Perchlorate has been linked with thyroid dysfunction in humans and thus represents a serious potential health risk. Prior research on perchlorate remediation has shown that (1) perchlorate-degrading bacteria are present in nature but are often electron donor limited; (2) plants release electron donors and carbon sources into soil; (3) perchlorate-degrading bacteria require low redox potential to reduce perchlorate; and (4) plants raise redox potential in the subsurface. These findings are somewhat contradictory and may impact perchlorate remediation schemes. We propose to study the relationship between plants and bacteria to determine whether the integrated effect of plants on bacteria is synergistic or antagonistic, whether the release of electron donor and carbon by plants is sufficient to overcome the inhibition to bacterial perchlorate reduction caused by the higher redox potential. Our focus is on higher concentrations of perchlorate (>25mg/L) because we believe it is important to control contamination at its source to effectively reduce health risks.