Planted Studies

Rhizoremediation experiments conducted by planting and monitoring microbial populations and or contaminant levels over time are powerful approaches since they can be constructed and operated with replication, randomisation and controlled conditions. Perhaps the major limitation of planted studies is time, since for reasons of practicality planted studies are typically only run for 1-3 years. Because roots are estimated to occupy less than 1 of soil 16 , it is reasonable to anticipate that many...

Forensic Field Studies

While conventional wisdom may dictate a progression from bench to greenhouse to field-testing of remedial technologies, there are distinct advantages to starting directly in the field to examine the rhizoremediation capabilities of natural vegetation. This approach affords a view of the long-term impacts of a diverse array of plant species, including mature trees, on microbial communities and or contaminant disappearance otherwise inaccessible due to the practical time limitations of most...

Molecular Ecological Methods

Molecular microbial ecology methods bypass culture-bias to provide direct measures of a variety of microbial community parameters. This section highlights some methods that are of particular value to bioremediation studies because of their ability to directly detect the presence, activity, diversity and abundance of degradative organisms. 4.2.1 DNA and RNA extraction methods Many molecular ecological analyses require bacterial DNA and or RNA to be extracted from soil. Depending on both the soil...

Phytoremediation Of Lindane Using Water Hyacinth

Time course experiment of lindane disappearance in solution with chilli and coriander. Controls (white columns), chilli (black columns), coriander (grey columns). Data points represent the means of 5 replicates determinations. Bar SD. the effect of the rhizosphere on these compounds. Five plant species were harvested and separated into roots, stems and leaves Chenopodium vulgare, Solanum nigrum, Cytisus striatus, Vicia sativa and Avena sativa. Concentrations of total HCH in plant...

Organic Compounds

It was shown that dissipation of condensed PAHs might be enhanced in the presence of AM fungi in the soil spiked with a mixture of different PAHs 127 . These results were consecutively verified in pot experiments conducted in two different industrially polluted soils 128 . In general, following explanations were suggested by the authors to elucidate the contribution of AM to PAH degradation i) mycorrhiza modifies root enzyme activity, exudation and architecture in a manner that stimulates PAH...

Uptake And Translocation Of Organic Pollutants

Physicochemical and structural properties determine the uptake of organic chemicals by plant roots from the soil 16 . Aqueous solutions of moderately hydrophobic organic chemicals (characterized with an octanol-water partition coefficient log Kow of 1.03.5), such as low molecular weight aliphatics and aromatics, and chlorinated solvents dissolved in water are readily taken up by roots of trees and translocated to the aerial parts of the plant. Uptake of hydrophilic (log K< ,w< 1.0) and...

Info

Several plants have been used in combination with chelating agents for enhanced phytoextraction. The ideal plant should be fast growing and produce a large biomass while accumulating high concentrations of polluting metals. It should also be tolerant enough to grow in contaminated soils and be resistant to the chelating agent. It should have known agronomics practice and produce usable fruit or biomass to generate some financial income after harvesting. B. juncea possesses several of these...

Phytoremediation

The uptake of pesticides by plants depends on the physicochemical properties of the compound, mode of application, soil type, climatic factors and plant species. Once in the roots, the chemical may be translocated to shoot via xylem. The permeation from plant roots to xylem is optimal for moderately hydrophobic molecules, with a log Kow between 0.5 and 3.5. More hydrophobic chemicals tend to bind with lipid membranes or oil possibly present in plant roots. Translocation of non-ionic pesticides...

Cultivationbased Methods

4.1.1 Microbial recovery from the soil-root interface In preparation for cultivation, it is often necessary to extract microorganisms from the soil, rhizosphere, rhizoplane or endorhizosphere. Typically a bacterial suspension is created that may then be serial diluted or used directly as an inoculum using the following methods. Soil bacteria are suspended by shaking or vortexing soil in liquid along with sterile glass beads 37 , sometimes followed by standing for 30 min or short low-speed...

Materials And Methods

Immature inflorescences of Poaceae and Typhaceae were harvested while unemerged and still covered by leaf sheaths. For Cyperaceae and Juncaceae, inflorescences were gathered while the flowers were small early in their development. The explants were surface sterilized by dilute bleach solution then cultured on primary explant medium DM-8 in the dark at 26-28oC. DM-8 medium 10 contained (in mg l-1, unless indicated otherwise) Murashige and Skoog (MS) salts 11 , Sigma Fine Chemicals) 4,300...

Joel G Burken And Xingmao Ma

Department of Civil, Architectural & Environmental Engineering Butler Carlton Civil Engineering Hall University of Missouri-Rolla Rolla, Missouri 65409-0030 USA Phone 573-341-6547 FAX573-341-4729 E-mail burken umr.edu Many volatile organic compounds pose a unique type of threat to our environment, existing over vast areas in multiple media water, soil and vapour. Phytoremediation applications are also unique as they are both highly visible and publicly acceptable and are also both long-term...

GSR glutathione conjugate of the pollutant

Glutathione-conjugation reaction of a pollutant containing an X' leaving group. GSTs represent a family of enzymes with usually broad and overlapping substrate specificities, which facilitate the above reactions of hydrophobic, electrophilic substrates. Our knowledge on plant GSTs in trees has expanded greatly in recent years. Evidence is accumulating on the regulation of gene expression, molecular characteristics, and specific catalytic action of the multiple forms of these enzymes....

Acc Deaminase And The Reduction Of Plant Ethylene

In higher plants, ethylene is produced from L-methionine via the intermediates, S-adenosyl-L-methionine (SAM) and 1-aminocyclopropane-1-carboxylic acid (ACC) 12 . The enzymes involved in this metabolic sequence are SAM synthetase, which catalyzes the conversion of methionine to SAM 13 ACC synthase, which is responsible for the hydrolysis of SAM to ACC and 5-methylthioadenosine 14 and ACC oxidase, which metabolizes ACC to ethylene, carbon dioxide and cyanide 15 . In 1978, an enzyme capable of...

Removal Of Pollutants Via Plants

Phytoextraction refers to the removal of pollutants from soils or water through plant uptake 66 . In this approach, the pollutants are not simply recycled back into the wetland, as is the case in phytostabilisation, but they are removed from the system by harvesting the plants or by volatilisation through the plants. The latter only applies to substances that can form gaseous compounds, such as Se 22, 67 and Hg 28 . For phytoextraction through uptake and harvest to be effective, uptake by the...

Oxygen Release By Roots Into Rhizosphere Of Helophytes

Oxygen reaching the root aerenchyma is respired by the root tissues and diffuses towards to the root apex and radially to the rhizosphere, to be consumed in the surrounding soil 54 . The oxygen flux from the root aerenchyma to the rhizosphere, known as radial oxygen loss ROL , is determined by the concentration gradient, the consumption of oxygen by the cells along the radial path, and the physical resistance to oxygen diffusion 54, 56 . As a result, 30-40 of the oxygen supplied via the...

Metabolism And Genetic Engineering Studies For Herbicide Phytoremediation

SCHNOOR2 1Biochemistry and Cell Biology, Rice University, Houston, Texas, USA 2Civil and Environmental Engineering, University of Iowa, Iowa City, IA, 52242, USA - Fax 01 319 3355660 E-mail jerald-schnoor uiowa.edu Herbicides are extensively used for the purpose of crop cultivation and still remain as an important strategy for the commercial agriculture. However, the widespread use of herbicides has resulted in both point source and non-point source...

Cdna Libraries

Numerous enzyme sequences have been identified in Arabidopsis, but little headway has been made in matching specific enzymes with their function on herbicide substrates. Molecular information on enzymes and function identification towards herbicides has been studied based on cDNA libraries. cDNA libraries are prepared from the mRNA of interest that is synthesized to DNA cDNA strand, which contains a specific coding region of a genome that is inserted into vectors and cloned 30 . Studies on P450...

Ericoid Mycorrhizal Fungi

The data on the effects of HMs on occurrence of ericoid mycorrhizal fungi in the soil are very limited due to rather difficult quantification of ericoid mycorrhiza in the field samples - the ErM fungi generally do not form spores or fruiting bodies. However, occurrence of ericoid mycorrhizal fungi can be linked together with occurrence of their ericaceous hosts, which are usually highly mycorrhizal at both disturbed and undisturbed sites. For the ErM fungi, there are only few reports on how...