Academic literature on the topic 'Soil plant interactions'
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Journal articles on the topic "Soil plant interactions"
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Krumins, Jennifer Adams, Nina M. Goodey, and Frank Gallagher. "Plant–soil interactions in metal contaminated soils." Soil Biology and Biochemistry 80 (January 2015): 224–31. http://dx.doi.org/10.1016/j.soilbio.2014.10.011.
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Fernando, Denise R. "Plant–Metal Interactions in the Context of Climate Change." Stresses 2, no. 1 (February 5, 2022): 79–89. http://dx.doi.org/10.3390/stresses2010007.
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Expanding fundamental understanding of the complex and far-reaching impacts of anthropogenic climate change is essential for formulating mitigation strategies. There is abundant evidence of ongoing damage and threat to plant health across both natural and cultivated ecosystems, with potentially immeasurable cost to humanity and the health of the planet. Plant–soil systems are multi-faceted, incorporating key variables that are individually and interactively affected by climatic factors such as rainfall, solar radiation, air temperature, atmospheric CO2, and pollution. This synthesis focuses on climate effects on plant–metal interactions and related plant–soil dynamics. Ecosystems native to metalliferous soils incorporate vegetation well adapted to metal oversupply, yet climate-change is known to induce the oversupply of certain immobile soil metals by altering the chemistry of non-metalliferous soils. The latter is implicated in observed stress in some non-metal-adapted forest trees growing on ‘normal’ non-metalliferous soils. Vegetation native to riverine habitats reliant on flooding is increasingly at risk under drying conditions caused by anthropogenic water removal and climate change that ultimately limit plant access to essential trace-metal nutrients from nutrient poor sandy soils. In agricultural plant systems, it is well known that environmental conditions alter soil chemistries and plant responses to drive plant metal toxicity stress. These aspects are addressed with reference to specific scenarios and studies linking climate to plant–metal interactions, with emphasis on land plants.
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Fox, R. L., N. V. Hue, R. C. Jones, and R. S. Yost. "Plant-soil interactions associated with acid, weathered soils." Plant and Soil 134, no. 1 (July 1991): 65–72. http://dx.doi.org/10.1007/bf00010718.
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M, Meena. "Tomato: A Model Plant to Study Plant-Pathogen Interactions." Food Science & Nutrition Technology 4, no. 1 (January 7, 2019): 1–6. http://dx.doi.org/10.23880/fsnt-16000171.
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Tomato (Solanum lycopersicum) is a very important vegetable plant in the worldwide because of its importance as food, quality of fruit, improves productivity, and resistance to biotic and abiotic stresses. Tomato has been extensively used not just for food however conjointly as a research (plant-pathogen interactions) material. Generally, most of the tomato traits are agronomically imperative and cannot be studied using other model plant systems. It belongs to family Solanaceae and intimately associated with several commercially important plants like potato, tobacco, peppers, eggplant, and petunias. Production of tomato yield is affected each year due to range of pathogenic diseases that square measure caused by fungi, bacteria, viruses and roundworm, enlarge all the methods through soil-borne, above-ground infections and in some instances are transmitted through insect feeding. This review is focused on the way to tomato-pathogen interactions analysis is very important and role of pathological processes connected factors and genes.
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Soto, B., and F. Diaz-Fierros. "Interactions Between Plant Ash Leachates and Soil." International Journal of Wildland Fire 3, no. 4 (1993): 207. http://dx.doi.org/10.1071/wf9930207.
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We studied a) leaching of Ulex, Pinus and Eucalyptus ashes; b) leaching from the surface layer (0 - 5 cm) of 6 types of soil subjected to thermal shock at a range of temperatures equivalent to those reached in a wildfire (25-degrees-C to 700-degrees-C); and c) leaching of Ulex, Pinus and Eucalyptus ashes through a subsurface soil layer not subjected to thermal shock. Element release from plant ashes and heat-treated soils was highly dependent on the solubility of the principal chemical forms in which that element occurred. The monovalent cations Na and K, largely present as chlorides and carbonates, were mobilized much more rapidly than the divalent cations Ca and Mg, largely present as oxides and carbonates. Element release from heat-treated soil was also dependent on shock temperature. The monovalent cations were extensively mobilized following shocks at less than 380-degrees-C, and the divalent cations following higher-temperature shocks. These differences appear to be related to element volatilization and mineralization of organic matter. The subsurface soil not subjected to thermal shock showed a tendency to retain the elements released from plant ashes and from heat-treated surface soil. The subsurface layers may also release hydrogen ions and organic matter, as a result of cation exchange and dissolution processes respectively.
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Lazarus, Brynne E., James H. Richards, Victor P. Claassen, Ryan E. O’Dell, and Molly A. Ferrell. "Species specific plant-soil interactions influence plant distribution on serpentine soils." Plant and Soil 342, no. 1-2 (January 26, 2011): 327–44. http://dx.doi.org/10.1007/s11104-010-0698-2.
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Prisa, Domenico. "Soil Microbiota and Its Plant Interactions." International Journal of Current Research and Review 14, no. 08 (2022): 40–46. http://dx.doi.org/10.31782/ijcrr.2022.14807.
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Microbial biodiversity comprises microorganisms belonging to all kingdoms: from prokaryotes (archaea and bacteria) to eukaryotes (fungi, microalgae, moulds, yeasts and protists). Microorganisms make up a large part of the earth’s biomass, are extraordinarily diverse and are widespread in all habitats. More than two thirds of the total biodiversity consists of bacteria, while archaea and eukaryotes occupy less than one third. Microorganisms interact with each other and with the biotic and abiotic components of their environment, creating ecosystems in which there is a dynamic balance between the different components. The rhizosphere is the portion of soil surrounding the roots of plants, from which they absorb the essential nutrients and water they need to grow. In addition to the roots, there are further biotic components in the rhizosphere, such as: symbiotic microorganisms, beneficial and pathogenic bacteria, microscopic and macroscopic fungi. The aim of this review is to increase the knowledge about the interactions between plants and soil microorganisms
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Etherington, J. R., R. J. Wright, V. C. Baligar, and R. P. Murrmann. "Plant--Soil Interactions at Low pH." Journal of Ecology 81, no. 1 (March 1993): 204. http://dx.doi.org/10.2307/2261248.
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REDDY, M. R. "Plant and Soil Interfaces and Interactions." Soil Science 147, no. 4 (April 1989): 308. http://dx.doi.org/10.1097/00010694-198904000-00011.
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&NA;. "Plant-Soil Interactions at Low pH." Soil Science 154, no. 1 (July 1992): 84. http://dx.doi.org/10.1097/00010694-199207000-00013.
Full textDissertations / Theses on the topic "Soil plant interactions"
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Kraus, Tamara Esther Caroline. "Tannins and nutrient dynamics in forest soils : plant-litter-soil interactions /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2002. http://uclibs.org/PID/11984.
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Sørensen, L. I. (Louise Ilum). "Grazing, disturbance and plant soil interactions in northern grasslands." Doctoral thesis, University of Oulu, 2009. http://urn.fi/urn:isbn:9789514291395.
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Plants and soil organisms are closely linked. Plants are the sole source of carbon in the soil and soil organisms are responsible for recycling of nutrients, making them available for plant growth. To understand the function of a system, it is important to understand the interactions between the soil and plants. These interactions have mainly been studied in temperate areas, with few studies in the arctic and subarctic. The aim of this thesis was to investigate the effect of ecological disturbances in sub- and low-arctic grasslands on soil organisms and plant-soil feedback relationships. The effect of removal of vegetation, replanting of a local plant species, and different components of grazing (trampling, defoliation and return of nutrients) on soil decomposer organisms were studied. Whether short term effects of defoliation depended on plant species community was also studied, as well as whether defoliation in the field could create changes in the soil system systems that affect the growth of seedlings. Experiments were conducted under both controlled greenhouse conditions and in field sites.
The results showed that physical disturbance (removal of vegetation and trampling) reduced the abundance and diversity of soil biota. Defoliation increased soil decomposer abundance in the short term. Plant species composition did not affect soil biota and only in a few cases did it changes their responses to defoliation. In the long-term, effects of fertilization and defoliation on the soil biota were context-dependent. However, defoliation did create changes in the soil that reduced the growth of seedlings planted into the soil. Furthermore, plant species community and spatial heterogeneity (revealed by blocking) had important effects on the soil communities.
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Bonnett, Samuel A. F. "Biogeochemical implications of plant-soil interactions in peatland ecosystems." Thesis, Bangor University, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.428831.
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Bergmann, Joana [Verfasser]. "Root traits and their effect in plant-soil interactions / Joana Bergmann." Berlin : Freie Universität Berlin, 2018. http://d-nb.info/1159900531/34.
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Hänninen, Kaarina. "Tree-cover crop interactions : birch growth, competition and soil properties /." Oulu : Oulun Yliopisto, 2002. http://herkules.oulu.fi/isbn9514267184.
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Card, Marcella. "Interactions among soil, plants, and endocrine disrupting compounds in livestock agriculture." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1311287470.
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Monteil, Oscar Vazquez. "Wastewater irrigation of crops : the influence of nitrogen on soil-plant interactions." Thesis, University of Leeds, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303449.
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Macpherson, Stuart Alexander. "Interactions between lead and phosphate : soil chemistry, plant uptake and ecological implications." Thesis, University of Bristol, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.294125.
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Al-Turki, Ahmad I. "Myrosinase activity in soil and impact of Brassica on plant-microbe interactions /." The Ohio State University, 2001. http://rave.ohiolink.edu/etdc/view?acc_num=osu1486394475979013.
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Navarro, Patricia D. "Entomopathogenic Nematodes: Their Interactions with Plant Pathogens and Insecticides in the Soil." Diss., The University of Arizona, 2012. http://hdl.handle.net/10150/265815.
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Entomopathogenic nematodes (EPNs) in the families Heterorhabditidae and Steinernematidae, and their bacterial symbionts, have been studied intensively because of their role as natural mortality factor for soil-dwelling arthropods, and their potential as biological control agents for belowground insect pests. Moreover, EPN are recognized as key players in regulating soil food webs and triggering trophic cascades. However, most studies of interactions with EPN have been conducted under laboratory setting and simplified conditions, without consider the dynamic of the EPN and their interactions with other soil components in a wider context. In this respect, knowledge of the effect that other soil organisms or human induced factor may have on EPN dynamic and life cycle in the soil may contribute to improve tactics for their implementation and success as natural regulators of herbivores. The present investigation focused on the interactions of EPN with a selection of insecticides, and biotic (saprobic fungus and plant parasitic nematodes) elements that may be present in the soil, and may potentially interact with EPN. Specifically, I investigated how these factors may affect the life cycle (host search behavior, virulence and reproduction) of EPN. Appendix A shows the effect that a group of selected synthetic and biological insecticides have on EPN virulence and reproduction. The results obtained from this study revealed that most combinations of EPN and insecticides under study increased the mortality of the insect host. However, it was also found that some of these combinations reduced the nematode progeny production and emergence of IJs from the insect cadaver. In contrast in Appendix B, when examining the effect of the saprobic fungus Fusarium oxysporum in the life cycle of the EPN Heterorhabditis sonorensis, it was found that this fungus negatively affected the virulence and reproduction of the EPN in the insect host. In the third study of this dissertation (Appendix C) the interactions studied considered the effect of two EPN on an organism of a different trophic guild, the plant parasitic nematode Tylenchulus semipenetrans. This plant parasitic nematode causes serious diseases in citrus plants by infecting their roots and defoliating their branches. Previous studies have shown that some EPN species may negatively affect the life cycle of plant parasitic nematodes by reducing the damage produced by this plant parasite. Results from this study confirm the antagonistic effect between the selected EPN and the citrus nematode. Specifically, it was found that the presence in the soil of both EPN reduced the survival of infective juveniles of the citrus nematode and their penetration to the root. Moreover, the presence of EPN had an antagonistic effect in the production of eggs of T. semipenetrans females.
Books on the topic "Soil plant interactions"
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Crespi, Martin. Root genomics and soil interactions. Hoboken, N.J: John Wiley & Sons, 2012.
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Van Diest, A., ed. Plant and Soil Interfaces and Interactions. Dordrecht: Springer Netherlands, 1987. http://dx.doi.org/10.1007/978-94-009-3627-0.
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Dighton, John, and Jennifer Adams Krumins, eds. Interactions in Soil: Promoting Plant Growth. Dordrecht: Springer Netherlands, 2014. http://dx.doi.org/10.1007/978-94-017-8890-8.
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Wright, R. J., V. C. Baligar, and R. P. Murrmann, eds. Plant-Soil Interactions at Low pH. Dordrecht: Springer Netherlands, 1991. http://dx.doi.org/10.1007/978-94-011-3438-5.
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Date, R. A., N. J. Grundon, G. E. Rayment, and M. E. Probert, eds. Plant-Soil Interactions at Low pH: Principles and Management. Dordrecht: Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-011-0221-6.
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Traveset, Anna, and David M. Richardson, eds. Plant invasions: the role of biotic interactions. Wallingford: CABI, 2020. http://dx.doi.org/10.1079/9781789242171.0000.
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Abstract This book contains 23 chapters divided into seven parts. Part I reviews the key hypotheses in invasion ecology that invoke biotic interactions to explain aspects of plant invasion dynamics; and reviews models, theories and hypotheses on how invasion performance and impact of introduced species in recipient ecosystems can be conjectured according to biotic interactions between native and non-native species. Part II deals with positive and negative interactions in the soil. Part III discusses mutualistic interactions that promote plant invasions. Part IV describes antagonistic interactions that hinder plant invasions, while part V presents the consequences of plant invasions for biotic interactions among native species. In part VI, novel techniques and experimental approaches in the study of plant invasions are shown. In the last part, biotic interactions and the management of ecosystems invaded by non-native plants are discussed.
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van, Diest A., ed. Plant and soil: Interfaces and interactions : proceedings of the International Symposium, Plant and Soil, Interfaces and Interactions, Wageningen, the Netherlands, August 6-8, 1986. Dordrecht: M. Nijhoff, 1987.
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P, Hammond John, and SpringerLink (Online service), eds. The Ecophysiology of Plant-Phosphorus Interactions. Dordrecht: Springer Science + Business Media B.V, 2008.
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J, Wright R., Baligar V. C, and Murrmann R. P, eds. Plant-soil interactions at low pH: Proceedings of the Second International Symposium on Plant-Soil Interactions at Low pH, 24-29 June, 1990, Beckley, West Virginia, USA. Dordrecht: Kluwer Academic, 1991.
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Blum, Udo. Plant-Plant Allelopathic Interactions: Phenolic Acids, Cover Crops and Weed Emergence. Dordrecht: Springer Science+Business Media B.V., 2011.
Find full textBook chapters on the topic "Soil plant interactions"
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Abrahamsen, Gunnar, Bjørn Tveite, and Arne O. Stuanes. "Plant-Soil Interactions." In Ecological Studies, 204–20. New York, NY: Springer New York, 1994. http://dx.doi.org/10.1007/978-1-4612-2604-8_10.
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Roose, Tiina. "Plant–Soil Interactions, Modeling." In Encyclopedia of Agrophysics, 637. Dordrecht: Springer Netherlands, 2011. http://dx.doi.org/10.1007/978-90-481-3585-1_246.
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Haj-Amor, Zied, and Salem Bouri. "Soil–Plant–Climate Interactions." In Climate Change Impacts on Coastal Soil and Water Management, 13–22. First edition. | Boca Raton, FL : CRC Press/ Taylor & Francis Group, 2020.: CRC Press, 2020. http://dx.doi.org/10.1201/9780429356667-2.
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Blum, Udo. "Simple Phenolic Acids in Soil Culture II: Biological Processes in Soil." In Plant-Plant Allelopathic Interactions III, 197–238. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-22098-3_7.
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Braeken, Kristien, Ruth Daniels, Maxime Ndayizeye, Jos Vanderleyden, and Jan Michiels. "Quorum Sensing in Bacteria-Plant Interactions." In Soil Biology, 265–89. Berlin, Heidelberg: Springer Berlin Heidelberg, 2008. http://dx.doi.org/10.1007/978-3-540-75575-3_11.
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Callaway, Ragan M., and Jacob E. Lucero. "Soil biota and non-native plant invasions." In Plant invasions: the role of biotic interactions, 45–66. Wallingford: CABI, 2020. http://dx.doi.org/10.1079/9781789242171.0045.
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Abstract The trajectory of plant invasions - for better or for worse - can be tied to interactions between plants and the soil community. Here, we highlight five broad ways in which belowground interactions can influence the trajectory of biological invasions by non-native plant species. First, many non-native plant species in their non-native ranges can interact very differently with the resident soil community than do native species. Second, non-native plant species often interact very differently with the soil community in their non-native ranges than in their native ranges, which can result in enemy release from antagonistic interactions. Third, non-native plant species can cultivate a soil community that disproportionately harms native competitors in invaded communities. Fourth, antagonistic soil biota in invaded communities can reduce the performance of non-native plant species, resulting in meaningful biotic resistance against invasion. Fifth, besides or in addition to antagonistic interactions with soil biota, soil mutualisms can promote the success of invasive plant species (i) when mutualists co-invade with non-native plant species that require obligate specialist mutualists, (ii) when mutualists enhance the performance of non-native plant species in their non-native ranges, and (iii) when biotic interactions in the invaded community suppress the soil mutualists of native plant species. We conclude that management practices aimed at manipulating plant - soil interactions have considerable potential to help control plant invasions, but further work is needed to understand the spatial, temporal, taxonomic and biogeographic drivers of context dependence in interactions among plants and soil biota.
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Blum, Udo. "Hypothetical Soil-Culture System Sub-Models." In Plant-Plant Allelopathic Interactions III, 281–343. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-22098-3_9.
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Mekala, Srikanth, and Srilatha Polepongu. "Impact of Climate Change on Soil Microbial Community." In Plant Biotic Interactions, 31–41. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-26657-8_3.
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Reid, C. P. P. "Mycorrhizae: A Root-Soil Interface in Plant Nutrition." In Microbial-Plant Interactions, 29–50. Madison, WI, USA: American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, 2015. http://dx.doi.org/10.2134/asaspecpub47.c3.
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Dubey, Ashutosh. "Climate Changes in Soil Microorganism–Plant Interactions." In Soil Biology, 187–98. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-76863-8_9.
Full textConference papers on the topic "Soil plant interactions"
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Vannette, Rachel L. "Mutualistic soil fungi and plant nutrition jointly influence plant-herbivore interactions." In 2016 International Congress of Entomology. Entomological Society of America, 2016. http://dx.doi.org/10.1603/ice.2016.94331.
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Khalidy, Reza, Fatima Haque, Rafael Santos, and Yi Wai Chiang. "Enhanced weathering of wollastonite in agricultural soils and mineral-soil-plant interactions." In Goldschmidt2021. France: European Association of Geochemistry, 2021. http://dx.doi.org/10.7185/gold2021.4956.
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Kreis, Kevin F., and Sangjin Ryu. "Automated Mini-Channel Platform for Studying Plant Root Environments." In ASME 2021 Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/fedsm2021-65493.
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Abstract Plants are crucial to our lives because they provide us with building materials, oxygen, and food. A season’s crop yield can be significantly affected by local environmental factors. In particular, improving fundamental understanding of plant root interactions with their local soil environment, or rhizosphere, will help improve crop yield. Studying such interactions is challenging because roots are underground, making it difficult to observe interactions and to manipulate the local soil environment. The goal of this study was to develop an automated mini-channel platform to investigate how plant roots respond to changes in their environment using corn as a model plant. Considering the size of corn seedling roots, mini-channel devices were fabricated in soft lithography using master molds produced with a 3D printer and polydimethylsiloxane (PDMS). Our use of a 3D printer instead of photolithography allowed for a broader range of PDMS mold designs, such as including embedded rubber gaskets built into the mold. Then, corn seedlings were grown inside the transparent mini-channel devices, and they were found to consume an observable amount of nitrate over time. Image processing was employed to measure the contour length of the roots for quantitative characterization of root growth. Then, an automated platform was developed to measure the growth rate of the corn seedling roots and the consumed nitrate over time. The automated platform maintained the level of growth medium in the channel device, and was equipped with a digital camera to image the root growing in the channel, electrochemical sensors to measure changes in nitrate concentration in the channel, and sensors to measure temperature and humidity. Therefore, the platform could automatically measure root growth while simultaneously measuring root environment. The platform’s adaptable design, simple fabrication, and low cost make it simple to replicate and use to study different plants and environmental stimuli.
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Breica Borozan, Aurica, Despina-Maria Bordean, Gabriel Bujanca, Delia Dumbrava, and Sorina Popescu. "CONTROL OF PLANTS OF LOTUS CORNICULATUS L. ON AEROBIC AND ANAEROBIC FREE NITROGEN-FIXING BACTERIA." In GEOLINKS International Conference. SAIMA Consult Ltd, 2020. http://dx.doi.org/10.32008/geolinks2020/b1/v2/07.
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The free nitrogen fixing bacteria are able to mobilize important soil nutrients, transforming through biological processes the unusable molecular nitrogen into an active form and to improve soil fertility, influence many aspects of plant health and ensure their growth, showing interest for the scientific world and farmers. But, on the other hand, this bacterial segment may be influenced by the edaphic factors and the interconnection with the plants, the growth phase, the physiological state and the root system of the plant, by the root exudates, which demonstrates the importance of the bacterial community monitoring from the area of plants influence throughout the growing periods The aim of this study was to evaluate the influence of the age of the plants used as biofertilizer and soil moisture on the free nitrogen fixing bacterial communities (the genera Azotobacter and Clostridium) associated with the roots of the perennial plants of Lotus corniculatus L. There were two zones of interest, namely the area of influence of the roots of the plants (rhizosphere) but also the more distant area (edaphosphere). For the study of aerobic and anaerobic free nitrogen fixing bacteria soil samples were taken together with adjacent plants of Lotus corniculatus L. The experimental variants were located in the western part of Romania, the plants being cultivated on the same soil type, but on different plots, that were in the I-IV years of culture. The influence of Lotus corniculatus L. plants on the free nitrogen fixing bacteria has been reported in control experimental variants. Isolation and study of this bacterial group from the 8 experimental variants was performed on a specific mineral medium, favorable for the growth of the two bacterial genera. The results were evaluated after 5 and 10 days of incubation. Between the two assesments there were no noticeable differences in the nitrogen fixing bacterial community, except for the stimulatory effect observed in the control vatiant and rhizosphere of the first year culture. The plants influence on aerobic and anaerobic free nitrogen fixing bacteria was obvious in the II and IV years of the Lotus corniculatus L. culture, compared to the 76 control variants and varies substantially depending on the age of the plant. In most analyzed soil samples, both bacterial genera, Azotobacter and Clostridium were present, confirming the known ecological relation of unilateral advantage or passive stimulation of the aerobic bacteria compared to the anaerobic clostridia. Exceptions were the samples from the cultures of the first year (rhizosphere and control), but also the rhizosphere from the culture of the year II, where only anaerobic nitrogen fixing bacteria were detected. Our results suggested that plant-soil interactions exert control over the bacteria being studied.
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El-Bahey, Samer, and Yasser Alzeni. "Effect of Soil Structure Interaction on the Seismic Fragility of a Nuclear Reactor Building." In 2016 24th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/icone24-60714.
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In recent years, the nuclear industry and the Nuclear Regulatory Commission (NRC) have made a tremendous effort to assess the safety of nuclear power plants as advances in seismology have led to the perception that the potential earthquake hazard in the United States may be higher than originally assumed. The Seismic Probabilistic Risk Assessment (S-PRA) is a systematic approach used in the nuclear power plants in the U.S. to realistically quantify the seismic risk as by performing an S-PRA, the dominant contributors to seismic risk and core damage can be identified. The assessment of component fragility is a crucial task in the S-PRA and because of the conservatism in the design process imposed by stringent codes and regulations for safety related structures, structures and safety related items are capable of withstanding earthquakes larger than the Safe Shutdown Earthquake (SSE). One major aspect of conservatism in the design is neglecting the effect of Soil-Structure-Interaction (SSI), from which conservative estimates of In-Structure Response Spectra (ISRS) are calculated resulting in conservative seismic demands for plant equipment. In this paper, a typical Reactor Building is chosen for a case study by discretizing the building into a lumped mass stick model (LMSM) taking into account model eccentricities and concrete cracking for higher demand. The model is first analyzed for a fixed base condition using the free field ground motion imposed at the foundation level from which ISRS are calculated at different elevations. Computations taking into account the SSI effects are then performed using the subtraction method accounting for inertial interactions by using frequency dependent foundation impedance functions depicting the flexibility of the foundation as well as the damping associated with foundation-soil interaction. Kinematic interactions are also taken into account in the SSI analysis by using frequency dependent transfer functions relating the free-field motion to the motion that would occur at the foundation level as the presence of foundation elements in soil causes foundation motions to deviate from free-field motions as a result of ground motion incoherence and foundation embedment. Comparing the results of the seismic response analyses, the effects of the SSI is quantified on the overall seismic risk and the SSI margin is calculated. A family of realistic seismic fragility curves of the structure are then developed using common industry safety factors (capacity, ductility, response, and strength factors), and also variability estimates for randomness and uncertainty. Realistic fragility estimates for structures directly enhances the component fragilities from which enhanced values of Core Damage Frequency (CDF) and Large Energy Release Frequency (LERF) are quantified as a final S-PRA deliverable.
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Duma Copcea, Anisoara Claudia, Teodor Mateoc-Sirb, Casiana Mihut, Karel Iaroslav Lato, and Nicoleta Mateoc-Sirb. "THE PEDOLOGICAL STUDY OF LANDS IN DUBOVA, MEHEDINTI COUNTY, ROMANIA." In 22nd SGEM International Multidisciplinary Scientific GeoConference 2022. STEF92 Technology, 2022. http://dx.doi.org/10.5593/sgem2022/3.1/s13.40.
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The objective of this paper is the morphological characterization as well as the establishment of soil quality classes in the commune of Dubova, Mehedinti County, Romania. Soil is a primary component for plant production, although it is often considered only as a physical support for plant growth. However, the concerns of mankind over the sustainability of agriculture have made it possible to consider that soil is a living, high-quality system and should, therefore, be preserved. This is the result of several interactions between biological components, including microbial communities, essential for physical-chemical operation. Agricultural crops are threatened by diseases transmitted through the soil, making them difficult to control because of the �hidden� character of pathogens and low efficiency of conventional treatments. These practices greatly affect the quality of the soil, which, in turn, affects the state of crop quality. One of the goals of this paper is to show that, despite the age of the concept of soil quality and the existence of numerous studies, the application of soil quality recommendations would play an important role in crops. However, there is a certain methodology for obtaining soil quality indices that could be suggested in this paper, a methodology based and developed on the basis of previously conducted research in the field. Under current conditions, highlighted by an intensification of globalization processes, sustainable development brings together the main economic and social factors to meet the present needs of mankind without compromising those of future generations.
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Majumdar, Arnab, Munish kumar Upadhyay, Ashish Kumar Srivastava, Sudhakar Srivastava, and Sutapa Bose. "Soil Geochemical Dynamics of Arsenic and Nutrients Affects Microbial Diversity, Elemental Release and Plant-Microbe Interactions: A Long-term Study from Field to Genomics." In Goldschmidt2022. France: European Association of Geochemistry, 2022. http://dx.doi.org/10.46427/gold2022.8539.
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Shi, Jianfeng, Yuhua Cao, Di Jiao, Fa Yu, Yu Li, Jiayin Jiang, and Jinyang Zheng. "Comparison of Technical Standards Between Buried and Above Ground Polyethylene Pipe in the Application of Nuclear Power Plant." In ASME 2022 Pressure Vessels & Piping Conference. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/pvp2022-84477.
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Abstract High-density polyethylene (HDPE) pipes have been used in essential service water (ESW) systems of nuclear power plants (NPP) for years. Some NPPs use buried HDPE pipes, while some others use above ground (gallery-installed) HDPE pipes, and this paper will discuss the differences in the design methods of these two construction methods in related technical standards. The design requirements and related load types of buried and above ground HDPE pipes in safety-related Class 3 service water or cooling water piping systems are compared. Pipeline models under different load types are introduced, including model assumption, material simplification, boundary conditions, interactions, etc. The differences in design loads are summarized, i.e., soil and surcharge load, negative internal pressure, flotation due to flood of buried HDPE pipe, and axial forces due to different supporting or fixing methods of above ground HDPE pipe. The design methods of buried and above ground HDPE pipeline are discussed and compared, i.e., design of mechanical load, temperature load, non-repeated anchor movements and seismic load. A case study is presented by using different technical standards of buried and above ground HDPE pipes. This work can provide a reference for the selection of HDPE pipes for safety-related Class 3 service water or cooling water piping systems in different NPPs.
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Anghel, Ioana, Crina Bucur, Stuart D. Ware, and Margarit Pavelescu. "The Importance of Geochemical Characterization of Repository Host Horizons for Radioactive Waste Disposal: Saligny Repository Site for L/ILW, Romania." In ASME 2003 9th International Conference on Radioactive Waste Management and Environmental Remediation. ASMEDC, 2003. http://dx.doi.org/10.1115/icem2003-4760.
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The Saligny Site, situated in the vicinity of the Cernavoda Nuclear Power Plant in Romania, has been chosen as a repository site for placement of future Low and Intermediate Level Nuclear Waste. Scientific investigations are on going to help assess the long-term performance of the nuclear waste repository and include the development of a site conceptual model, geochemical characterization of the proposed liner material and the geologic formations surrounding the repository. Geochemical characteristics of the proposed waste site and of repository liner material are essential information in providing key model parameters needed to determine the mechanisms and rates for the potential release and transport of radionuclides in the environment. A series of laboratory sorption and diffusion experiments in support of the site conceptual model were run at Los Alamos National Laboratory, USA and Institute for Nuclear Research, Romania. These experiments compared responses of cesium-137 and tritiated water as radionuclides, and included natural soil samples from Saligny site and cement liner material. Sorption experiments focused on studying the affinity of cesium-137 for soil samples from: a clay rich loess horizon, a compacted red clay horizon and a Portland type cement, proposed as liner for the repository. A Saligny synthetic water was used for the soil sorption experiments. For the cement sorption and diffusion experiments, NaCl 10mM water was necessary in order to avoid insolubility problems at the high pH (around 12) when in contact with the cement. Preliminary studies of the geochemistry for radionuclide-soil matrix and radionuclide-concrete liner interactions were obtained through the sorption and diffusion experiments. The sorption isotherms were linear for all samples with high Kd values for soil samples and low values for the cement. Mineralogical information obtained through quantitative X-ray diffraction (QXRD) analysis, for the studied soil samples were in agreement with the sorption results. The high amount of clay present in the soil samples was determined to be the main contributor for the strong sorption. Diffusion cells were prepared for comparing hydrologic response characteristics for tritiated water and cesium-137, through the measurement of diffusion coefficients as influenced by the soil and cement matrices. Tritiated water and cesium-137 diffusion coefficients were determined from the change in radionuclide concentration profile over time while diffusing through the soil or cement matrix, and were found in agreement with the values listed in literature findings.
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Li, Hong-Nan, Shi-Yun Xiao, and Su-Yan Wang. "Model of Transmission Tower-Pile-Soil Dynamic Interaction Under Earthquake: In-Plane." In ASME 2002 Pressure Vessels and Piping Conference. ASMEDC, 2002. http://dx.doi.org/10.1115/pvp2002-1439.
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In this paper, the mechanical model of Soil-Pile-Structure interaction of transmission tower-cable system in in-plane is presented and the corresponding equations of motion are derived, in which the nonlinear characteristics of soil is included in the dynamic time history analysis. The computer program for the system is complied and used to calculate the earthquake response of an actual transmission tower. The results of numerical calculation are compared with and without considering soil-pile-structure interactions, which show that the dynamic interaction should be taken into account in the soft foundation.
Reports on the topic "Soil plant interactions"
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Mitchell, Joshua. Leveraging GCxGC-TOFMS to explore plant-soil-microbiome interactions in Maize. Office of Scientific and Technical Information (OSTI), September 2022. http://dx.doi.org/10.2172/1888206.
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Crowley, David E., Dror Minz, and Yitzhak Hadar. Shaping Plant Beneficial Rhizosphere Communities. United States Department of Agriculture, July 2013. http://dx.doi.org/10.32747/2013.7594387.bard.
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PGPR bacteria include taxonomically diverse bacterial species that function for improving plant mineral nutrition, stress tolerance, and disease suppression. A number of PGPR are being developed and commercialized as soil and seed inoculants, but to date, their interactions with resident bacterial populations are still poorly understood, and-almost nothing is known about the effects of soil management practices on their population size and activities. To this end, the original objectives of this research project were: 1) To examine microbial community interactions with plant-growth-promoting rhizobacteria (PGPR) and their plant hosts. 2) To explore the factors that affect PGPR population size and activity on plant root surfaces. In our original proposal, we initially prqposed the use oflow-resolution methods mainly involving the use of PCR-DGGE and PLFA profiles of community structure. However, early in the project we recognized that the methods for studying soil microbial communities were undergoing an exponential leap forward to much more high resolution methods using high-throughput sequencing. The application of these methods for studies on rhizosphere ecology thus became a central theme in these research project. Other related research by the US team focused on identifying PGPR bacterial strains and examining their effective population si~es that are required to enhance plant growth and on developing a simulation model that examines the process of root colonization. As summarized in the following report, we characterized the rhizosphere microbiome of four host plant species to determine the impact of the host (host signature effect) on resident versus active communities. Results of our studies showed a distinct plant host specific signature among wheat, maize, tomato and cucumber, based on the following three parameters: (I) each plant promoted the activity of a unique suite of soil bacterial populations; (2) significant variations were observed in the number and the degree of dominance of active populations; and (3)the level of contribution of active (rRNA-based) populations to the resident (DNA-based) community profiles. In the rhizoplane of all four plants a significant reduction of diversity was observed, relative to the bulk soil. Moreover, an increase in DNA-RNA correspondence indicated higher representation of active bacterial populations in the residing rhizoplane community. This research demonstrates that the host plant determines the bacterial community composition in its immediate vicinity, especially with respect to the active populations. Based on the studies from the US team, we suggest that the effective population size PGPR should be maintained at approximately 105 cells per gram of rhizosphere soil in the zone of elongation to obtain plant growth promotion effects, but emphasize that it is critical to also consider differences in the activity based on DNA-RNA correspondence. The results ofthis research provide fundamental new insight into the composition ofthe bacterial communities associated with plant roots, and the factors that affect their abundance and activity on root surfaces. Virtually all PGPR are multifunctional and may be expected to have diverse levels of activity with respect to production of plant growth hormones (regulation of root growth and architecture), suppression of stress ethylene (increased tolerance to drought and salinity), production of siderophores and antibiotics (disease suppression), and solubilization of phosphorus. The application of transcriptome methods pioneered in our research will ultimately lead to better understanding of how management practices such as use of compost and soil inoculants can be used to improve plant yields, stress tolerance, and disease resistance. As we look to the future, the use of metagenomic techniques combined with quantitative methods including microarrays, and quantitative peR methods that target specific genes should allow us to better classify, monitor, and manage the plant rhizosphere to improve crop yields in agricultural ecosystems. In addition, expression of several genes in rhizospheres of both cucumber and whet roots were identified, including mostly housekeeping genes. Denitrification, chemotaxis and motility genes were preferentially expressed in wheat while in cucumber roots bacterial genes involved in catalase, a large set of polysaccharide degradation and assimilatory sulfate reduction genes were preferentially expressed.
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Chefetz, Benny, and Baoshan Xing. Sorption of hydrophobic pesticides to aliphatic components of soil organic matter. United States Department of Agriculture, 2003. http://dx.doi.org/10.32747/2003.7587241.bard.
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Sorption of hydrophobic compounds to aliphatic components of soil organic matter (SOM) is poorly understood even though these aliphatic carbons are a major fraction of SOM. The main source of aliphatic compounds in SOM is above- and below-ground plant cuticular materials (cutin, cutan and suberin). As decomposition proceeds, these aliphatic moieties tend to accumulate in soils. Therefore, if we consider that cuticular material contributes significantly to SOM, we can hypothesize that the cuticular materials play an important role in the sorption processes of hydrophobic compounds (including pesticides) in soils, which has not yet been studied. The overall goal of this research was to illustrate the mechanism and significance of the refractory aliphatic structures of SOM in sorbing hydrophobic compounds (nonionic and weakly polar pesticides). The importance of this study is related to our ability to demonstrate the sorption relationship between key pesticides and an important fraction of SOM. The specific objectives of the project were: (1) To isolate and characterize cuticular fractions from selected plants; (2) To investigate the sorption mechanism of key hydrophobic pesticides and model compounds to cuticular plant materials; (3) To examine the sorption mechanisms at the molecular level using spectroscopic techniques; (4) To investigate the sorption of key hydrophobic pesticides to synthetic polymers; (5) To evaluate the content of cuticular materials in agricultural soils; and (6) To study the effect of incubation of plant cuticular materials in soils on their sorptive capabilities. This project demonstrates the markedly high sorption capacity of various plant cuticular fractions for hydrophobic organic compounds (HOCs) and polar organic pollutants. Both cutin (the main polymer of the cuticle) and cutan biopolymers exhibit high sorption capability even though both sorbents are highly aliphatic in nature. Sorption by plant cuticular matter occurs via hydrophobic interactions and H-bonding interactions with polar sorbates. The cutin biopolymer seems to facilitate reversible and noncompetitive sorption, probably due to its rubbery nature. On the other hand, the epicuticular waxes facilitate enhance desorption in a bi-solute system. These processes are possibly related to phase transition (melting) of the waxes that occur in the presence of high solute loading. Moreover, our data highlight the significance of polarity and accessibility of organic matter in the uptake of nonpolar and polar organic pollutants by regulating the compatibility of sorbate to sorbent. In summary, our data collected in the BARD project suggest that both cutin and cutan play important roles in the sorption of HOCs in soils; however, with decomposition the more condensed structure of the cutin and mainly the cutan biopolymer dominated sorption to the cuticle residues. Since cutin and cutan have been identified as part of SOM and humic substances, it is suggested that retention of HOCs in soils is also controlled by these aliphatic domains and not only by the aromaticrich fractions of SOM.
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Chefetz, Benny, Baoshan Xing, Leor Eshed-Williams, Tamara Polubesova, and Jason Unrine. DOM affected behavior of manufactured nanoparticles in soil-plant system. United States Department of Agriculture, January 2016. http://dx.doi.org/10.32747/2016.7604286.bard.
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The overall goal of this project was to elucidate the role of dissolved organic matter (DOM) in soil retention, bioavailability and plant uptake of silver and cerium oxide NPs. The environmental risks of manufactured nanoparticles (NPs) are attracting increasing attention from both industrial and scientific communities. These NPs have shown to be taken-up, translocated and bio- accumulated in plant edible parts. However, very little is known about the behavior of NPs in soil-plant system as affected by dissolved organic matter (DOM). Thus DOM effect on NPs behavior is critical to assessing the environmental fate and risks related to NP exposure. Carbon-based nanomaterials embedded with metal NPs demonstrate a great potential to serve as catalyst and disinfectors. Hence, synthesis of novel carbon-based nanocomposites and testing them in the environmentally relevant conditions (particularly in the DOM presence) is important for their implementation in water purification. Sorption of DOM on Ag-Ag₂S NPs, CeO₂ NPs and synthesized Ag-Fe₃O₄-carbon nanotubebifunctional composite has been studied. High DOM concentration (50mg/L) decreased the adsorptive and catalytic efficiencies of all synthesized NPs. Recyclable Ag-Fe₃O₄-carbon nanotube composite exhibited excellent catalytic and anti-bacterial action, providing complete reduction of common pollutants and inactivating gram-negative and gram-positive bacteria at environmentally relevant DOM concentrations (5-10 mg/L). Our composite material may be suitable for water purification ranging from natural to the industrial waste effluents. We also examined the role of maize (Zeamays L.)-derived root exudates (a form of DOM) and their components on the aggregation and dissolution of CuONPs in the rhizosphere. Root exudates (RE) significantly inhibited the aggregation of CuONPs regardless of ionic strength and electrolyte type. With RE, the critical coagulation concentration of CuONPs in NaCl shifted from 30 to 125 mM and the value in CaCl₂ shifted from 4 to 20 mM. This inhibition was correlated with molecular weight (MW) of RE fractions. Higher MW fraction (> 10 kDa) reduced the aggregation most. RE also significantly promoted the dissolution of CuONPs and lower MW fraction (< 3 kDa) RE mainly contributed to this process. Also, Cu accumulation in plant root tissues was significantly enhanced by RE. This study provides useful insights into the interactions between RE and CuONPs, which is of significance for the safe use of CuONPs-based antimicrobial products in agricultural production. Wheat root exudates (RE) had high reducing ability to convert Ag+ to nAg under light exposure. Photo-induced reduction of Ag+ to nAg in pristine RE was mainly attributed to the 0-3 kDa fraction. Quantification of the silver species change over time suggested that Cl⁻ played an important role in photoconversion of Ag+ to nAg through the formation and redox cycling of photoreactiveAgCl. Potential electron donors for the photoreduction of Ag+ were identified to be reducing sugars and organic acids of low MW. Meanwhile, the stabilization of the formed particles was controlled by both low (0-3 kDa) and high (>3 kDa) MW molecules. This work provides new information for the formation mechanism of metal nanoparticles mediated by RE, which may further our understanding of the biogeochemical cycling and toxicity of heavy metal ions in agricultural and environmental systems. Copper sulfide nanoparticles (CuSNPs) at 1:1 and 1:4 ratios of Cu and S were synthesized, and their respective antifungal efficacy was evaluated against the pathogenic activity of Gibberellafujikuroi(Bakanae disease) in rice (Oryza sativa). In a 2-d in vitro study, CuS decreased G. fujikuroiColony- Forming Units (CFU) compared to controls. In a greenhouse study, treating with CuSNPs at 50 mg/L at the seed stage significantly decreased disease incidence on rice while the commercial Cu-based pesticide Kocide 3000 had no impact on disease. Foliar-applied CuONPs and CuS (1:1) NPs decreased disease incidence by 30.0 and 32.5%, respectively, which outperformed CuS (1:4) NPs (15%) and Kocide 3000 (12.5%). CuS (1:4) NPs also modulated the shoot salicylic acid (SA) and Jasmonic acid (JA) production to enhance the plant defense mechanisms against G. fujikuroiinfection. These results are useful for improving the delivery efficiency of agrichemicals via nano-enabled strategies while minimizing their environmental impact, and advance our understanding of the defense mechanisms triggered by the NPs presence in plants.
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Suir, Glenn, and Jacob Berkowitz. Inundation depth and duration impacts on wetland soils and vegetation : state of knowledge. Engineer Research and Development Center (U.S.), September 2021. http://dx.doi.org/10.21079/11681/42146.
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The following synthesizes studies investigating plant and soil responses to increased inundation in order to support ecosystem restoration efforts related to the alteration of natural wetland hydrodynamics. Specific topics include hydrologic regimes, soil response to inundation, and implications for vegetation communities exposed to increased water depths. Results highlight the important interactions between water, soils, and vegetation that determine the trajectory and fate of wetland ecosystems, including the development of feedback loops related to marsh degradation and subsidence. This report then discusses the knowledge gaps related to implications of inundation depth, timing, and duration within an ecosystem restoration context, identifying opportunities for future research while providing source materials for practitioners developing restoration projects.
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Avnimelech, Yoram, Richard C. Stehouwer, and Jon Chorover. Use of Composted Waste Materials for Enhanced Ca Migration and Exchange in Sodic Soils and Acidic Minespoils. United States Department of Agriculture, June 2001. http://dx.doi.org/10.32747/2001.7575291.bard.
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Restoration of degraded lands and the development of beneficial uses for waste products are important challenges facing our society. In addition there is a need to find useful and environmentally friendly applications for the organic fractions of municipal and other solid waste. Recent studies have shown that composted wastes combined with gypsum or gypsum-containing flue gas desulfurization by-products enhance restoration of sodic soils and acidic minespoils. The mechanism by which this synergistic effect occurs in systems at opposite pH extremes appears to involve enhanced Ca migration and exchange. Our original research objectives were to (1) identify and quantify the active compost components involved in Ca transport, (2) determine the relative affinity of the compost components for Ca and competing metals in the two soil/spoil systems, (3) determine the efficacy of the compost components in Ca transport to subjacent soil and subsequent exchange with native soil cations, and (4) assess the impacts of compost enhanced Ca transport on soil properties and plant growth. Acidic mine spoils: During the course of the project the focus for objective (1) and (2) shifted more towards developing and evaluating methods to appropriately quantify Ca2+ and Al3+ binding to compost derived dissolved organic matter (DOM). It could be shown that calcium complexation by sewage sludge compost derived DOM did not significantly change during the composting process. A method for studying Al3+ binding to DOM was successfully developed and should allow future insight into DOM-Al3+ interactions in general. Laboratory column experiments as well as greenhouse experiments showed that in very acidic mine spoil material mineral dissolution controls solution Al3+ concentration as opposed to exchange with Ca2+. Therefore compost appeared to have no effect on Al3+ and Ca2+ mobility and did not affect subsoil acidity. Sodic alkaline soils: Batch experiments with Na+ saturated cation exchange resins as a model for sodic soils showed that compost home cations exchanged readily with Na+. Unlike filtered compost extracts, unfiltered compost suspensions also significantly increased Ca2+ release from CaCO3. Soil lysimeter experiments demonstrated a clear impact of compost on structural improvement in sodic alkaline soils. Young compost had faster, clearer and longer lasting effects on soil physical and chemical properties than mature compost. Even after 2 growing seasons differences could still be observed. Compost increased Ca2+ concentration in soil solution and solubility of pedogenic CaCO3 that is highly insoluble under alkaline conditions. The solubilized Ca2+ efficiently exchanged Na+ in the compost treated soils and thus greatly improved the soil structure.
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Chefetz, Benny, and Jon Chorover. Sorption and Mobility of Pharmaceutical Compounds in Soils Irrigated with Treated Wastewater. United States Department of Agriculture, 2006. http://dx.doi.org/10.32747/2006.7592117.bard.
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Research into the fate of pharmaceutical compounds (PCs) in the environment has focused on aspects of removal efficiency during sewage treatment, degradation in surface water and accumulation in soils and sediments. However, very little information is available on the binding interactions of pharmaceuticals with dissolved organic matter (DOM) originating from wastewater treatment. Such interactions can significantly affect the transport potential of PCs in soils by altering compound affinity for soil particle surfaces. Our primary hypothesis is that the transport potential of PCs in soils is strongly impacted by the type and strength of interaction with DOM and the stability of resulting DOM-PC complexes. The overarching goal of the proposed work is to develop a better understanding of the risk associated with introduction of PCs into the environment with treated wastewater. This goal has been achieved by elucidating the mechanisms of the interaction of selected pharmaceuticals (that have shown to be widespread wastewater contaminants) with DOM constituents; by determining the stability and fate of DOM-PC complexes introduced to soils and soil constituents; and by evaluating the potential uptake of these compounds by plants. Based on the results obtained in this study (column and batch sorption-desorption experiments), we suggest that PCs can be classified as slow-mobile compounds in SOM-rich soil layers. When these compounds pass this layer and/or are introduced into SOM-poor soils, their mobility increases significantly. Our data suggest that in semiarid soils (consisting of low SOM), PCs can potentially be transported to the groundwater in fields irrigated with reclaimed wastewater. Moreover, the higher mobility of the acid PCs (i.e., naproxen and diclofenac) in freshwater column systems suggests that their residues in soils irrigated with reclaimed wastewater can leach from the root zone and be transported to the groundwater after rain events. Our data obtained from the binding experiments of PCs with DOM demonstrate that the hydrophobic DOM fractions were more efficient at sorbing PCs than the more polar hydrophilic fractions at a pH near the pKa of the analytes. At the pH of natural semiarid water and soil systems, including that of reclaimed wastewater and biosolids, the role of the hydrophobic fractions as sorption domains is less important than the contribution of the hydrophilic fractions. We also hypothesize that the DOM fractions interact with each other at the molecular level and do not act as independent sorption domains. In summary, our data collected in the BARD project demonstrate that the sorption abilities of the DOM fractions can also significantly affect the mobility of pharmaceutical compounds in soils influenced by intensive irrigation with treated wastewater or amended with biosolids.
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Chefetz, Benny, and Jon Chorover. Sorption and Mobility of Pharmaceutical Compounds in Soils Irrigated with Treated Wastewater. United States Department of Agriculture, 2006. http://dx.doi.org/10.32747/2006.7709883.bard.
Full textAbstract:
Research into the fate of pharmaceutical compounds (PCs) in the environment has focused on aspects of removal efficiency during sewage treatment, degradation in surface water and accumulation in soils and sediments. However, very little information is available on the binding interactions of pharmaceuticals with dissolved organic matter (DOM) originating from wastewater treatment. Such interactions can significantly affect the transport potential of PCs in soils by altering compound affinity for soil particle surfaces. Our primary hypothesis is that the transport potential of PCs in soils is strongly impacted by the type and strength of interaction with DOM and the stability of resulting DOM-PC complexes. The overarching goal of the proposed work is to develop a better understanding of the risk associated with introduction of PCs into the environment with treated wastewater. This goal has been achieved by elucidating the mechanisms of the interaction of selected pharmaceuticals (that have shown to be widespread wastewater contaminants) with DOM constituents; by determining the stability and fate of DOM-PC complexes introduced to soils and soil constituents; and by evaluating the potential uptake of these compounds by plants. Based on the results obtained in this study (column and batch sorption-desorption experiments), we suggest that PCs can be classified as slow-mobile compounds in SOM-rich soil layers. When these compounds pass this layer and/or are introduced into SOM-poor soils, their mobility increases significantly. Our data suggest that in semiarid soils (consisting of low SOM), PCs can potentially be transported to the groundwater in fields irrigated with reclaimed wastewater. Moreover, the higher mobility of the acid PCs (i.e., naproxen and diclofenac) in freshwater column systems suggests that their residues in soils irrigated with reclaimed wastewater can leach from the root zone and be transported to the groundwater after rain events. Our data obtained from the binding experiments of PCs with DOM demonstrate that the hydrophobic DOM fractions were more efficient at sorbing PCs than the more polar hydrophilic fractions at a pH near the pKa of the analytes. At the pH of natural semiarid water and soil systems, including that of reclaimed wastewater and biosolids, the role of the hydrophobic fractions as sorption domains is less important than the contribution of the hydrophilic fractions. We also hypothesize that the DOM fractions interact with each other at the molecular level and do not act as independent sorption domains. In summary, our data collected in the BARD project demonstrate that the sorption abilities of the DOM fractions can also significantly affect the mobility of pharmaceutical compounds in soils influenced by intensive irrigation with treated wastewater or amended with biosolids.
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Borch, Thomas, Yitzhak Hadar, and Tamara Polubesova. Environmental fate of antiepileptic drugs and their metabolites: Biodegradation, complexation, and photodegradation. United States Department of Agriculture, January 2012. http://dx.doi.org/10.32747/2012.7597927.bard.
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Many pharmaceutical compounds are active at very low doses, and a portion of them regularly enters municipal sewage systems and wastewater-treatment plants following use, where they often do not fully degrade. Two such compounds, CBZ and LTG, have been detected in wastewater effluents, surface waters, drinking water, and irrigation water, where they pose a risk to the environment and the food supply. These compounds are expected to interact with organic matter in the environment, but little is known about the effect of such interactions on their environmental fate and transport. The original objectives of our research, as defined in the approved proposal, were to: Determine the rates, mechanisms and products of photodegradation of LTG, CBZ and selected metabolites in waters exposed to near UV light, and the influence of DOM type and binding processes on photodegradation. Determine the potential and pathways for biodegradation of LTG, CBZ and selected metabolites using a white rot fungus (Pleurotusostreatus) and ADP, and reveal the effect of DOM complexation on these processes. Reveal the major mechanisms of binding of LTG, CBZ and selected metabolites to DOM and soil in the presence of DOM, and evaluate the effect of this binding on their photodegradation and/or biodegradation. We determined that LTG undergoes relatively slow photodegradation when exposed to UV light, and that pH affects each of LTG’s ability to absorb UV light, the efficiency of the resulting reaction, and the identities of LTG’sphotoproducts (t½ = 230 to 500 h during summer at latitude 40 °N). We observed that LTG’sphotodegradation is enhanced in the presence of DOM, and hypothesized that LTG undergoes direct reactions with DOM components through nucleophilic substitution reactions. In combination, these data suggest that LTG’s fate and transport in surface waters are controlled by environmental conditions that vary with time and location, potentially affecting the environment and irrigation waters. We determined that P. ostreatusgrows faster in a rich liquid medium (glucose peptone) than on a natural lignocellulosic substrate (cotton stalks) under SSF conditions, but that the overall CBZ removal rate was similar in both media. Different and more varied transformation products formed in the solid state culture, and we hypothesized that CBZ degradation would proceed further when P. ostreatusand the ᵉⁿᶻʸᵐᵃᵗⁱᶜ ᵖʳᵒᶠⁱˡᵉ ʷᵉʳᵉ ᵗᵘⁿᵉᵈ ᵗᵒ ˡⁱᵍⁿⁱⁿ ᵈᵉᵍʳᵃᵈᵃᵗⁱᵒⁿ. ᵂᵉ ᵒᵇˢᵉʳᵛᵉᵈ ¹⁴C⁻Cᴼ2 ʳᵉˡᵉᵃˢᵉ ʷʰᵉⁿ ¹⁴C⁻ᶜᵃʳᵇᵒⁿʸˡ⁻ labeled CBZ was used as the substrate in the solid state culture (17.4% of the initial radioactivity after 63 days of incubation), but could not conclude that mineralization had occurred. In comparison, we determined that LTG does not degrade in agricultural soils irrigated with treated wastewater, but that P. ostreatusremoves up to 70% of LTG in a glucose peptone medium. We detected various metabolites, including N-oxides and glycosides, but are still working to determine the degradation pathway. In combination, these data suggest that P. ostreatuscould be an innovative and effective tool for CBZ and LTG remediation in the environment and in wastewater used for irrigation. In batch experiments, we determined that the sorption of LTG, CBZ and selected metabolites to agricultural soils was governed mainly by SOM levels. In lysimeter experiments, we also observed LTG and CBZ accumulation in top soil layers enriched with organic matter. However, we detected CBZ and one of its metabolites in rain-fed wheat previously irrigated with treated wastewater, suggesting that their sorption was reversible, and indicating the potential for plant uptake and leaching. Finally, we used macroscale analyses (including adsorption/desorption trials and resin-based separations) with molecular- level characterization by FT-ICR MS to demonstrate the adsorptive fractionation of DOM from composted biosolids by mineral soil. This suggests that changes in soil and organic matter types will influence the extent of LTG and CBZ sorption to agricultural soils, as well as the potential for plant uptake and leaching.
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McClure, Michael A., Yitzhak Spiegel, David M. Bird, R. Salomon, and R. H. C. Curtis. Functional Analysis of Root-Knot Nematode Surface Coat Proteins to Develop Rational Targets for Plantibodies. United States Department of Agriculture, October 2001. http://dx.doi.org/10.32747/2001.7575284.bard.
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The goal of this research was to provide a better understanding of the interface between root-knot nematodes, Meloidogyne spp., and their host in order to develop rational targets for plantibodies and other novel methods of nematode control directed against the nematode surface coat (SC). Specific objectives were: 1. To produce additional monoclonal SC antibodies for use in Objectives 2, 3, and 4 and as candidates for development of plantibodies. 2. To determine the production and distribution of SC proteins during the infection process. 3. To use biochemical and immunological methods to perturbate the root-knot nematode SC in order to identify SC components that will serve as targets for rationally designed plantibodies. 4. To develop SC-mutant nematodes as additional tools for defining the role of the SC during infection. The external cuticular layer of nematodes is the epicuticle. In many nematodes, it is covered by a fuzzy material termed "surface coat" (SC). Since the SC is the outermost layer, it may playa role in the interaction between the nematode and its surroundings during all life stages in soil and during pathogenesis. The SC is composed mainly of proteins, carbohydrates (which can be part of glycoproteins), and lipids. SC proteins and glycoproteins have been labeled and extracted from preparasitic second-stage juveniles and adult females of Meloidogyne and specific antibodies have been raised against surface antigens. Antibodies can be used to gain more information about surface function and to isolate genes encoding for surface antigens. Characterization of surface antigens and their roles in different life-stages may be an important step towards the development of alternative control. Nevertheless, the role of the plant- parasitic nematode's surface in plant-nematode interaction is still not understood. Carbohydrates or carbohydrate-recognition domains (CROs) on the nematode surface may interact with CROs or carbohydrate molecules, on root surfaces or exudates, or be active after the nematode has penetrated into the root. Surface antigens undoubtedly play an important role in interactions with microorganisms that adhere to the nematodes. Polyclonal (PC) and monoclonal (MC) antibodies raised against Meloidogyne javanica, M. incognita and other plant-parasitic nematodes, were used to characterize the surface coat and secreted-excreted products of M. javanica and M. incognita. Some of the MC and PC antibodies raised against M. incognita showed cross-reactivity with the surface coat of M. javanica. Further characterization, in planta, of the epitopes recognized by the antibodies, showed that they were present in the parasitic juvenile stages and that the surface coat is shed during root penetration by the nematode and its migration between root cells. At the molecular level, we have followed two lines of experimentation. The first has been to identify genes encoding surface coat (SC) molecules, and we have isolated and characterized a small family of mucin genes from M. incognita. Our second approach has been to study host genes that respond to the nematode, and in particular, to the SC. Our previous work has identified a large suite of genes expressed in Lycopersicon esculentum giant cells, including the partial cDNA clone DB#131, which encodes a serine/threonine protein kinase. Isolation and predicted translation of the mature cDNA revealed a frame shift mutation in the translated region of nematode sensitive plants. By using primers homologous to conserved region of DB#131 we have identified the orthologues from three (nematode-resistant) Lycopersicon peruvianum strains and found that these plants lacked the mutation.