Rhizodeposits of Trifolium pratense and Lolium perenne: Their comparative effects on 2,4-D mineralization in two contrasting soils

L J Shaw; Richard G Burns

doi:10.1016/j.soilbio.2004.10.020

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Rhizodeposits of Trifolium pratense and Lolium perenne: Their comparative effects on 2,4-D mineralization in two contrasting soils

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Rhizodeposits of Trifolium pratense and Lolium perenne: Their comparative effects on 2,4-D mineralization in two contrasting soils

L J Shaw and Richard G Burns

Soil Biology and Biochemistry, Vol.37(5), pp.995-1002

2005

DOI: https://doi.org/10.1016/j.soilbio.2004.10.020

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Abstract

biodegradation

2,4-Dichlorophenoxyacetic acid

rhizosphere

rhizoremediation

rhizodeposition

TfdA

trifolium repens

lolium perenne

Rhizosphere enhanced biodegradation of organic pollutants has been reported frequently and a stimulatory role for specific components of rhizodeposits postulated. As rhizodeposit composition is a function of plant species and soil type, we compared the effect of Lolium perenne and Trifolium pratense grown in two different soils (a sandy silt loam: pH 4, 2.8% OC, no previous 2,4-D exposure and a silt loam: pH 6.5, 4.3% OC, previous 2,4-D exposure) on the mineralization of the herbicide 2,4-D (2,4-dichlorophenoxyacetic acid). We investigated the relationship of mineralization kinetics to dehydrogenase activity, most probable number of 2,4-D degraders (MPN2,4-D) and 2,4-D degrader composition (using sequence analysis of the gene encoding ?-ketoglutarate/2,4-D dioxygenase (tfdA)). There were significant (P<0.01) plant-soil interaction effects on MPN2,4-D and 2,4-D mineralization kinetics (e.g. T. pratense rhizodeposits enhanced the maximum mineralization rate by 30% in the acid sandy silt loam soil, but not in the neutral silt loam soil). Differences in mineralization kinetics could not be ascribed to 2,4-D degrader composition as both soils had tfdA sequences which clustered with tfdAs representative of two distinct classes of 2,4-D degrader: canonical R. eutropha JMP134-like and oligotrophic ?-proteobacterial-like. Other explanations for the differential rhizodeposit effect between soils and plants (e.g. nutrient competition effects) are discussed. Our findings stress that complexity of soil-plant-microbe interactions in the rhizosphere make the occurrence and extent of rhizosphere-enhanced xenobiotic degradation difficult to predict. © 2004 Elsevier Ltd. All rights reserved.

Details

Title: Rhizodeposits of Trifolium pratense and Lolium perenne: Their comparative effects on 2,4-D mineralization in two contrasting soils
Authors: L J Shaw (Author) - Imperial College London, United Kingdom
Richard G Burns (Author) - University of Queensland
Publication details: Soil Biology and Biochemistry, Vol.37(5), pp.995-1002
Publisher: Pergamon
Date published: 2005
DOI: 10.1016/j.soilbio.2004.10.020
ISSN: 0038-0717
Organisation Unit: University of the Sunshine Coast, Queensland; Office of the Deputy Vice-Chancellor (Research and Innovation)
Language: English
Record Identifier: 99449323002621
Output Type: Journal article

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Collaboration types: Domestic collaboration; International collaboration
Web Of Science research areas: Soil Science