Action of plant root exudates in bioremediations: a review

Dundek, Peter; Holík, Ladislav; Hromádko, Ladislav; Rohlík, Tomáš; Vranová, Valerie; Rejšek, Klement; Formánek, Pavel

doi:10.11118/actaun201159010303

Cited by 7 publications

(3 citation statements)

References 55 publications

(57 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The observed high below-ground 36 Cl org formation in the plant treatment indicates that root and rhizosphere may influence specific chlorination rates in soil. Plant roots can stimulate microorganisms in the rhizosphere by creating a favourable microenvironment and by means of root exudates that supply labile organic carbon (Cheng et al 2014;Dundek et al 2011). The information regarding Cl in roots and rhizosphere around the roots are scarce.…”

Section: Org Levels In Plant Biomassmentioning

confidence: 99%

Radiotracer evidence that the rhizosphere is a hot-spot for chlorination of soil organic matter

et al. 2019

View full text Add to dashboard Cite

Aims The ubiquitous and extensive natural chlorination of organic matter in soils, leading to levels of chlorinated soil organic matter that often exceed the levels of chloride, remains mysterious in terms of its causes and regulation. While the composition of plant species and the availability of labile organic matter was recently shown to be important, the physical localization of chlorination in soils remains unclear but is a key for understanding regulation and patterns observed. Here we assess the relative importance of organic matter chlorination in (a) bulk soil, (b) the plant roots plus the rhizosphere zone surrounding the roots, and (c) above-ground plant biomass, in an experimental plant-soil system.Methods A radiotracer, 36 Cl, was added to study translocation and transformations of Cl − and Cl org in agricultural soil with and without wheat (Triticum vulgare) over 50 days.Results The specific chlorination rates (the fraction of the added 36 Cl − converted to 36 Cl org per day) in soil with plants was much higher (0.02 d −1 ) than without plants (0.0007 d −1 ) at peak growth (day 25). The plant root and rhizosphere showed much higher formation of 36 Cl org than the bulk soil, suggesting that the rhizosphere is a hotspot for chlorination in the soil. In addition, the treatment with plants displayed a rapid and high plant uptake of Cl − . Conclusions Our results indicate that the rhizosphere harbour the most extensive in-situ chlorination process in soil and that root-soil interaction may be key for terrestrial chlorine cycling.

show abstract

Section: Org Levels In Plant Biomassmentioning

confidence: 99%

Radiotracer evidence that the rhizosphere is a hot-spot for chlorination of soil organic matter

et al. 2019

View full text Add to dashboard Cite

show abstract

“…Increased Clorg formation as well as high chlorination activity was found in the root zone and this indicate that roots may influence specific chlorination rates in soil. Plant roots can stimulate microorganisms in the rhizosphere by supporting a favourable microenvironment and by root exudates (Dundek et al, 2011) which supplies soil microorganisms with labile organic carbon (Cheng et al, 2014). The root zone seems to be an active site for the formation of Clorg in soils.…”

Section: Influence Of Vegetation On Chlorination In Soilmentioning

confidence: 99%

Chlorine Cycling in Terrestrial Environments

Montelius¹

2016

Linköping Studies in Arts and Sciences

View full text Add to dashboard Cite

Chlorinated organic compounds (Clorg) are produced naturally in soil. Formation and degradation of Clorg affect the chlorine (Cl) cycling in terrestrial environments and chlorine can be retained or released from soil. Cl is known to have the same behaviour as radioactive chlorine-36 ( 36 Cl), a long-lived radioisotope with a half-life of 300,000 years. 36Cl attracts interest because of its presence in radioactive waste, making 36 Cl a potential risk for humans and animals due to possible biological uptake. This thesis studies the distribution and cycling of chloride (Cl -) and Clorg in terrestrial environments by using laboratory controlled soil incubation studies and a forest field study. The results show higher amounts of Cl -and Clorg and higher chlorination rates in coniferous forest soils than in pasture and agricultural soils. Tree species is the most important factor regulating Cl -and Clorg levels, whereas geographical location, atmospheric deposition, and soil type are less important. The root zone was the most active site of the chlorination process. Moreover, this thesis confirms that bulk Clorg dechlorination rates are similar to, or higher than, chlorination rates and that there are at least two major Clorg pools, one being dechlorinated quickly and one remarkably slower. While chlorination rates were negatively influenced by nitrogen additions, dechlorination rates, seem unaffected by nitrogen. The results implicate that Cl cycling is highly active in soils and Cl -and Clorg levels result from a dynamic equilibrium between chlorination and dechlorination. Influence of tree species and the rapid and slow cycling of some Cl pools, are critical to consider in studies of Cl in terrestrial environments. This information can be used to better understand Cl in risk-assessment modelling including inorganic and organic 36 Cl.Keywords: chloride, organic chlorine, chlorination, dechlorination, 36Cl, risk assessment modelling SammanfattningKlorerade organiska föreningar (Clorg) bildas naturligt i mark och påverkar klorets kretslopp genom att de stannar kvar längre i marken. Detta stabila klor anses ha samma egenskaper som klor-36, som är en långlivad radioisotop med en halveringstid på 300 000 år. Klor-36 förekommer i olika typer av radioaktivt avfall och om klor-36 sprids i naturen finns det en potentiell risk för människor och djur genom biologiskt upptag. Syftet i denna avhandling är att öka kunskapen om fördelningen och cirkulationen av klorid (Cl -) och Clorg i terrestra miljöer med hjälp av studier i laboratoriemiljö samt en fältstudie i skogsmiljö. Resultaten visar att bildningshastigheten av Clorg är högst i barrskogsjord och rotzonen tycks vara en aktiv plats. Det finns också en större mängd Cl -och Clorg i barrskogsjordar än i betesmark och jordbruksmark. Den mest betydande faktorn som styr halterna av Cl -och Clorg är trädsort, medan geografiskt läge, atmosfäriskt nedfall, och jordmån är av mindre betydelse. Bildning och nedbrytning av Clorg sker med liknande hastigheter, men det tycks fin...

show abstract

“…Root exudates of some plants (e.g., Thlaspi caerulescens ) do not increase the mobility of heavy metals in soils . Model solutions were also tested in heavy–metal‐polluted soils to determine the response of the microbial community in concentrations of 15‐600 µg C.g ‐1 dry soil over a 24‐h period, being equivalent to the estimated carbon input into the rhizosphere . Root exudates have also been used for testing degradation of pollutants by microbial strains in different types of media such as Buschnell‐Hass or YEPG (yeast extract peptone glucose) medium or basal salts medium (BSM) using microplate analysis …”

Section: The Use Of Plant Root Exudates For Bioremediationsmentioning

confidence: 99%

Natural Occurrence of Enantiomers of Organic Compounds Versus Phytoremediations: Should Research on Phytoremediations Be Revisited? A Mini‐review

et al. 2013

Self Cite

View full text Add to dashboard Cite

Decontamination of polluted soils using plants is based on the ability of plant species (including transgenic plants) to enhance bioavailability of pollutants in the rhizosphere and support growth of pollutant-degrading microorganisms via root exudation and plant species-specific composition of the exudates. In this work, we review current knowledge of enantiomers of low-molecular-weight (LMW) organic compounds with emphasis on their use in phytoremediation. Many research studies have been performed to search for plants suitable for decontamination of polluted soils. Nevertheless, the natural occurrence of L- versus D-enantiomers of dominant compounds of plant root exudates which play different roles in the complexation of heavy metals, chemoattraction, and support of pollutant-degrading microorganisms were not included in these studies. D-enantiomers of aliphatic organic acids and amino acids or L-enantiomers of carbohydrates occur in high concentrations in root exudates of some plant species, especially under stress, and are less stimulatory for plants to extract heavy metals or for rhizosphere microflora to degrade pollutants compared with L-enantiomers (organic acids and amino acids) or D-carbohydrates. Determining the ratio of L- versus D-enantiomers of organic compounds as a criterion of plant suitability for decontamination of polluted soils and development of other types of bioremediation technologies need to be subjects of future research.

show abstract

Action of plant root exudates in bioremediations: a review

Cited by 7 publications

References 55 publications

Radiotracer evidence that the rhizosphere is a hot-spot for chlorination of soil organic matter

Radiotracer evidence that the rhizosphere is a hot-spot for chlorination of soil organic matter

Chlorine Cycling in Terrestrial Environments

Natural Occurrence of Enantiomers of Organic Compounds Versus Phytoremediations: Should Research on Phytoremediations Be Revisited? A Mini‐review

Contact Info

Product

Resources

About