Stability of a rhizosphere microbial community exposed to natural and manipulated environmental variability

Phospholipid fatty acid (PLFA) and artificial neural network analyses were used to examine the composition of the Spartina alterniflora rhizosphere microbial community after exposure to manipulations in the field designed to alter the availability of host plant-derived and abiotic nutrient resources, We also tracked the experiments over a sufficient duration to observe significant natural variability in edaphic variables. We determined the PLFA composition of axenic S. alterniflora roots in order to distinguish differences in PLFAs that were due to changes in the rhizosphere microbiota from those only due to variability in plant root mass among samples. There were no significant changes in the PLFA profiles in response to experimental treatments and little change over the 8-week duration of the experiments, The microbial communities in the S. alterniflora rhizosphere did not respond dramatically to changing environmental conditions in the absence of major physical or chemical disruptions of the rhizosphere. (C) 2001 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.