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Title: Exploratory Project: Rigid nanostructured organic polymer monolith for in situ collection and analysis of plant metabolites from soil matrices

Abstract

Plant metabolites released from litter leachates and root exudates enable plants to adapt and survive in a wide range of habitats by facilitating resource foraging and plant-organismal interactions, and could influence soil carbon storage. The biological functions of these plant inputs and the organismal interactions they facilitate in soil are strictly governed by their composition and molecular identity. Our current understanding about the molecular identity of exudates is based on physiological studies that are done in soil-less axenic cultures. On the other hand, ecological studies that rely on isotope labeling to track the fluxes of carbon from plants to soil have found the complexities of soil-microbe matrices as an insurmountable barrier to undertake any meaningful molecular level characterization of plant inputs. Although it is constantly advocated to undertake a molecular level identification of the dynamicity of plant metabolites in soils, the complexity of soil system has thus far prevented any such endeavors. We developed polymeric probes through in-situ polymerization of poly(styrene-co-vinylbenzyl chloride-co-divinylbenzene) to elucidate the chemical environment of the soil to which the plant roots are exposed. Hypercrosslinking of the polymeric probes through an in-situ Friedel-Crafts alkylation significantly increased the surface area and the sorption capacity of the probes. Surfacemore » functionalization of the probes using a hybrid approach was also attempted. The efficacy of these probes was tested using batch equilibration. Scanning electron microscopy revealed extensive modification of the surface of the probes through hypercrosslinking. The probes exhibited a lower site specific sorption (slope of Freundlich adsorption isotherm close to unity) and percent recovery of the sorbed compounds from the probes were >70, indicating a predominance of reversible sorption. Further we imparted specificity to this copolymer matrix by using molecular-template imprinting approach for the selective capture of less abundant plant metabolites from a crowded soil/litter leachate. Our results suggests that i) the root exudate pattern of plants is highly dependent on the nutrient status of the plant, with greater specificity of root exudation occurring in growing medium with low available form of nutrients, ii) the chemical composition of root exudation is a function of the distance of sampling from the source-roots, with the composition of root exudation being more enriched in polar metabolites farther from the source-roots, iii) Further we demonstrated that the compounds present in real root exudates diffuse farther from the source roots than those in artificial root exudates that are traditionally used. Thus, our project highlights how the soil matrix is instrumental in modifying the chemical composition of root exudates, and highlights that, apart from the plant physiology, the specificity and function of root exudates is also modified by environmental factors.« less

Authors:
 [1]
  1. Clemson Univ., SC (United States)
Publication Date:
Research Org.:
Clemson Univ., SC (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
OSTI Identifier:
1259701
Report Number(s):
DOE-Clemson-10832
DOE Contract Number:
SC0010832
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; root exudates, soil carbon

Citation Formats

Tharayil, Nishanth. Exploratory Project: Rigid nanostructured organic polymer monolith for in situ collection and analysis of plant metabolites from soil matrices. United States: N. p., 2016. Web. doi:10.2172/1259701.
Tharayil, Nishanth. Exploratory Project: Rigid nanostructured organic polymer monolith for in situ collection and analysis of plant metabolites from soil matrices. United States. doi:10.2172/1259701.
Tharayil, Nishanth. Wed . "Exploratory Project: Rigid nanostructured organic polymer monolith for in situ collection and analysis of plant metabolites from soil matrices". United States. doi:10.2172/1259701. https://www.osti.gov/servlets/purl/1259701.
@article{osti_1259701,
title = {Exploratory Project: Rigid nanostructured organic polymer monolith for in situ collection and analysis of plant metabolites from soil matrices},
author = {Tharayil, Nishanth},
abstractNote = {Plant metabolites released from litter leachates and root exudates enable plants to adapt and survive in a wide range of habitats by facilitating resource foraging and plant-organismal interactions, and could influence soil carbon storage. The biological functions of these plant inputs and the organismal interactions they facilitate in soil are strictly governed by their composition and molecular identity. Our current understanding about the molecular identity of exudates is based on physiological studies that are done in soil-less axenic cultures. On the other hand, ecological studies that rely on isotope labeling to track the fluxes of carbon from plants to soil have found the complexities of soil-microbe matrices as an insurmountable barrier to undertake any meaningful molecular level characterization of plant inputs. Although it is constantly advocated to undertake a molecular level identification of the dynamicity of plant metabolites in soils, the complexity of soil system has thus far prevented any such endeavors. We developed polymeric probes through in-situ polymerization of poly(styrene-co-vinylbenzyl chloride-co-divinylbenzene) to elucidate the chemical environment of the soil to which the plant roots are exposed. Hypercrosslinking of the polymeric probes through an in-situ Friedel-Crafts alkylation significantly increased the surface area and the sorption capacity of the probes. Surface functionalization of the probes using a hybrid approach was also attempted. The efficacy of these probes was tested using batch equilibration. Scanning electron microscopy revealed extensive modification of the surface of the probes through hypercrosslinking. The probes exhibited a lower site specific sorption (slope of Freundlich adsorption isotherm close to unity) and percent recovery of the sorbed compounds from the probes were >70, indicating a predominance of reversible sorption. Further we imparted specificity to this copolymer matrix by using molecular-template imprinting approach for the selective capture of less abundant plant metabolites from a crowded soil/litter leachate. Our results suggests that i) the root exudate pattern of plants is highly dependent on the nutrient status of the plant, with greater specificity of root exudation occurring in growing medium with low available form of nutrients, ii) the chemical composition of root exudation is a function of the distance of sampling from the source-roots, with the composition of root exudation being more enriched in polar metabolites farther from the source-roots, iii) Further we demonstrated that the compounds present in real root exudates diffuse farther from the source roots than those in artificial root exudates that are traditionally used. Thus, our project highlights how the soil matrix is instrumental in modifying the chemical composition of root exudates, and highlights that, apart from the plant physiology, the specificity and function of root exudates is also modified by environmental factors.},
doi = {10.2172/1259701},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Jun 29 00:00:00 EDT 2016},
month = {Wed Jun 29 00:00:00 EDT 2016}
}

Technical Report:

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  • This Quality Assurance Project Plan (QAPP) establishes the requirements for control of quality affecting activities associated with the field-scale demonstration project designed to produce an effective solution for environmental restoration of chlorinated solvent contaminated soils beneath the X-231B Oil Biodegradation Unit at the Portsmouth Gaseous Diffusion Plant (PORTS) located near Piketon, Ohio. The project objectives are to demonstrate, test, and evaluated multiple treatment processes to document successful in situ immobilization and removal/destruction processes for volatile organic compounds and other potential problem constituents. The results of the demonstration may then be used for full-scale remediation of the X-231B Unit and extendedmore » to other similar sites at PORTS, within the DOE system, and elsewhere. The project was divided into two major phases: Phase 1-- Technology Evaluation and Screening and Phase 2-- Technology Demonstration, Testing, and Evaluation. This QAPP presents the specific policies, organization, objectives, functional activities and the specific Quality Assurance (QA) and Quality Control (QC) activities designed to achieve the data quality goals for Phase 2 of the project. Phase 1 has been completed and documented. Phase 2 is further subdivided into two separate components, (i.e., treatability studies and technology demonstrations). These activities are delineated in the Project Description, which was prepared to convey the overall nature of the project.« less
  • This Quality Assurance Project Plan (QAPP) establishes the requirements for control of quality affecting activities associated with the field-scale demonstration project designed to produce an effective solution for environmental restoration of chlorinated solvent contaminated soils beneath the X-231B Oil Biodegradation Unit at the Portsmouth Gaseous Diffusion Plant (PORTS) located near Piketon, Ohio. The project objectives are to demonstrate, test, and evaluated multiple treatment processes to document successful in situ immobilization and removal/destruction processes for volatile organic compounds and other potential problem constituents. The results of the demonstration may then be used for full-scale remediation of the X-231B Unit and extendedmore » to other similar sites at PORTS, within the DOE system, and elsewhere. The project was divided into two major phases: Phase 1-- Technology Evaluation and Screening and Phase 2-- Technology Demonstration, Testing, and Evaluation. This QAPP presents the specific policies, organization, objectives, functional activities and the specific Quality Assurance (QA) and Quality Control (QC) activities designed to achieve the data quality goals for Phase 2 of the project. Phase 1 has been completed and documented. Phase 2 is further subdivided into two separate components, (i.e., treatability studies and technology demonstrations). These activities are delineated in the Project Description, which was prepared to convey the overall nature of the project.« less
  • The collection of subsurface soil or sediment samples in survey or screening studies for subsequent volatile organic analysis in the laboratory introduces many considerations including the number of samples to be collected along a depth profile, which subsample to submit, and what treatment and preservation are ideal before sample analysis. Ideally, the sample with the greatest probability for confirming a leaking tank or a spill site would reduce project costs considerably. Using a field compatible photoionization detector, a series of studies using xylene, benzene, and trichloroethylene contaminated soils or water placed in small chambers under temperature control were conducted tomore » simulate field situations. The water contamination study was designed to mimic sampling well headspace for the presence of volatile organic compounds. The results have provided a basis for field screening and sample selection for soils containing volatile organic contaminants and identified some important considerations for screening well headspaces for organic contamination. 4 refs., 7 figs., 4 tabs.« less
  • A preliminary study was conducted to elucidate the nature of the polar metabolites reported for plant tissues and xylem exudates following root accumulation of trinitrotoluene. Studies focused on the nature of the proposed conjugates of TNT-residues in xylem exudates of bush beam plants. Use of enzymatic methods failed to demonstrate that the conjugates were carbohydrate based, but acid hydrolysis indicated that the conjugates may be protein based. Of the five polar conjugates isolated from exudates, the presence of aminodinitrotoluene isomers and one unknown TNT residue was demonstrated.