Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 10/22/2001
Publication Date: 10/22/2001
Citation: KREMER, R.J., ZDOR, R., LI, J. PHYSIOLOGICAL TRAITS OF WEED GROWTH-SUPPRESSIVE RHIZOBACTERIA. ASA-CSSA-SSSA ANNUAL MEETING ABSTRACTS. 2001. CD-ROM. MADISON, WI.
Technical Abstract: Deleterious rhizobacteria (DRB) may contribute to weed suppression in soils under specific management practices or as applied biological control agents. To understand the mechanisms for growth suppression of weeds, we examined rhizobacteria from several important weed species in seven agroecosystms for a wide array of physiological traits. About 50% of isolates produced auxins in excess of 10 ug/ml, a threshold level for seedling growth inhibition. A majority of DRB produced relatively high levels of siderophores under Fe-deficient conditions. About one-third of DRB produced abundant exopolysaccharides, which may contribute to colonizing ability in the rhizosphere. Higher proportions of DRB able to produce protease, amylase, pectinase, and 1-aminocyclopropane-1-carboxylate deaminase were in diverse cropping systems relative to monocultures with chemical inputs. Bioassays confirmed potential phytotoxicity of DRB. The most active DRB possessed several physiological traits involved in plant growth suppression. DRB with these properties may be detected in several agroecosystems, however, relative proportions of DRB in weed rhizospheres and levels of physiological activity, which might be manipulated to enhance weed suppression, will vary among these systems.