RKN; Meloidogyne spp.) are among the most destructive of the plant parasitic nematodes, infecting almost all cultivated plants and resulting in yield losses of billions of dollars annually. NPR1 (nonexpresser of pathogenesis related genes 1, AtNPR1) plays a positive role in the ...

  20. Striga seed-germination activity of root exudates and compounds present in stems of Striga host and nonhost (trap crop) plants is reduced due to root colonization by arbuscular mycorrhizal fungi.

    NARCIS (Netherlands)

    Lendzemo, V.W.; Kuyper, T.W.; Vierheilig, H.

    2009-01-01

    Root colonization by arbuscular mycorrhizal (AM) fungi reduces stimulation of seed germination of the plant parasite Striga (Orobanchaceae). This reduction can affect not only host plants for Striga, resulting in a lower parasite incidence, but also false hosts or trap crops, which induce suicidal

  1. Growth of plant root cultures in liquid- and gas-dispersed reactor environments.

    Science.gov (United States)

    McKelvey, S A; Gehrig, J A; Hollar, K A; Curtis, W R

    1993-01-01

    The growth of Agrobacterium transformed "hairy root" cultures of Hyoscyamus muticus was examined in various liquid- and gas-dispersed bioreactor configurations. Reactor runs were replicated to provide statistical comparisons of nutrient availability on culture performance. Accumulated tissue mass in submerged air-sparged reactors was 31% of gyratory shake-flask controls. Experiments demonstrate that poor performance of sparged reactors is not due to bubble shear damage, carbon dioxide stripping, settling, or flotation of roots. Impaired oxygen transfer due to channeling and stagnation of the liquid phase are the apparent causes of poor growth. Roots grown on a medium-perfused inclined plane grew at 48% of gyratory controls. This demonstrates the ability of cultures to partially compensate for poor liquid distribution through vascular transport of nutrients. A reactor configuration in which the medium is sprayed over the roots and permitted to drain down through the root tissue was able to provide growth rates which are statistically indistinguishable (95% T-test) from gyratory shake-flask controls. In this type of spray/trickle-bed configuration, it is shown that distribution of the roots becomes a key factor in controlling the rate of growth. Implications of these results regarding design and scale-up of bioreactors to produce fine chemicals from root cultures are discussed.

  2. Inhibition of ethylene production by putrescine alleviates aluminium-induced root inhibition in wheat plants.

    Science.gov (United States)

    Yu, Yan; Jin, Chongwei; Sun, Chengliang; Wang, Jinghong; Ye, Yiquan; Zhou, Weiwei; Lu, Lingli; Lin, Xianyong

    2016-01-08

    Inhibition of root elongation is one of the most distinct symptoms of aluminium (Al) toxicity. Although putrescine (Put) has been identified as an important signaling molecule involved in Al tolerance, it is yet unknown how Put mitigates Al-induced root inhibition. Here, the possible mechanism was investigated by using two wheat genotypes differing in Al resistance: Al-tolerant Xi Aimai-1 and Al-sensitive Yangmai-5. Aluminium caused more root inhibition in Yangmai-5 and increased ethylene production at the root apices compared to Xi Aimai-1, whereas the effects were significantly reversed by ethylene biosynthesis inhibitors. The simultaneous exposure of wheat seedlings to Al and ethylene donor, ethephon, or ethylene biosynthesis precursor, 1-aminocyclopropane-1-carboxylic acid (ACC), increased ethylene production and aggravated root inhibition, which was more pronounced in Xi Aimai-1. In contrast, Put treatment decreased ethylene production and alleviated Al-induced root inhibition in both genotypes, and the effects were more conspicuous in Yangmai-5. Furthermore, our results indicated that Al-induced ethylene production was mediated by ACC synthase (ACS) and ACC oxidase, and that Put decreased ethylene production by inhibiting ACS. Altogether, these findings indicate that ethylene is involved in Al-induced root inhibition and this process could be alleviated by Put through inhibiting ACS activity.

  3. Metaproteomic identification of diazotrophic methanotrophs and their localization in root tissues of field-grown rice plants.

    Science.gov (United States)

    Bao, Zhihua; Okubo, Takashi; Kubota, Kengo; Kasahara, Yasuhiro; Tsurumaru, Hirohito; Anda, Mizue; Ikeda, Seishi; Minamisawa, Kiwamu

    2014-08-01

    In a previous study by our group, CH4 oxidation and N2 fixation were simultaneously activated in the roots of wild-type rice plants in a paddy field with no N input; both processes are likely controlled by a rice gene for microbial symbiosis. The present study examined which microorganisms in rice roots were responsible for CH4 oxidation and N2 fixation under the field conditions. Metaproteomic analysis of root-associated bacteria from field-grown rice (Oryza sativa Nipponbare) revealed that nitrogenase complex-containing nitrogenase reductase (NifH) and the alpha subunit (NifD) and beta subunit (NifK) of dinitrogenase were mainly derived from type II methanotrophic bacteria of the family Methylocystaceae, including Methylosinus spp. Minor nitrogenase proteins such as Methylocella, Bradyrhizobium, Rhodopseudomonas, and Anaeromyxobacter were also detected. Methane monooxygenase proteins (PmoCBA and MmoXYZCBG) were detected in the same bacterial group of the Methylocystaceae. Because these results indicated that Methylocystaceae members mediate both CH4 oxidation and N2 fixation, we examined their localization in rice tissues by using catalyzed reporter deposition-fluorescence in situ hybridization (CARD-FISH). The methanotrophs were localized around the epidermal cells and vascular cylinder in the root tissues of the field-grown rice plants. Our metaproteomics and CARD-FISH results suggest that CH4 oxidation and N2 fixation are performed mainly by type II methanotrophs of the Methylocystaceae, including Methylosinus spp., inhabiting the vascular bundles and epidermal cells of rice roots. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  4. Can liming change root anatomy, biomass allocation and trace element distribution among plant parts of Salix × smithiana in trace element-polluted soils?

    Science.gov (United States)

    Vondráčková, Stanislava; Tlustoš, Pavel; Száková, Jiřina

    2017-08-01

    Willows (Salix spp.) are considered to be effective for the phytoremediation of trace elements from contaminated soils, but their efficiency is limited in heavily polluted soils because of poor growth. Liming can be a desirable measure to decrease the plant availability of elements, resulting in improved plant development. Notably, large root area and maximum soil penetration are basic parameters that improve the efficiency of phytoremediation. The impact of soil chemical properties on willow root anatomy and the distribution of trace elements below-ground have rarely been studied. The effect of liming on root parameters, biomass allocation and trace element distribution in non-harvestable (coarse roots, fine roots, stumps) and harvestable plant parts (twigs and leaves) of Salix × smithiana was assessed at the end of a 4-year pot experiment with two trace element-polluted soils that differed in terms of soil pH. Stump biomass predominated in weakly acidic soil. In neutral soil, the majority of biomass was located in fine roots and stumps; the difference from other plant parts was minor. Trace elements were the most concentrated in fine roots. Translocation to above-ground biomass increased as follows: Pb roots roots). Lime application decreased the concentrations of mobile Cd and Zn and related levels in plants, improved biomass production and root parameters and increased the removal of all trace elements in weakly acidic soil. None or minimum differences in the monitored parameters were recorded for dolomite treatments in both soils. The dose and source of liming had crucial effects on root anatomy. Growing willows in limed trace element-polluted soils is a suitable measure for combination of two remediation strategies, i.e. phytoextraction of Cd and Zn and assisted phytostabilization of As and Pb.

  5. Biocontrol traits of plant growth suppressive arbuscular mycorrhizal fungi against root rot in tomato caused by Pythium aphanidermatum

    DEFF Research Database (Denmark)

    Larsen, John; Graham, James H.; Cubero, Jaime

    2012-01-01

    Arbuscular mycorrhizal (AM) fungi known to cause plant growth depressions in tomato were examined for their biocontrol effects against root rot caused by Pythium aphanidermatum. The main hypothesis was that plant growth suppressive AM fungi would elicit a defence response in the host plant reduci...

  6. CO2 fixation in alfalfa and birdsfoot trefoil root nodules and partitioning of 14C to the plant

    International Nuclear Information System (INIS)

    Maxwell, C.A.; Vance, C.P.; Heichel, G.H.; Stade, S.

    1984-01-01

    The objectives of this study were to determine if nonphotosynthetic CO 2 fixation by root nodules contributes carbon for the assimilation of fixed N 2 in alfalfa (Medicago sativa L.) and birdsfoot trefoil (Lotus corniculatus L.) and if assimilation products are partitioned to different plant organs. Effective alfalfa nodules excised from or attached to roots had apparent 14 CO 2 fixation rates of 50 to 80 μg CO 2 kg -1 s -1 (dry weight) at 0.0012 to 0.0038 mole fraction CO 2 . Nodule CO 2 fixation rates increased six- to seven-fold as ambient CO 2 was raised from 0.0038 to 0.0663 mole fraction. Respiration rates of nodules (3 to 4 mg CO 2 kg -1 s -1 ) were 10 to 100-fold higher than 14 CO 2 fixation rates of nodules. Pulse chase experiments with 14 CO 2 combined with nodule and xylem sap analysis demonstrated the initial products of root and nodule CO 2 fixation were organic acids. However, the export of fixed 14 C from effective nodules was primarily in the form of amino acids. In contrast, nodule and/or root fixed 14 C in ineffectively nodulated alfalfa and denodulated effective alfalfa and birdsfoot trefoil was transported primarily as organic acids. Aspartate, asparagine, alanine, glutamate, and glutamine were the most heavily labeled compounds in the amino acid fraction of both effective alfalfa and birdsfoot trefoil nodules exposed to 14 CO 2 . By contrast, asparate, asparagine, and glutamine were the predominantly labeled amino acids in xylem sap collected from nodulated effective roots exposed to 14 CO 2 . The occurrence of nodule CO 2 fixation in alfalfa and birdsfoot trefoil and the export of fixed carbon as asparagine and aspartate to roots and shoots is consistent with a role for CO 2 fixation by nodules in providing carbon skeletons for assimilation and transport of symbiotically fixed N 2

  7. Concerted transcription of auxin and carbohydrate homeostasis-related genes underlies improved adventitious rooting of microcuttings derived from far-red treated Eucalyptus globulus Labill mother plants.

    Science.gov (United States)

    Ruedell, Carolina Michels; de Almeida, Márcia Rodrigues; Fett-Neto, Arthur Germano

    2015-12-01

    Economically important plant species, such as Eucalyptus globulus, are often rooting recalcitrant. We have previously shown that far-red light enrichment applied to E. globulus donor-plants improved microcutting rooting competence and increased rooting zone/shoot carbohydrate ratio. To better understand this developmental response, the relative expression profiles of genes involved in auxin signaling (ARF6, ARF8, AGO1), biosynthesis (YUC3) and transport (AUX1, PIN1, PIN2); sucrose cleavage (SUS1, CWINV1), transport (SUC5), hexose phosphorylation (HXK1, FLN1) and starch biosynthesis (SS3) were quantified during adventitious rooting of E. globulus microcuttings derived from donor plants exposed to far-red or white light. Expression of auxin transport-related genes increased in the first days of root induction. Far-red enrichment of donor plants induced ARF6, ARF8 and AGO1 in microcuttings. The first two gene products could activate GH3 and other rooting related genes, whereas AGO1 deregulation of the repressor ARF17 may relief rooting inhibition. Increased sink strength at the basal stem with sucrose unloading in root tissue mediated by SUC and subsequent hydrolysis by SUS1 were also supported by gene expression profile. Fructose phosphorylation and starch biosynthesis could also contribute to proper carbon allocation at the site of rooting, as evidenced by increased expression of related genes. These data are in good agreement with increased contents of hexoses and starch at the cutting base severed from far-red exposed donor plants. To sum up, pathways integrating auxin and carbohydrate metabolism were activated in microcuttings derived from donor plants exposed to far red light enrichment, thereby improving rooting response in E. globulus. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  8. Bacterial antagonists of fungal pathogens also control root-knot nematodes by induced systemic resistance of tomato plants.

    Directory of Open Access Journals (Sweden)

    Mohamed Adam

    Full Text Available The potential of bacterial antagonists of fungal pathogens to control the root-knot nematode Meloidogyne incognita was investigated under greenhouse conditions. Treatment of tomato seeds with several strains significantly reduced the numbers of galls and egg masses compared with the untreated control. Best performed Bacillus subtilis isolates Sb4-23, Mc5-Re2, and Mc2-Re2, which were further studied for their mode of action with regard to direct effects by bacterial metabolites or repellents, and plant mediated effects. Drenching of soil with culture supernatants significantly reduced the number of egg masses produced by M. incognita on tomato by up to 62% compared to the control without culture supernatant. Repellence of juveniles by the antagonists was shown in a linked twin-pot set-up, where a majority of juveniles penetrated roots on the side without inoculated antagonists. All tested biocontrol strains induced systemic resistance against M. incognita in tomato, as revealed in a split-root system where the bacteria and the nematodes were inoculated at spatially separated roots of the same plant. This reduced the production of egg masses by up to 51%, while inoculation of bacteria and nematodes in the same pot had only a minor additive effect on suppression of M. incognita compared to induced systemic resistance alone. Therefore, the plant mediated effect was the major reason for antagonism rather than direct mechanisms. In conclusion, the bacteria known for their antagonistic potential against fungal pathogens also suppressed M. incognita. Such "multi-purpose" bacteria might provide new options for control strategies, especially with respect to nematode-fungus disease complexes that cause synergistic yield losses.

  9. Bacterial antagonists of fungal pathogens also control root-knot nematodes by induced systemic resistance of tomato plants.

    Science.gov (United States)

    Adam, Mohamed; Heuer, Holger; Hallmann, Johannes

    2014-01-01

    The potential of bacterial antagonists of fungal pathogens to control the root-knot nematode Meloidogyne incognita was investigated under greenhouse conditions. Treatment of tomato seeds with several strains significantly reduced the numbers of galls and egg masses compared with the untreated control. Best performed Bacillus subtilis isolates Sb4-23, Mc5-Re2, and Mc2-Re2, which were further studied for their mode of action with regard to direct effects by bacterial metabolites or repellents, and plant mediated effects. Drenching of soil with culture supernatants significantly reduced the number of egg masses produced by M. incognita on tomato by up to 62% compared to the control without culture supernatant. Repellence of juveniles by the antagonists was shown in a linked twin-pot set-up, where a majority of juveniles penetrated roots on the side without inoculated antagonists. All tested biocontrol strains induced systemic resistance against M. incognita in tomato, as revealed in a split-root system where the bacteria and the nematodes were inoculated at spatially separated roots of the same plant. This reduced the production of egg masses by up to 51%, while inoculation of bacteria and nematodes in the same pot had only a minor additive effect on suppression of M. incognita compared to induced systemic resistance alone. Therefore, the plant mediated effect was the major reason for antagonism rather than direct mechanisms. In conclusion, the bacteria known for their antagonistic potential against fungal pathogens also suppressed M. incognita. Such "multi-purpose" bacteria might provide new options for control strategies, especially with respect to nematode-fungus disease complexes that cause synergistic yield losses.

  10. Effect of exo-polysaccharides producing bacterial inoculation on growth of roots of wheat(Triticum aestivum L. ) plants grown in a salt-affected soil

    International Nuclear Information System (INIS)

    Ashraf, M.; Hasnain, S.; Berge, O.

    2006-01-01

    Effect of soil salinity on physico-chemical and biological properties renders the salt-affected soils unsuitable for soil microbial processes and growth of the crop plants. Soil aggregation around roots of the plants is a function of the bacterial exo-polysaccharides, however, such a role of the EPS-producing bacteria in the saline environments has rarely been investigated. Pot experiments were conducted to observe the effects of inoculating six strains of exo-polysaccharides-producing bacteria on growth of primary (seminal) roots and its relationship with saccharides, cations (Ca 2+, Na +, K +) contents and mass of rhizosheath soils of roots of the wheat plants grown in a salt-affected soil. A strong positive relationship of RS with different root growth parameters indicated that an integrated influence of various biotic and abiotic RS factors would have controlled and promoted growth of roots of the inoculated wheat plants. The increase in root growth in turn could help inoculated wheat plants to withstand the negative effects of soil salinity through an enhanced soil water uptake, a restricted Na +i nflux in the plants and the accelerated soil microbial process involved in cycling and availability of the soil nutrients to the plants. It was concluded that inoculation of the exo- polysaccharides producing would be a valuable tool for amelioration and increasing crop productivity of the salt-affected soils

  11. The Application of Contrast Media for In Vivo Feature Enhancement in X-Ray Computed Tomography of Soil-Grown Plant Roots.

    Science.gov (United States)

    Keyes, Samuel D; Gostling, Neil J; Cheung, Jessica H; Roose, Tiina; Sinclair, Ian; Marchant, Alan

    2017-06-01

    The use of in vivo X-ray microcomputed tomography (μCT) to study plant root systems has become routine, but is often hampered by poor contrast between roots, soil, soil water, and soil organic matter. In clinical radiology, imaging of poorly contrasting regions is frequently aided by the use of radio-opaque contrast media. In this study, we present evidence for the utility of iodinated contrast media (ICM) in the study of plant root systems using μCT. Different dilutions of an ionic and nonionic ICM (Gastrografin 370 and Niopam 300) were perfused into the aerial vasculature of juvenile pea plants via a leaf flap (Pisum sativum). The root systems were imaged via μCT, and a variety of image-processing approaches used to quantify and compare the magnitude of the contrast enhancement between different regions. Though the treatment did not appear to significantly aid extraction of full root system architectures from the surrounding soil, it did allow the xylem and phloem units of seminal roots and the vascular morphology within rhizobial nodules to be clearly visualized. The nonionic, low-osmolality contrast agent Niopam appeared to be well tolerated by the plant, whereas Gastrografin showed evidence of toxicity. In summary, the use of iodine-based contrast media allows usually poorly contrasting root structures to be visualized nondestructively using X-ray μCT. In particular, the vascular structures of roots and rhizobial nodules can be clearly visualized in situ.

  12. Efficacy of four plant extracts in the control of root rot disease of ...

    African Journals Online (AJOL)

    Garcinia cola) and neem (Azadirachta indica) extracts in the control of root rot of cowpea caused by Pythium aphanidermatum was carried out in vitro and in the field (in vivo). They were evaluated for their antifungal activity over P.

  13. A mathematical model for investigating the effect of cluster roots on plant nutrient uptake

    KAUST Repository

    Zygalakis, K. C.; Roose, T.

    2012-01-01

    phase and can also solubilised due to citrate exudation. Using multiple scale homogenisation techniques we derive an effective model that accounts for the cumulative effect of citrate exudation and phosphate uptake by cluster roots whilst still retaining

  14. Nanobiotechnology approach using plant rooting hormone synthesized silver nanoparticle as “nanobullets” for the dynamic applications in horticulture – An in vitro and ex vitro study

    Directory of Open Access Journals (Sweden)

    Raja Muthuramalingam Thangavelu

    2018-01-01

    Full Text Available Horticulture is the branch of agriculture that deals with science and technology and business of plant cultivation and it is considered to be the foremost part of the world economy. Even though, one of the major challenges which has seriously influenced the economic loss of horticulture is rooting of cuttings and root growth inhibiting plant pathogens. To address this issue through nanobiotechnology, we ingeniously build a concept of silver nanoparticles (AgNPs as “nano-bullets” can act for a dual mode like root enhancer and pathogen destroyer on the target site. After that, we succeeded in AgNPs synthesis, using two auxin rooting hormones of Indole-3-acetic acid and Indole-3-butyric acid as a reducing cum stabilizing agent. Further, its efficacy of root promoting and pathogen inhibitory action was sufficiently validated through in vitro and ex vitro studies with model plants and plant pathogens. As a result, the action duality of hormone-stabilized AgNPs was manifested to threefold enhanced root growth compared to controls and it increased the rooting capabilities against root growth inhibiting phytopathogens. This feature was also proved by the direct antifungal assay. Moreover, hormone-AgNPs left no toxicity to treated plants which was revealed by RAPD molecular markers. Therefore, with a detailed study and analysis with instruments such as Spectroscopy, TEM, Zetasizer, FTIR, Cyclic Voltammetry, Fluorescence microscopy (nanoparticles uptake, SEM coupled with EDS (bioaccumulation, TGA (grafting density and PCR (RAPD analysis, this study can unravel the relevance, scope and current challenges at horticulture plants root development and plant disease management for the sustainable agricultural crop production.

  15. Tomato transgenic plants expressing hairpin construct of a nematode protease gene conferred enhanced resistance to root-knot nematodes

    Directory of Open Access Journals (Sweden)

    Tushar Kanti Dutta

    2015-04-01

    Full Text Available Root-knot nematodes (Meloidogyne incognita cause substantial yield losses in vegetables worldwide, and are difficult to manage. Continuous withdrawal of environmentally-harmful nematicides from the global market warrants the need for novel nematode management strategies. Utility of host-delivered RNAi has been demonstrated in several plants (Arabidopsis, tobacco and soybean that exhibited resistance against root-knot and cyst nematodes. Herein, a M. incognita-specific protease gene, cathepsin L cysteine proteinase (Mi-cpl-1, was targeted to generate tomato transgenic lines to evaluate the genetically modified nematode resistance. In vitro knockdown of Mi-cpl-1 gene led to the reduced attraction and penetration of M. incognita in tomato, suggesting the involvement of Mi-cpl-1 in nematode parasitism. Transgenic expression of the RNAi construct of Mi-cpl-1 gene resulted in 60-80% reduction in infection and multiplication of M. incognita in tomato. Evidence for in vitro and in vivo silencing of Mi-cpl-1 was confirmed by expression analysis using quantitative PCR. Our study demonstrates that Mi-cpl-1 plays crucial role during plant-nematode interaction and plant-mediated downregulation of this gene elicits detrimental effect on M. incognita development, reinforcing the potential of RNAi technology for management of phytonematodes in crop plants.

  16. Functionality of resistance gene Hero, which controls plant root-infecting potato cyst nematodes, in leaves of tomato.

    Science.gov (United States)

    Poch, H L Cabrera; López, R H Manzanilla; Kanyuka, K

    2006-07-01

    The expression of host genomes is modified locally by root endoparasitic nematode secretions to induce the development of complex cellular structures referred as feeding sites. In compatible interactions, the feeding sites provide the environment and nutrients for the completion of the nematode's life cycle, whereas in an incompatible (resistant) interaction, the host immune system triggers a plant cell death programme, often in the form of a hypersensitive reaction, which restricts nematode reproduction. These processes have been studied in great detail in organ tissues normally infected by these nematodes: the roots. Here we show that host leaves can support a similar set of programmed developmental events in the potato cyst nematode Globodera rostochiensis life cycle that are typical of the root-invading nematodes. We also show that a gene-for-gene type specific disease resistance that is effective against potato cyst nematodes (PCN) in roots also operates in leaves: the expression of the resistance (R) gene Hero and members of its gene family in leaves correlates with the elicitation of a hypersensitive response only during the incompatible interaction. These findings, and the ability to isolate RNA from relevant parasitic stages of the nematode, may have significant implications for the identification of nematode factors involved in incompatible interactions.

  17. Rapid ammonia gas transport accounts for futile transmembrane cycling under NH3/NH4+ toxicity in plant roots.

    Science.gov (United States)

    Coskun, Devrim; Britto, Dev T; Li, Mingyuan; Becker, Alexander; Kronzucker, Herbert J

    2013-12-01

    Futile transmembrane NH3/NH4(+) cycling in plant root cells, characterized by extremely rapid fluxes and high efflux to influx ratios, has been successfully linked to NH3/NH4(+) toxicity. Surprisingly, the fundamental question of which species of the conjugate pair (NH3 or NH4(+)) participates in such fluxes is unresolved. Using flux analyses with the short-lived radioisotope (13)N and electrophysiological, respiratory, and histochemical measurements, we show that futile cycling in roots of barley (Hordeum vulgare) seedlings is predominately of the gaseous NH3 species, rather than the NH4(+) ion. Influx of (13)NH3/(13)NH4(+), which exceeded 200 µmol g(-1) h(-1), was not commensurate with membrane depolarization or increases in root respiration, suggesting electroneutral NH3 transport. Influx followed Michaelis-Menten kinetics for NH3 (but not NH4(+)), as a function of external concentration (Km = 152 µm, Vmax = 205 µmol g(-1) h(-1)). Efflux of (13)NH3/(13)NH4(+) responded with a nearly identical Km. Pharmacological characterization of influx and efflux suggests mediation by aquaporins. Our study fundamentally revises the futile-cycling model by demonstrating that NH3 is the major permeating species across both plasmalemma and tonoplast of root cells under toxicity conditions.

  18. Plant-specific Histone Deacetylases HDT½ Regulate GIBBERELLIN 2-OXIDASE 2 Expression to Control Arabidopsis Root Meristem Cell Number

    KAUST Repository

    Li, Huchen

    2017-08-31

    Root growth is modulated by environmental factors and depends on cell production in the root meristem (RM). New cells in the meristem are generated by stem cells and transit-amplifying cells, which together determine RM cell number. Transcription factors and chromatin-remodelling factors have been implicated in regulating the switch from stem cells to transit-amplifying cells. Here we show that two Arabidopsis thaliana paralogs encoding plant-specific histone deacetylases, HDT1 and HDT2, regulate a second switch from transit-amplifying cells to expanding cells. Knockdown of HDT½ (hdt1,2i) results in an earlier switch and causes a reduced RM cell number. Our data show that HDT½ negatively regulate the acetylation level of the C19-GIBBERELLIN 2-OXIDASE 2 (GA2ox2) locus and repress the expression of GA2ox2 in the RM and elongation zone. Overexpression of GA2ox2 in the RM phenocopies the hdt1,2i phenotype. Conversely, knockout of GA2ox2 partially rescues the root growth defect of hdt1,2i. These results suggest that by repressing the expression of GA2ox2, HDT½ likely fine-tune gibberellin metabolism and they are crucial for regulating the switch from cell division to expansion to determine RM cell number. We propose that HDT½ function as part of a mechanism that modulates root growth in response to environmental factors.

  19. Rooting of healthy and CVC-affected 'Valência' sweet orange stem cuttings, through the use of plant regulators

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    Gustavo Habermann

    2006-01-01

    Full Text Available Citrus variegated chlorosis (CVC is a disease caused by Xylella fastidiosa. Using different concentrations of plant regulators, such as auxins (indole-3-butyric acid and gibberellic acid biosynthesis-inhibitor (paclobutrazol, physiological rooting capacity of healthy and CVC-affected stem cuttings were evaluated in order to investigate the importance of plant hormone imbalance and xylem occlusion in plants with CVC. The percentages of dead, alive and rooted cuttings, cuttings with callus and mean number of roots per cuttings did not show statistical differences in response to the distinct concentrations of synthetic plant regulators. There were differences only between healthy and CVC-affected cuttings. This showed the importance of xylem occlusion and diffusive disturbances in diseased plants, in relation to root initiation capacity and hormonal translocation in the plant tissue.Clorose variegada dos citros (CVC é uma doença causada por Xylella fastidiosa, podendo determinar oclusão do xilema e desbalanço hormonal, o que por fim está relacionado ao processo de iniciação radicial em estacas. Usando diferentes concentrações de fitorreguladores, como auxinas (ácido 3-indol butírico e inibidores da biossíntese de ácido giberélico (paclobutrazol, que são promotores do enraizamento de estacas, verificou-se a capacidade fisiológica de enraizamento de estacas sadias e com CVC, a fim de investigar a importância do desbalanço hormonal e oclusão do xilema em plantas doentes. As porcentagens de estacas mortas, vivas, enraizadas e com calo e o número médio de raízes por estaca não mostraram diferenças estatísticas em resposta às diferentes concentrações dos reguladores vegetais sintéticos. Houve diferenças apenas entre estacas sadias e doentes. Isto aponta a importância da oclusão do xilema e distúrbios difusivos em plantas doentes, em relação à capacidade de iniciação radicial e à translocação hormonal no tecido

  20. Endophytic Bacteria Improve Plant Growth, Symbiotic Performance of Chickpea (Cicer arietinum L. and Induce Suppression of Root Rot Caused by Fusarium solani under Salt Stress

    Directory of Open Access Journals (Sweden)

    Dilfuza Egamberdieva

    2017-09-01

    Full Text Available Salinity causes disturbance in symbiotic performance of plants, and increases susceptibility of plants to soil-borne pathogens. Endophytic bacteria are an essential determinant of cross-tolerance to biotic and abiotic stresses in plants. The aim of this study was to isolate non–rhizobial endophytic bacteria from the root nodules of chickpea (Cicer arietinum L., and to assess their ability to improve plant growth and symbiotic performance, and to control root rot in chickpea under saline soil conditions. A total of 40 bacterial isolates from internal root tissues of chickpea grown in salinated soil were isolated. Four bacterial isolates, namely Bacillus cereus NUU1, Achromobacter xylosoxidans NUU2, Bacillus thuringiensis NUU3, and Bacillus subtilis NUU4 colonizing root tissue demonstrated plant beneficial traits and/or antagonistic activity against F. solani and thus were characterized in more detail. The strain B. subtilis NUU4 proved significant plant growth promotion capabilities, improved symbiotic performance of host plant with rhizobia, and promoted yield under saline soil as compared to untreated control plants under field conditions. A combined inoculation of chickpea with M. ciceri IC53 and B. subtilis NUU4 decreased H2O2 concentrations and increased proline contents compared to the un-inoculated plants indicating an alleviation of adverse effects of salt stress. Furthermore, the bacterial isolate was capable to reduce the infection rate of root rot in chickpea caused by F. solani. This is the first report of F. solani causing root rot of chickpea in a salinated soil of Uzbekistan. Our findings demonstrated that the endophytic B. subtilis strain NUU4 provides high potentials as a stimulator for plant growth and as biological control agent of chickpea root rot under saline soil conditions. These multiple relationships could provide promising practical approaches to increase the productivity of legumes under salt stress.

  1. Proteomic analysis of the salt-responsive leaf and root proteins in the anticancer plant Andrographis paniculata Nees.

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    Daryush Talei

    Full Text Available Separation of proteins based on the physicochemical properties with different molecular weight and isoelectric points would be more accurate. In the current research, the 45-day-old seedlings were treated with 0 (control and 12 dS m(-1 of sodium chloride in the hydroponic system. After 15 days of salt exposure, the total protein of the fresh leaves and roots was extracted and analyzed using two-dimensional electrophoresis system (2-DE. The analysis led to the detection of 32 induced proteins (19 proteins in leaf and 13 proteins in the root as well as 12 upregulated proteins (four proteins in leaf and