FIG. 6.

Mineralization of ¹⁴C-naphthalene in the bulk (open bar) or rhizosphere (solid bar) soil and prevalence of ndoB in the cultured community of the rhizosphere and bulk soil of specific plant species. Plant species-specific rhizosphere samples were collected on July 1998, January 1999, and April 1999 with four replicates per treatment for each sampling period (n = 12). Error bars indicate the standard error of the estimate for mineralization, which is based on the normal distribution. The standard deviation for catabolic gene prevalence is based on the binomial distribution with 7,476 and 22,338 colonies probed for the rhizosphere and bulk soils, respectively.