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Bacterial inoculants of forage grasses that enhance degradation of 2‐chlorobenzoic acid in soil
Author(s) -
Siciliano Steven D.,
Germida James J.
Publication year - 1997
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.5620160602
Subject(s) - microbial inoculant , biology , germination , agronomy , forage , environmental remediation , inoculation , soil contamination , bacteria , bromus inermis , elymus , biomass (ecology) , horticulture , poaceae , contamination , ecology , genetics
Biological remediation of contaminated soil is an effective method of reducing risk to human and ecosystem health. Bacteria and plants might be used to enhance remediation of soil pollutants in situ. This study assessed the potential of bacteria (12 isolates), plants (16 forage grasses), and plant‐bacteria associations (selected pairings) to remediate 2‐chlorobenzoic acid (2CBA)‐contaminated soil. Initially, grass viability was assessed in 2CBA‐contaminated soil. Soil was contaminated with 2CBA, forage grasses were grown under growth chamber conditions for 42 or 60 d, and the 2CBA concentration in soil was determined by gas chromatography. Only five of 16 forage grasses grew in 2CBA‐treated (816 mg/kg) soil. Growth of Bromus inermis had no effect on 2CBA concentration, whereas Agropyron intermedium, B. biebersteinii, A. riparum , and Elymus dauricus decreased 2CBA relative to nonplanted control soil by 32 to 42%. The 12 bacteria isolates were screened for their ability to promote the germination of the five grasses in 2CBA‐contaminated soil. Inoculation of A. riparum with Pseudomonas aeruginosa strain R75, a proven plant growth‐promoting rhizobacterium, increased seed germination by 80% and disappearance of 2CBA by 20% relative to noninoculated plants. Inoculation of E. dauricus with a mixture of P. savastanoi strain CB35, a 2CBA‐degrading bacterium, and P. aeruginosa strain R75 increased disappearance of 2CBA by 112% relative to noninoculated plants. No clear relationship between enhanced 2CBA disappearance and increased plant biomass was found. These results suggest that specific plant‐microbial systems can be developed to enhance remediation of pollutants in soil.