Increased plant productivity and decreased microbial respiratory C loss by plant growth-promoting rhizobacteria under elevated CO?.

ABSTRACT: Increased plant productivity and decreased microbial respiratory C loss can potentially mitigate increasing atmospheric CO?, but we currently lack effective means to achieve these goals. Soil microbes may play critical roles in mediating plant productivity and soil C/N dynamics under future climate scenarios of elevated CO? (eCO?) through optimizing functioning of the root-soil interface. By using a labeling technique with (13)C and (15)N, we examined the effects of plant growth-promoting Pseudomonas fluorescens on C and N cycling in the rhizosphere of a common grass species under eCO?. These microbial inoculants were shown to increase plant productivity. Although strong competition for N between the plant and soil microbes was observed, the plant can increase its capacity to store more biomass C per unit of N under P. fluorescens addition. Unlike eCO? effects, P. fluorescens inoculants did not change mass-specific microbial respiration and accelerate soil decomposition related to N cycling, suggesting these microbial inoculants mitigated positive feedbacks of soil microbial decomposition to eCO?. The potential to mitigate climate change by optimizing soil microbial functioning by plant growth-promoting Pseudomonas fluorescens is a prospect for ecosystem management.

SUBMITTER: Nie M 

PROVIDER: S-EPMC4363858 | biostudies-other | 2015

REPOSITORIES: biostudies-other