FIG. 3.

Contribution of extracellular DNA to QC-PCR results and comparison of the latter with the numbers of CFU (A) and total cells (B) of P. fluorescens CHA0 exposed to CuSO₄ stress (18 samples). In each case, half the sample was digested with Sau3AI to eliminate extracellular DNA (+), whereas the other half was not digested (⋄). CFU are arbitrarily plotted as zero when below the detection limit (0.92 log CFU/ml). The line of best fit for control samples obtained for Fig. 2 is also represented.